CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63/278,025 filed on November 10, 2021, U.S. Provisional Patent Application No. 63/287,277 filed on December 8, 2021, and U.S. Provisional Patent Application No. 63/298,031 filed on January 10, 2022, each of which is hereby incorporated by reference in its entirety.

BACKGROUND

[0002] There are approximately 25 million tractors in the world, and the number of tractors has historically doubled about every 20 years. Collectively, tractors make a significant contribution to fossil fuel usage and harmful emissions production worldwide.

[0003] Farmers in developed countries generally operate large farms and use fossil fuel- powered tractors with up to 600 horsepower. These tractors may consume thirty or more gallons of diesel fuel per hour and produce carbon dioxide emissions and other environmental pollutants.

[0004] Farmers in developing countries generally lack financial resources to purchase a fossil fuel-powered tractor and an ongoing fuel supply. As a result, farmers in developing countries are generally limited to practicing subsistence-level farming that requires strenuous manual labor and produces relatively low crop yields.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 A shows a side view of an electric two-wheel tractor.

[0006] FIG. IB shows a side view of the electric tractor of FIG. 1 A with front and rear stabilizers.

[0007] FIG. 2 shows a top view of the electric tractor of FIG. 1 A with a lid removed.

[0008] FIG. 3 shows a top view of the electric tractor of FIG. 1 A with a lid removed. [0009] FIG. 4 shows a top view of the electric tractor of FIG. 1 A.

[0010] FIG. 5 shows a rear view of the tractor of FIG. 1 A with the lid removed.

[0011] FIG. 6 shows a front view of the tractor of FIG. 1 A with the lid removed.

[0012] FIG. 7 shows a rear view of the tractor of FIG. 1 A.

[0013] FIG. 8 A shows a side view of the tractor of FIG. 1 A with the lid removed.

[0014] FIG. 8B shows a cutaway side view of the tractor of FIG. 1 A with the lid removed.

[0015] FIG. 8C shows a cutaway side view of the tractor of FIG. 1 A with a chain guard and the lid removed.

[0016] FIG. 9 shows a side view of the tractor of FIG. 1A.

[0017] FIG. 10 shows a side view of the tractor of FIG. 1A with a front stabilizer and rear implement.

[0018] FIG. 11 shows a side view of the tractor of FIG. 1 A with a front and rear stabilizer.

[0019] FIG. 12 shows a top view of the tractor of FIG. 1A with the handle deployed in a central position.

[0020] FIG. 13 shows a top view of the tractor of FIG. 1 A with the handle pivoted to a right side of the tractor.

[0021] FIG. 14 shows a top view of the tractor of FIG. 1A with the handle pivoted to a left side of the tractor.

[0022] FIG. 15 shows a side view of the tractor with an exchangeable battery pack and a removable power take-off unit.

[0023] FIG. 16 shows a side view of the tractor of FIG. 15 with the exchangeable battery pack and power take-off unit installed.

[0024] FIG. 17 shows a side view of the tractor with an exchangeable battery pack, power take-off unit, and rear-mounted farm implement. [0025] FIG. 18 shows a side view of the tractor with an exchangeable battery pack, power take-off unit, and front-mounted farm implement.

[0026] FIGS. 19A shows a rear view of a removable power take-off (PTO) unit.

[0027] FIG. 19B shows a side view of the PTO unit of FIG. 19A.

[0028] FIG. 19C shows a front view of the PTO unit of FIG. 19 A.

[0029] FIG. 19D shows a bottom view of the PTO unit of FIG. 19A.

[0030] FIG. 19E shows a top view of the PTO unit of FIG. 19 A.

[0031] FIG. 20A is a side view of an exchangeable battery pack.

[0032] FIG. 20B is a side sectional view of the exchangeable battery pack of FIG. 20A.

[0033] FIG. 20C is a side view of an exchangeable battery pack of 20A with a lid installed.

[0034] FIG. 20D is a bottom view of the exchangeable battery pack of FIG. 20A.

[0035] FIG. 20E is a top view of the exchangeable battery pack of FIG. 20A.

[0036] FIG. 21 is a side view of the tractor of FIG. 1A with an AC power inverter and an exchangeable battery pack.

[0037] FIG. 22 is a side view of the tractor of FIG. 1A with an AC power inverter, exchangeable battery pack, and a solar charging panel.

[0038] FIG. 23 is a side view of the tractor of FIG. 1A with an AC power inverter, exchangeable battery pack, solar charging panel, and ride-behind assembly.

[0039] FIG. 24 is a side view of the tractor of FIG. 1A with an AC power inverter, exchangeable battery pack, solar charging panel canopy, and ride-behind assembly.

[0040] FIG. 25 is a top vie of the tractor of FIG. 1A with an exchangeable battery pack and a compost spreader.

[0041] FIG. 26 is a side view of the tractor of FIG. 25 with the compost spreader in a loading position. [0042] FIG. 27 is a side view of the tractor of FIG. 25 with the compost spreader in a hauling position or spreading position.

[0043] FIG. 28 shows a side sectional view of the tractor of FIG. 25 with the compost spreader in the loading position.

[0044] FIG. 29 shows a side sectional view of the tractor of FIG. 25 with the compost spreader in the hauling position.

[0045] FIG. 30 shows a side sectional view of the tractor of FIG. 25 with the compost spreader in the spreading position.

[0046] FIG. 31 shows a top view of the tractor of FIG. 25 with the compost spreader in the spreading position.

[0047] FIG. 32 shows is a side view of the tractor of FIG. 1A with a transplant rack and a ride-behind assembly.

[0048] FIG. 33A is a front view of the tractor of FIG. 32.

[0049] FIG. 33B is a rear view of the tractor of FIG. 32.

[0050] FIG. 34 is a top view of the tractor of FIG. 32.

[0051] FIG. 35 is a top view of the tractor of FIG. 32.

[0052] FIG. 36 is a top view of the tractor of FIG. 32 with a solar charging panel canopy.

[0053] FIG. 37 is a side view of the tractor of FIG. 1A with upper and lower harvest racks.

[0054] FIG. 38 is a top view of the tractor of FIG. 37 with the upper harvest rack removed.

[0055] FIG. 39 is a top view of the tractor of FIG. 37.

[0056] FIG. 40 is a top view of the tractor of FIG. 37.

[0057] FIG. 41 is a side view of the tractor of FIG. 37 with a solar charging panel canopy.

[0058] FIG. 42 is a side view of the tractor of FIG. 1 A with a harvest seat, harvest conveyor belt, and harvest trailer. [0059] FIG. 43 A is a top view of the tractor of FIG. 1A with an exchangeable battery pack, adjustable seat, and zero turn mower assembly.

[0060] FIG. 43B is a bottom view of the zero-turn mower assembly.

[0061] FIG. 44 is a side view of the tractor of FIG. 43 A.

[0062] FIG. 45 is a top view of the tractor of FIG. 43 A.

[0063] FIG. 46 is a side view of the tractor of FIG. 43 A with a solar charging panel canopy.

[0064] FIG. 47 is a side view of the tractor of FIG. 1 A in a remote-control tug configuration and having an exchangeable battery pack and a trailer.

[0065] FIG. 48 is a side view of the tractor of FIG. 47 with a solar charging panel canopy.

[0066] FIG. 49 A shows a front view of a first gear drive drop axel.

[0067] FIG. 49B shows a cross-sectional side view of the gear drive drop axel of FIG. 49A.

[0068] FIG. 49C shows a front view of a second gear drive drop axel.

[0069] FIG. 50 A shows a front view of a first chain-in-oil drop axel.

[0070] FIG. 50B shows a cross-sectional side view of the chain-in-oil drop axel of FIG. 49A.

[0071] FIG. 50C shows a front view of a second chain-in-oil drop axel.

[0072] FIG. 51 is top view of the tractor of FIG. 1A with a chain drive drop axel.

[0073] FIG. 52 is a side view of the tractor of FIG. 1A with a chain drive drop axel, three- point hitch, and exchangeable battery pack.

[0074] FIG. 53 is a side view of the tractor of FIG. 1A with a stand-on riding platform.

[0075] FIG. 54 is a top view of the tractor of FIG. 1 A.

[0076] FIG. 55 is a top view of the tractor of FIG. 1A.

[0077] FIG. 56 is a top view of the tractor of FIG. 1 A with an exchangeable battery pack and a zero-turn mower assembly.

[0078] FIG. 57 is a side view of the tractor of FIG. 56. [0079] FIG. 58 is a side view of the tractor of FIG. 56 with a solar charging panel canopy.

[0080] FIG. 59 is a top view of the tractor of FIG. 56.

[0081] FIG. 60 is a side view of the tractor of FIG. 1A with a stand-on riding platform.

[0082] FIG. 61 is a top view of the tractor in FIG. 60.

[0083] FIG. 62 is a top view of the tractor in FIG. 60.

[0084] FIG. 63 shows multiple views of the riding platform of FIG. 60.

[0085] FIG. 63 A shows an adjustable riding assembly with a riding platform.

[0086] FIG. 63B shows cross-sectional side views of the riding platform of FIG. 63 A.

[0087] FIG. 63C shows the adjustable riding assembly with a seat platform.

[0088] FIG. 64 shows the tractor of FIG. 1A with a ride-behind assembly and a transplant rack.

[0089] FIG. 65 A is a front view of the tractor of FIG. 64.

[0090] FIG. 65B is a rear view of the tractor of FIG. 64.

[0091] FIG. 66 is a top view of the tractor of FIG. 65.

[0092] FIG. 67 is a top view of the tractor of FIG. 64.

[0093] FIG. 68 is a side view of the tractor of FIG. 64 with a solar charging panel canopy.

[0094] FIG. 69 is a side view of a remote-control configuration of the tractor of FIG. 1 A with an AC power inverter, exchangeable battery pack, front and rear stabilizers, and a solar charging panel.

[0095] FIG. 70 is a side view of a remote-control configuration of the tractor of FIG. 1 A with an exchangeable battery pack, zero-turn mower assembly, front and rear stabilizers, and solar charging panel.

[0096] FIG. 71 is a side view of a remote-control configuration of the tractor of FIG. 1 A with an exchangeable battery pack, trailer, and front stabilizers. [0097] FIG. 72 is a remote-control configuration of the tractor of FIG. 1A with an exchangeable battery pack, trailer, front stabilizers, and solar charging panel.

[0098] FIG. 73 is a side view of a remote-control configuration of the tractor of FIG. 1 A with a power take-off unit and exchangeable battery.

[0099] FIG. 74 is a side view of the remote-control tractor of FIG. 73 with a stabilizer.

[00100] FIG. 75 is a side view of the remote-control tractor of FIG. 73 with a stabilizer and three-point hitch.

DETAILED DESCRIPTION

[00101] Farmers in developing countries would benefit from quiet, inexpensive, and nonpolluting tractors that are well-suited to small farms and do not require fossil fuels. Likewise, farmers in developed countries would benefit from quiet, inexpensive, nonpolluting tractors that enable small-scale sustainable farming practices at the community level.

[00102] This disclosure is directed to modular electric two-wheel tractors that can replace traditional fossil fuel-powered two-wheel tractors, thereby enabling farmers to sever their reliance on fossil fuels. For farmers in developing countries who do not have access to fossil fuels, the electric two-wheel tractor may serve as an affordable tractor that can be powered by electricity generated by, for example, an array of solar panels located onsite at their farm. In this way, remote farms can advance beyond subsistence-level farming, reduce manual labor, and increase crop yields to better support the nutritional needs of people living near the farm.

[00103] The tractor may include a receiver system that allows the tractor to receive modular components that allow the base two-wheel tractor to be affordably reconfigured for a variety of farming and non-farming applications. In one configuration, the tractor can serve as a selfloading over-the-bed compost spreader. In another configuration, the tractor can serve as a self- charging ride behind over the bed transplanter. In another configuration, the tractor can serve as a self-charging ride-on over-the-bed harvester with incorporated racks to receive harvested crops. In another configuration, the tractor can serve as a self-charging ride-on over-the-bed harvester that incorporates electric conveyor belts to load a trailer towed behind the two-wheel tractor. In another configuration, the tractor can serve as a self-charging ride-on zero-turn mower. In another configuration, the tractor may serve as a remote-controlled or robotic tug for hauling everything from airport baggage to harvesting bins or mid-sized trailers.

[00104] The electric two-wheel tractor may include features such as independent variable wheel speed, forward and reverse, and the ability to receive electrical charge from an on-site renewable energy source, such as solar or wind power. The tractor may be equipped with a drop axel to provide over-the-bed clearance for the motor and battery box in raised bed farming applications. The tractor may be equipped with adjustable swivel stabilizer wheels. The tractor may utilize battery weight and position to improve wheel traction and handling. The tractor may have the ability to use walk-behind tools, such as tools made by the Tilmor® company of Dalton, Ohio.

[00105] When in the walk-behind configuration, the tractor may include a handlebar having an adjustable height. The handlebar may be adjustable from side to side to allow an operator to comfortably walk in a left or right wheel track of the tractor, and thereby avoid stepping on and compacting a raised bed located between the left and right wheel tracks. The tractor may enable increased productivity at the community scale thereby lifting people out of poverty, promoting local food security and capturing additional carbon through photosynthesis to naturally regenerate soil without the need for chemical fertilizers. The electric two-wheel tractor can reduce the need for strenuous manual labor and replace the need for methane producing draft animals. The electric two-wheel tractor described herein can also replace a significant number of fossil fuel-powered tractors worldwide and thereby play an important role in stabilizing the

Earth’s climate. [00106] The tractor may have the ability to receive exchangeable battery packs to both balance the weight of certain implements and extend operating time. In some instances, the tractor may function as a self-charging, quiet, zero emission mobile power source. The tractor may be configured to include a quick-mount power-take-off (PTO) to receive farm implements (e.g., category 1 implements) that are similar or identical to implements that are used with internal combustion engine-powered two-wheel tractors.

[00107] As used herein, the term “two-wheel” refers to two driven wheels of the tractor. In some examples, the tractor may include more than two wheels, but the additional wheels may be non-driven wheels, such as non-driven wheels associated with stabilizers or a ride-behind, stand-on, or ride-on assembly.

[00108] FIG. 1 A shows a side view of an electric two-wheel tractor 100. The tractor 100 may replace a traditional fossil fuel-powered two-wheel tractor. As shown, the tractor 100 may include a tractor body 105. Two independently driven wheels 120 may be attached to the tractor body 105. A handle 400 may be attached to the tractor body 105. The handle 400 may enable a person to maneuver and control the tractor 100.

[00109] Optionally, as shown in FIG. IB, the tractor 100 may be equipped with one or more stabilizers 200 connected to the tractor body 105. Each stabilizer 200 may include a stabilizer member 205 that is attached to a swivel wheel 210. The swivel wheel 210 may serve as a contact point with the ground, in which the swivel wheel 210 is configured to swivel to align with the travel direction of the tractor 100. The stabilizer tube 205 may be inserted into a stabilizer receiver 130 that is mounted to the tractor body 105. For example, the stabilizer member 205 and the stabilizer receiver 130 may have similar cross-sectional shapes (e.g., square, rectangular, circular, etc.), and the outside cross-sectional dimension of the stabilizer member 205 may be slightly smaller than the inside cross-sectional dimension of the stabilizer receiver 130. Accordingly, following insertion of the stabilizer member 205 into the stabilizer receiver 130, the stabilizer member 205 may be locked inside the stabilizer receiver 130 by a friction fit or by one or more removable pins or fasteners that are inserted into corresponding holes in both the stabilizer member and the stabilizer holder.

[00110] The tractor 100 may include a pair of stabilizer receivers 130 mounted on each of the two sides of the tractor body 105. Accordingly, the tractor 100 may be equipped with up to four stabilizers 200 for stabilization. In the example shown in FIG. 1, a first stabilizer receiver 130 may be angled downward and rearward from the right side 109 of the tractor body 105, and a second stabilizer receiver is angled downward and forward from the right side 109 of the tractor body 105.

[00111] As shown in FIGS. 1A and IB, the tractor 100 may be equipped with a handle 400. The handle 400 may include a handle body 405 attached to the tractor body 105. The handle 400 may include a handlebar 410 mounted to a handle body 405. The handle body 405 may include a lockable swivel joint 415 that enables a first section 406 of the handle body 405 that is mounted to the tractor body 105 to pivot with respect to a second section 407 of the handle body 405 that is coupled to the handlebar 410. Further, the handlebar 410 may be attached to the handle body 405 in such a manner, such as via a lockable swivel joint, that the handlebar 410 may be pivoted up and down relative to the handle body 405 and locked in various height positions.

[00112] The rear view of the tractor 100 in FIG. 7 shows that the back of the tractor is equipped with multiple receivers 135. Each receiver 135 has an opening that is configured to accept a mating insert (not shown) of a tractor accessory or a farm implement. For example, a receiver 135 and the insert may have similar cross-sectional shapes (e.g., square, rectangular, circular, etc.), and the outside cross-sectional dimension of the insert may be slightly smaller than the inside cross-sectional dimension of the receiver. Accordingly, following the insertion of the insert into a receiver 135, the receiver insert may be locked inside the receiver by a friction fit or by one or more removable pins or fasteners that are inserted into corresponding holes in both the insert and the receiver.

[00113] In some instances, the receiver 135 may be equipped with an electrical and/or data connector that is capable of being detachably coupled to a corresponding mating electrical and/or data connector (e.g., male-to-female connector) in the insert of a tractor accessory or farm implement. At the other end, the electrical and/or data connector of the receiver may be electrically coupled to an electrical power source and/or a controller of the tractor 100. Likewise, the other end of the electrical and/or data connector of the insert may be connected to an electrical component (e.g., battery, motor, controller, and/or so forth) of the tractor accessory or farm implement. As such, the tractor 100 may use a receiver to provide electrical power, control signals, and/or so forth to a tractor accessory or farm implement equipped with the insert, as well as receive electrical, control signals, and/or so forth from the tractor accessory or farm implement. Alternatively, in lieu of an electrical and/or data connector that is built into a receiver, an external electrical and/or data connector at the end of a wiring harness that achieves the same purpose (e.g., couples to a corresponding mating external electrical and/or data connector of a tractor accessory or farm implement wiring harness) may be positioned near the receiver instead for power and/or signal hookup.

[00114] FIG. 2 is a top view of the tractor body 105 with a lid removed, revealing a body compartment 140. A left-to-right midplane 150 may divide the body compartment 140 into a front half and a rear half. A front-to-rear midplane 55 may divide the body compartment 140 into a left half and a right half. Together, the left-to-right midplane 150 and the front-to-rear midplane 155 may divide the body compartment 140 into four quadrants, including a front-left quadrant, a front-right quadrant, a rear-left quadrant, and a rear-right quadrant. The body compartment 140 may house internal components of the tractor 100, including one or more electric motors 110. The internal components may include one or more batteries 115 that are electrically coupled to and supply electric power to the other components of the tractor 100, such as controllers and electric motors. As shown, the tractor body 105 may be equipped with multiple receivers 135 at a rear side of the body compartment 140, and/or multiple receivers 135 at a front side of the body compartment 140. The openings of the receivers 135 may be located on or through a back wall of the body compartment 140 and/or on or through a front wall of the body compartment. Each battery 115 may be secured within the body compartment 140 by a battery hold down 116 to prevent movement of the battery while the tractor is in motion.

[00115] The tractor 100 may have a first electric motor 110 configured to drive the right wheel 120. The tractor 100 may have a second electric motor 110 configured to drive the left wheel 120. Each of the electric motors 110 may be powered by one or more batteries 115. Each electric motor 110 may be configured to be independently controllable by a corresponding controller. In this way, the tractor 100 may be steered by having the electric motors 110 rotate at differing speeds and/or directions. Each electric motor 110 may turn a corresponding motor shaft 180 via a transmission 142 (e.g., a chain drive, belt drive, or gear drive). For example, the first electric motor 110 may rotate a first motor shaft connected to the left wheel 120 (either directly or via a first transmission), and the second electric motor 110 may rotate a right motor shaft connected to the right wheel 120 (either directly or via a second transmission). In one example, each motor shaft driven by an electric motor 110 may send rotational force directly to a corresponding wheel. In another example, each motor shaft driven by an electric motor 110 may be an input shaft to a transmission or a gearbox that is capable of changing the rotational speed and/or rotational torque of the rotational force input to the shaft by the electric motor before sending the rotational force to an output shaft. The output shaft may be further connected to a corresponding wheel by, for example, a chain or belt drive to turn the wheel. As shown, the chain drives may turn sprockets that are attached to the corresponding motors, shafts, and/or hubs of wheels to transfer power. In another example, the electric motors 110 for the left and right drive wheels 120 may be integrated into a respective hub of each respective wheel, which may lower the center of gravity of the tractor 100 and improve handling.

[00116] In some instances, the left and right shafts that are driven by the left and right electrical motors may be temporarily locked together by a releasable differential lock 185. The activation of the releasable differential lock 185 may serve to lock the shafts together so that the shafts rotate in unison. Accordingly, the locking of the differential lock 185 may ensure that the two wheels of the tractor 100 rotate at the same speed, which may be helpful for moving the tractor after one of the wheels loses traction (e.g., in muddy conditions). Further, it is possible to drive both the left and right shafts via a single electrical motor when the differential lock 185 is engaged.

[00117] In one example shown in FIG. 2, the left and right electrical motors 110 may be relatively small diameter motors with relatively long motor lengths. The electrical motors 110 may be positioned in the body compartment 140 in an overlapping front-and-back configuration to optimize space usage, such that the chain drives connecting the motor shafts to the corresponding left and right shafts are of unequal length.

[00118] The handle 400 may be connected to the tractor body 105 by the use of a lockable swivel j oint that enables the handle 400 to pivot from a position that is aligned with a centerline of the body compartment 140 (see, e.g., FIG. 12) to a position that is offset right or left of the centerline (see, e.g., FIGS. 13 and 14, respectively), and then the swivel joint can be locked in the selected position. Accordingly, a person may pivot the handle 400 such that the person may be directly behind the tractor, to one side of the tractor, or any position in between, as the person guides and controls the tractor. The handlebar 410 may be equipped with control mechanisms (not shown) that enable a person to command the tractor 100 to perform various actions, such as move forward, reverse, brake, turn, and/or so forth. The control mechanisms may be used to send electrical inputs to the left and right controllers 117. In this way, turning of the tractor 100 may be achieved by operating the electrical motors at different speeds via the controllers. In another example, the control mechanisms may be used to control the tractor accessories or farm implements connected to the tractor by the receivers using the controllers, such as powering them up or down, speeding them up or down, electrically connecting or disconnecting them, and/or so forth. The control mechanisms may include switches, rotary selectors, selector levers, shift levers, touch sensors, touch screens, and/or so forth. For example, the handlebar 410 may be equipped with twist grips for throttle control and adjusting the speed of a PTO plug-in unit, thumb switches for turning on and off various functions of the tractor, and/or so forth. In some instances, the handlebar 410 may include controls for activating a traditional disc and/or drum brakes of the tractor 100. In other example instances, the handlebar 410 may include controls for activating regenerative braking via the electric motors of the tractor, or a combination of regenerative and traditional braking.

[00119] FIG. 3 is a top view of another example of the tractor 100 showing the body compartment 140 that houses the internal components of the tractor, including larger diameter motors 110. The tractor 100 shown in FIG. 3 may be equipped with substantially the same components as shown in FIG. 2 but with larger diameter left and right motors 110. The larger diameter left and right motors 110 may be placed in a side-by-side configuration in the body compartment 140, and the chain drives connecting the motor shafts to the corresponding left and right shafts may have substantially similar lengths.

[00120] FIG. 4 is a top view of the tractor 100 with the body compartment 140 enclosed by a lid 145. Stabilizers receivers 130 are shown attached to the sides of the tractor 100. The lid 145 may serve to protect the internal components of the tractor 100 from damage as well as serve as a platform for mounting additional accessories. FIG. 4 also shows the positions of the stabilizer receivers 130 relative to each other in some embodiments. The stabilizer receivers 130 on each side of the tractor 100 may be misaligned with respect to each other, such that the distance between a pair of front stabilizer receivers 130 may be shorter than the distance between a pair of rear stabilizer receivers 130.

[00121] FIG. 5 is a rear view of the tractor 100 showing the tractor with the lid 145 removed from the body compartment 140 and multiple rear receivers 135 that are configured for the attachment of external accessories and agricultural implements. With the lid 145 removed, the components in the body compartment 140, such as the batteries 115 and the battery hold downs 116, may be visible when the tractor 100 is observed from the rear. As shown, the tractor 100 may be equipped with three rear receivers 135, in which the opening of the central rear receiver 130 is in line with a mounting location where the handle 400 attaches to the tractor body 105, and the two remaining rear receivers 135 are positioned on each side of the central receiver 135.

[00122] FIG. 6 is a front view of the tractor 100 showing the lid 145 removed from the body compartment 140 and multiple front receivers 135 that are configured for the attachment of external accessories and farm implements. With the lid 145 removed, the components in the body compartment 140, such as the batteries 115 and the battery hold downs 116, may be visible when the tractor 100 is observed from the front. As shown, the tractor 100 may be equipped with three front receivers 135, in which the opening of the central front receiver 135 is aligned with a centerline of the tractor body 105. The two remaining front receivers 135 may be positioned on each side of the central receiver. FIG. 6 also shows the tractor 100 in an over- the-bed application where the raised bed 190 for planting is located below the tractor body 105 and between the left and right drive wheels 120 and where the left and right drive wheels 120 are positioned in the left and right wheel tracks (191, 192) to avoid compacting the raised bed 190.

[00123] FIG. 7 is a rear view of the tractor 100 showing the body compartment 140 enclosed by the lid 145 and multiple rear receivers 135 that are configured for the attachment of external accessories and farm implements. In some embodiments, the lid 145 may be attached to the tractor body 105 by one or more fasteners inserted into corresponding holes in the lid and the tractor body 105. For example, the holes may be present near each of the four corners and the lid 145 as well as walls of the tractor body 105. In other embodiments, the lid 145 may be attached to the tractor body 105 by a hinge mechanism (not shown) that allows the lid 145 to swing open and provide access to the body compartment 140. Further, the opposite side may be equipped with a latching mechanism and/or a locking mechanism (not shown) that enables the lid 145 to be detachably secured to the tractor body 105 and prevents the lid 145 from opening during use.

[00124] As shown in FIG. 4, the tractor body 105 may have a front side 106, a rear side 107, a left side 108, a right side 109, a top side 111, and a bottom side 112. The body compartment 140 may be located between the front side 106 and the rear side 107 of the tractor body 105 and between the left side 108 and the right side 109 of the tractor body 105. The bottom side

112 of the tractor body 105 may be located above a first axel of the first drive wheel and above a second axel of the second drive wheel. As shown in FIG. 7, a distance between a ground plane and the bottom side 112 of the tractor body may define a ground clearance 112 of the tractor. The ground clearance 112 may allow the tractor 100 to operate over a raised bed without compacting the soil of the raised bed and without disturbing crops. In one example, the ground clearance 113 may be at least 8 inches. In another example, the ground clearance

113 may be at least 12 inches. In yet another example, the ground clearance 113 may be at least 18 inches.

[00125] As shown in FIG. 7, a distance between the interior sidewalls of the tires of the left and right drive wheels 120 may define an interior track width 114 of the tractor 100. A distance between the exterior sidewalls of the tires of the left and right drive wheels 120 may define an exterior track width 118 of the tractor 100. In one example, the exterior track width 118 may be about 40 inches, and the drive wheels 120 may be about 4 to 6 inches wide. In one example, the interior track width 114 may be at least 30 inches. In another example, the interior track width may be at least 32 inches. In yet another example, the interior track width 114 may be at least 34 inches.

[00126] FIG. 8 A is a side view of the tractor 100 without a chain guard. FIG. 8B is a side view of the tractor 100 of FIG. 8 A revealing the chain 178 and other components of the transmission 142. FIG. 8C is a side view of the tractor 100 with a chain guard 175. FIGS. 8B and 8C show the drive chain for a wheel 120 of the tractor in relation to a drive shaft and an electric motor 110 of the tractor. As shown in FIG. 8C, the tractor 100 may be equipped with a chain guard 175 on each side of the tractor. A chain guard 175 may attach to the tractor body 105 and extend downward to cover a sprocket 177 that is attached to the wheel 120. The sprocket 177 may be driven by a drive chain 178 that rotationally connects the sprocket 177 to another sprocket 179 associated with a drive shaft 181. The drive shaft 181 may be driven, directly or indirectly, by the electric motor 110 that receives electrical power from the battery 115. In various instances, the chain guard 175 may further extend to cover the wheel rim of the wheel 120, such that the side profile of the wheel 120 other than the tire is completely covered by the chain guard 175. Accordingly, the chain guard 175 may serve to protect the drive chain 178 and a substantial portion of the wheel from obstacles and protrusions (e.g., rock or roots) extending up from the ground and/or objects that may impact the wheel 120 from the side.

[00127] FIG. 9 is a side view of the tractor 100 without stabilizers 200. The body compartment 140 is enclosed by a lid 145. In some instances, the weight distribution of the tractor may be configured such that without any attached tractor accessory or farm implements, the tractor 100 may be self-balancing while at a standstill or while traveling across flat or substantially flat terrain. In other words, the tractor 100 may remain upright on its two wheels even without any side stabilizers or be easily balanced by an operator holding the handle 400.

[00128] FIG. 10 is a side view of the tractor 100 having a stabilizer 200 and a farm implement 500 removably mounted to the stabilizer receivers 130 on a side of the tractor. As shown, the tractor 100 may be equipped with a set of front stabilizers at the front end of the tractor and a set of farm implements at the backend of the tractor. The set of farm implements may be configured to be compatible with the stabilizer receivers 130. For example, one end of the farm implement 500 may be configured to fit within the stabilizer receiver 130. The other end of the implement 500 may include a sliding retainer 505 having a hollow interior that is able to slide along the length of the implement. The sliding retainer 505 may be locked down to any position along the length of the implement tube 500. A series of holes may be disposed along the length of the implement 500 at regular intervals, and a pin or fastener may be removably inserted into a hole in the sliding retainer 505 and one of the series of holes to lock the sliding retainer 505 in position with respect to the implement 500. In another example, the sliding retainer 505 may include a movable clamping plate (not shown) in its hollow interior in which the movable clamping plate can be screwed down against a side of the implement 500 to frictionally lock the sliding retainer 505 in a position along the length of the implement. Accordingly, the sliding retainer 505 may enable the adjustment of a distance between a tool head 510 of the farm implement 500 and the tractor body 105.

[00129] The sliding retainer 505 may be joined to an extension tube holder 515 by a lockable rotational joint 520. In turn, the extension tube holder 515 may have a hollow interior that is configured to hold an extension tube 525 attached to the tool head 510 of the farm implement 500. The extension tube 525 may be slidably positioned within the extension tube holder 515 along the length of the extension tube. The extension tube holder 515 may be locked down to any position along the length of the extension tube 525. For example, a series of holes may be disposed along the length of the extension tube 525 at regular intervals, and a pin or fastener may be removably inserted into a hole in the extension tube holder 515 and one of the series of holes to lock the extension tube holder in position with respect to the extension tube 525. In another example, the extension tube holder 515 may include a movable clamping plate in its hollow interior in which the movable clamping plate can be screwed down against a side of the extension tube to frictionally lock the extension tube holder 515 in a position along the length of the extension tube 525.

[00130] The lockable rotational joint 520 may enable the extension tube holder 515 to rotate with respect to the sliding retainer 505. In this way, the extension tube 525 of the farm implement 500 may be rotated to align perpendicular to a ground level as well as being oriented in other directions relative to the ground level. Furthermore, the ability of the extension tube 525 to slide within the extension tube holder 515 may enable the tool head 510 of the farm implement 500 to be raised and lowered with respect to the ground level, including a position that enables the tool head 510 to work beneath ground level.

[00131] FIG. 11 is a side view of the tractor 100 having a pair of stabilizers 200. The stabilizers may be removably mounted to stabilizer receivers 130. As shown, the stabilizers 200 may be adjusted so they rest on the same planar surface as the two wheels 120 of the tractor 100, such that the tractor remains upright without operator assistance. The tractor 100 may include an adjustable handlebar 410. The adjustable handlebar 410 may be attached to the handle body 405 in such a manner, such as via a lockable swivel joint 415, that the handlebar 410 may be pivoted up and down relative to the handle body 405 and locked in multiple height positions.

[00132] FIG. 12 is a top view of the tractor 100 showing farm implements mounted to the rear stabilizer receivers 130 on the left and right sides of the tractor, and stabilizers mounted to the front stabilizer holders on the left and right sides of the tractor. As shown, the tractor 100 is equipped with a pair of stabilizers 200 at a front side of the tractor, and a pair of farm implements 500 at a rear side of the tractor to work the ground and cultivate plants. The handle 400 of the tractor 100 is deployed in a central position such that the person operating the tractor may walk directly behind the tractor.

[00133] FIG. 13 is a top view of the tractor 100 showing a handle 400 of the tractor being pivoted at a pivot point to a first side of the tractor. The pivoting of the handlebar 410 to the first side of the tractor 100 is achieved by adjusting two lockable swivel joints. The first lockable swivel joint 415 may connect the handle 400 to the tractor body 105. The second lockable swivel joint may be located between a first section of the body of the handle that is mounted to the body of the tractor and a second section of the body of the handle that is coupled to the handlebar. In this configuration, the operator can walk in a right wheel track while operating the tractor and thereby avoid disturbing a raised bed that is positioned between the wheels.

[00134] FIG. 14 is a top view of the tractor 100 showing a handle 400 of the tractor being pivoted at a pivot point to a second side of the tractor that is opposite of the first side. The pivoting of the handlebar 410 to the second side of the tractor may be achieved in substantially the same manner using the two lockable swivel joints as described in FIG. 13. In this configuration, the operator can walk in a left wheel track while operating the tractor and thereby avoid disturbing a raised bed that is positioned between the wheels.

[00135] FIG. 15 is a side sectional view of the tractor 100 having a power take-off (PTO) plug-in unit 600 that is removably mountable to one or more of the receivers 135 on a first end of the tractor body 105. The tractor 100 may include a battery plug-in unit 700 that is removably mountable to one or more of the receivers 135 on a second end of the tractor body 105. The PTO plug-in unit 600 may include one or more first inserts 605 that plug into the one or more of the receivers 135. The mating of the first inserts 605 into the one or more first receivers 135 may serve to secure the PTO plug-in unit 600 to the tractor 100. Further, the mating may form an electrical connection between the PTO plug-in unit 600 and an electric power source of the tractor 100. In other instances, external wiring and mating wiring connectors may be used to electrically connect the PTO plug-in unit 600 to the controller and/or an electrical power source of the tractor 100. Accordingly, a controller 615 and an electric motor 610 of the PTO plug-in unit 600 may be powered by the tractor 100 to perform various tasks. For example, the electric motor 610, under the control of the controller 615, may be used to drive additional tractor accessories and/or farm implements.

[00136] The battery plug-in unit 700 may include one or more inserts 705 that plug into the one or more receivers 135. The mating of the inserts 705 into the one or more receivers 135 may serve to secure the battery plug-in unit 700 to the tractor 100. Further, the mating may form an electrical connection between the battery plug-in unit 700 and a controller and/or a built-in battery 115 within the tractor body 105. However, in other instances, external wiring and mating wiring connectors may be used to electrically connect the battery plug-in unit 700 to the controller and/or the built-in battery 115. Accordingly, the battery plug-in unit 700 may serve to provide supplemental electrical power to the tractor 100. In one example, the battery plug-in unit 700 may be used to power the electric motors 110 that drive the wheels 120 of the tractor 100. In another example, the battery plug-in unit 700 may be used to power the PTO plug-in unit 600. In this latter example, the battery plug-in unit 600 may have a voltage rating (e.g., DC 48 volts) that is different than the voltage rating of the tractor’ s built-in batteries (e.g., DC 24 volts) but which is compatible with the voltage requirements of the PTO plug-in unit 600.

[00137] FIG. 16 is a sectional view of the tractor 100 showing the PTO plug-in unit 600 removably mounted to one or more receivers 135 on a rear end of the tractor 100 and an exchangeable battery pack 700 removably mounted to one or more receivers on a front end of the tractor 100. As shown, upon the mounting of the exchangeable battery 700 to the front end of the tractor 100, the battery may rest flush against a front side of the tractor body 105. Further, upon the mounting of a PTO plug-in unit 600, the PTO plug-in unit 600 may hang at a position that is at least partially underneath the tractor body 105 and at least partially between the drive wheels 120.

[00138] FIG. 17 is a sectional view of the tractor 100 as illustrated in FIG. 16., showing the PTO plug-in unit 600 mounted on the rear end of the tractor 100 being used to power a rear mounted implement 500. As shown, the PTO plug-in unit 600 attached to the rear end of the tractor 100 may be further attached to a rear mounted implement such that the PTO plug-in unit 600 may power the implement. In this configuration, the weight of the exchangeable battery 700 may serve to balance out or substantially balance out the weight of the PTO plugin unit, or a combination of the PTO plug-in unit and the rear mounted implement 500.

[00139] FIG. 18 is a side view of the tractor 100 showing PTO plug-in unit 600 removably mounted to one or more receivers 135 on a front end of the tractor 100. The tractor 100 may include an exchangeable battery pack 700 removably mounted to one or more receivers 135 on a back end of the tractor, with a front mount implement 500 attached to the PTO plug-in unit 600. As shown, upon mounting the exchangeable battery 700 to the rear end of the tractor 100, the battery 700 may be flush against a rear side of the tractor body 105. The PTO plug-in unit 600 may hang at a position that is at least partially underneath the tractor body 105 and at least partially between the wheels 120. The PTO plug-in unit 600 may be further attached to a front mount implement 500 such that the PTO plug-in unit 600 may power the implement 500. In this configuration, the weight of the exchangeable battery pack 700 may serve to balance out or substantially balance out the weight of the PTO plug-in unit 600, or a combination of the PTO plug-in unit 600 and the front mounted implement 500.

[00140] FIGS. 19A-D show views that illustrate internal and external components of the PTO plug-in unit 600. The PTO plug-in unit 600 can be removably mountable to a receiver 135 of the tractor 100. FIG. 19A shows a front view of the PTO plug-in unit 600. FIG. 19B shows a side section view of the PTO plug-in unit 600. FIG. 19C shows a rear view of the PTO plug-in unit 600. FIG. 19D shows a top view of the PTO plug-in unit 600. FIG. 19E shows a bottom view of the PTO plug-in unit 600. The PTO plug-in unit 600 may include a controller 615 that is configured to control an electric motor 610 of the PTO plug-in unit 600. The controller 615 may receive inputs or commands from a user interface or another controller 117 of the tractor 100. In turn, the controller 615 may control the operations of the electric motor 610, such as start, stop, rotational speed, torque, rotational direction, and/or so forth. The electric motor 610 may drive a shaft 620 or shaft spindle that may protrude from an end of the body 625 of the PTO plug-in unit or may be recessed within a receptacle built into the body 625 of the PTO plug-in unit 600. The shaft 620 or shaft spindle may be further connected to an additional tractor accessory or farm implement 500 to supply a working force to the additional accessory or implement. The end of PTO plug-in unit body 625 or receptacle that houses the shaft 620 or shaft spindle may be configured with a coupler mechanism 630 that removably secures the accessory or the implement 500 to the PTO plug-in unit 600. The coupler mechanism 630 may also couple the shaft 620 to a mating shaft spindle of the accessory or implement, or vice versa. The PTO plug-in unit 600 may be supplied electrical power by electrical connectors built into the inserts or external wiring and mating wiring connectors that route electric power to PTO plug-in unit 600.

[00141] FIGS. 20A-E show various views of the battery plug-in unit 700 that is removably mountable to a receiver 135 of the tractor 100. As shown, the battery plug-in unit 700 may include a battery housing 710 with built-in inserts 705 that mate with the receivers 135 on the tractor body 105. The battery housing 710 may include a lid 715 that can be opened and closed to enable the placement and removal of a battery 700 inside the battery housing 710. For example, the lid 715 may be a hinged lid that swings up to open or a lid that can be completely detached from the battery housing 710. The battery housing 710 may further include electrical conductors that electrically connect the terminals of the battery to electrical connectors of the tractor 100. For example, the terminals of the battery housed in the battery housing 710 may be electrically connected to electrical connectors inside the inserts 705 of the battery plug-in unit 700. In another example, electrical power may be routed from the terminals of the battery to the exterior of the battery plug-in unit 700 via an electrical wiring harness that terminates into an electrical connector.

[00142] FIG. 21 is a sectional view of the tractor 100 showing an AC power inverter 800 that is removably mounted to one or more receivers 135 on a first end of the tractor 100 and an exchangeable battery pack 700 that is removably mounted to one or more receivers 135 on a second end of the tractor 100. As shown, the battery plug-in unit (exchangeable battery pack) 700 may include one or more inserts 705 that plug into the one or more receivers 135. The battery plug-in unit 700 may supply DC power to the tractor 100. The AC power inverter 800 may include one or more inserts 705 that plug into the one or more receivers 135. The mating of the inserts 705 into the one or more receivers 135 may serve to secure the AC power inverter 800 to the tractor 100. Mating of the inserts 705 to the one or more receivers 135 may form an electrical connection between the AC power inverter 800 and an electric power source (e.g., battery 115) of the tractor 100. In other instances, external wiring and mating wiring connectors may be used to electrically connect the AC power inverter 800 to an electrical power source of the tractor. The electrical power source of the tractor 100 may include DC power supplied by one or more internal batteries 115 of the tractor 100 and/or the DC power supplied by the exchangeable battery pack 700. The AC power inverter 800 may turn the DC power provided by the electric power source of the tractor 100 into AC power. The AC power inverter 800 may be used to supply electric power to one or more electric devices that consume AC power or a main electrical panel of a building, such as a dwelling, an emergency shelter, a clinic, a school, etc. In other instances, the AC power inverter 800 may be used to return AC power to an electrical energy grid that serves a geographical area. In this configuration, the weight of the exchangeable battery pack 700 may serve to balance out or substantially balance out the weight of the AC power inverter 800 and enable to the tractor to remain substantially upright.

[00143] FIG. 22 is a side view of the tractor 100 as illustrated in FIG. 21 with stabilizers 200 removably mounted in the receivers 135 and a solar charging panel 300 mounted to the stabilizers 200. As shown, the stabilizers 200 that are installed on the tractor 100 illustrated in FIG. 21 may include attachment points for support members 305 that support the solar charging panel 300. Each support member 305 of the solar charging panel 300 may be attached to a stabilizer 200 by a pin or fastener inserted into corresponding holes of the stabilizer 200 and the support member 305. The solar charging panel 300 may be oriented in a sloped orientation using pairs of struts having different lengths. In various instances, the solar charging panel 300 may be configured to supply DC power that charges the internal batteries 115 of the tractor 100 and/or the exchangeable battery pack 700.

[00144] FIG. 23 is a side view of the tractor 100 as illustrated in FIG. 22 with a solar charging panel 300 attached to the tractor 100 via insert members 310 removably mounted to the receivers 135. The tractor 100 may include a ride-behind assembly 900 attached to the tractor 100 via support members 905 that are removably mounted to the tractor 100. As shown, the ride-behind assembly 900 may include support members 905 that can be inserted into the rear receivers 135 of the tractor 100. The support members 905 may function substantially in the same manner as the stabilizer members 205 of stabilizers 200 in terms of connecting the ride- behind assembly 900 to the tractor 100. The support members 905 may be pivotally attached to a chassis of the ride-behind assembly 900.

[00145] The ride-behind assembly 900 may further include an adjustable seat 910 and one or more swivel wheels 902 that are attached to the assembly 900 to support and provide mobility to the ride-behind assembly 900. The adjustable seat 910 may be mounted on a support member 905 of the ride-behind seat assembly 900 in such a way that the seat 910 may slide back and forth on the support member 905. For example, the support member 905 may be a hollow tube with holes located at regular intervals along its length. The adjustable seat 910 may be mounted on a slider unit 915 that sits atop and at least partially surrounds the support member 905, as shown in FIG. 23. The slider unit 915 may include a spring-loaded pin with a handle, in which the spring of the spring-load pin normally urges the pin into a hole of the holes positioned on the main spar. By pulling the handle, the spring-loaded pin may be taken out of the hole so that the slider unit 915 may be slide along the support member 905 until the spring-load pin aligns with another hole. If the spring-load pin is released, the spring may urge the pin into the hole and lock the adjustable seat 910 in the new position. In this way, a person may slide the adjustable seat 910 along the support member 905 to find a seating position that enables the person to comfortably reach a footrest 920 and a foot-operated throttle 925 while seated in the adjustable seat 910. In some instances, the adjustable seat 910 may further include a height adjustment mechanism (e.g., a ratchet mechanism or an adjustable pneumatic piston) that allows the person to raise and lower the seat relative to a ground plane.

[00146] The ride-behind assembly 900 may include a cross member 906 that is substantially orthogonal to and attached to the support member 905 (see, e.g., FIG. 34). The cross member 906, together with the support member 905, may support the adjustable seat 910. The cross member 906 may have a first end and a second end. The ride-behind assembly 900 may include a first swivel wheel 902 attached at or near the first end of the cross member 906. The ride- behind assembly 900 may include a second swivel wheel 902 attached at or near the second end of the cross member 906. The swivel wheels 902 may be positioned between the cross member 906 and a ground plane and serve to support a load applied to the adjustable seat 910 by the weight of a person. [00147] The footrest 920 of the ride-behind assembly 900 may enable a person who is sitting in the adjustable seat 910 to rest their feet on the footrests. The footrests 920 may be equipped with throttle controls 925 that send control commands to the controllers 117 of the tractor 100. Accordingly, a person may use the throttle controls 925 to command the tractor 100 to perform various actions, such as move forward, reverse, brake, turn, and so forth. The use of the throttle controls 925 on the footrests 920 may free the person’s hands to perform other tasks, such as doing the work of planting and harvesting crops. In one example, the ride-behind assembly 900 may include one throttle control 925 mounted on one of the footrests 920. In another example, the ride behind assembly 900 may include a throttle control 925 mounted on each of the two footrests 920, where each of the left and right throttle controls are configured to control a corresponding electric motor 110.

[00148] With the use of the throttle controls 925 on the footrests 920, the handle 400 may be removed from the tractor 100. For example, the throttle controls 925 may be connected to an interface that formerly connected to the handlebar control mechanism. As a result, the handle 400 may be removed from the tractor 100 to accommodate a horizontally positioned solar charging panel 300, as shown in FIG. 23. A pair of the support members 305 of solar charging panel 300 may be attached to attachment points on the insert members 310 of the ride-behind assembly 900. Another pair of support members 305 of the solar charging panel 300 may be attached to support members 910 that are inserted into the receivers 135 on a front side of the tractor 100. In various instances, the solar charging panel 300 may be configured to supply DC power that charges the internal batteries 115 of the tractor 100 and/or the exchangeable battery pack 700 (e.g., while the tractor is operating or not operating).

[00149] FIG. 24 is a side view of the tractor 100 as illustrated in FIG. 23 with a ride-behind assembly 900 and a solar charging panel 300 that serves as a solar shade for a person seated in the adjustable seat 910. The solar charging panel 300 may be attached to the tractor 100 via the insert members 310 that may be removably mounted to one or more stabilizer receivers 135 on the tractor 100 and one or more receivers 930 on the ride-behind assembly 900. The support members 305 of the solar charging panel 300 may have sufficient length to enable a person sitting in the adjustable seat 910 to fit under and be sheltered by the solar charging panel 300. Thus, the solar charging panel 300 may form a canopy that at least partially protects the person from sun exposure, rain, or other weather conditions.

[00150] FIG. 25 is a top view of the tractor 100 equipped with an exchangeable battery pack 700 removably mounted on a rear side of the tractor. The tractor 100 may include a self-loading compost spreader 850 removably mounted to tractor 100. As shown, the self-loading compost spreader 850 may be attached to a front end of the tractor 100. The tractor 100 may be further equipped with a pair of stabilizers 200 at the back end of the tractor 100 to stabilize the tractor. An exchangeable battery pack 700 may be connected to the tractor 100 to increase the range and/or the operational endurance of the tractor during compost spreading. The handle 400 of the tractor 100 may be pivoted to align with a wheel track of the tractor such that the person operating the tractor may walk behind a corresponding wheel of the tractor and in the wheel track instead of on the raised bed. This configuration allows the person to avoid compacting the soil of the raised bed with their body weight. In the configuration of FIG. 25, the weight of the exchangeable battery pack 700 may serve to balance out or substantially balance out the weight of the self-loading compost spreader 850, or a combination of the self-loading compost spreader and the material carried in the self-loading compost spreader.

[00151] FIG. 26 is a sectional view of the tractor 100 as illustrated in FIG. 25, in which the sectional view is cut along section A-A of FIG. 25. This sectional view shows the self-loading compost spreader 850 in a load position. In various embodiments, the spreader 850 is in the general form of a scoop bucket 890 that can scoop up material (e.g., compost) as the tractor 100 advances forward into a compost pile. The spreader 850 may be attached to the tractor body 105 by a pair of hinges 855 located at a top rear end of the spreader 850. The spreader 850 may also have a scoop bracket 860 centrally positioned at a bottom rear end of the spreader. The scoop bracket 860 may be pivotally attached to one end of an electric linear actuator 865 that may be positioned under the tractor 100 and between the wheels 120 of the tractor 100. The other end of the electric linear actuator 865 may be pivotally attached to an actuator bracket 870 mounted on the tractor body 105. The electric linear actuator 865 may receive power from the internal batteries 115 of the tractor 100 or the exchangeable battery pack 700 and may be controlled by the control mechanism installed on the handlebar 400 of the tractor 100. The bottom rear end of the spreader 850 may be configured with a longitudinal opening 875 that allows material, such as compost, to exit the spreader 850. The spreader 850 may be equipped with a rotating spreader mechanism 880 that helps to push material through the longitudinal opening 875 and out of the self-loading compost spreader 850. The rotating spreader mechanism 880 may include a rotating auger screw with a central shaft, or a shaft with radial impellers (e.g., paddles, brushes, etc.) affixed perpendicularly along its length, in which the screw or shaft runs lengthwise along the longitudinal opening. The operation of the rotating spreader mechanism 880 is further explained below.

[00152] FIG. 27 is a sectional view of the tractor 100 as illustrated in FIG. 26, in which the self-loading compost spreader 850 is in a spreading mode. As shown, the extension of the electric linear actuator 865 may push the bottom rear end of the spreader 850 away from the tractor body 105. Such an action may cause the spreader 850 to pivot at the hinges 855 and swing up to a spread position. In this position, gravity may propel the material inside the spreader to concentrate near and on top of the longitudinal opening 875 and the rotating spreader mechanism 880. Accordingly, the rotation of the rotating spreader mechanism 880 may force the material out of the opening 875 and onto the ground, in a substantially uniform distribution across the width of the longitudinal opening 875. [00153] FIG. 28 is a side view of the tractor 100 as illustrated in FIG. 25, in which the selfloading compost spreader 850 is in a load position and a drive wheel 881 of the spreader 850 is in a stowed position. As shown, the self-loading compost spreader 850 is in a load position. The components of the rotating spreader mechanism 880 that are external to the scoop bucket 890 are also illustrated. The components may include the drive wheel 881 that is structurally connected to a drive gear 895 by a link bar 886, and rotationally connected to the drive gear 895 by a drive chain 887. In turn, a central hub of the drive gear 895 may be connected to a central shaft of the auger screw or the shaft with impellers through an opening on the sidewall of the scoop bucket 890. The drive wheel 881 may be equipped with radial teeth or paddles. In this arrangement, the rotation of the drive wheel 881 (e.g., through contact with ground during forward propulsion of the tractor 100) ultimately rotates the auger screw or the impeller- equipped shaft inside the self-loading compost spreader 850 and distributes compost from the longitudinal opening 875.

[00154] FIG. 29 is a side view of the tractor 100 as illustrated in FIG. 25, in which the self- loading compost spreader 850 is in a hauling position and the drive wheel 881 of the spreader 850 is in a stowed position. As shown, the extension of the electric linear actuator 865 puts the self-loading compost spreader 850 in the hauling position so that the tractor 100 may be moved around without material being discharged from the longitudinal opening 875 of the self-loading compost spreader, or with only a minimal spillage of the material through the longitudinal opening.

[00155] FIG. 30 is a side view of the tractor 100 as illustrated in FIG. 25, in which the drive wheel 881 of the self-loading compost spreader 850 is in a deployed position against the ground. As shown, the spreading position differs from the hauling position of FIG. 29 in that the drive wheel 881 of the self-loading compost spreader 850 is pivoted with respect to the drive gear 895 such that the teeth or paddles of the drive wheel 881 are contacting the ground. This pivoting of the drive wheel 881 may be achieved using a lockable pivoting mechanism that is built into a base on the side of the scoop bucket 890 that also holds the hub of the drive gear. Once the drive wheel 881 of the drive wheel assembly 880 is in contact with the ground in the deployed position, the drive wheel 881 may be driven to rotate as the tractor 100 moves forward. The teeth or paddles of the drive wheel 881 may serve to generate friction with the ground that helps the drive wheel rotate during movement of the tractor instead of sliding without rotation. The rotation of the drive wheel 881 is transmitted by the drive chain to the drive gear 895, which ultimately rotates the auger screw or the impeller-equipped shaft inside the self-loading compost spreader 850. In turn, the rotation of the auger screw or the impeller- equipped shaft may propel material out of the longitudinal opening 875 of the scoop bucket 890.

[00156] FIG. 31 is a top view of the tractor 100 as illustrated in FIG. 25, in which the selfloading compost spreader 850 is in a spreading position. This view shows the auger screw or the impeller-equipped shaft 896 of the self-loading compost spreader 850 that runs from one side of the scoop bucket 890 to the other side of the scoop bucket and is rotationally mounted in place at the two sides. The auger screw or the impeller-equipped shaft 896 is further coupled to and driven by the drive wheel assembly of the self-loading compost spreader. The tractor 100 may be equipped with a pair of stabilizers 200 located at the rear end of the tractor for stability. An exchangeable battery pack 700 may be connected to the tractor 100 to increase the range and/or the operational endurance of the tractor as it performs compost spreading. Furthermore, the handle 400 of the tractor 100 may be pivoted to align with a wheel 120 track of the tractor 100 such that the person operating the tractor may walk in a wheel track behind a corresponding wheel of the tractor to avoid disturbing or compacting soil of the raised bed 190 located between the left and right wheel tracks (191, 192). [00157] FIG. 32 is a side view of the tractor 100 equipped with the ride-behind assembly 900 and a transplant rack 750. As shown, the ride-behind assembly 900 may include a support member 905 that is equipped with a lockable swivel joint 940. As shown in the sectional view, the lockable swivel joint 940 may enable a first section of the support member 905 that is attached to the tractor 100 to longitudinally flex in relation to a second section of the support member 905 that is attached to the adjustable seat 910. In some embodiments, the lockable swivel joint 940 may include a resilient mechanism (e.g., a flexible spring, a gas strut, and/or so forth) that exerts a return force in response to an external force that causes the resilient mechanism to flex. In this way, the lockable swivel joint 940 may help to keep the swivel wheels 945 of the ride-behind assembly 900 and the wheels 120 of the tractor 100 in contact with the ground as the vehicle assembly moves over uneven ground.

[00158] As further shown, a transplant rack 750 may be mounted to the tractor body 105 by support members 755. For example, the support members 755 may be removably attached to tractor body 105 by pins or fasteners. The transplant rack 750 may be tilted toward the adjustable seat 910. The tilting of the transplant rack 750 may enable items (e.g., trays containing starter packs of small plants) to be compelled by gravity to slide to the lowest side of the transplant rack 750. The lowest side of the transplant rack 750 may include a lip that catches and retains the items in the transplant rack. Accordingly, the person sitting in the adjustable seat 910 may conveniently grab items from the transplant rack 750 while seated and then plant the items in the raised bed 190 located beneath the support member 905.

[00159] FIGS. 33A and 33B show a front view and a rear view, respectively, of the tractor 100 illustrated in FIG. 32. The tractor 100 may be equipped with the ride-behind assembly 900 and transplant rack 750. The transplant rack 750 may be mounted to the tractor body 105. The transplant rack 750 may be substantially rectangular in shape and have parallel sides. As shown in the rear view of FIG. 33B, the transplant rack 750 may be mounted so that a tilted face of the transplant rack faces the adjustable seat 910.

[00160] FIG. 34 is a top view of the tractor 100 illustrated in FIG. 32, in which the tractor is equipped with the ride-behind assembly 900 and the transplant rack 750. As shown, in addition to the transplant rack 750, the tractor 100 may include a shelf 760 that is attached to the tractor body 105. The shelf 760 may be located adjacent to the transplant rack 750 and between the adjustable seat 910 and the transplant rack 750. In some embodiments, the shelf 760 and the adjustable seat 910 may be centrally aligned with each other along a central axis of the tractor 100. The shelf 760 may serve as a staging area for items that have been removed from the transplant rack 750 (e.g., trays containing starter packs of small plants). As shown, the wheels 902 of the ride-behind assembly 900 may be mounted at distal ends of a crossbar 906 that is perpendicular to the support member 905 of the ride-behind assembly 900. The footrests 920 may be mounted to the ride-behind assembly 900 in a toe-out configuration. In some embodiments, each of the left and right footrests 920 may be equipped with a corresponding throttle pedal 926 of a throttle control 925 that enables the person to input commands to the electrical motor controllers 117 of the tractor 100. For example, pressing the left pedal 926 with a left foot may cause the left wheel 120 to turn faster, while lifting a left foot off the left pedal may cause the left wheel to slow down and/or stop. Likewise, pressing the right pedal 926 with a right foot may cause the right wheel 120 to turn faster, while lifting a right foot off the right pedal may cause the right wheel to slow down and/or stop. The use of the throttle controls 925 on the footrests 920 in this manner frees up the hands of the person to perform other tasks, such as planting or harvesting crops.

[00161] FIG. 35 is a top view of the tractor 100 illustrated in FIG. 32, depicting the turning action of the tractor at the end of a row. As shown, the wheels 902 of the ride-behind assembly 900 may pivot while turning the tractor 100. The pivoting of the wheels 902 may be caused by the drive wheels 120 of the tractor 100 turning at different speeds thereby causing the tractor 100 to turn. Since the wheels 120 of the ride-behind assembly 900 trail the drive wheels 120 of the tractor 100, the force of the turn may exert a turning force on the wheels 902 of the ride- behind assembly 900 and cause the wheels to pivot at their swivel points. In various embodiments, turning the tractor 100 be performed by the person operating the tractor at the end of a crop row.

[00162] FIG. 36 is a side view of the tractor 100 illustrated in FIG. 32, in which the tractor is further equipped with a solar charging panel 300. The solar charging panel 300 may include multiple support members 305 that can be mounted to the tractor 100. One pair of the support members 305 of the solar charging panel 300 may be attached to the chassis of the ride-behind assembly 900. Another pair of support members 305 may be attached to the insert members 310 that may be inserted into the stabilizer receivers 130 or other receivers 135 on the front end of the tractor body 105. The support members 305 of the solar charging panel 300 may be of sufficient length as to enable a person sitting in the adjustable seat 910 to fit under and be sheltered by the solar charging panel 300. Thus, the solar charging panel 300 may form a canopy that at least partially protects the person from sun exposure and/or other weather conditions. The solar charging panel 300 may generate DC power that can be used to charge the internal batteries of the tractor 100 and/or the exchangeable battery pack 700 that is mounted at the front of the tractor body 105. The tractor 100 may be further equipped with an AC power inverter 800 mounted at the rear end of the tractor body 105. The AC power inverter 800 may convert DC power from the internal batteries 115 in the body compartment 140 and/or the exchangeable battery pack 700 into AC power to supply, for example, one or more electric devices that consume AC power or a main electrical panel of a dwelling. In this configuration, the weight of the exchangeable battery pack 700 may serve to balance out or substantially balance out the weight of the AC power inverter 800. [00163] FIG. 37 is a side view of the tractor 100 with a harvest assembly 650. The harvest assembly 650 may include a harvest seat 655 and multiple harvest racks 660. The harvest assembly 650 may be mounted to the tractor 100 by insert members 665 that can be inserted into the stabilizer receivers 130 of the tractor 100. The insert members 665 may serve to attach the harvest assembly 650 to the tractor 100. An upper harvest rack 661 of the harvest assembly 600 may include support members 670, in which a rear pair of support members 670 are connected to insert members 665 that can be inserted into the rear stabilizer receivers 130 of the tractor 100. The front pair of support members 670 can attach the upper harvest rack 661 to a chassis 685 of the harvest assembly 650. The support members 670 of the upper harvest rack 661 may be dimensioned in such a way that the upper harvest rack 661 is a horizontal shelf that sits above the body compartment 140 of the tractor 100. As a result, the handle 400 may be removed from the tractor 100 to accommodate the horizontally positioned upper harvest rack 661. The support members 670 may be attached to the corresponding insert members 665 via pins or fasteners inserted into corresponding holes in the support members 670 and insert members 665. One or more lower harvest racks 662 may be mounted directly to the chassis 685. The harvest assembly 650 may further include a pair of swivel wheels 680 that are attached to the chassis to support and provide mobility to the harvest assembly 650.

[00164] The harvest assembly 650 may include footrests 690. The footrests 690 may enable a person that is sitting in the harvest seat 655 to place their feet in the footrests. The footrests 690 may be equipped with throttle controls 695 that send control commands to the controllers 117 of the tractor 100. Accordingly, a person may use the throttle controls 695 to command the tractor 100 to perform various actions, such as move forward, reverse, brake, turn, and/or so forth. With the use of the throttle controls 695, the handle 400 may be removed from the tractor 100. For example, the throttle controls 695 may be connected to an electric interface that was formerly connected to the handlebar control mechanism. The harvest seat 655 may be an adjustable seat that is slidably along a longitudinal axis of the tractor 100.

[00165] FIG. 38 is a top view of the tractor 100 illustrated in FIG. 37 showing the positions of the lower harvest racks 662 relative to the harvest seat 655. As shown, the chassis 685 of the harvest assembly 650 may include two main members 653 that are coupled to the insert members 665 described in FIG. 37. Each of the members may have a corresponding swivel wheel 680 and a corresponding footrest 690 attached such that the footrests are in a toe-out configuration. In some embodiments, each of the left and right footrests 690 may be equipped with a corresponding throttle pedal 691 of a control mechanism that enables the person to input commands to the motor controllers 117 of the tractor 100. For example, pressing the left pedal with a left foot may cause the left wheel 120 to turn faster, while lifting a left foot off the left pedal may cause the left wheel to slow down and/or stop. Likewise, pressing the right pedal with a right foot may cause the right wheel 120 to turn faster, while lifting a right foot off the right pedal may cause the right wheel to slow down and/or stop.

[00166] The main members 653 may be joined together by a crossbar 654 that supports a harvest seat 655 that is located between the main members 653. Alternatively, the harvest seat 655 may be mounted to one or more receivers 135 on the tractor body 105. Lower harvest racks 662 may be mounted on each side of the seat on the main members 653. In some instances, the lower harvest racks 662 may also be mounted to and supported by the crossbar 654. A central portion of the crossbar 654 may be coupled to a pair of braces that are positioned perpendicularly to the crossbar 654. The pair of braces may be positioned to contact the tractor body 105. For example, the pair of braces may serve to brace the harvest assembly 650 against the tractor body 105 once the front assembly tubes of the harvest assembly 650 are inserted into the front stabilizer receivers 130 of the tractor 100. Each of the braces may include an end that is formed to reach a corresponding receiver 135 at the front side of the tractor body 105 and has a corresponding insert that can be inserted into the corresponding receiver 135. In some embodiments, the throttle pedals 691 positioned on the footrests 690 may be electrically linked to the controllers 117 in the tractor 100 via electrical connectors in the receiver inserts and the receivers 135. In another embodiment, the electrical connection between the throttle pedals 691 and the controllers of the tractor may be achieved using a wiring harness. As further described above with respect to FIG. 37, the harvest seat 655 of the harvest assembly 650 may be an adjustable seat that is slidably along a longitudinal axis of the tractor 100. For example, the crossbar 654 or the pair of braces inserted into the receivers 135 may be coupled to a seat adjustment tube that runs along the longitudinal axis. The harvest seat 655 may be mounted on a slider unit that sits on top of and at least partially surrounds the tube. The slider unit may include a spring-loaded pin with a handle, in which the spring of the spring-load pin normal urges the pin into a hole of the holes positioned on the main member. By pulling the handle, the spring-loaded pin may be taken out of the hole so that the slider unit may be slid along the tube until the spring-load pin aligns with another hole of the holes on the tube. If the springload pin is released, the spring may urge the pin into the hole and lock the harvest seat in the new position. A person sitting in the harvest seat 655 as the tractor 100 is moving down a row of crops may remove plants from the ground and place them in the lower harvest racks 662.

[00167] FIG. 39 is a top view of the tractor 100 illustrated in FIG. 37 showing the position of the upper harvest rack 661 relative to the harvest seat 655. As shown, the upper harvest rack 661 may form a U-shaped platform that surrounds the harvest seat 655 from behind and around the sides of the seat. Accordingly, as the tractor 100 is moving down a row of crops, the person sitting in the harvest seat 655 may remove plants from the ground and place them in the upper harvest rack 661.

[00168] FIG. 40 is a top view of the tractor 100 illustrated in FIG. 37, in which the tractor is turning at the end of a row. As shown, the tractor with the harvest assembly may have the wheels of the harvest assembly 650 pivoted during the turning of the tractor. The pivoting of the wheels 680 may be caused by the drive wheels 120 of the tractor 100 turning at different speeds to make the tractor turn. In various embodiments, the turn may be performed by the person operating the tractor at the end of a row of crops.

[00169] FIG. 41 is a side view of the tractor 100 illustrated in FIG. 37, in which the tractor is further equipped with a solar charging panel 300. The solar charging panel 300 may include support members 305 that can be mounted to the tractor 100. One pair of the support members 305 of the solar charging panel 300 may be attached to the chassis 685 of the harvest assembly 650, and another pair of the support members 305 may be attached to the support members 310 that are inserted in the rear stabilizer receivers 130. The support members 305 of the solar charging panel 300 may be of sufficient length to enable a person sitting in the adjustable seat to fit under and be sheltered underneath the solar charging panel 300. Thus, the solar charging panel 300 may form a canopy that at least partially protects the person from sun exposure and/or other weather conditions.

[00170] FIG. 42 is a side view of the tractor 100 showing the tractor equipped with a harvest seat 655, a harvest conveyor belt 675, and a harvest trailer 676. As shown, a harvest assembly may be attached to the front end of the tractor body 105. A two-wheeled harvest trailer 676 may be attached to the rear receivers 135 of the tractor 100. Additionally, a harvest conveyor belt 675 may be coupled to the tractor body 105. The harvest conveyor belt 675 may be powered by an electrical power source of the tractor 100 to convey items from a first position near the harvest seat 655 to a second position that overhangs a top opening of the trailer 676. Accordingly, any item placed on the conveyor belt 675 by the person sitting in the seat may be transported to and then deposited into the trailer 676 by the harvest conveyor belt 675.

[00171] FIG. 43 A is a top view of the tractor 100 in a zero-turn mower configuration. As shown, the tractor 100 may be equipped with four stabilizers 200 in the stabilizer receivers 130. A zero-turn mower assembly 450 may be attached to the front end of the tractor 100. The zeroturn mower assembly 450 may include receiver inserts 451 that are used to attach the assembly to the tractor 100 via receivers 130 on the tractor body 105. The zero-turn mower assembly 450 may include one or more electric motors 452 that rotate one or more corresponding mower blades 453 (as illustrated in FIG. 43B showing the underside of the assembly 450). The one or more electric motors 452 may be powered by internal batteries 115 of the tractor 100 and/or the exchangeable battery pack 700 that is coupled to the receivers 135 of the tractor 100. In some embodiments, the one or more electric motors 452 of the assembly may be electrically connected to the controllers 117 and/or batteries 115 of the tractor via electrical connectors in the receiver inserts and the receivers 135. In other embodiments, the electrical connection between the one or more electric motors 452 and the controller 117 and/or batteries 115 of the tractor 100 may be achieved using a wiring harness.

[00172] An adjustable seat 455 may be positioned on top of the tractor 100, as shown in FIG. 44. For example, the adjustable seat 455 may be mounted to the lid 145 or tractor body 105 and above the body compartment 140. The adjustable seat 455 may be mounted in a way that enables the seat to slide back and forth along a longitudinal axis of the tractor 100 relative to the handlebars 410 of the handle 400. In some instances, the adjustable seat 455 may further include a height adjustment mechanism (e.g., a geared ratchet mechanism, an adjustable pneumatic piston, and/or so forth).

[00173] FIG. 44 is a side view of the tractor 100 of FIG. 43, showing the tractor in a zero-turn mower configuration. As shown, the zero-turn mower assembly 450 may include a height of cut adjustment mechanism that enables the entire assembly to be raised or lowered. For example, the zero-turn mower assembly 450 may include a crank mechanism the drives a geared mechanism that is configured to move the mower blades 453 up or down with respect to a mower base of the assembly. The lockable swivel joint 415 that joins a first section 406 of the body of the handle 400 that is mounted to the tractor body 105 and the second section 407 of the body of the handle that is coupled to the handlebar 410 may be rotated 180° so that the second section 407 overlaps the first section 406. In this way, the person sitting in the seat 455 may use the control mechanisms on the handlebar 410 to control the tractor 100 and/or the zero-turn mower assembly 450. As previously described, the handlebar 410 may be height adjustable.

[00174] FIG. 45 is a top view of the tractor 100 of FIG. 43, in which the wheels 210 of the stabilizers 200 of the tractor are in turning positions. In various instances, the tractor 100 may be turned by varying the speeds of the electric motors 110 such that the drive wheels 120 rotate at different speeds. As the tractor 100 turns, the wheels 210 of the stabilizers 200 may be propelled by the motion of the tractor to pivot in the direction in which the tractor is turning.

[00175] FIG. 46 is a side view of the tractor of FIG. 43, in which the tractor 100 is further equipped with a solar charging panel 300, which may also serve as a solar shade. The solar charging panel 300 may include multiple support members 305. One pair of the support members 305 of the solar charging panel 300 may be attached to the rear stabilizers 200, and another pair of the support members 305 may be attached to the front stabilizers 200. In various instances, the attachment may be achieved using pins or fasteners inserted into corresponding holes in the support members 305 and the stabilizers 200. The support members 305 of the solar charging panel 300 may be of sufficient length as to enable a person sitting in the adjustable seat 455 to fit under and be sheltered underneath the solar charging panel. Thus, the solar charging panel 300 may form a canopy that at least partially protects the person from sun exposure and/or other weather conditions. The solar charging panel 300 may generate DC power that can be used to charge the internal batteries 115 of the tractor 100 and/or the exchangeable battery pack 700 that is mounted at the front of the tractor. [00176] The embodiments of the controllers 117 of the tractor described herein with respect to various figures may be implemented using software that are executable by one or more computing devices. The one or more computing devices may be equipped with a communication interface, a user interface, one or more processors, and memory.

[00177] The communication interface may include wireless and/or wired communication components that enable the computing devices to transmit or receive data via a network, such as the Internet. The user interface may enable a user to provide inputs and receive outputs from the computing devices. The user interface may include a data output device (e.g., visual display, audio speakers), and one or more data input devices. The data input devices may include, but are not limited to, combinations of one or more of keypads, keyboards, mouse devices, touch screens, microphones, speech recognition packages, and any other suitable devices or other electronic/software selection methods.

[00178] Each of the processors may be a single-core processor or a multi-core processor. Memory may be implemented using computer-readable media, such as computer storage media. Computer-readable media includes, at least, two types of computer-readable media, namely computer storage media and communication media. Computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD), Blu-Ray, or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that may be used to store information for access by a computing device. In contrast, communication media may embody computer-readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave, or other transmission mechanisms. As defined herein, computer storage media does not include communication media.

[00179] In some embodiments, the tractor 100 may be further equipped with various sensors, such as video sensors, audio sensors, radar sensors, a compass, a speed sensor, a global positioning system (GPS) sensor, vehicle health sensors, and/or other sensors. Accordingly, the controllers 117 may enable the tractor 100 to function as a remotely controlled vehicle that is controlled using computing devices at a remote-control station and/or as an autonomous vehicle that is able to travel along predetermined routes to perform multiple pre-programmed tasks. The sensors may enable the controllers of the tractor to detect obstacles, make course adjustments, determine that the tractor has arrived at pre-assigned positions, provide data such as location data, video data, audio data, vehicle health status data to the remote-control station, and/or so forth. In turn, the controllers 117 may enable the tractor 100 to receive remote control commands from computing devices at the remote-control station that remotely controls the movements of the tractor via the control mechanisms of the tractor. As further described below, the tractor 100 may be used as a robotic tug for hauling airport baggage at an airport, hauling harvesting bins in fields, or hauling trailers for transporting goods between locations, etc.

[00180] FIG. 47 is a side view of the tractor 100 showing the tractor with an exchangeable battery pack 700 and a trailer 676 in a remote-control tug configuration. As shown, the tractor may be equipped with an exchangeable battery pack 700 that is attached to a front end of the tractor 100 and a two-wheeled trailer 676 that is attached to the back end of the tractor. The two-wheeled trailer 676 may be attached to the tractor 100 by one or more receivers 135 that are located on the rear end of the tractor. The exchangeable battery pack 700 may be used to increase the operational endurance of the tractor 100 in this remote-control tug configuration. Further, the weight of the battery pack 700 may serve to balance out or substantially balance out the weight of the trailer 676 towed by the tractor 100, or a combination of the weight of the trailer and the weight of the cargo in the trailer. The tractor 100 may be equipped with a pair of stabilizers 200 at the front end of the tractor to provide the tractor with additional stability during the tug operation. In this configuration, the tractor 100 may be operated as a remotely controlled tug for hauling items without an operator accompanying the tractor. Accordingly, the handle 400 of the tractor can be removed, and the tractor 100 can be controlled remotely by commands sent via radio signals from a remote-control station.

[00181] FIG. 48 is a side view of the tractor 100 of FIG. 47, in which the tractor acting as a remote-controlled tug is further equipped with a solar charging panel 300. The solar charging panel 300 may include multiple support members 305. One pair of the support members 305 of the solar charging panel 300 may be attached to the rear stabilizer receivers 130, and another pair of the support members 305 may be attached to the front stabilizer receivers 130. In various instances, the attachment may be achieved using pins or fasteners inserted into corresponding holes in the support members 305 and the stabilizers 200. The solar charging panel 300 may generate DC power that can be used to charge or recharge the internal batteries 115 of the tractor 100 and/or the exchangeable battery pack 700 that is mounted at the front of the tractor 100. Thus, the solar charging panel 300 may increase the operational endurance of the remote- controlled tug.

[00182] FIGS. 49A-C show various views of a gear drive drop axel 250 for the tractor 100. FIGS. 49A and 49C show front views of gear drive drop axels 250 for a left side and a right side, respectively, of the tractor 100. FIG. 49B shows a cross-sectional side view of a gear drive drop axel 250. The gear drive drop axel may enable the tractor to be configured with exchangeable wheels 120. The gear drive drop axel 250 may replace the chain drive combination for powering the wheels 120 of the tractor 100 as shown and described in at least FIGS. 2, 3, and 8C. As shown, a smaller primary gear 251 housed in an axel housing 254 of the axel is rotationally driven by a motor drive shaft of a corresponding electric motor 110 of the tractor 100. In turn, the teeth of the smaller primary gear 251 are intermeshed with the teeth of a larger secondary gear 252 that is positioned lower in the axel housing. Each of the smaller primary gear 251 and the larger secondary gear 252 is mounted inside the axel via a corresponding bearing contained inside a corresponding cavity formed by the axel housing. Accordingly, the rotation of the smaller primary gear drives the rotation of the larger secondary gear inside the axel housing. The hub of the larger secondary gear 252 inside the axel housing 254 is further connected via a wheel drive shaft to a wheel hub external to the axel housing. In turn, the wheel hub includes a set of wheel bolts 253 for mounting a wheel 120.

[00183] In various embodiments, the axel housing 254 may be formed using two separate housing pieces that are assembled together via bolts inserted into corresponding holes disposed along the perimeter flanges of the housing pieces, in which the bolts are tightened down with nuts along the perimeter flanges. A gasket or other sealing material that has the shape of the perimeter flanges may be sandwiched between the two housing pieces to seal the pieces together. Furthermore, one of the housing pieces may be formed with a filler opening and a drain opening to enable a lubrication fluid, such as oil, to be added to and removed from the internal space of the axel housing. Such openings may be sealed using corresponding plugs that may be threaded into or otherwise inserted and secured in the openings. The lubricating fluid may reduce the friction generated by the rotation of the gears.

[00184] FIGS. 50A-C show various views of an alternative chain-in-oil drop axel 275 for the tractor 100, in which the chain-in-oil drop axel enables the tractor to be configured with exchangeable wheels 120. FIGS. 50A and 50C show front views of chain-in-oil drop axels 275 for a left side and a right side, respectively, of the tractor 100. FIG. 49B shows a cross-sectional side view of the chain-in-oil drop axel 275. The chain-in-oil drop axel 275 may replace the chain drive combination for powering the wheels of the tractor as shown and described in at least FIGS. 2, 3, and 8C. As shown, a smaller primary sprocket 276 housed in an axel housing 277 of the axel is rotationally driven by a motor drive shaft of a corresponding electric motor of the tractor. In turn, the smaller primary sprocket 276 is rotationally linked to a larger secondary sprocket 278 by a drive chain. The larger secondary sprocket 278 may be positioned lower in the axel housing 277, by a drive chain. Each of the smaller primary sprocket 276 and the larger secondary sprocket 278 may be mounted inside the axel housing 276 via a corresponding bearing contained inside a corresponding cavity formed by the axel housing 277. Accordingly, the rotation of the smaller primary sprocket 276 drives the rotation of the larger secondary sprocket 277 inside the axel housing. The hub of the larger secondary sprocket 278 may be further connected via a wheel drive shaft to a wheel hub external to the axel housing 277. In turn, the wheel hub includes a set of wheel bolts for mounting a wheel 120.

[00185] In various embodiments, the axel housing 277 may be formed using two separate housing pieces that are assembled together via bolts inserted into corresponding holes disposed along the perimeter flanges of the housing pieces, in which the bolts are tightened down with nuts along the perimeter flanges. A gasket or other sealing material that has the shape of the perimeter flanges may be sandwiched between the two housing pieces to seal the pieces together. Furthermore, one of the housing pieces may be formed with a filler opening and a drain opening to enable a lubrication fluid, such as oil, to be added to and removed from the internal space of the axel housing. Such openings may be sealed using corresponding plugs that may be threaded into or otherwise inserted and secured in the openings. The lubricating fluid may reduce the friction generated by the rotation of the sprockets as the sprockets are spun while linked together by the drive chain.

[00186] FIG. 51 is a top view of the tractor 100 equipped with the chain-in-oil drop axels 275. In FIG. 51, the lid 145 is removed from the tractor body 105, thereby exposing the drive components, including the batteries 115, left and right electric motors 110, chain drives that transfer the power from the electric motors 110 to the first ends of the left and right shafts, and the differential locks 185 that are similar to those described in FIG. 2 and FIG. 3. The chainin-oil drop axels 275 may be connected to the second ends of the left and right shafts. By mounting differently sized wheels 120 to the wheel bolts of the drop axels, the tractor 100 may be adapted for different tasks. For example, larger diameter wheels may be used to raise the height of the tractor, while wheels with larger widths may be used to provide the tractor with more load-carrying capacity. While the tractor of FIG. 51 is described with respect to the chain- in-oil drop axels 275, the gear drive drop axels 250 may be used for the same purpose in a similar manner with the tractor 100.

[00187] FIG. 52 is a side view of the tractor 100 illustrated in FIG. 51, in which the tractor is further equipped with a three-point hitch 350 and an exchangeable battery pack 700. Once again, due to the use of drop axels (e.g., 250 or 275), the tractor 100 can receive different sized tires 120. As shown, the exchangeable battery pack 700 may be mounted via one or more receivers 135 to a first end of the body compartment 140 of the tractor 100. A second end of the tractor body 105 may include mounting points for mounting the three-point hitch 350. For example, two lower link bars 351 of the three-point hitch may be mounted at or near the lower corners of the second end, while a third top link bar 352 may be centrally mounted at or near a top edge of the second end. In various embodiments, link bar brackets for attaching the link bars may be mounted at the lower corners and the top edge of the second end of the tractor body 105. Each of the link bars may include link end loops with holes at the two ends of the link bar. Accordingly, each link bar bracket may include a corresponding hole that enables a link bar to be pivotally joined at one end to the link bar bracket via a pin or bolt inserted into the corresponding holes of the bracket and the link bar. Once joined, the holes of the free loops at the other ends of the link bars of the three-point hitch 350 may be used to connect the link bars to farm implements or other implements. The weight of the exchangeable battery pack 700 may serve to balance out or substantially balance out the weight of three-point hitch 350 and/or the implement attached to the three-point hitch. Further, while the tractor of FIG. 52 is shown with the chain-in-oil drop axels 275, the gear drive drop axels 250 may be used for the same purpose in a similar manner with the tractor.

[00188] FIG. 53 is a side view of the tractor 100 equipped with a stand-on riding assembly 550. As shown, the tractor 100 may include a tractor body 105 that is equipped with two wheels 120, a handle 400 attached to the tractor body that enables a person to guide and control the tractor. The tractor 100 may be equipped with stabilizer receivers 130 on the sides of the tractors. While each of the stabilizer receivers 130 may hold a stabilizer 200 equipped with a swivel wheel 210 that is capable of providing additional stabilization support to the tractor, each of the stabilizer holders 130 may also be used to join additional tractor accessories to the tractor. For example, as shown in FIG. 53, a pair of insert members 555 of a stand-on riding assembly 550 may be inserted into the rear stabilizer holders 130 of the tractor. The stand-on riding assembly 550 may include a pair of support members 560 that are connected at first ends of the struts by a cross member 565. A riding platform 570 may be mounted to the cross member 565 at or near the center of the cross member. For example, the riding platform 570 may be welded or bolted to the cross member 565 such that at least a portion of the riding platform 570 sits on and is at least partially supported by a top surface of the cross member. In some instances, at least a portion of the riding platform 570 may be positioned at a level that is closer to the ground than a bottom of the cross member 565. The riding platform 570 may provide a top footrest surface for a person to stand on. In some instances, such a top footrest surface of the riding platform may be inclined at an angle. For example, the top surface may be inclined to slope down in a direction that points away rear-wise from a longitudinal axis of the tractor/ stand-on riding platform assembly.

[00189] The bottom of the cross member 565 may be equipped with a pair of swivel wheels

575 that are mounted at or close to the distal ends of the cross member 565. Each swivel wheel 575 may serve as a contact point with the ground for the stand-on riding platform 570, in which the swivel wheel is configured to swivel and align with a travel direction of the tractor.

[00190] Each of the second ends of the support members 560 may be connected by a corresponding limited-range hinge 580 to a corresponding insert member 555. In turn, each of the insert members 555 may be inserted into a corresponding stabilizer receiver 130 of the tractor 100. For example, an insert member 555 and a corresponding stabilizer receiver 130 may have similar cross-sectional shapes (e.g., square, rectangular, circular, etc.), and the outside cross-sectional dimension of the insert member 555 may be slightly smaller than the inside cross-sectional dimension of the stabilizer receiver 130. Accordingly, following the insertion of the insert member 555 into the corresponding stabilizer receiver 130, the adapter tube may be locked inside the stabilizer receiver by friction, by one or more removable pins or fasteners that are inserted into corresponding holes in both the adapter tube and the stabilizer holder, and/or so forth. Each of the limited-range hinges 580 may enable a corresponding insert member 555 to pivot within a predetermined range of angles with respect to a corresponding support member 560, such that the stand-on riding platform 570 may pivot with respect to the tractor body 105 as the entire assembly 550 moves over uneven terrain. The riding platform 570 may be configured such that a person standing on the platform 570 may reach the adjustable handlebar 410 of the handle 400 with their hands when the handle is extended in a straight line away from the rear of the tractor and towards the riding platform. The adjustable handlebar 410 may be attached to the body of the handle in such a manner, such as via a lockable swivel joint 415, that the handlebar may be pivoted up and down relative to the body of the handlebar and locked in multiple height positions.

[00191] FIG. 54 is a top view of the tractor equipped with a stand-on riding platform 570 as shown in FIG. 53. The cross member 565 of the stand-on riding platform may be positioned substantially perpendicular to the support members 560 of the platform. The cross member 565 may be coupled to the support members 560 via pins, screws, nuts, bolts, and/or any other fasteners. Alternatively, the cross member 560 may be joined to the support members 560 by welding or some other form of joining the handle of the tractor may be extended along a longitudinal axis of the tractor that is parallel or substantially parallel to the struts of the stand- on riding platform such that the handlebar is proximate to the riding platform. Once again, the bottom of the cross member 565 may be equipped with a pair of swivel wheels 575 that are mounted at or close to the distal ends of the cross member. Each swivel wheel may serve as a contact point with the ground for the stand-on riding platform.

[00192] Each of the limited-range hinges 580 may include a pin or fastener that is inserted into corresponding holes positioned at a first end of a corresponding support member 560 and a second end of a corresponding insert member 555. The first end of the support member or the entire support member may be formed out of a hollow tube. The first and second ends of the support member 560 and insert member 555 may have similar square or rectangular cross- sectional shapes, such that each of the ends include a top side, a bottom side that is parallel or substantially parallel to the top side, a left side that is perpendicular or substantially perpendicular to the top side and the bottom side, and a right side that is parallel or substantially parallel to the left side. Further, the outside cross-sectional dimension of the insert member 555 may be smaller than the inside cross-sectional dimension of the support member 560, such that the adapter tube is capable of fitting inside the support member.

[00193] The left and right sides of the insert member 555 may be configured with holes that accept a pin, in which the holes are positioned at locations that are of a predetermined distance from the second end of the insert member 555. This predetermined distance may allow the insert member 555 to pivot with respect to the support member 560 when the insert member is connected to the support member via the pin. The predetermined distance may be configured so that the top side of the insert member 555 may eventually contact an edge of the top side of the support member 560 to form an obtuse angle between the top sides of the insert member and the support member as the tubes pivot. Such contact may prevent the insert member 555 from pivoting with respect to the support member 560 at an axis provided by the pin in such a way that decreases this obtuse angle further.

[00194] The top side of the support member 560 may extend farther out than the bottom side of the support member, so the pivoting of the insert member 555 with respect to the support member may increase the obtuse angle to a maximum of a straight angle, i.e., 180°, such that the adapter tube is parallel to the support member. However, the obtuse angle may not increase beyond the straight angle to become a reflex angle (angle greater than 180°), because the top side of the insert member 555 may be constrained by a bottom surface of the top side of the support member 560 from pivoting beyond the straight angle. In other words, the contact between the top side of the insert member 555 and the bottom surface of the top side of the support member 560 may limit the pivotal freedom of the insert member with respect to the support member. Accordingly, the pair of limited-range hinges 580 of the stand-on riding assembly 550 may serve to provide flexible yet constrained connections of the stand-on riding platform to the tractor 100.

[00195] FIG. 55 is a top view of the tractor equipped with a stand-on riding platform as shown in FIG. 54, in which the tractor is performing an example turn. As shown, the tractor 100 with the stand-on riding platform 570 may have the swivel wheels 575 of the platform pivoted during the turning of the tractor. The pivoting of the swivel wheels 575 may be caused by the drive wheels 120 of the tractor 100 turning at different speeds to cause a tractor to turn. Since the wheels 575 of the stand-on riding platform 570 trail the drive wheels of the tractor, the force of the turn exerts a turning force on the swivel wheels of the stand-on riding platform and causes these swivel wheels to pivot at their swivel points. In various embodiments, the turn may be initiated by the person operating the tractor via the handlebar control mechanism built into the adjustable handlebar of the tractor.

[00196] FIG. 56 is a top view of the tractor 100 showing the tractor in a zero-turn mower configuration. As shown, the tractor 100 may be equipped with four stabilizers 200 in the stabilizer receivers 130. A zero-turn mower assembly 450 may be coupled to the rear end of the tractor 100. For example, the zero-turn mower assembly 450 may include receiver inserts 451 that are used to attach the assembly to the tractor 100 via receivers 135 on the rear side of the tractor. The zero-turn mower assembly 450 may include one or more electric motors 452 that rotate one or more corresponding blades or trimming strings. The one or more electric motors 452 may be powered by internal batteries 115 of the tractor and/or exchangeable battery pack 700 that is coupled to the front side receivers 135 of the tractor. In some embodiments, the one or more electric motors 452 of the assembly may be electrically linked to the controllers 117 and/or batteries 115 of the tractor via electrical connectors in the receiver inserts 451 and the receivers. In other embodiments, the electrical linking between the one or more electric motors 452 and the controller 117 and/or batteries 115 of the tractor lOOmay be achieved using a wiring harness.

[00197] An adjustable seat 455 may be positioned on top of the body compartment 140 of the tractor 100. For example, the adjustable seat 455 may be mounted to the lid 145 of the body compartment 140. The adjustable seat 455 may be mounted in a way that allows the seat to slide back and forth along a longitudinal axis of the tractor relative to the handlebars 410 of the handle. In some instances, the adjustable seat 455 may further include a height adjustment mechanism (e.g., a geared ratchet mechanism, an adjustable pneumatic piston, and/or so forth). [00198] FIG. 57 is a side view of the tractor illustrated in FIG. 56, showing the tractor in a zero-turn mower configuration. As shown, the zero-turn mower assembly 450 may include a height of cut adjustment mechanism that enables the entire assembly to be raised or lowered. For example, the assembly may include a crank mechanism that drives a geared mechanism that is configured to move the trimmer heads up or down with respect to a trimmer base of the assembly. Additionally, the lockable swivel joint 415 that joins a first section 406 of the body of the handle that is mounted to the body of the tractor to the second section 407 of the body of the handle that is coupled to the handlebar, may be rotated 180° so that the second section 407 overlaps the first section 406. In this way, the person sitting in the seat may use the control mechanisms on the handlebar to control the tractor and/or the zero-turn mower assembly 450. Furthermore, the handlebar 410 may be height adjustable.

[00199] FIG. 58 is a side view of the tractor 100 illustrated in FIG. 56, in which the tractor is further equipped with a solar charging panel 300, which may also act as a solar canopy. The solar charging panel 300 may include multiple support members 305 that attach the solar charging panel to the tractor 100. One pair of support members 305 of the solar charging panel 300 may be attached to the rear stabilizers 200, and another pair of support members 305 may be attached to the front stabilizers 200. In various instances, the attachment may be achieved using pins or fasteners inserted into corresponding holes in the support members and the stabilizers. The support members 305 may be of sufficient length to enable a person sitting in the adjustable seat 455 to fit under and be sheltered underneath the solar charging panel 300. Thus, the solar charging panel 300 may form a canopy that at least partially protects the person from sun exposure and/or other weather conditions. The solar charging panel 300 may generate DC power that can be used to charge the internal batteries 115 of the tractor 100 and/or the exchangeable battery pack 700.

[00200] FIG. 59 is a top view of the tractor illustrated in FIG. 56, in which the swivel wheels 210 of the stabilizer 200 are in turning positions. In various instances, the tractor 100 may be turned by varying the speeds of the electric motors 110 so the drive wheels 120 rotate at different speeds. As the tractor 100 turns, the non-driven swivel wheels 210 of the stabilizers 200 may be propelled by the motion of the tractor 100 to pivot to the direction to which the tractor is turning.

[00201] FIG. 60 a side view of the tractor 100 equipped with an adjustable platform assembly 1000 that may be used for standing or sitting. As shown, the tractor 100 includes a tractor body 105 that is equipped with two drive wheels 120, a handle 400 attached to the tractor body 105. The handle 400 may enable a person to guide and control the tractor 100. The tractor 100 may be equipped with stabilizer receivers 130 on the sides of the tractor 100. While each of the stabilizer receivers 130 may hold a stabilizer 200 equipped with a swivel wheel 210 that can provide additional stabilization support to the tractor, each of the stabilizer receivers 130 may be used to join additional tractor accessories to the tractor. For example, as shown in FIG. 60, a pair of insert members 1050 of the adjustable platform assembly 1000 may be inserted into the rear stabilizer receivers 130 of the tractor 100. The adjustable platform assembly 1000 may include a pair of side rails 1060, in which first ends of the side rails are attached to the corresponding first ends of a pair of cross members 1065, and second ends of the side rails are attached to the adapter tubes via limited-range hinges 1070.

[00202] For example, the first end of each side rail 1060 may be a hollow tube with holes positioned at regular intervals along its length. Each of the first ends of the pair of cross members may be equipped with a corresponding slider unit 1080 that surrounds or at least partially surrounds the tube. Each slider unit 1080 may include a spring-loaded pin with a handle, in which the spring of the spring-load pin normal urges the pin into a hole of the holes positioned on a first end of a corresponding side rail. By pulling the handle, the spring-loaded pin may be taken out of the hole so that a slider unit 1080 may be slid along the main pair until the spring-load pin aligns with another hole of the holes on the first end of the corresponding side rail. If the spring-load pin is released, the spring may urge the pin into the hole and lock the adjustable seat in the new position. In various embodiments, each side rail 1060 and its corresponding slider unit 1080 may have similar cross-sectional shapes (e.g., square, rectangular, circular, etc.), and the outside cross-sectional dimension of a side rail may be slightly smaller than the inside cross-sectional dimension of the corresponding slider unit.

[00203] A riding platform 1005 may be connected to the cross member 1065 such that the riding platform is positioned above the cross member. As shown, the riding platform 1005 may be a rectangular or square platform having two pairs of parallel edges that are perpendicular with respect to each other. Further, at least three sides of the riding platform may be surrounded by side walls that partially enclose the riding platform 1005 to form a footrest area. For example, the side walls may enclose the left and right edges of the riding platform. In some embodiments, while no side wall is present at the back edge of the riding platform 1005, a side wall may be present at the front edge of the riding platform. Accordingly, the cross member 1065 may be connected to the left and right side walls of the riding platform, i.e., side walls that are parallel to a longitudinal axis of the tractor 100 equipped with the adjustable platform assembly 1000. For example, as further described with respect to FIGS. 63A and 63B, a corresponding metal plate may be affixed (e.g., welded, bolted, etc.) to the cross member 1065. The two metal plates may be attached to the left and right side walls of the riding platform 1005 via fasteners, such as bolts, screws, pins, etc.

[00204] Each of the second ends of the pair of side rails 1060 may be connected by a corresponding limited-range hinge 1070 to a corresponding insert member 1050. In turn, each of the adapter tubes may be inserted into a corresponding stabilizer holder of the tractor. For example, an adapter tube and a corresponding stabilizer holder may have similar cross- sectional shapes (e.g., square, rectangular, circular, etc.), and the outside cross-sectional dimension of the adapter tube may be slightly smaller than the inside cross-sectional dimension of the stabilizer holder. Accordingly, following the insertion of the adapter tube into the corresponding stabilizer holder, the adapter tube may be locked inside the stabilizer holder by friction, by one or more removable pins or bolts that are inserted into corresponding holes in both the adapter tube and the stabilizer holder, and/or so forth. Each of the limited-range hinges may enable a corresponding adapter tube to pivot within a predetermined range of angles with respect to a corresponding side rail, such that the RS platform assembly may pivot with respect to the body of the tractor as the entire assembly moves over uneven terrain. The riding platform may be positioned such that a person standing on the platform may reach the adjustable handlebar of the handle with the hands of the person when the handle is extended in a straight line away from the rear of the tractor and towards the riding platform. The adjustable handlebar may be attached to the body of the handle in such a manner, such as via a lockable swivel joint, that the handlebar may be pivoted up and down relative to the body of the handlebar and locked in multiple height positions.

[00205] The bottom of each side rail 1060 of the pair of side rails may be equipped with a corresponding swivel wheel 1020. For example, each swivel wheel 1020 may be attached to a corresponding side rail 1060 so that the wheel is located between the riding platform 1005 and the limited-range hinge 1070 along the side rail. Each swivel wheel 1020 may serve as a contact point with the ground for the stand-on riding platform, in which the swivel wheel is configured to swivel and align with a travel direction of the tractor.

[00206] FIG. 61 is a top view of the tractor 100 equipped with the adjustable platform assembly 1000 as shown in FIG. 60. As shown, the cross member 1065 may be positioned perpendicular to the side rails 1060 of the assembly. As described above, each of the cross members 1065 may be coupled to a corresponding side rail 1060 via a corresponding slider unit 1080 that is capable of sliding along the side rail. The handle 400 of the tractor may be extended along a longitudinal axis of the tractor that is parallel or substantially parallel to the side rails 1060. The distance between the riding platform 1005 and the handle of the tractor may be slidably adjusted via the use of the slider units 1080. Once again, the bottom of the cross member 1065 may be equipped with a pair of swivel wheels 1020. Each swivel wheel 1020 may serve as a contact point with the ground for the assembly 1000. In some embodiments, the riding platform 1005 may be equipped with holes for receiving fasteners (e.g., bolts, screws, pins, etc.). Such holes may enable fixtures, e.g., tools, accessories, etc., to be mounted to the riding platform 1005 using fasteners. For example, in the illustrative and non-limiting example shown in FIG. 61, two rows of holes may penetrate the riding platform 1005.

[00207] Each of the limited-range hinges 1070 may include a pin or bolt that is inserted into corresponding holes positioned at a first end of a corresponding side rail 1060 and a second end of a corresponding insert member 1050. The first end of the side rail or the entire side rail may be formed out of a hollow tube. The first and second ends of the side rails 1060 and insert members 1050 may have similar square or rectangular cross-sectional shapes, such that each of the ends include a top side (visible in FIG. 2), a bottom side that is parallel or substantially parallel to the top side, a left side that is perpendicular or substantially perpendicular to the top side and the bottom side, and a right side that is parallel or substantially parallel to the left side. Further, the outside cross-sectional dimension of the insert member 1050 may be smaller than the inside cross-sectional dimension of the side rail 1060, such that the insert member is capable of fitting inside the side rail.

[00208] The left and right sides of the insert members 1050 may be configured with holes that accept a pin, in which the holes are positioned at locations that are of a predetermined distance from the second end of the insert member. This predetermined distance may allow the insert member 1050 to pivot with respect to the side rail 1060 hollow tube when the insert member 1050 is connected to the side rail via the pin. Nevertheless, the predetermined distance is configured so that the top side of the insert member 1050 may eventually contact an edge of the top side of the side rail 1060 hollow tube to form an obtuse angle between the top sides of the adapter tube and the side rail hollow tube as the tubes pivot. Such contact prevents the adapter tube from pivoting with respect to the side rail at an axis provided by the pin in such a way that decreases this obtuse angle further.

[00209] FIG. 62 is a top view of the tractor of FIG. 60 in which the tractor is in an example turn. As shown, the tractor 100 with the adjustable platform assembly 1000 may have the swivel wheels 1020 of the platform assembly pivoted during the turning of the tractor. The pivoting of the swivel wheels 1020 may be caused by the drive wheels of the tractor turning at different speeds to cause the tractor to turn. Since the wheels 1020 of the assembly 1000 trail the drive wheels 120 of the tractor 100, the force of the turn exerts a turning force on the swivel wheels of the assembly and causes these swivel wheels to pivot at their swivel points. In various embodiments, the turn may be initiated by the person operating the tractor via the handlebar control mechanism built into the adjustable handlebar of the tractor.

[00210] FIGS. 63A-C illustrate various detailed views of the riding platform 1005 of the adjustable platform assembly 1000 in relation to the side rails 1060 of the assembly. As shown in a FIG. 63 A, each end of the cross member 1065 may be coupled to a corresponding side rail via a slider unit 1080 that is capable of sliding along the corresponding side rail 1060. A corresponding metal plate 1005 may be affixed (e.g., welded, bolted, etc.) to a corresponding second end of the cross member 1065. The slider units 1080 may enable the riding platform to slide back and forth along the pair of side rails.

[00211] The side views shown in FIG. 63B illustrates additional details with respect to the attachment of the of the cross member 1065 to the left and right side walls of the riding platform 1005. As shown in the section A-A view, each of the left and right side walls of the riding platform 1005 may be equipped with rows of holes in which the pattern of the holes enable a corresponding metal plate 1085 with rows of holes to be attached to a corresponding side wall at multiple positions using fasteners. For example, as shown in the section A-A view, the metal plate 1085 may be equipped with two rows of holes, while a side wall of the riding platform may be equipped with three rows of holes. The spacing between the holes and between the rows of holes of the side wall and the metal plate may be identical. Accordingly, the metal plate 1085 may be mounted at a high position with respect to a side wall using the middle and upper rows of holes of the side wall (as shown in a first A-A view). Alternatively, the metal plate 1085 may be mounted at a low position with respect to a side wall using the middle and lower rows of the side wall (as shown in a second A-A view). The number of rows of holes in the side walls and the metal plates as shown in FIG. 4 are illustrative rather than limiting, and the sides walls of the riding platform 1005 and the metal plates 1085 may have any number of rows of holes for fastening at multiple positions.

[00212] As shown in FIG. 63C, the riding platform 1005 of the adjustable platform assembly 1000 may be substituted with a seat platform 1090 in some embodiments. The seat platform 1090 may be similar to the riding platform 1005 but rotated in the opposite direction (i.e., rotated 180°) so that it lacks a front side wall but may have a rear side wall, and may also be equipped with left and right side walls in the same manner as the riding platform for attachment to the cross member 1065. The seat platform 1090 may include multiple holes that penetrate the seat platform for receiving fasteners (e.g., bolts, screws, pins, etc.). Such holes may enable fixtures, e.g., a seat, tools, accessories, etc. to be mounted to the seat platform 1090 using fasteners. As an illustrative and non-limiting example, two rows of holes may penetrate the seat platform.

[00213] FIG. 64 is a side view of the tractor 100 equipped with the adjustable platform assembly 1000, adjustable seat 1095, a transplant rack 750, and a shelf 760. As shown, the adjustable platform assembly 1000, which may be equipped with a pair of limited-range hinges 1070, may be connected to the tractor 100 via insert members 1055 that are inserted into the stabilizer receivers 130 of the tractor. An adjustable seat 1095 may be mounted to the seat platform 1090. The slider units 1080 of the adjustable platform assembly 1000 may enable the seat platform 1090 that holds the adjustable seat to slide back and forth along the side rails 1060.

[00214] As further shown in FIG. 64, a transplant rack 750 may be mounted via support members 755 to the tractor body 105. For example, the support members 755 may be removably attached to the lid 145 of the body compartment 140 via one or more fasteners. The transplant rack 750 may be tilted to face the person sitting on the adjustable seat 1095. The tilting of the transplant rack 750 may enable items (e.g., trays containing starter packs of small plants) to be compelled by gravity to slide to the lowest side of the transplant rack. The lowest side of the transplant rack 750 may include a lip that catches and holds the items in the transplant rack. Accordingly, the person sitting in the adjustable seat may continually grab items out of the transplant rack to perform tasks with the items (e.g., planting in a raised bed that the tractor is traveling over).

[00215] In addition to the transplant rack 750, the tractor 100 is further equipped with a shelf 705 that is attached to the tractor body 105. The shelf 705 may hold items that have been removed from the transplant rack by the person prior to the person performing further actions with the items. A pair of footrests 1010 may be mounted to the insert members 1050 of the adjustable platform assembly 1000. In some embodiments, each of the left and right footrests 1010 may be equipped with a corresponding throttle pedal 1015 of a control mechanism that enables the person to input commands to the electrical motor controllers 117 of the tractor 100. In turn, the electrical motor controllers 117 may control the electric motors 110 that turn the drive wheels 120 of the tractor. For example, pressing the left pedal with a left foot may cause the left wheel to turn faster, while lifting a left foot off the left pedal may cause the left wheel to slow down and/or stop. Likewise, pressing the right pedal with a right foot may cause the right wheel to turn faster, while lifting a right foot off the right pedal may cause the right wheel to slow down and/or stop.

[00216] FIG. 65 A and 65B show a front view and a rear view, respectively, of the tractor 100 and adjustable platform assembly 1000 illustrated in FIG. 64, in which the tractor 100 is equipped with an adjustable seat 1095, transplant rack 750, and shelf 760. The transplant rack 750 may be mounted to the tractor body 105. The transplant rack 750 may be rectangular in shape with parallel sides. As shown FIG. 65B, the transplant rack 750 may be mounted so that a tilted face of the transplant rack faces the adjustable seat.

[00217] FIG. 66 is a top view of the tractor 100 and adjustable platform assembly 1000 illustrated in FIG. 64. The transplant rack 750, shelf 760, and adjustable seat 1095 may be centrally aligned with each other along a central axis. The swivel wheels 1020 of the adjustable platform assembly 1000 may be mounted under the side rails 1060 in positions between the slider units 1080 for the seat platform 1090 holding the adjustable seat 1095 and the limitedrange hinges 1070. The footrests 1010 may be arranged in a toe-out configuration.

[00218] FIG. 67 is a top view of the tractor 100 and adjustable platform assembly 1000 illustrated in FIG. 64, depicting the turning action of the tractor at the end of a row. As shown, the tractor may have the swivel wheels 1020 of the adjustable platform assembly 1000 pivoted during turning of the tractor. The pivoting of the swivel wheels 1020 may be caused by the drive wheels 120 of the tractor 100 turning at different speeds to cause a tractor to turn. For example, the speed of the electric motors 110 of the tractor 100 may be varied such that the drive wheels 120 rotate at different speeds. Since the swivel wheels 1020 of the adjustable platform assembly 1000 trail the drive wheels 120 of the tractor 100, the force of the turn exerts a turning force on the swivel wheels and causes them to swivel. In various embodiments, the turn may be performed by the person operating the tractor 100 at the end of a row of crops. [00219] FIG. 68 is a side view of the tractor 100 illustrated in FIG. 64, in which the tractor is further equipped with a solar charging panel 300, which may serve as a solar shade. The solar charging panel 300 may include multiple support members 305 to attach the solar charging panel to the tractor body 105 and the adjustable platform assembly 1000. A front pair of support members 305 may be attached to the stabilizer receivers 130, and a rear pair of support members 305 may be attached to the rear stabilizer receivers 130. In various instances, the attachment may be achieved using pins or other fasteners inserted into corresponding holes in the support members 305 and the stabilizer receivers 130. The support members 305 of the solar charging panel 300 may be of sufficient length to enable a person sitting in the adjustable seat 1095 to fit under and be sheltered underneath the solar charging panel 300. Thus, the solar charging panel 300 may form a canopy that at least partially protects the person from sun exposure and/or other weather conditions. The solar charging panel 300 may generate DC power that can be used to charge the internal batteries 115 of the tractor 100 and/or the exchangeable battery pack 700 that is mounted to the tractor.

[00220] FIG. 69 is a side view of a remote-controlled configuration of the tractor 100 with an AC power inverter 800, exchangeable battery pack 700, front and rear stabilizers 200, and a solar charging panel 300. The tractor 100 may serve as a mobile energy storage and supply source. The tractor 100 may collect solar energy through the solar charging panel 300 and convert the solar energy to electrical energy that is stored in the exchangeable battery pack 700 or internal batteries 115 of the tractor 100. The AC power inverter 800 may be used to supply electric power to one or more electric devices that consume AC power or a main electrical panel of a building, such as a dwelling, an emergency shelter, a clinic, a school, etc.

[00221] FIG. 70 is a side view of a remote-controlled configuration of the tractor 100 with an exchangeable battery pack 700, zero-turn mower assembly 450, front and rear stabilizers 200, and solar charging panel 300. The zero-turn mower assembly 450 may be attached to a first side of the tractor body 105 through the one or more receivers 135. The exchangeable battery pack 700 may be attached to a second and opposite side of the tractor body through the one or more receivers 135. The zero-turn mower assembly 450 may include a height adjustment mechanism 460 that raises and lowers a cutting mechanism (e.g., mower blades 453, strings, etc.). The zero-turn mower assembly 450 may include a servo motor connected to the height adjustment mechanism 460 to allow the height of the cutting mechanism to be raised and lowered remotely (i.e., without manual input).

[00222] FIG. 71 is a side view of a remote-control configuration of the tractor 100 with an exchangeable battery pack 700, trailer, and front stabilizers 200. The tractor 100 may serve as a tug to transport a load in the trailer 676. The exchangeable battery pack 700 may serve to extend a duty cycle of the tractor. The tractor 100 may include a pair of front stabilizers 200 to support the cantilevered weight of the exchangeable battery pack 700. The pair of front stabilizers 200 may be attached to the tractor body 105 through a pair of stabilizer receivers 135. In the example show in FIG. 72, the tractor 100 may include a solar charging panel 300. The solar charging panel 300 may be attached to the tractor body 105 and be positioned above the lid 145. A front pair of support members 305 may attach the solar charging panel 300 to the stabilizers 200. A rear pair of support members 305 may attach to a rear pair of insert members 310 that are inserted into a pair of rearward-facing stabilizer receivers 130.

[00223] FIG. 73 is a side view of a remote-controlled configuration of the tractor 100 with a power take-off unit 600 and exchangeable battery 700 ready to be attached to the tractor body 105. The power take-off unit 600 may include one or more inserts 605 that are configured to mate with one or more receivers 135 on the rear side of the tractor body 105. The exchangeable battery pack 700 may include one or more inserts 705 that are configured to mate with one or more receivers 135 on the front side of the tractor body 105. FIG. 74 is a side view of the remote-controlled tractor 100 after the power take-off unit 600 and exchangeable battery pack 700 have been attached to the tractor body 105. The tractor 100 may include a stabilizer 200 that serves to support the weight of the cantilevered exchangeable battery pack 700.

[00224] FIG. 75 is a side view of the remote-controlled tractor of FIG. 74 with a three-point hitch 350 attached to the tractor body 105. The tractor body 105 may include mounting points for mounting the three-point hitch 350. For example, two lower link bars 351 of the three-point hitch 350 may be mounted at or near the lower corners of the rear side of the tractor body, while a third top link bar 352 may be centrally mounted at or near a top edge of the rear side of the tractor body. In various embodiments, link bar brackets for attaching the link bars may be mounted at the lower corners and the top edge of the rear side of the tractor body 105. Each of the link bars may include link end loops with holes at the two ends of the link bar. Accordingly, each link bar bracket may include a corresponding hole that enables a link bar to be pivotally joined at one end to the link bar bracket via a pin or bolt inserted into the corresponding holes of the bracket and the link bar. Once joined, the holes of the free loops at the other ends of the link bars of the three-point hitch 350 may be used to connect the link bars to farm implements or other implements. The weight of the exchangeable battery pack 700 may serve to balance out or balance out the weight of three-point hitch 350 and/or the implement attached to the three-point hitch 350.

[00225] The tractor 100 of FIG. 75 may include a transmission 142 for each drive wheel 120. Each transmission 142 may include a chain-in-oil drop axel 275, like the one shown in FIG. 50. The chain-in-oil drop axel 275 may allow the tractor 100 to receive tires having a range of circumferences and widths and thereby be adapted for various applications. The chain-in-oil drop axel 275 may increase ground clearance of the tractor body above, for example, a raised bed. While the tractor of FIG. 75 is described with respect to the chain-in-oil drop axels 275, the gear drive drop axels 250 may be used for the same purpose in a similar manner with the tractor. [00226] The embodiments of the controllers 117 described herein with respect to various figures, such as the electrical motor controllers, may be implemented using software that are executable by one or more computing devices. The one or more computing devices may be equipped with a communication interface, a user interface, one or more processors, and memory.

[00227] The communication interface may include wireless and/or wired communication components that enable the computing devices to transmit or receive data via a network, such as the Internet. The user interface may enable a user to provide inputs and receive outputs from the computing devices. The user interface may include a data output device (e.g., visual display, audio speakers), and one or more data input devices. The data input devices may include, but are not limited to, combinations of one or more of keypads, keyboards, mouse devices, touch screens, microphones, speech recognition packages, and any other suitable devices or other electronic/software selection methods.

[00228] Each of the processors may be a single-core processor or a multi-core processor. Memory may be implemented using computer-readable media, such as computer storage media. Computer-readable media includes, at least, two types of computer-readable media, namely computer storage media and communication media. Computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD), Blu-Ray, or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that may be used to store information for access by a computing device. In contrast, communication media may embody computer-readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave, or other transmission mechanisms. As defined herein, computer storage media does not include communication media.

[00229] Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing any claims based on this disclosure.