CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Israel Application No. 263131, entitled “Multiaxial drive system for robotic parking system,” filed November 19, 2018, whose disclosure is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention is related generally to the field of automated drive systems, and particularly to automated drive systems for use in an automated (or“robotic”) parking garage.

BACKGROUND

With ever-increasing urban congestion, it is becoming increasingly challenging to provide ample parking space on urban roads. As a result, above-ground and subterranean parking garages are becoming increasingly common. Some such garages are automated, in that an automated system controls the movement of vehicles into and out of the garage, along with the positions of the vehicles within the garage. In an automated parking garage, each vehicle typically sits on a respective pallet, which the automated system moves through the garage.

SUMMARY OF THE INVENTION

There is provided, in accordance with some embodiments of the present invention, a system that includes at least one frame, configured to lie beneath a vehicle pallet having an underside that includes multiple sets of one or more tracks, the sets running parallel to different respective axes. The system further includes one or more wheel-bearing platforms coupled to the frame, and one or more wheels mounted on the wheel-bearing platforms, respectively, such that the wheels are configured to fit within the tracks while the vehicle pallet sits on the wheels. The wheel-bearing platforms are configured to rotate, such as to align the wheels with any particular one of the axes. The system further includes one or more motors configured to move the vehicle pallet along the particular one of the axes by turning the wheels within the set of tracks running parallel to the particular one of the axes.

In some embodiments, the motors are mounted on the wheel-bearing platforms, respectively, each of the motors being configured to turn a respective one of the wheels. In some embodiments, the frame is rectangular.

In some embodiments, the wheels include four wheels arranged in a rectangular arrangement.

In some embodiments, the system further includes respective actuator units configured to rotate the wheel-bearing platforms.

In some embodiments,

the actuator units include:

respective jointed arms including respective joints, respective ends of the jointed arms being coupled to the wheel-bearing platforms, respectively; and

respective linear actuators including respective shafts that are distally coupled to the jointed arms, respectively, and

the actuator units are configured to rotate the wheel-bearing platforms by linearly moving the shafts of the linear actuators such that the jointed arms swivel at the joints.

In some embodiments, the system further includes one or more other motors configured to rotate the wheel-bearing platforms.

In some embodiments, the system further includes one or more rollers mounted on the frame, the rollers being configured to facilitate the movement of the vehicle pallet by rolling along the underside of the vehicle pallet.

In some embodiments, at least some of the rollers are disposed beyond an edge of the frame.

There is further provided, in accordance with some embodiments of the present invention, an apparatus that includes a top surface, configured to support a vehicle, and an underside, including multiple sets of one or more trucks, the sets running parallel to different respective axes. Each truck has a first width along a majority of the track, and pairs of the tracks that ran parallel to different respective ones of the axes meet at respective junctions having a second width that is greater than the first width.

In some embodiments, the second width is 50%-100% greater than the first width.

In some embodiments, tire underside further includes a bottom surface, and tire tracks include multiple brackets attached to the bottom surface.

In some embodiments, the sets of tracks include two perpendicular sets of tracks. There is further provided, in accordance with some embodiments of the present invention, an apparatus for use with multiple sets of tracks running parallel to different respective axes. The apparatus includes a vehicle pallet, including an underside, one or more wheel-bearing platforms coupled to the underside of the vehicle pallet, and one or more wlieels mounted on the wheel bearing platforms, respectively, such that the % _' heels are configured to fit within the tracks while the vehicle pallet sits over the tracks. The wheel-bearing platforms are configured to rotate, such as to align the wheels with any particular one of the axes. The apparatus further comprises one or more motors configured to move the vehicle pallet along the particular one of the axes by turning the wheels within the set of tracks running parallel to tire particular one of the axes.

In some embodiments, the motors are mounted on the wheel-bearing platforms, respectively, each of the motors being configured to turn a respective one of the wheels.

There is further provided, in accordance with some embodiments of the present invention, a method that includes rotating one or more wheel-bearing platforms, on which are mounted respective wheels, such as to align the wheels with a particular axis. The method further includes, subsequently to rotating the wheel-bearing platforms, moving a vehicle pallet, w'hich has an underside that includes multiple sets of one or more tracks, tire sets running parallel to different respective axes that include the particular axis, along the particular axis, by turning the wheels within the set of tracks running parallel to the particular axis.

In some embodiments, pairs of the tracks that run parallel to different respective ones of the axes meet at respective junctions, and rotating the wheel-bearing platforms includes rotating the wheel-bearing platforms while the wheels are within respective ones of the junctions.

In some embodiments, rotating the wheel-bearing platforms includes rotating the wheel bearing platforms using respective actuator units.

In some embodiments,

the actuator units include:

respective jointed arms including respective joints, respective ends of the jointed arms being coupled to the wheel-bearing platforms, respectively, and

respective linear actuators including respective shafts that are distally coupled to the jointed arms, respectively, and

rotating the wheel-bearing platforms includes rotating the wheel-bearing platforms by linearly moving the shafts of the linear actuators such that the jointed arms swivel at the joints.

In some embodiments, moving the vehicle pallet includes moving the vehicle pallet over one or more rollers that roll along the underside of the vehicle pallet.

There is further provided, in accordance with some embodiments of the present invention, a method for use with multiple sets of tracks, the sets running parallel to different respective axes. The method includes rotating one or more wheel-bearing platforms on which are mounted respective wheels, such as to align the wheels with a particular one of the axes, the wheel-hearing platforms being coupled to an underside of a vehicle pallet. The method further includes, subsequently to rotating the wheel-bearing platforms, moving the vehicle pallet along the particular one of the axes, by turning the wheels within the set of tracks running parallel to the particular one of the axes.

In some embodiments, pairs of the tracks that ran parallel to different respective ones of the axes meet at respective junctions, and rotating the wheel-bearing platforms includes rotating the wheel-bearing platforms while the wheels are within respective ones of the junctions.

In some embodiments, rotating the wheel-bearing platforms includes rotating the wheel- bearing platforms using respective actuator units.

In some embodiments,

the actuator units include:

respective jointed arms including respective joints, respective ends of the jointed ar s being coupled to the wheel-bearing platforms, respectively, and

respective linear actuators including respective shafts that are distally coupled to the jointed arms, respectively, and

rotating the wheel-bearing platforms includes rotating the wheel-bearing platforms by linearly moving the shafts of the linear actuators such that the jointed arms swivel at the joints.

In some embodiments, the tracks lie on a surface, and moving the vehicle pallet includes rolling one or more rollers, which are mounted to the underside of the vehicle pallet, along the surface.

The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1A is a schematic illustration of a system for moving vehicles in an automated parking garage, in accordance with some embodiments of the present invention;

Fig. IB is a schematic illustration of a drive system and vehicle pallet carrying a vehicle, in accordance with some embodiments of the present invention;

Fig. 2 is a schematic illustration of the underside of a vehicle pallet, in accordance with some embodiments of the present invention;

Fig 3 is a schematic illustration of a drive system, in accordance with some embodiments of the present invention; and

Fig. 4 is an enlarged drawing of a portion of Fig. 3, in accordance with some embodiments of the present invention

DETAILED DESCRIPTION OF EMBODIMENTS OVERVIEW

Embodiments of the present invention provide a drive system for moving vehicle pallets in an automated parking garage. Advantageously, the drive system is multiaxial, in that the drive system may move the vehicle pallets along multiple non-parallei horizontal axes, including, for example, two perpendicular horizontal axes. On each floor of the garage, a network of such drive systems is arranged, such that each vehicle pallet may he moved across the floor by passing through the network of drive systems.

Typically, the drive system comprises a frame, along with one or more wheel-bearing platforms coupled to the frame. Each wheel-bearing platform carries a wheel, along with a motor that is mechanically coupled to the wheel. The drive system further comprises a wheel-rotating mechanism, configured to rotate the wheel-bearing platforms.

The underside of each vehicle pallet is shaped to define multiple sets of tracks that run parallel to different respective axes (including, for example, two perpendicular sets of tracks ), with pairs of non-parallel tracks intersecting at respective junctions. The vehicle pallet sits on the drive system such that the wheels are disposed within one of the sets of tracks. To move the vehicle pallet to an adjacent drive system, the motors turn the wheels within the tracks, thus generating a tractive force that moves tire vehicle pallet. To change the axis of movement, the wheel-rotating mechanism rotates the wheel-bearing platforms while the wheels are disposed within the junctions, such that the w'heels become aligned with another set of tracks.

In some embodiments, the wheel-rotating mechanism comprises one or more actuator units, each of which is configured to rotate a respective one of the wheel-bearing platforms. Each actuator unit comprises a linear actuator, comprising a shaft, and a jointed arm, which comprises two arm-segments joined to one another at a joint. The distal end of the distal arm-segment is coupled to the wheel-bearing platform, which is mounted onto the inner, rotatable ring of a rotational bearing coupled to the frame, while the proximal end of the proximal arm-segment is coupled to the stationary outer ring of the bearing. The distal end of the shaft of the linear actuator is coupled to one of the arm-segments. As the shaft moves linearly, the jointed arm swivels at the joint, such that the wheel-heari ng platform rotates.

The multiaxial drive system described herein has several advantages over a compound system comprising multiple uniaxial drive systems, in each of which the wheels are fixed in a particular orientation. For example, a compound system typically requires positioning the vehicle pallet at a greater height from the floor, so that the different sets of wheels may be a!ternating!y raised to the underside of the pallet. In contrast, the system described herein allows positioning the pallet at a lesser height, thus increasing the maximum allowable height of the vehicles. Furthermore, using tire system described herein, oblique movement, such as movement along an axis oriented at a 45° angle relative to the edges of the frame, may be enabled more easily. Moreover, the system described herein allows greater flexibility in the size and shape of tire frame, thus facilitating more efficient utilization of the available space in the garage.

SYSTEM DESCRIPTION

Reference is initially made to Fig. 1A, which is a schematic illustration of a system 20 for moving vehicles 26 in an automated parking garage 21 , in accordance with some embodiments of the present invention. Reference is further made to Fig. IB, which is a schematic illustration of a drive system 22 and vehicle pallet 24 carrying a vehicle 26, in accordance with some embodiments of the present invention.

System 20 comprises a network of drive systems 22, which lie on a floor 36 of parking garage 21, and a plurality of vehicle pallets 24. As described in detail below, system 20 is configured to move vehicle pallets 24 through the network of drive systems 22, so as to facilitate the parking of vehicles 26 in the garage.

Drive system 22 comprises a frame 23, which is configured to lie on any surface, such as floor 36. Typically, frame 23 comprises legs 29 that are fastened to the floor, eg., using screws. In the event that floor 36 is sloped, the frame may be levelled by adjusting the respective heights of legs 29.

As further described below with reference to Fig. 4, drive system 22 further comprises one or more wheels 25 coupled to frame 23. While the frame lies on floor 36, wheels 25 contact the undersides of vehicle pallets 24. Wheels 25 may thus support the vehicle pallets, and, by turning, apply a tractive force to the undersides of the vehicle pallets, thus moving the pallets.

In some embodiments, drive system 22 further comprises one or more rollers 27, which are also coupled to the frame, and which also contact the undersides of the vehicle pallets. Rollers 27 provide further support to, and facilitate the movement of, vehicle pallets 24.

Typically, each frame 23 is generally rectangular, comprising two longer edges 38 and two shorter edges 40. In some embodiments, the length of each longer edge - i.e., the length the frame - is between 4 and 6 meters, while the length of each shorter edge - i.e., the width of the frame - is between 1.8 and 2 6 meters. In other embodiments, the frame may be larger or smaller, depending on the dimensions of the vehicles that are to be parked in the garage.

Each drive system may comprise any suitable number of wheels, such as one wheel, two wheels, or four wheels. In the latter case, the four wheels are typically arranged in a rectangular arrangement, as shown in Fig. 1A It is noted that, by virtue of the weight-bearing support provided by rollers 27, even a relatively large drive system may comprise a relatively small number of wheels, provided that the wheels provide sufficient tractive force to the vehicle pallets.

In general, drive systems 22 may be arranged in any suitable arrangement, so as to best utilize the available space in garage 21. Adjacent frames are arranged such that respective longer edges 38 of the frames, or respective shorter edges 40 of the frames, are parallel to one another. The distance between each pair of adjacent frames is typically between 5 and 20 cm.

To further optimize the use of the available space in the garage, the sizes of the drive systems may be varied. For example, as shown in Fig. 1A, system 20 may comprise multiple standard-size drive systems 22s, along with at least one half-size drive system 22h. The frame of half-size drive system 22h may have a length that is half that of standard-size drive system 22s, or, as shown in Fig. 1 A, a width that is half that of standard-size drive system 22s. Typically, half size drive system 22h comprises half the number of wheels as standard-size drive system 22s.

Typically, the dimensions of vehicle pallet 24 are similar to those of frame 23. For example, vehicle pallet 24 may be generally rectangular, and may comprise two longer edges and two shorter edges that are similar in length to the longer and shorter edges of the frame, respectively. The vehicle pallets sit over tire frames such that the longer edges of the pallets are generally parallel to the longer edges of the frames, and the shorter edges of the pallets are generally parallel to the shorter edges of the frames. Each pallet comprises a top surface 31, configured to support vehicle 26. Typically, vehicle 26 sits on top surface 31 such that the length of the vehicle is aligned with the longer edge of the pallet. Each drive system is configured to move pallets 24 along multiple different axes of movement, which typically include two axes that are perpendicular to one another. For example, given a rectangular frame as described above, pallets 24 may be moved along two perpendicular horizontal axes: an x-axis, which is parallel to longer edge 38, and a y-axis, which is parallel to shorter edge 40. Alternatively or additionally, pallets 24 may be moved along one or more oblique horizontal axes, which are parallel neither to longer edge 38 nor to shorter edge 40.

Typically, each drive system is connected, via electrical wiring 34, to a respective control unit 32, which controls the supply of electricity to the drive system. Typically, control unit 32 comprises a controller, along with other relevant electrical components, such as one or more relays and/or circuit breakers. Typically, control units 32 are connected wiredly or wirelessly to a central control unit 35, comprising a central controller, which is configured to control the movement of pallets 24 by issuing instructions to control units 32. For example, to move a pallet from a first drive system to a second drive system, central control unit 35 may instruct the control unit of the first drive system to turn the wheels of the first drive system toward the second drive system. The central control unit may further instruct the control unit of the second drive system to turn the wheels of the second drive system in the same direction, until the pallet is positioned entirely over the second drive system.

In some embodiments, parking garage 21 includes multiple levels, and an elevator 28 moves pallets 24 between the levels. In such embodiments, elevator 28 may comprise an elevator platform that supports another drive system 22 (or a single-axis drive system), which is configured to move vehicle pallets to and from the elevator. (The control unit for this drive system may be located, for example, beneath the elevator platform.) In such embodiments, half-size drive system 22h may be positioned next to elevator 28, to help load and unload the elevator. For example, to unload a vehicle pallet from the elevator, the vehicle pallet may be moved onto half-size drive system 22h, such that the vehicle pallet sits halfway on the elevator and halfway on the half-size drive system. Subsequently, the vehicle pallet may be moved to a neighboring drive system.

It is noted that in addition to being used in a networ of drive systems, as in Fig. 1 A, drive system 22 may be used alone, e.g., to transfer a vehicle pallet between two elevators.

THE VEHICLE PALLET

Reference is now made to Fig. 2, which is a schematic illustration of the underside 42 of a vehicle pallet 24, in accordance with some embodiments of the present invention.

As shown in Fig 2, vehicle pallet 24 comprises multiple sets of one or more tracks 44, which run parallel to different respective axes along underside 42 Each wheel of the drive system is configured to fit within any one of tracks 44. Movement of the pallet along a particular axis is achieved by virtue of the wheels turning within the tracks that are parallel to the axis.

For example, to facilitate movement along tire perpendicular x- and y-axes as described above with reference to Fig. 1A, a first set 44a of“x-direction tracks” may ran parallel to the x- axis, while a second set 44b of“y-direction tracks” may run parallel to the y-axis. Pairs of tracks that run parallel to different respective axes meet at respective junctions 48. For example, as shown in Fig. 2, each track belonging to first set 44a may meet each track belonging to second set 44b at a different respective junction 48. The orientation of wheels 25 is changed while the wheels are positioned within junctions 48.

In some embodiments, as shown in Fig. 2, tracks 44 comprise brackets 47, such as U- shaped brackets or omega brackets, which are attached to the bottom surface of the pallet. (Each track may comprise multiple brackets.) In other embodiments, the tracks comprise grooves that are formed in the bottom surface of the pallet.

Typically, the width wl of each track along the majority of the track - which may, for example, be between 4 and 10 cm - is only slightly greater than the thickness of each wheel 25. Thus, the wheels turn within the tracks with minimal or no w _' obbling, such that the vehicle pallet moves stably over the drive system. To facilitate changing the orientation of the wheels, however, the width w2 of each track at junctions 48 is typically greater than width wl , e.g., between 50% and 100% greater than width wl. Junction 48 may thus include an area of size w2 x w ^? 2, in which the wheels may be rotated so as to change their orientation.

As described above with reference to Fig. 1A, in some embodiments, drive system 22 comprises one or more rollers, which facilitate the movement of the vehicle pallets by rolling along the underside of the vehicle pallets. For example, the underside of vehicle pallet 24 may comprise one or more roller tracks 46, analogous to tracks 44, in which the rollers may roll. (Each of the roller tracks may ran parallel to any one of tracks 44; for example, Fig. 2 shows four roller tracks 46, each tunning parallel to the y-axis.) Alternatively or additionally, some rollers may roll along the bottom surface of the pallet, not within any tracks. For example, some rollers may roll along pathways 49 that run, from one side of vehicle pallet to the other, through breaks 50 in tracks 44 and roller tracks 46. Fig. 2 shows two such pathways 49, each running parallel to the x-axis.

THE DRIVE SYSTEM

Reference is now made to Fig. 3, which is a schematic illustration of drive system 22, in accordance with some embodiments of the present invention.

As described above with reference to Figs. 1 A-B, drive system 22 comprises frame 23. In general, frame 23 may have any suitable structure, and may comprise any suitable materials, such as a metal or metallic alloy (e.g., stainless steel), a plastic, and/or wood.

For example, as shown in Fig. 3, frame 23 may comprise a plurality of metallic or plastic outer bars 52, which define the edges of the frame. (For example, for the rectangular frame shown in Fig. 3, two longer outer bars 52 define longer edges 38 of the frame, while two shorter outer bars define shorter edges 40.) Frame 23 may further comprise one or more metallic or plastic cross bars 54, which, by running between the outer bars, provide strength and stability to the frame. Alternatively, the frame may have a honeycomb structure, or may be constructed from rectangular sections.

In some embodiments, drive system 22 further comprises one or more roller-holding bars 56, which are coupled to frame 23. Rollers 27 - which, as described above with reference to Fig. 1A, facilitate the movement of the vehicle pallets over the frame - are mounted on roller-holding bars 56. For example, each roller may be held within a bearing at the top of a respective vertical roller-bearing shaft 33 that is mounted on the roller-holding bars. Each roller is configured to freely rotate around any axis of rotation; in other words, in contrast to wheel 25, the rotation of the roller is not constrained to any particular axis of rotation.

For example, as shown in Fig. 3, drive system 22 may comprise multiple roller-holding bars 56 that are interconnected so as to define an auxiliary, upper frame 57 that is coupled to frame 23. To secure upper frame 57 to frame 23, at least some ends of the roller-holding bars may be welded onto outer bars 52, as shown, for example, in portion 58 of Fig. 3. Alternatively or additionally, at least some roller-holding bars may be secured within indentations in outer bars 52, e.g., by strips of metal 62 that are welded onto the top surface of the outer bars, as shown, for example, in portion 60 of Fig. 3. in some such cases, the roller-holding bars may protrude from frame 23, and some rollers 27 may be mounted on the protrusions, such that these rollers are disposed beyond the edge of the frame. Such“external” rollers may facilitate the transfer of vehicle pallets between the frames.

Other notable components of drive system 22 are hereby described with reference to Fig. 4, which is an enlarged drawing of a portion 63 of Fig. 3, in accordance with some embodi ents of the present invention.

As described above with reference to Fig. 1A, drive system 22 comprises one or more wheels 25. Each wheel is mounted on a respective wheel-bearing platform 70; for example, each wheel 25 may be mounted on a horizontal axle 68, which is in turn mounted on wheel-bearing platform 70. Each wheel is carried atop the wheel-bearing platform, and is thus configured to fit within any one of tracks 44 (and contact the underside of the vehicle pallet) while the vehicle pallet sits on the wheel.

Drive system 22 further comprises one or more motors 66 configured to turn wheels 25. In some embodiments, multiple wheels (e.g., all of the wheels) belonging to the drive system are turned by a single motor. Typically, however, each motor 66 is mounted on a different respective one of the wheel-bearing platforms, and is configured to rotate the wheel that is mounted on the same wheel-bearing platform. For example, motor 66 may be mechanically coupled, via a system of gears 76, to axle 68, such that, by rotating the axle, the motor rotates the wheel around an axis of rotation 64 that is parallel to the axle. The motor thus causes the wheel to turn within one of the tracks on the underside of the vehicle pallet, such that the vehicle pallet moves along an axis of movement 65 that is perpendicular to axis of rotation 64 and is parallel to the track.

Typically, each motor 66 is an alternating current (AC) motor, such that the direction of movement along axis 65 is a function of the phase of the AC current supplied to the motor. For example, with reference to Fig. 4, the vehicle pallet may be moved toward the top of the page by supplying an AC-current phase of zero to the motor shown in Fig. 4 (while supplying the same or a different phase to each of the other motors), and toward the bottom of the page by supplying the motor with an AC-current phase of 180 degrees.

In some embodiments, the wheel-bearing platform comprises multiple portions disposed at different respective heights, i.e., different respective distances from the vehicle pallet. For example, the wheel-bearing platform may comprise an upper platform portion 70a, on which axle 68 is mounted, and a lower platform portion 70b, on which motor 66 is mounted.

Advantageously, wheel-bearing platform 70 is configured to rotate so as to align wheel 25 with any particular axis of movement 65. (In general, at any given time, all of the wheels belonging to the drive system share the same alignment.) Wheel-bearing platform 70 may be coupled to frame 23 in any suitable way that facilitates this rotation. For example, the outer, stationary ring of a rotational bearing 72 may be mounted on a supporting member 74 that is welded or otherwise attached to an outer bar 52 of the frame, and the wheel-bearing platform may be mounted on the inner, rotatable ring of bearing 72. As another example, a first ring, made of a low-friction material (e.g., polyamide nylon), may be attached to supporting member 74, and the wheel-bearing platform may be mounted onto a second low-friction ring that is rotatably disposed atop the first ring. Thus, for example, when wheels 25 are aligned with the y-axis as shown in Figs. 3-4 (i.e., when axis of rotation 64 is parallel to the x-axis and axis of movement 65 is parallel to the y-axis), the wheels turn within second set 44h of tracks (Fig. 2), thus moving the vehicle pallet along the y-axis. Conversely, when wheels 25 are aligned with the x-axis (i.e., when axis of rotation 64 is parallel to the y-axis and axis of movement 65 is parallel to the x-axis), the wheels turn within first set 44a of tracks (Fig. 2), thus moving the vehicle pallet along the x-axis.

In some embodiments, the drive system comprises one or more actuator units 78, each actuator unit 78 being configured to rotate a respective one of the wheel-bearing platforms. Typically, each actuator unit 78 comprises a jointed arm 80 that comprises a joint 82 and is coupled, at its distal end 84, to the wheel-bearing platform. For example, jointed arm 80 may comprise a proximal aim-segment 86a and a distal aim-segment 86b, the distal end of proximal arm-segment 86a being pivotably coupled, at joint 82, to the proximal end of distal arm-segment 86b. The actuator unit further compri es a linear actuator 88, comprising a shaft 90 that is dista!ly coupled to jointed arm 80; for example, shaft 90 may be distally coupled to proximal arm-segment 86a.

Typically, proximal arm-segment 86a is proximaily coupled to the outer, stationary ring of bearing 72, or to supporting member 74, while distal arm-segment 86b is distally coupled to the wheel-bearing platform. Thus, as shaft 90 moves linearly, the jointed a m swivels at joint 82, such that the wheel-bearing platform rotates.

For example, for the embodiment shown in Figs. 3-4, wheel 25 is aligned with the y-axis when shaft 90 is extended. To align wheel 25 with the x-axis, the shaft is withdrawn, as indicated in Fig. 4 by a first movement indicator 92. As the shaft pulls on jointed arm 80, jointed arm 80 swivels at joint 82 - and in particular, folds inward, such that joint 82 moves outward - as indicated by a second movement indicator 94. As the jointed arm swivels, the w'heel-bearing platform is rotated by 90 degrees, as indicated by a third movement indicator 96. Conversely, to return to the y-axis alignment, the shaft is extended, such that the jointed arm unfolds, and the wheel-bearing platform is rotated in the opposite direction.

Alternatively to actuator unit 78, the drive system may comprise one or more other motors, each one being configured to rotate a respective one of the wheel-bearing platforms. Hach of these other motors may be mounted, for example, to the underside of supporting member 74, and connected to wheel-bearing platform 70 via a system of gears. (Such a system may comprise at least one chain that mechanically couples the gears to each other.)

Alternatively, the drive system may comprise jointed arms 80, but not linear actuators 88. Instead of linear actuators 88, multiple arms may extend from a central vertical shaft coupled to the center of frame 23, the respective ends of the arms being coupled to jointed arms 80, respectively. As the central shaft is turned (e.g., by a central motor or linear actuator), the arms may extend or retract, thus swiveling the jointed arms and rotating the wheel --bearing platforms as described above.

As yet another option, a central gear may be coupled, via one or more chains, to respective local gears coupled to the undersides of wheel-bearing platforms 70. A central motor may be configured turn the central gear, thus also turning the local gears and rotating the wheel-bearing platforms.

Alternatively, any other suitable mechanism may be used to rotate wheel-bearing platforms 70, and thus change the alignment of wheels 25.

It is noted that, as described above with reference to Fig. 1A, wheels 25 may aligned with an oblique axis“oa” that is not parallel to any of the edges of the pallet or of the frame. To facilitate movement of the vehicle pallet along the oblique axis, vehicle pallet 24 may comprise a set of tracks that is parallel to the oblique axis. Alternatively, provided that the angle Q between the oblique axis and the y-axis, or between the oblique axis and the x-axis, is sufficiently small (e.g., less than two degrees), the vehicle pallet may be moved (for a small distance) along the oblique axis even without the provision of oblique tracks. In other words, the width of the tracks may be sufficiently wider (e.g., between 50% and 100% wider) than the thickness Ti of the wheels, such that the wheels may adopt the oblique orientation, and then rotate slightly within the x- direction or y-direction tracks. This slight oblique movement may be helpful, for example, in the event that a drive system cannot be laid exactly opposite its neighbor, e.g., due to irregularities in the interior wall of garage 21.

As shown in Fig. 3, for embodiments in which the drive system comprises four wheel bearing platforms arranged in a rectangular arrangement, the wheel-bearing platforms (and linear actuators) may be arranged such that, for any given orientation of the wheels, the drive system exhibits mirror symmetry with respect to a hypothetical vertical plane of symmetry that is parallel to either the x-axis or the y-axis and passes through the center of the drive system. This symmetry may facilitate the supply of AC current to the drive system.

ALTERNATE EMBODIMENTS

In some embodiments, instead of multiple wheel-bearing platforms being coupled to a single frame, each wheel-bearing platform 70 is coupled to a different respective frame. Each of the components used for rotating the wheel-beari ng platform (e.g., actuator unit 78) may be coupled to the frame, or directly to the floor of garage 21. Aside from this difference, the structure of each wheel-bearing platform and actuator unit 78 may be generally as shown in Fig. 4.

In such alternate embodiments, the spacing between tire wheels may be as shown in Fig. 1A, such that any given vehicle pallet sits on four wheels at any given time. Alternatively, for added stability, the number of wheels may be increased, and the spacing between the wheels decreased, such that, for example any given vehicle pallet sits on six or nine wheels at any given time. Optionally, rollers 27 may also be coupled to the floor of the garage, e.g., by coupling each roller-bearing shaft 33 (Fig. 3) directly to the floor, or to an adjustment ring, used for adjusting the height of the roller, that is coupled to the floor. Each wheel-bearing platform, or subset of wheel bearing platforms, may be connected to a respective control unit 32.

In these embodiments, the vehicle pallets are generally moved as described above. That is, to move a vehicle pallet along a particular axis, the relevant subset of wheels is aligned with the axis, and the motors that are coupled to the subset of wheels then turn the subset of wheels within the set of tracks running parallel to the axis.

In yet other embodiments, tracks 44 run along the floor of the garage, while vehicle pallets 24 comprise wheels 25. In other words, one or more wheel-bearing platforms, along with the components that rotate the wheel-bearing platforms, are coupled to the underside of each vehicle pallet. As described above, a respective wheel and a respective motor may be mounted on each of the wheel-bearing platforms, such that each motor is configured to turn a respective one of the wheels. Alternatively, a single motor may turn all of the wheels, or multiple motors may turn respective subsets of multiple wheels.

Typically, a respective battery, coupled to each vehicle pallet, supplies power to the motors that turn the wheels. Such a battery may be rechargeable, and respective docking stations may be provided at each parking position, such that the battery may be recharged when the vehicle pallet is not in motion. A respective control unit 32, which is configured to wirelessly communicate with central control unit 35, may also be coupled to each vehicle pallet.

In such alternate embodiments, the wheels are configured to fit within the tracks while the pallet sits over the tracks, and to move the vehicle pallet along the tracks by applying a tractive force to the tracks or to the floor. In general, the vehicle pallets are generally moved as described above. That is, to move a vehicle pallet along a particular axis, the wheels of the pallet are aligned with the axis, and the motors then turn the wheels within the set of tracks running parallel to the axis. To facilitate moving the vehicle pallet, one or more rollers may be mounted to the underside of the vehicle pallet, such that the rollers roll along the floor, and/or along roller tracks 46 that run along the floor, as the vehicle pallet moves.

Although the present application pertains mainly to vehicle pallets, it is noted that the drive system described herein may be used to move any suitable type of pallet or platform.

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of embodiments of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description. Documents incorporated by reference in the present patent application are to be considered an integral part of the application except that to the extent any terms are defined in these incorporated documents in a manner that conflicts with the definitions made explicitly or implicitly in the present specification, only the definitions in the present specification should be considered.