TRACTOR-TRAILER LANDING GEAR APPARATUS Cross Reference To Related Application This application claims priority to U. S. Provisional Patent Application No.

60/466,004 filed on April 28, 2003 entitled"Tractor-Trailer Landing Gear Apparatus". The disclosure of the above-identified provisional application is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to tractor-trailers in general, and more particularly to landing gear apparatus for stabilizing and/or raising and lowering the trailer portion of a tractor-trailer.

Background Information Very often the trailer portion of a tractor-trailer rig is uncoupled from the tractor portion during loading and unloading. Many trailers have front landing gear for supporting the front of the trailer when the tractor is detached. Such landing gear systems generally have two spaced-apart, jack-type structures joined by a driven connecting shaft to coordinate operation of the jack-type structures between an extended position and a retracted position. The connecting shaft is usually engaged by a gearbox assembly driven by a manually operated crank. The gearbox assembly commonly may be shifted between gearing ratios, for example, a low gear and a high gear. Manually operated landing gear systems are often difficult to use, require much time and physical effort for operation and expose the operator to fatigue and potential injury.

What is needed is an apparatus that is easy to operate and reduces the time and effort required to stabilized the trailer with landing gear.

SUMMARY OF THE INVENTION According to the present invention, a landing gear apparatus for supporting the trailer portion of a tractor-trailer is provided. The landing gear apparatus includes a drive leg, an actuation mechanism, a drive mechanism, a motor, and a controller. The drive leg has a first member slidably received within a second member. The actuation mechanism is engaged with the first member and operable to actuate the first member relative to the second member between a retracted position and an extended position. The drive mechanism is disposed within the drive leg. The drive mechanism includes an output shaft, an input shaft, an intermediate shaft, a first gear, a second gear, and a pair of intermediate shaft gears. The first gear is mounted on the output shaft and engaged with the actuation mechanism. The second gear is mounted on the input shaft. The intermediate shaft gears are mounted on the intermediate shaft. The input shaft is selectively axially movable between a first position where the first gear and second gear are engaged and in contact with one another, and a second position where the first gear and the second gear are not in contact with one another. The motor is coupled to the intermediate shaft of the drive mechanism. The controller selectively controls the motor to operate the drive mechanism and the actuation mechanism to actuate the first member and second member between the retracted position and the extended position.

In a preferred embodiment, the motor is a pneumatic motor that can be connected to a source of compressed air, for example, the pre-existing air supply of the tractor-trailer's emergency brake system. A pneumatic motor avoids the problems associated with hydraulic motors and electrical motors in an outdoor environment.

The present apparatus for actuating a tractor-trailer's landing gear provides several advantages over existing landing gear systems. For example, the present apparatus can be operated in a power-assist mode or a manual mode. In the power assist mode, a motor is used to drive the landing gear between an extended position and a retracted position. In the event the power required to operate the motor is not available, the present apparatus can be operated manually. In the <BR> <BR> power assist mode, the apparatus can be operated remotely, e. g. , from the cab of the truck.

Another advantage of the present apparatus is the labor and physical effort saved by the operator. In the power-assist mode, the landing gear is driven by the

present apparatus, not the operator. Saved time equates to lower labor costs, and reduced manual effort decreases the risk for operator injury.

Another advantage of the present invention is its ability to be retrofitted onto existing landing gear systems. An embodiment of the present invention can be combined with certain manually operated landing gear systems to enable operation in a power-assist mode. Because this embodiment advantageously utilizes certain existing components, the modifications and cost to retrofit is minimized. In addition, the retrofit is compatible with the existing manual actuation system. Hence, a landing gear system retrofitted with the present invention can be operated in a power-assist mode or a manual mode.

Another advantage of the present invention is that it can be used with a variety of power sources. If a pneumatic motor is employed, compressed air can be used from a source independent of the tractor-trailer. In the preferred embodiment, however, the pneumatic motor is connected to a source of compressed air portable with the vehicle, e. g. , brake system air. As a result, the medium that powers the pneumatic motor is readily available when the landing gear is to be actuated.

Another advantage of the present invention is that the gear assembly of the present invention provides a mechanism that substantially increases the load capacity of the landing gear. The gear assembly also permits the use of a smaller, and therefore lighter, motor.

These and other objects, features, and advantages of the present invention will become apparent in light of the drawings and detailed description of the present invention provided below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic side view of a trailer disengaged from a tractor and having the landing gear apparatus of the present invention installed thereon.

FIG. 2 is a diagrammatic end view of the trailer shown in FIG. 1.

FIG. 3 is a diagrammatic sectional partial view of a leg of the landing gear apparatus of the present invention showing the gear assembly engaged in low gear.

FIG. 4 is a diagrammatic sectional partial view of the leg shown in FIG. 3, now showing the landing gear assembly engaged in high gear.

FIG. 5 is a diagram of an embodiment of a pneumatic air system adapted for use with the present invention.

DETAILED DESCRIPTION OF THE INVENTION Now referring to FIGS. 1-5, the present landing gear apparatus 10 includes an actuation mechanism 12, a drive mechanism 14, a motor 16, and a controller 18 operable with respect to vertically extendable and retractable legs 20. FIGS. 1 and 2 show an embodiment of the present landing gear apparatus 10 mounted on a trailer 22 portion of a standard tractor-trailer. As will be discussed below, the landing gear apparatus 10 may be operated in a power-assist mode or a manual mode.

Landing gear generally includes a pair of vertically extendable and retractable legs 20 disposed on opposite sides of the trailer 22. A first leg 24 is disposed on the driver's side of the trailer 22 and a second leg 26 is disposed on the passenger's side of the trailer 22. As is typical of landing gear systems, the first leg 24 is generally a"drive"leg and the second leg 26 is a"slave"leg, though the operative roles may be reversed in alternative embodiments envisioned by the present invention. Both legs 24,26 are extended or retracted through the drive leg 24-e. g. , traditionally, the operator would manually operate a hand crank attached to the first leg. The second leg 26 will react to the operation of the first leg 24, for example through a connecting shaft 28. Accordingly, the operator can operate the entire landing gear through the first leg 24.

Each leg 24,26 includes an inner member 30, an outer member 32, and a base 34. The inner member 30 is telescopically received within the outer member 32.

The base 34 (e. g. , a foot) is connected to the lower end of the inner member 30. In operation, the inner member 30 is actuated from and within the outer member 32.

Actuation of the first and second legs 24,26 can be coordinated via the connecting shaft 28. Vertical support structures for tractor-trailer landing gear such as that shown in FIGS. 1 and 2 are well known to those skilled in the art, and are not discussed in further detail herein.

Referring to FIGS. 3 and 4, actuation of the inner member 30 with respect to the outer member 32 is effected by the actuation mechanism 12. In the embodiment shown, the actuation mechanism 12 is provided in each leg 24,26 and includes a bevel gear 36, and a threaded shaft 38 and nut 40 pair. The nut 40 is fixed to the upper end of the inner member 30 and receives the threaded shaft 38,

which is vertically disposed within the leg 24,26. The bevel gear 36 is attached to an end of the threaded shaft 38. A second bevel gear (not shown), disposed within the slave leg 26, is connected to the connecting shaft 28. A bevel gear is also present within the drive leg 24 as will be discussed below. In alternative <BR> <BR> embodiments, other gear arrangements (e. g. , a rack and pinion gear set, a worm<BR> gear arrangement, etc. ) can be used to convert motion of the drive mechanism 14 to linear motion. of the inner member 30 so that the inner and outer members 30,32 can be driven between a retracted position and an extended position as will be discussed below.

The outer member 32 of the drive leg 24 includes a first side 42 and a second side 44. The second side 44 faces the slave leg 26. The first side 42 faces the opposite direction. Disposed within the drive leg 24 is the drive mechanism 14 that includes a gear assembly 46, an input shaft 48, an output shaft 50, and an intermediate shaft 52. The gear assembly 46 includes an input gear 54, an output gear 56, a first intermediate gear 58, and a second intermediate gear 60. The input shaft 48 and the output shaft 50 are mounted in the outer member 32 axially in line with one another. The input shaft 48 has a first end 62 and a second end 64. The first end 62 of the input shaft 48 is adapted to receive a hand crank (not shown) on the first side 42 of the outer member 32. The second end 64 of the input shaft 48 extends through an opening in the first side 42 of the outer member 32 and into the interior of the outer member 32.

The output shaft 50 also has a first end 66 and a second end 68. The second end 68 of the output shaft 50 is operatively connected to the connecting shaft 28 on the second side 44 of the outer member 32. The connecting shaft 28 extends over to the slave leg 26. The first end 66 of the output shaft 50 extends through an opening in the second side 44 of the outer member 32 and into the interior of the outer member 32. The output gear 56 is attached to the output shaft 50. The output gear 56 includes a spur gear portion 70, a bevel gear portion 72, and a spline portion 74.

The bevel gear portion 72 of the output gear 56 is engaged with the bevel gear 36 of the actuation mechanism 12.

The input shaft 48 is adapted for axial movement within the outer member 32 between a first position (FIG. 3) and a second position (FIG. 4). An input gear 54 is attached to the input shaft 48 and moves with the input shaft 48 both rotationally and axially. The input gear 54 includes a spur gear portion 76 and a spline portion 78. In the first position, the spur gear portion 76 of the input gear 54 is engaged

with the first intermediate gear 58 (as will be discussed below) and disengaged from the output gear 56. In this position, the input shaft 48 and the output shaft 50 are not directly coupled. In the second position, the spur gear portion 76 of the input gear 54 is disengaged from the first intermediate gear 58 and the spline portion 78 of the input gear 54 is engaged with spline portion 74 of the output gear 56, thereby directly coupling the input shaft 48 and the output shaft 50.

The intermediate shaft 52 is mounted in the outer member 32, extending substantially parallel to the input and output shafts 48,50. The second intermediate gear 60 is engaged with the spur portion 70 of the output gear 56. When the input shaft 48 is in the first position (FIG. 3), wherein the input gear 54 is engaged with the first intermediate gear 58, the input shaft 48 is indirectly coupled with the output shaft 50 via the intermediate shaft 52. In other words, rotation of the input shaft 48 is transmitted to the input gear 54, which rotation is in turn transmitted to the first intermediate gear 58, intermediate shaft 52, and second intermediate gear 60. Rotation of the second intermediate gear 60, in turn, is transmitted to the output shaft 50 via the output gear 56. The gear ratios between the input shaft 48 <BR> <BR> and the output shaft 50 are a product of the gearing therebetween; e. g. , a low gear when the input shaft 48 is directly engaged with the output shaft 50, and a high gear when the input shaft 48 is indirectly engaged with the output shaft 50 via the intermediate shaft 52 and gears 58,60.

The connecting shaft 28 operatively connects the output shaft 50 of the drive leg 24 to an input shaft of the slave leg 26. The slave leg 26 preferably has the drive <BR> <BR> mechanism of known slave legs-i. e. , no intermediate shaft or shifting mechanism<BR> is needed. For example, the second leg can utilize a drive shaft (e. g. , the input shaft) and a bevel gear set such as that used for the actuation mechanism described herein.

The motor 16 is mounted on the second side 44 of the outer member 32 of the drive leg 24. The shaft 80 of the motor ("motor shaft") is connected to the intermediate shaft 52. In the embodiment shown in FIGS. 3 and 4, the motor 16 is attached to a bracket 82 secured to the outer member 32 and mates directly with the second intermediate gear 60, though the motor shaft 80 may be connected to the second intermediate gear 60 or the intermediate shaft 52 in a variety of ways.

Operation of the motor 16 causes rotation of the motor shaft 80, which in turn causes rotation of the intermediate shaft 52 and at least the second intermediate gear 60. The engagement between the second intermediate gear 60 and the output

gear 56 drives the actuation mechanism 12 in the drive leg 24, and causes rotation of the output shaft 50, which in turn drives the connecting shaft 28 to operate the actuation mechanism 12 of the slave leg 26. The input shaft 48 is bypassed in the power-assist mode. The attachment of the motor 16 to the intermediate shaft 52 does not affect the ability of the landing gear apparatus 10 to operate in the manual operation mode.

Referring to FIG. 5, the motor 16 is preferably a commercially available pneumatic gear motor that is powered by an external air source 84. An example of an acceptable pneumatic gear motor is a WADCO pneumatic gear motor model no.

33MA-220S1 produced by WADCO, a division of Ingersoll-Rand. Preferably, the motor 16 is a vane-type rotary driven motor having a gear reduction assembly with an 80-100 to 1 gear reduction ratio.

A variety of air sources 84 can be used for the preferred pneumatic motor 16.

For example, a compressed air storage cylinder can be attached to the trailer 22, or a local source of compressed air can be used. Preferably, the air source 84 is portable with the tractor-trailer so that it is readily available to operate the landing gear. In a preferred embodiment, the compressed air source 84 is the existing air supply from the emergency brake assembly of the tractor-trailer 22.

Referring to FIG. 5,. a tee connector 86 is provided on the emergency brake line to provide an airflow from the brake line to the motor 16. The tee connector has an input line 88 connected to the air source 84, a first output line 90 connected to the emergency brake system of the tractor-trailer 22, and a second output line 92 connected to the motor 16. The controller 18 is provided between the tee connector 86 and the motor 16 to control the flow of compressed air to the motor 16.

In a preferred embodiment, the controller 18 includes a valve 94. The valve 94 acts as an air shutoff valve that controls the direction and amount of air the motor 16 receives. In some embodiments, the valve 94 will only provide an airflow to the motor 16 if the valve 94 is manually opened and retained in the open position (e. g., by manually moving a spring-biased lever 96 as shown in FIG. 5). That is, air will be directed to the motor 16 if the operator moves and holds the lever 96. Once the lever 96 is returned to an"off"position, the air supply to the motor 16 will be shut off. If the lever 96 is released, the valve will automatically shut off. This prevents the valve from being left in a position where the air source 84 is connected only to the motor 16.

The valve 94 is also preferably a three-position valve that includes an "neutral"position, a first supply position ("down"), and a second supply position ("up"). As noted above, the valve 94 is biased to the"neutral"position. The lever 96 enables the operator to move the valve 94 between the"neutral"position and either of the first or second supply positions. The valve 94 is connected to the motor 16 such that air passing through the valve 94 when in the first supply <BR> <BR> position causes the motor 16 to rotate in a first direction (e. g. , clockwise) associated with downwardly extending the landing gear legs 24,26. Likewise, the valve 94 is connected to the motor 16 such that air passing through the valve 94 when its in the second supply position causes the motor 16 to rotate in a second direction (e. g., counterclockwise) associated with upwardly retracting the landing gear legs 24,26.

The specific directions identified herein are used for illustration purposes only, and the present invention is not intended to prescribe specific directions for specific actions (i. e. , clockwise may be used to retract the landing gear legs 24,26). The valve 94 employs one or more air escape ports that utilize mufflers to allow unneeded or excess air to escape. Pneumatic control valves 94 are known in the art and the operation thereof need not be discussed further herein.

In alternative embodiments, the valve 94 can be a power-assisted type control valve that utilizes one or more solenoids, for example to actuate the valve 94 to the first or second positions. Such a power-assisted valve 94 may be configured so that the user operates the valve 94 in proximity of the valve 94, or at <BR> <BR> a position remote from the valve 94 (e. g. , from the cab of the tractor-trailer). Even with such alternative valve designs, however, the valve 94 is preferably biased towards the"neutral"position., In a preferred embodiment, an automatic lubrication unit 98 (e. g. , an oil mist lubricator) is provided upstream of the motor 16, and more preferably upstream of the motor 16 and the valve 94. The lubricator 98 treats the air with a fine oil mist so that the valve 94 and the motor 16 are lubricated and so that they can operate efficiently. Automatic lubrication units 98 are known in the art and will not, therefore, be further described herein.

When it is desired to manually operate the landing gear legs 24,26 in the low gear, the input shaft 48 is axially moved to the first axial position (FIG. 3). Such outward axial movement causes the input gear 54 to engage the first intermediate gear 58, and the input shaft 48 to disengage from the output shaft 50. As a result, the input shaft 48 is not directly connected with the output shaft 50. Rotation of the

input shaft 48 causes the intermediate shaft 52 to rotate, and the intermediate shaft 52 causes the output shaft 50 to rotate as described above. The rotation of the output shaft 50 drives the actuation mechanism 12 to extend or retract the leg 24 depending on the direction of rotation of the input shaft 48, the intermediate shaft 52 and the output shaft 50. When it is desired to manually operate the landing gear legs 24,26 in the high gear, the input shaft 48 is axially moved to the second axial position (FIG. 4). Such outward axial movement causes the input gear 54 to disengage the first intermediate gear 58, and the input shaft 48 to engage the output shaft 50. As a result, the input shaft 48 is directly connected to the output shaft 50. Rotation of the input shaft 48 causes the output shaft 50 to rotate. The rotation of the output shaft 50 drives the actuation mechanism 12. In the manual operation mode, the input shaft 48 is driven by a hand crank (not shown) attached thereto. The hand crank is replaced by a knob 98 on the first end of the input shaft 62 when the landing gear is operated in a power-assist mode.

In the power-assist operation mode of the present invention, the tractor- trailer is parked and the operator then moves the control valve 94 into the supply position designated"down"for extending the landing gear legs 24,26. In the "down"position, the compressed air powers the motor 16, which in turn drives the drive mechanism 14, which in turn drives the actuation mechanisms 12 in both the drive leg 24 and the slave leg 26, resulting in actuation of the respective inner members 30 until the bases 34 for each leg 24,26, contact the ground. Once the desired position of the inner members 30 and the bases 34 is reached, the operator releases the valve lever 96 and the valve 94 automatically returns to the"neutral" position. When the operator elects to retract the landing gear, the valve 94 is moved into the supply position designated"up". In the"up"position, the compressed air powers the motor 16, and therefore the attached drive mechanism 14, in the opposite rotational direction as assumed for the"down"direction. As a result, the movement of the actuation mechanisms 12 of the drive and slave legs 24,26 are reversed and the respective inner members 30 are actuated upwardly within the outer members 32 to bring the bases 34 clear of the ground. Once a desired position of the inner members 30 and the bases 34 is reached, the operator releases the valve lever 96 and the valve 94 automatically returns to the"neutral" position.

If a compressed air source is not available, the present invention can be still used with the hand crank and the landing gear legs 24,26 can be manually

extended or retracted as desired in accordance with known practice. The drive mechanism 14 can be operated by rotating the input shaft 48. Such a capability is helpful in situations where the air source of the tractor-trailer must remain dedicated to the emergency brake line, or is not available.

Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail thereof may be made without departing from the spirit and scope of the invention.