초록 ▼

The trailer steering mechanism automatically steers the trailer wheels in accordance with the tow vehicle steering and articulation between the tow vehicle and trailer during backing maneuvers to facilitate backing maneuvers and to prevent or greatly reduce the possibility of jackknifing between tow

The trailer steering mechanism automatically steers the trailer wheels in accordance with the tow vehicle steering and articulation between the tow vehicle and trailer during backing maneuvers to facilitate backing maneuvers and to prevent or greatly reduce the possibility of jackknifing between tow vehicle and trailer. The mechanism includes a pivotally attached steering frame connected between the steerable wheels of the trailer and one or more hydraulic cylinders that, when locked, create a very strong link between the tow vehicle and the trailer and its steering system. An alternative embodiment employs two non-powered hydraulic cylinders in tandem. The cylinders are able to withstand great loads, and more importantly, are able to disengage while under great load without jamming. The cylinders provide links that exert lateral force to the trailer to push or pull the trailer into a turn while backing, in addition to controlling the steering mechanism of the trailer.

대표청구항 ▼

1. A sealed, pumpless hydraulic trailer steering mechanism for a trailer, the trailer having steerable wheels, a frame, and a rigid tongue pivotally attachable to a tow vehicle, the trailer steering mechanism comprising: a hydraulic steering cylinder having a selectively extendable rod and a cylinde

1. A sealed, pumpless hydraulic trailer steering mechanism for a trailer, the trailer having steerable wheels, a frame, and a rigid tongue pivotally attachable to a tow vehicle, the trailer steering mechanism comprising: a hydraulic steering cylinder having a selectively extendable rod and a cylinder base opposite the rod, the rod having a tow vehicle connection end;a double-rod hydraulic axle lock cylinder adapted for being immovably affixed to the trailer frame, the axle lock cylinder having a front rod directly connected to the cylinder base of the steering cylinder and a rear rod;a steering linkage adapted for connection between the axle lock cylinder and the steerable wheels of the trailer; anda hydraulic control valve communicating hydraulically with the steering cylinder and the axle lock cylinder, the control valve selectively opening hydraulic flow to the steering cylinder and closing hydraulic flow to the axle lock cylinder when in forward operating mode and closing hydraulic flow to the steering cylinder and opening hydraulic flow to the axle lock cylinder when in backing operating mode. 2. The trailer steering mechanism according to claim 1, further including a trailer, the trailer having a frame with at least one axle laterally disposed thereacross, the axle having first and second steerable wheels extending therefrom, the frame having a rigid tongue pivotally attachable to a tow vehicle. 3. The trailer steering mechanism according to claim 2, wherein said trailer axle has mutually opposed first and second spindles extending therefrom, the trailer steering mechanism further comprising first and second steering hubs mounted on the spindles, the hubs being connected to the steering linkage. 4. The trailer steering mechanism according to claim 1, wherein the axle lock cylinder comprises: an elongated cylindrical housing having end caps at opposing ends of the housing, the front and rear rods being slidably disposed through the end caps;a piston slidably disposed within the housing, the front and rear rods extending from the piston, the piston having at least one valve shaft passage disposed therethrough, the piston defining first and second hydraulic fluid chambers within the housing, the chambers having volumes varying according to movement of the rods and piston within the cylinder housing, the trailer wheels being aligned straight with the tow vehicle when the piston is centered between the end caps; andat least one valve shaft disposed within the axle lock cylinder, the at least one valve shaft extending axially between the end caps, the valve shaft passing through the valve shaft passage of the piston, the valve shaft having mutually opposed first and second relief portions defined therein and a seal portion disposed centrally between the relief portions, the seal portion selectively blocking hydraulic fluid flow through the piston when the piston is substantially centered in the cylinder housing so that the seal portion is seated in the valve shaft passage in the piston, the seal portion allowing hydraulic fluid flow along the relief portions and through the piston when the piston is axially offset within the cylinder housing so that the seal portion is not seated in the valve shaft passage. 5. The trailer steering mechanism according to claim 4, further including first and second helical springs coaxially disposed upon the front and rear rods, respectively, external to the housing, the front and rear rods having a distal end and a flange around the distal end, the springs being disposed between the end caps and the flanges, the spring biasing the piston to the center of the cylinder housing. 6. The trailer steering mechanism according to claim 1, wherein the control valve further includes: first and second flow passages selectively connected to the steering cylinder;first and second flow blocking ports selectively connected to the steering cylinder;third and fourth flow passages selectively connected to the axle lock cylinder;third and fourth flow blocking ports selectively connected to the axle lock cylinder; anda selector valve, the selector valve having a forward operating position simultaneously connecting the first and second flow passages to the steering cylinder and the third and fourth flow blocking ports to the axle lock cylinder, and a backing operating position simultaneously connecting the first and second flow blocking ports to the steering cylinder and the third and fourth flow passages to the axle lock cylinder. 7. The trailer steering mechanism according to claim 6, further including a plurality of pressure relief valves disposed within the first and second flow blocking ports to the steering cylinder and within the third and fourth flow blocking ports to the axle lock cylinder. 8. A sealed, pumpless hydraulic trailer steering mechanism and a steerable trailer, comprising in combination: a trailer having a frame and at least one axle laterally disposed across the frame, the axle having first and second steerable wheels extending therefrom and a steering linkage operably connected to the steerable wheels, the frame having a rigid tongue pivotally attachable to a tow vehicle:a hydraulic steering cylinder, the steering cylinder having a selectively extendable rod and a cylinder base opposite the rod, the rod having a tow vehicle connection end;a double-rod hydraulic axle lock cylinder immovably affixed to the trailer frame, the axle lock cylinder having a front rod directly connected to the cylinder base of the steering cylinder and a rear rod connected to the steering linkage; anda hydraulic control valve communicating hydraulically with the steering cylinder and the axle lock cylinder, the control valve selectively opening hydraulic flow to the steering cylinder and closing hydraulic flow to the axle lock cylinder when in forward operating mode and closing hydraulic flow to the steering cylinder and opening hydraulic flow to the axle lock cylinder when in backing operating mode. 9. The trailer steering mechanism and steerable trailer according to claim 8, further including: mutually opposed first and second spindles extending from the axle; andfirst and second steering hubs mounted on the wheel spindles, the hubs being connected to the steering linkage. 10. The trailer steering mechanism and steerable trailer according to claim 8, wherein the axle lock cylinder comprises: an elongated cylindrical housing having end caps at opposing ends of the housing, the front and rear rods being slidably disposed through the end caps;a piston slidably disposed within the housing, the front and rear rods extending from the piston, the piston having at least one valve shaft passage disposed therethrough, the piston defining first and second hydraulic fluid chambers within the housing, the chambers having volumes varying according to movement of the rods and piston within the cylinder housing, the trailer wheels being aligned straight with the tow vehicle when the piston is centered between the end caps; andat least one valve shaft disposed within the axle lock cylinder, the at least one valve shaft extending axially between the end caps, the valve shaft passing through the valve shaft passage of the piston, the valve shaft having mutually opposed first and second relief portions defined therein and a seal portion disposed centrally between the relief portions, the seal portion selectively blocking hydraulic fluid flow through the piston when the piston is substantially centered in the cylinder housing so that the seal portion is seated in the valve shaft passage in the piston, the seal portion allowing hydraulic fluid flow along the relief portions and through the piston when the piston is axially offset within the cylinder housing so that the seal portion is not seated in the valve shaft passage. 11. The trailer steering mechanism and steerable trailer according to claim 10, further including first and second helical springs coaxially disposed upon the front and rear rods, respectively, external to the housing, the front and rear rods having a distal end and a flange around the distal end, the springs being disposed between the end caps and the flanges, the spring biasing the piston to the center of the cylinder housing. 12. The trailer steering mechanism and steerable trailer according to claim 8, wherein the control valve further includes: first and second flow passages selectively connected to the steering cylinder;first and second flow blocking ports selectively connected to the steering cylinder;third and fourth flow passages selectively connected to the axle lock cylinder;third and fourth flow blocking ports selectively connected to the axle lock cylinder; anda selector valve, the selector valve having a forward operating position simultaneously connecting the first and second flow passages to the steering cylinder and the third and fourth flow blocking ports to the axle lock cylinder, and a backing operating position simultaneously connecting the first and second flow blocking ports to the steering cylinder and the third and fourth flow passages to the axle lock cylinder. 13. The trailer steering mechanism and steerable trailer according to claim 12, further including a plurality of pressure relief valves disposed within the first and second flow blocking ports to the steering cylinder and within the third and fourth flow blocking ports to the axle lock cylinder. 14. A trailer steering kit for a trailer, the trailer having a frame, a rigid tongue pivotally attachable to a tow vehicle, and at least one axle laterally disposed across the frame, the axle having first and second wheel spindles extending therefrom, the spindles each having a wheel removably attached thereto, the trailer steering kit comprising; a hydraulic steering cylinder having a selectively extendable rod and a cylinder base opposite the rod, the rod having a tow vehicle connection end;a double-rod hydraulic axle lock cylinder adapted for being immovably affixed to the trailer frame, the axle lock cylinder having a front rod directly to connected to the cylinder base of the steering cylinder and a rear rod;a hydraulic control valve adapted for operable connection with the steering cylinder and the axle lock cylinder;a steering linkage adapted for attachment to the axle of the trailer frame, the rear rod being attached to the steering linkage; andfirst and second steering hubs adapted for installation upon the wheel spindles, the hubs being connected to the steering linkage. 15. The trailer steering kit according to claim 14, further including a trailer, the trailer having a frame and at least one axle laterally disposed across the frame, the axle having first and second steerable wheels extending therefrom, the frame having a rigid tongue pivotally attachable to a tow vehicle. 16. The trailer steering kit according to claim 14, wherein the axle lock cylinder comprises: an elongated cylindrical housing having end caps at opposing ends of the housing, the front and rear rods being slidably disposed through the end caps;a piston slidably disposed within the housing, the front and rear rods extending from the piston, the piston having at least one valve shaft passage disposed therethrough, the piston defining first and second hydraulic fluid chambers within the housing, the chambers having volumes varying according to movement of the rods and piston within the cylinder housing, the trailer wheels being aligned straight with the tow vehicle when the piston is centered between the end caps; andat least one valve shaft disposed within the axle lock cylinder, the at least one valve shaft extending axially between the end caps, the valve shaft passing through the valve shaft passage of the piston, the valve shaft having mutually opposed first and second relief portions defined therein and a seal portion disposed centrally between the relief portions, the seal portion selectively blocking hydraulic fluid flow through the piston when the piston is substantially centered in the cylinder housing so that the seal portion is seated in the valve shaft passage in the piston, the seal portion allowing hydraulic fluid flow along the relief portions and through the piston when the piston is axially offset within the cylinder housing so that the seal portion is not seated in the valve shaft passage. 17. The trailer steering kit according to claim 16, further including first and second helical springs coaxially disposed upon the front and rear rods, respectively, external to the housing, the front and rear rods having a distal end and a flange around the distal end, the springs being disposed between the end caps and the flanges, the spring biasing the piston to the center of the cylinder housing. 18. The trailer steering kit according to claim 14, wherein the control valve further includes: first and second flow passages selectively connected to the steering cylinder;first and second flow blocking ports selectively connected to the steering cylinder;third and fourth flow passages selectively connected to the axle lock cylinder;third and fourth flow blocking ports selectively connected to the axle lock cylinder; anda selector valve, the selector valve having a forward operating position simultaneously connecting the first and second flow passages to the steering cylinder and the third and fourth flow blocking ports to the axle lock cylinder, and a backing operating position simultaneously connecting the first and second flow blocking ports to the steering cylinder and the third and fourth flow passages to the axle lock cylinder. 19. The trailer steering kit according to claim 18, further including a plurality of pressure relief valves disposed within the first and second flow blocking ports to the steering cylinder and within the third and fourth flow blocking ports to the axle lock cylinder.