Hydraulic power lift system for tractor and implement

Claim 2

A tractor and implement arrangement in which the tractor includes pivotally mounted trailing draft links, tractor-mounted hydraulic motor means for raising and lowering the draft links, a source of fluid pressure for the motor means, and a control valve for controlling the flow of fluid from the source to the motor means, and the implement comprises a transversely elongated frame formed from a plurality of frame sections pivotally connected at adjoining ends for independent vertical movement, means connecting one of the frame sections to the trailing ends of the tractor draft links to be raised and lowered thereby, a plurality of lift assist wheels adjustably mounted on the frame with at least one lift assist wheel being mounted on each frame section not connected to the tractor draft links, a plurality of hydraulic motors mounted on the frame and operatively connected to the wheels to raise and lower the frame relative to the wheels, and fluid line means connecting the control valve, implement-mounted motors and tractor-mounted motor means in series so that the frame section connected to the draft links is movable vertically in unison with and in substantially equal amounts as the frame sections not connected to the draft links.

Claim 3

The tractor and implement arrangement set forth in claim 1 wherein the tractor-mounted motor means and implement-mounted motors are extensible and retractable cylinders having anchor and rod ends with the anchor end of each cylinder having an effective cross-sectional area greater than the effective cross-sectional area of the rod end of the cylinder, the fluid line means interconnects the rod end of each implement-mounted cylinder with the anchor end of another cylinder, the anchor end of the first cylinder in series when raising the implement with the control valve and the rod end of the last implement-mounted cylInder in series when raising the implement with the tractor-mounted cylinder.

Claim 4

The tractor and implement arrangement set forth in claim 2 wherein the rod end of each implement-mounted cylinder has an effective cross-sectional area substantially equal to the effective cross-sectional area of the anchor end of the implement-mounted cylinder to which it is connected by the fluid line means.

Claim 5

The tractor and implement arrangement set forth in claim 3 wherein each of the implement-mounted cylinders is provided with bypass circuit means which allows free flow of fluid through the cylinder when the cylinder has been moved to its limit in one direction, and wherein a pressure relief valve is provided in the fluid line means between the tractor-mounted cylinder and the last cylinder in the series of implement-mounted cylinders.

Claim 6

The tractor and implement arrangement set forth in claim 3 wherein each of the cylinders is provided with a bypass circuit means which affords free flow of fluid through the cylinder when it has been moved to its limit in one direction.

Claim 7

The tractor and implement arrangement set forth in claim 5 further including a pressure relief valve provided in the further fluid line means between the tractor-mounted cylinder and the last cylinder in the series of implement-mounted cylinders.

Claim 8

The tractor and implement arrangement set forth in claim 1 wherein an additional fluid line means interconnects the source of fluid pressure and the fluid line means between the tractor-mounted motor means and the last motor in the series of implement-mounted motors, and wherein a manual directional flow control valve is provided in the additional fluid line means.

Claim 9

The tractor and implement arrangement set forth in claim 1 wherein the forward portion of the one frame section is pivotally connected to and supported by the tractor draft links and the rearward portion of the one frame section is supported by one of the plurality of lift assist wheels.

Claim 10

A tractor and implement arrangement in which the tractor has draft links pivotally mounted to the rear of the tractor in trailing relationship, tractor-mounted hydraulic motor means for raising and lowering the draft links, a source of fluid pressure, a control valve for controlling the flow of fluid from the source, a pair of remote hydraulic motor outlets, and a selector valve movable between a first position in which it interconnects the control valve and hydraulic motor means and a second position in which it interconnects the control valve with one remote motor outlet and the motor means with the other remote motor outlet, and the implement comprises a transversely elongated frame having a center section mounted medially its ends to the trailing ends of the draft links, a pair of outrigger sections pivotally connected to the sides of the center section for independent vertical movement about generally horizontal axes, a plurality of lift assist wheels, means connecting the lift assist wheels to the frame for vertical movement relative thereto, there being at least one lift assist wheel connected to each outrigger section, a plurality of hydraulic motors mounted on the frame and operatively connected to the lift assist wheels to raise and lower the frame relative to the wheels, fluid line means connecting the plurality of hydraulic motors in series, and further fluid line means connecting the hydraulic motors with the remote motor outlets on the tractor.

Claim 11

A tractor and implement arrangement in which the tractor has draft links pivotally mounted to the rear of the tractor in trailing relationship, tractor-mounted hydraulic motor means for raising and lowering the draft links, a source of fluid pressure, a control valve for controlling the flow of fluid from the source, a pair of remote hydraulic motor outlets, and a selector valve movable between a first position in which it interconnects the control valve and hydraulic motor means and a second position in which it interconnects the control valve with one remote motor outlet and the motor means with the other remote motor outlet, and the implement comprises a transversely elongated frame having a center section mounted medially its ends to the trailing ends of the draft links, a pair of outrigger sections pivotally connected to the sides of the center section for independent vertical movement about generally horizontal axes, a plurality of lift assist wheels, means connecting the lift assist wheels to the frame for vertical movement relative thereto, there being at least one lift assist wheel connected to each outrigger section, a plurality of hydraulic motors mounted on the frame and operatively connected to the lift assist wheels to raise and lower the frame relative to the wheels, fluid line means connecting the plurality of hydraulic motors in series, and further fluid line means connecting the hydraulic motors with the remote motor outlets on the tractor.

Claim 12

The tractor and implement arrangement set forth in claim 9 wherein each of the frame-mounted hydraulic motors is a double-acting extensible and retractable hydraulic cylinder having a rod end and an anchor end, and the tractor-mounted hydraulic motor means includes an extensible and retractable hydraulic cylinder having a rod end and an anchor end.

Claim 13

The tractor and implement arrangement set forth in claim 10 wherein the further fluid line means connects the anchor end of the first frame-mounted cylinder in series when raising the framEs with the one remote motor outlet and the rod end of the last frame-mounted cylinder in series when raising the frames with the other remote motor outlet, and wherein the first-mentioned fluid line means connects the rod end of each cylinder in series with the anchor end of the next adjacent cylinder in series.

Claim 14

The tractor and implement arrangement set forth in claim 11 wherein the rod end of each frame-mounted cylinder has a displacement substantially equal to the displacement of the anchor end of the cylinder to which it is connected by the first-mentioned fluid line means.

Claim 15

The tractor and implement arrangement set forth in claim 12 wherein each of the cylinders is provided with a bypass circuit means which affords free flow of fluid through the cylinder when it has been moved to its limit in one direction.

Claim 16

The tractor and implement arrangement set forth in claim 13 wherein a pressure relief valve is provided between the other remote motor outlet and the tractor-mounted cylinder.

Claim 17

The tractor and implement arrangement set forth in claim 10 wherein each frame-mounted cylinder is provided with a fluid bypass circuit means which affords the free flow of fluid through the cylinder when the cylinder is fully extended, and wherein a pressure relief valve is provided between the other remote motor outlet and the tractor-mounted cylinder.

Claim 18

The tractor and implement arrangement set forth in claim 9 wherein means are provided to selectively supply and exhaust fluid to the fluid line means between each pair of adjacent motors.

Claim 19

The tractor and implement arrangement set forth in claim 9 wherein means are provided to selectively supply and exhaust fluid between the tractor-mounted motor means and the frame-mounted motor which is last in the series when raising.

Claim 20

The tractor and implement arrangement set forth in claim 9 wherein the means mounting the lift assist wheels on the outrigger sections extend forwardly of the frame to position the lift assist wheels mounted on the outrigger sections in advance of the frame.

Claim 21

The combination of a tractor having a pair of pivotally mounted trailing draft links, an upper pivotally mounted trailing compression link, hydraulic cylinder means operatively connected to and for raising and lowering the draft links, a source of fluid pressure and a control valve for controlling the flow of fluid pressure from the source, and means carried by the tractor and responsive to the draft forces imposed upon the tractor to move the control valve from a neutral position upon variation from a selected draft force, and a tillage implement having a flexible frame including a center frame section carried by the draft and compression links, a pair of outrigger frame sections pivotally connected to the center frame section for independent vertical movement about generally longitudinally extending axes; a pair of lift assist wheels, means mounting the lift assist wheels on the outrigger frame sections for vertical movement relative thereto; a pair of extensible and retractable hydraulic cylinders mounted on the outrigger frame sections and operatively connected to the lift assist wheels to raise and lower the outrigger frame sections relative to the wheels, and means connecting the control valve, the frame-mounted hydraulic cylinders and the tractor hydraulic cylinder means in series so that each of said frame sections is raised and lowered in unison with the other frame sections in accordance with the total draft load on the draft links.

Claim 22

The combination of a tractor having a pair of pivotally mounted trailing draft links, an upper pivotally mounted trailing compression link, hydraulic cylinder means operatively connected to and for raising and lowering the draft links, a source of fluid pressure and a control valve for controlling the flow of fluid pressure from the source, and means carried by the tractor and responsive to the draft forces imposed upon the tractor to move the control valve from a neutral position upon variation from a selected draft force, and a tillage implement having a flexible frame including a center frame section carried by the draft and compression links, a pair of outrigger frame sections pivotally connected to the center frame section for independent vertical movement about generally longitudinally extending axes; a pair of lift assist wheels, means mounting the lift assist wheels on the outrigger frame sections for vertical movement relative thereto; a pair of extensible and retractable hydraulic cylinders mounted on the outrigger frame sections and operatively connected to the lift assist wheels to raise and lower the outrigger frame sections relative to the wheels, and means connecting the control valve, the frame-mounted hydraulic cylinders and the tractor hydraulic cylinder means in series so that each of said frame sections is raised and lowered in unison with the other frame sections in accordance with the total draft load on the draft links.

Claim 23

The combination set forth in claim 19 wherein the frame-mounted cylinders are connected to the tractor hydraulic power lift system in series between the control valve and tractor-mounted hydraulic cylinder means, and a pressure relief valve is provided between the tractor-mounted hydraulic cylinder means and the last in the series of implement-mounted hydraulic cylinders.

Claim 24

The combination set forth in claim 19 wherein the means mounting the lift assist wheels on the outRigger frame sections includes link means extending forwardly of the sections to position the lift assist wheels in substantially transverse alignment with the rear wheels of the tractor.

Claim 25

A tractor and implement arrangement in which the tractor includes a pair of pivotally mounted trailing draft links and a pivotally mounted trailing compression link forming a three-point hitch, a tractor-mounted hydraulic motor means for raising and lowering the trailing ends of the draft links, a source of fluid pressure for the motor means, and a control valve for controlling the flow of fluid from the source to the motor means, and the implement comprises an elongated frame extending transversely of the tractor with its ends extending beyond the sides of the tractor, means integrally connecting the frame medially its ends to the trailing ends of the draft and compression links, a plurality of lift assist wheels adjustably connected to the frame with a pair thereof mounted adjacent the ends of the frame, a plurality of hydraulic motors mounted on the frame and operatively connected to the wheels to raise and lower the frame on the wheels, and fluid line means connecting the control valve, implement-mounted motors and tractor-mounted motor means in series so that the wheels will vertically adjust the respective ends of the frame in unison with the three-point hitch vertically adjusting the medial position of the frame.

Claim 26

A tractor and implement arrangement in which the tractor includes a pair of pivotally mounted trailing draft links and a pivotally mounted trailing compression link forming a three-point hitch, a tractor-mounted hydraulic motor means for raising and lowering the trailing ends of the draft links, a source of fluid pressure for the motor means, and a control valve for controlling the flow of fluid from the source to the motor means, and the implement comprises an elongated frame extending transversely of the tractor with its ends extending beyond the sides of the tractor, means integrally connecting the frame medially its ends to the trailing ends of the draft and compression links, a plurality of lift assist wheels adjustably connected to the frame with a pair thereof mounted adjacent the ends of the frame, a plurality of hydraulic motors mounted on the frame and operatively connected to the wheels to raise and lower the frame on the wheels, and fluid line means connecting the control valve, implement-mounted motors and tractor-mounted motor means in series so that the wheels will vertically adjust the respective ends of the frame in unison with the three-point hitch vertically adjusting the medial position of the frame.

Claim 27

The tractor and implement arrangement set forth in claim 22 wherein the implement frame includes a plurality of frame sections pivotally connected at adjoining ends for independent vertical movement, wherein one of the sections is connected to and carried by the tractor draft links, and wherein the remaining sections are supported by the vertically adjustable lift assist wheels.

Claim 28

The tractor and implement arrangement set forth in claim 22 wherein the implement frame includes a center frame section connected to and supported solely by the draft links and a pair of outrigger frame sections pivotally connected to the center frame section for independent vertical movement, and wherein each of the outrigger frame sections is supported by one of the plurality of lift assist wheels.

Claim 29

The tractor and implement arrangement set forth in claim 24 wherein the lift assist wheels supporting the outrigger frame sections are connected to the outrigger frame sections by four-bar linkages which extend forwardly of the frame.