Self steering tandem hitch

• US 5,725,230 A
• Filed: 06/17/1996
• Issued: 03/10/1998
• Est. Priority Date: 06/17/1996
• Status: Expired due to Fees

• Current Assignee: Joseph L. Walkup
• Original Assignee: Joseph L. Walkup
• Inventors: Walkup, Joseph L.
• Primary Examiner(s): AVILA, STEPHEN P
• Application Number:
  US08/665,335
• Time in Patent Office: 631 Days
• Field of Search: 280/416.1, 280/416.2, 280/416.3, 280/419, 280/433, 280/441, 280/442, 280/453, 280/426, 280/432, 280/445
• US Class Current: 280/442
• CPC Class Codes: B62D 13/04 for individually-pivoted wheels

Abstract

A tandem hitch that automatically steers a second implement so it will properly trail a first implement around corners. The hitch attaches to a tractor'"'"'s three point hookup, so it is held stationary on the tractor. The first implement or attachment attaches to the back of the tractor. The second implement or implement attaches to the back of the self steering tandem hitch.

A first steering apparatus maintains the implement in a proper following position during cornering by rotating the rear wheel assembly. The whole wheel assembly is rotated by the steering apparatus for proper following positioning. Without the automatic steering the second implement would underswing or overswing leaving an area untouched. The steering action accomplished by this device steers the second implement to give a true and correct trailing of the second implement.

The self steering tandem hitch is generally described as having a front upright support, a main beam, a rear upright support, an axle assembly, a first steering apparatus and a second steering apparatus. The bottom end of the front upright support is attachable to a three point hitch on a tractor. The main beam is pivotally and rotatably attached to the top end of the front upright support. The rear upright support is attached to the rear end of the main beam. The axle assembly is rotatably attached to the lower end of rear upright support. The first steering apparatus rotates the wheel assembly in respect to the main beam to automatically steer the rear end of the self steering tandem hitch during turning and cornering. The rotation of the wheel assembly during turning and cornering maintains alignment of a second farm implement attached to the rear end of the self steering tandem hitch. A first farm implement being attached directly to the tractor. The second steering apparatus pivots the wheels to hold and maintain the second or rear farm implement in a left or right offset position.

Claims

1. A self steering tandem hitch comprising:

a first upright support shaft having a top end and a bottom end, said first upright support having an attachment device attachable to a tractor;

a pivot joint attached to said top end of said first upright support shaft;

a front bottom twist plate having a top surface and bottom surface, said bottom surface attached to said pivot joint;

a front shaft having a bottom end and a top end, said bottom end attached to a center area of said top surface of said front bottom twist plate, said front shaft extending upward in an inline parallel alignment with said first upright support;

a front top twist plate having a center opening, top surface and a bottom surface that rests and rotates upon said top surface of said front bottom twist plate, said front shaft extending through said center opening on said front top twist plate;

a front tube having a top end, bottom end and side wall, said front tube installed over said front shaft with said bottom end rigidly attached to said top surface of said front top twist plate, said top end of said front shaft extending through said top end of said front tube, said front tube rotatable about said front shaft;

a main beam having a front end, rear end and center portion, said front end attached to said side wall of said front tube, said main beam extending perpendicular from said front tube;

a rear upright tube having a top end, bottom end and side wall, said side wall of said rear upright tube attached to said rear end of said main beam in a perpendicular relationship;

an upper rear twist plate rigidly attached to said bottom end of said rear upright tube, said upper rear twist plate having a center opening and a bottom surface;

a rear shaft insertable into and rotatable within said rear upright tube, said rear shaft having a top end and bottom end, said top end of said rear shaft extending through said top end of said rear upright tube and said bottom end of said rear shaft extending through said bottom end of said rear upright tube;

a bottom rear twist plate rigidly attached to said bottom end of said rear shaft, said bottom rear twist plate having a top surface and bottom surface, said top surface contacts and rotates upon said bottom surface of said upper rear twist plate;

an axle having wheels rigidly attached to said bottom surface of said bottom rear twist plate, said axle being rotatable in respect to said main beam by said rear shaft rotating within said rear upright tube;

an attachment means on said axle for attachment of a second farm implement;

a steering device attached to said axle to pivot said wheels on said axle in respect to said axle to cause a rear end of said self steering tandem hitch to maintain a left or right offset position, amount of said offset being determined by amount of pivot of said wheel in respect to said axle;

a front sprocket rigidly fixed to said top end of said front shaft, said front sprocket being rotated in respect to said main beam as the tractor on which said self steering tandem hitch is being used negotiates turns, said front sprocket being non-rotatable in respect to the tractor;

a rear sprocket rigidly fixed to said top end of said rear shaft, said rear sprocket having a predetermined gear ratio to said front sprocket, said rear shaft and said axle rotate as said rear sprocket rotates; and

a steering apparatus around and joining said front sprocket and said rear sprocket, said steering apparatus configured to rotate said rear sprocket in an opposite direction of said front sprocket as said front sprocket rotates thereby maintaining alignment of said second farm implement to a first farm implement attached to the tractor as the tractor negotiates turns and corners.

2. The self steering tandem hitch as set forth in claim 1 in which said attachment device comprises an inverted T attachment device, said inverted T attachment device attached to a lower end of said first upright support and adapted to attach said self steering tandem hitch to a three point hitch on a tractor.

3. The self steering tandem hitch as set forth in claim 1 in which said attachment device comprises an offset hookup device attachable to a tractor'"'"'s three point hitch, said offset hookup device comprising a frame member supporting a top cross member, a multi-position receiver on the top of said top cross member, and a hookup plate, said hookup plate rigidly attached a lower end of said first upright support, said hookup plate being attachable to said multi-position receiver in any one of a plurality of positions to provide an offset of an implement attached to said self steering tandem hitch.

4. The self steering tandem hitch as set forth in claim 3 in which said multi-position receiver further comprises a channel on which said hookup plate may slide, said hookup plate being secured at any position along said channel.

5. The self steering tandem hitch as set forth in claim 1 in which said pivot joint comprises a standard universal joint with attachment means.

6. The self steering tandem hitch as set forth in claim 1 in which said pivot joint comprises a yoke rigidly attached to said top end of said first upright support, a pivot pin rotatably installed in said yoke and a second yoke rigidly attached to said bottom surface of said front top twist plate, said second yoke being pivotally attached to said pivot pin.

7. The self steering tandem hitch as set forth in claim 1 in which said attachment device on said axle is a standard implement hitch attached in a fixed position on said axle.

8. The self steering tandem hitch as set forth in claim 1 in which said attachment device on said axle comprises a sliding hitch attached to said axle, said sliding hitch providing attachment of a farm implement any point along said sliding hitch to provide an offset for the implement.

9. The self steering tandem hitch as set forth in claim 1 further comprising additional support members, said support members attached to said main beam and extends down to and are attached to said rear upright tube to provide additional rigid support and structural strength to said self steering tandem hitch.

10. The self steering tandem hitch as set forth in claim 1 in which said steering device on said axle comprises pivot means for each wheel on said axle to allow said wheels to pivot in respect to said axle, tie rods attached to each pivot means, a cross link pivotally attached to and connecting said tie rods and a control device attached to said axle and to said cross link, said control device controlling travel position of said cross link in respect to said axle, said wheels pivot as said cross link travels.

11. The self steering tandem hitch as set forth in claim 10 in which said control device comprises a hydraulic cylinder.

12. The self steering tandem hitch as set forth in claim 10 in which said control device comprises a receiving plate having a plurality of holes attached in a parallel relationship to said axle, a second plate having plurality of holes attached to said cross link, and a locking pin, said locking pin extending through one of said holes on said second plate and one of said holes on said receiving plate to lock said cross link in a fixed position in respect to said axle.

13. The self steering tandem hitch as set forth in claim 1 in which said steering apparatus comprises a first chain, a first cable attached to one end of said first chain, a second chain attached to the other end of said first cable, a second cable attached to the other end of said second chain with the other end of said second cable being attached to a free end of said first chain to form a continuous chain/cable line, and a center idler pulley attached to said center portion of said main beam, said first chain interacting with teeth on said front sprocket, said second chain interacting with teeth on said rear sprocket, said chain/cable line being crossed at a point between said front sprocket and said rear sprocket to rotate said sprockets in opposite directions, said chain/cable line riding within said idle pulley to prevent entanglement of said chain/cable line.

14. A self steering tandem hitch comprising:

a front upright support having a top end and a bottom end, said bottom end being attachable to a tractor;

a main beam having a front end and rear end, said front end pivotally and rotatably attached to said top end of said front upright support;

a rear upright support having an upper end and a lower end attached to said rear end of said main beam;

an axle assembly rotatably attached to said lower end of said rear upright support, said axle assemble having wheels pivotally attached to said axle assembly;

a first steering apparatus rotating said axle assembly in respect to said main beam as the tractor negotiates corners and turns to maintain alignment of a second farm implement attached to a rear end of said self steering with a first farm implement attached to the tractor;

a second steering apparatus for pivoting said wheels in respect to said axle assembly to provide and maintain said rear end of said self steering tandem hitch in a left or right offset position.

15. The self steering tandem hitch as set forth in claim 14 in which said first steering device comprises;

a front sprocket fixed in respect to said front upright support so that said main beam rotates in respect to said front sprocket;

a rear sprocket fixed to said axle assembly so that as said rear sprocket rotates in respect to said main beam said axle assembly rotates in respect to said main beam; and

a steering link connecting said front sprocket and said rear sprocket so that as said main beam rotates about said front upright support said rear sprocket rotates to rotate said axle assembly.

16. The self steering tandem hitch as set forth in claim 14 in which said second steering apparatus comprises a hydraulic cylinder, tie rods and cross link attached to the axle assembly to pivot and hold said wheels in a fixed position.

17. The self steering tandem hitch as set forth in claim 14 further comprising a stand, said stand extending through an opening in said main beam, said stand being lockable in an upper position for an in-use position and a lower position to support said self steering tandem hitch when disconnected from a tractor.

18. A self steering tandem hitch comprising:

a front upright support having a top end and a bottom end, said bottom end being attachable to a tractor;

a main beam having a front end and rear end, said front end pivotally and rotatably attached to said top end of said front upright support;

a rear upright support having an upper end and a lower end attached to said rear end of said main beam;

an axle assembly rotatably attached to said lower end of said rear upright support, said axle assemble having wheels pivotally attached to said axle assembly;

a first steering apparatus comprising a front sprocket fixed in respect to said front upright support so that said main beam rotates in respect to said front sprocket, a rear sprocket fixed to said axle assembly so that as said rear sprocket rotates in respect to said main beam said axle assembly also rotates in respect to said main beam, and a steering line connecting said front sprocket and said rear sprocket so that as said main beam rotates about said front upright support said rear sprocket rotates to rotate said axle assembly to maintain alignment of a second farm implement attached to a rear end of said self steering with a first farm implement attached to the tractor;

a second steering apparatus comprising a hydraulic cylinder, tie rods and cross link attached to the axle assembly to pivot and hold said wheels in a fixed position and to provide and maintain said rear end of said self steering tandem hitch in a left or right offset position.