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A ground engaged vehicle includes a front portion and a rear portion joined by an articulation. The articulation rotates around a longitudinal axis. An engine drives a hydrostatic pump which drives four hydrostatic motors, each of the hydrostatic motors in operative engagement with one of four wheel

A ground engaged vehicle includes a front portion and a rear portion joined by an articulation. The articulation rotates around a longitudinal axis. An engine drives a hydrostatic pump which drives four hydrostatic motors, each of the hydrostatic motors in operative engagement with one of four wheels. The wheels are on wheel mounts, each of the wheel mounts having a vertical axis around which one of the four wheels with one of the hydrostatic motors is turnable. A steering system turns the two wheels of the front portion in a first direction and the two wheels of the rear portion in an opposite direction. The steering system is powered by the hydrostatic pump. A pedal control system has a first pedal controlling driving the vehicle in a forward direction and a second pedal controlling driving the vehicle in a rearward direction.

대표청구항 ▼

1. A ground engaged vehicle comprising: a front portion,a rear portion, said front and rear portion being joined by an articulation, said articulation rotating around a longitudinal axis of said vehicle;a hydrostatic drive system driving each of four wheels;at least two wheels being mounted on one o

1. A ground engaged vehicle comprising: a front portion,a rear portion, said front and rear portion being joined by an articulation, said articulation rotating around a longitudinal axis of said vehicle;a hydrostatic drive system driving each of four wheels;at least two wheels being mounted on one of said front portion or said rear portion and at least one other wheel being mounted on the other of said front portion or said rear portion;each of said wheels being mounted on a hydrostatic motor and each of said hydrostatic motors being fixedly mounted on a rotating, substantially vertical axis;said hydrostatic drive system having a high gear and a low gear;said wheels having an operational internal tire pressure of at or below about 10 psi andeach of said wheels being mounted without suspension;whereby said articulation and said low pressure tires providing shock absorption and substantially continuous ground contact for each of said wheels in both said high and low gear; anda valve assembly, said valve assembly having two intake ports and four output ports, said valve assembly having a first position and a second position, said first position directing hydrostatic fluid out of a first pair of output ports and said second position driving a hydrostatic fluid out of a second pair of output ports. 2. The vehicle of claim 1 wherein each of said wheel mounts is comprised of: a vertical cylinder fixedly mounted to one of said front portion or said rear portion;a vertical rod journaled into said cylinder such that said rod may rotate within said cylinder around a vertical axis; anda wheel mounting bracket fixedly attached to said vertical rod and adapted for receiving a wheel mounting. 3. The vehicle of claim 1 wherein said wheel mount includes a bracket, said bracket being adapted for mounting a hydrostatic drive motor such that said hydrostatic drive motor is in driving operative engagement with a wheel mounted on said wheel mount. 4. The vehicle of claim 1 wherein disc brakes are mounted on said wheel mounts. 5. The vehicle of claim 1 wherein said mount includes a vertical rod mounted to rotate around a vertical axis, and a lever arm fixedly attached to a top end of said vertical rod and adapted for pivoting engagement with a steering linkage. 6. The vehicle of claim 1 further comprising 15 inch wheels being mounted on said wheel brackets. 7. The vehicle of claim 1 wherein said hydrostatic drive system powers four wheels in diagonal pairs. 8. The vehicle of claim 1 wherein said hydrostatic drive system has a high gear and a low gear in each of a forward and a reverse direction. 9. The vehicle of claim 1 wherein said hydrostatic drive system has a low gear and a high gear, said hydrostatic drive system driving each of said hydrostatic motors in diagonal pairs in said low gear and said hydrostatic drive system driving all four hydrostatic motors in said high gear. 10. The vehicle of claim 1 wherein said hydrostatic drive system drives a first diagonal pair of said four hydrostatic motors with a first fluid volume, thereafter returning the first fluid volume to a hydrostatic pump and simultaneously drives the opposite diagonal pair of hydrostatic motors with a second fluid volume, thereafter returning said second fluid volume to said hydrostatic pump. 11. The vehicle of claim 1 wherein when in a low gear, said hydrostatic drive system drives a first diagonal pair of said four hydrostatic motors with a first fluid volume, thereafter returning the first fluid volume to a hydrostatic pump and simultaneously drives the opposite diagonal pair of hydrostatic motors with a second fluid volume, thereafter returning said second fluid volume to said hydrostatic pump; and when in a high gear a single volume of fluid drives all four hydrostatic motors before being returned to pump. 12. The vehicle of claim 1 wherein when a valve assembly is in said first position a first volume of hydrostatic fluid is directed to a first diagonal pair of said hydrostatic motors and then returned to the pump and a second volume of hydrostatic fluid is directed to an opposite diagonal pair of hydrostatic motors and then returned to the pump. 13. The vehicle of claim 12 wherein when a valve assembly is in a second position a single fluid volume is directed to all four hydrostatic motors before being returned to the pump. 14. The vehicle of claim 1 further comprising a flow divider in operative communication to receive pressurized fluid from a pump and in operative communication to direct fluid to diagonal pairs of hydrostatic motors. 15. The vehicle of claim 1 further comprising a pedal assembly and a lever, a first side of said lever being operatively connected to a forward drive control of said hydrostatic drive system and a second end of said lever being operatively connected to a rearward drive of said hydrostatic drive system. 16. The vehicle of claim 15 further comprising teeth on said pedals engaging slots in a disc, each of said slots being configured such that the sides of said slots receiving pressure from said teeth of said pedals are convex inwards. 17. The vehicle of claim 1 further comprises at least two cooling ports for an engine compartment, said engine compartment housing an internal combustion engine in operative engagement with a pump for said hydrostatic drive system. 18. A ground engaged vehicle comprising: a front portion having two wheels; a rear portion having two wheels;an articulation between said front portion and said rear portion, said articulation allowing said front portion and said rear portion to rotate relative to one another around an axis longitudinal to the vehicle;each of said wheels being mounted on a hydrostatic motor and each of said hydrostatic motors being fixedly mounted on a rotating, substantially vertical axis;said hydrostatic drive system disposed to drive each of said hydrostatic motors;said wheels having an operational internal tire pressure of at or below about 10 psi;each of said wheels being mounted without suspension; andeach of said four wheels being steerable;whereby said articulation and said low pressure tires providing shock absorption and substantially continuous ground contact for each of said wheels; wherein said two wheels on said front portion are connected to each other by a front tie rod, said front tie rod having a first end and second end, each of said first and second ends of said front tie rod being pivotably attached to a front lever arm, each of said lever arms being operatively engaged to turn each of said two wheels of said front portion, said front tie rod being driven by a front two way piston and cylinder assembly;said two wheels on said rear portion are connected to each other by a rear tie rod, said rear tie rod having a first end and second end, each of said first and second ends of said rear tie rod being pivotably attached to a front lever arm, each of said lever arms being operatively engaged to turn each of said two wheels of said rear portion, said rear tie rod being driven by a rear two way piston and cylinder assembly;said each of said front and rear two way cylinder and piston assemblies having an active chamber, one of said active chambers receiving pressurized fluid from said power steering system while the other of said front or rear active portions exhausts fluid to return to said power steering system; andeach of said front and rear piston and cylinder assemblies having a passive portion each of said front and rear passive portions being connected by a hydrostatic hose, and said first and second passive portions and said hose being in operative communication to trap a volume of fluid such that pressurization of a first active portion of a first piston cylinder assembly drives said trapped fluid volume into said second passive portion of said second piston cylinder assembly such that when a first piston cylinder assembly is driven to turn a first pair of wheels in a first direction, said second piston cylinder assembly is driven to drive a second pair of wheels in an opposite direction. 19. The vehicle of claim 18 wherein said two wheels on said front portion are steerable by a front steering linkage and said second two wheels on said rear portion are steerable by a rear steering linkage; wherein said front steering linkage and said rear steering linkage are coordinated by a hydrostatic powering steering system. 20. The vehicle of claim 18 wherein when said front two wheels on said front portion turn in a first direction, said rear two wheels on said rear portion turn in an opposite direction. 21. The vehicle of claim 18 wherein said front steering linkage for said two wheels on said front portion is coordinated with said rear steering linkage for said two wheels on said rear portion by a trapped a fluid volume. 22. The vehicle of claim 18 wherein said power steering system is driven through a charge pump. 23. The vehicle of claim 18 wherein said hydrostatic hose connected to said first and second passive sections travels through said articulation. 24. A ground engaged vehicle comprising: a front portion,a rear portion, said front and rear portion being joined by an articulation, said articulation rotating around a longitudinal axis of said vehicle;a hydrostatic drive system driving each of four wheels;at least two wheels being mounted on one of said front portion or said rear portion and at least one other wheel being mounted on the other of said front portion or said rear portion;each of said wheels being mounted on a hydrostatic motor and each of said hydrostatic motors being fixedly mounted on a rotating, substantially vertical axis;said hydrostatic drive system having a high gear and a low gear;said wheels having an operational internal tire pressure of at or below about 10 psi andeach of said wheels being mounted without suspension;whereby said articulation and said low pressure tires providing shock absorption and substantially continuous ground contact for each of said wheels in both said high and low gear; andwherein a valve assembly divides fluid when said vehicle is moving in a forward direction and said flow divider combines fluid when said vehicle is moving in a reverse direction.