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A low surface impact, skid steered, all terrain vehicle is disclosed which has a rectangular frame from which sets of tandem mounted, independently movable control arms are suspended. A hydraulic motor driven wheel axle is mounted on a lower end of each control arm with at least one pneumatic wheel

A low surface impact, skid steered, all terrain vehicle is disclosed which has a rectangular frame from which sets of tandem mounted, independently movable control arms are suspended. A hydraulic motor driven wheel axle is mounted on a lower end of each control arm with at least one pneumatic wheel mounted upon each wheel axle. Separate hydraulic control circuits having separate drive pumps drive the hydraulic motors on each side of the vehicle. Each of these hydraulic control circuits is operable in either a series connected mode or a parallel connected mode.

대표청구항 ▼

We claim: 1. An eight axle, skid steering vehicle comprising: a generally rectangular frame having a pair of opposed side members; four hanger brackets fixed to each side member of the frame; a pair of independently movable control arms suspended downwardly in opposite directions from each hanger b

We claim: 1. An eight axle, skid steering vehicle comprising: a generally rectangular frame having a pair of opposed side members; four hanger brackets fixed to each side member of the frame; a pair of independently movable control arms suspended downwardly in opposite directions from each hanger bracket, each control arm being pivotally mounted at a first end upon a hanger bracket; a wheel axle mounted on a second end of each control arm; at least one wheel hub mounted on each wheel axle; a pneumatic wheel mounted upon each wheel hub; a resilient spring located between the frame and each control arm to bias the control arms away from the frame; and a friction plate mounted upon each control arm, each pair of friction plates on each pair of control arms making contact with each other to limit movement of each pair of control arms toward one another. 2. A low surface impact, skid steered, all terrain vehicle comprising: a generally rectangular frame having a pair of opposed side members; at least one tandem suspension system on each of said side members; each suspension system comprising a pair of independently movable control arms pivotally suspended at one end from a side member, there being at least four control arms suspended from said side members; a wheel axle mounted on an opposite end of each control arm; at least one wheel hub mounted upon each wheel axle; a pneumatic wheel mounted upon each wheel hub; and a friction plate mounted upon each control arm, each pair of friction plates on each pair of control arms making contact with each other to limit movement of each pair of control arms toward one another. 3. The all terrain vehicle of claim 2 which further comprises an endless track mounted over the pneumatic wheels of each suspension system. 4. The all terrain vehicle of claim 3 wherein there are a pair of wheel hubs and pneumatic wheels mounted upon each wheel axle. 5. The all terrain vehicle of claim 4 wherein there are a plurality of lugs extending inwardly from an inside surface of each of said endless tracks, said lugs extending between an inside surface of each pair of pneumatic wheels on each of said wheel axles so as to prevent said endless tracks from running off of said wheel hubs. 6. The all terrain vehicle of claim 5 wherein selected ones of said lugs are engageable with an inside surface of one of said wheel hubs on each of said wheel axles and others of said lugs on each of said endless tracks are engageable with an inside surface of the other of said pair of wheel hubs on each of said wheel axles. 7. The all terrain vehicle of claim 2 which further comprises a resilient spring located between the frame and each control arm to bias the control arms away from the frame. 8. The all terrain vehicle of claim 2 wherein said pneumatic wheels comprise pneumatic tires mounted upon each wheel hub. 9. The all terrain vehicle of claim 8 wherein there are a pair of wheel hubs mounted upon each wheel axle. 10. The all terrain vehicle of claim 2 which further comprises a hydraulic motor secured to at least one wheel axle on each side of said frame, each hydraulic motor being operative to drive the wheel axle to which it is secured. 11. The all terrain vehicle of claim 10 further comprising: first and second motor driven pumps; a first hydraulic circuit for supplying fluid power from said first motor driven pump to all of the hydraulic motors drivingly secured to the wheel axles on a first side of said frame; a second hydraulic circuit for supplying fluid power from said second motor driven pump to all of the hydraulic motors drivingly secured to the wheel axles on a second side of said frame; and said first and second hydraulic circuits being operable to interconnect the hydraulic motors on one side of the frame either in a parallel connected circuit or a series connected circuit. 12. A low surface impact, skid steered, all terrain vehicle comprising: a generally rectangular frame having a pair of opposed side members; a pair of tandem suspension systems on each of said side members; each suspension system comprising a pair of independently movable control arms pivotally suspended at a first end from a side member, each control arm of each pair of control arms extending downwardly in opposite directions from a side member; a wheel axle mounted on a second end of each control arm; a hydraulic motor secured to at least one wheel axle on each side of said frame, each hydraulic motor being operative to drive the wheel axle to which it is secured; at least one wheel hub mounted upon each wheel axle; a pneumatic wheel mounted upon each wheel hub; and a friction element mounted upon said first end of each control arm to limit movement of each pair of control arms. 13. The all terrain vehicle of claim 12 further comprising: first and second motor driven pumps; a first hydraulic circuit for supplying fluid power from said first motor driven pump to all of the hydraulic motors drivingly secured to the wheel axles on a first side of said frame; a second hydraulic circuit for supplying fluid power from said second motor driven pump to all of the hydraulic motors drivingly secured to the wheel axles on a second side of said frame; said first and second hydraulic circuits being operable in a first mode to interconnect the hydraulic motors on one side of the frame in series and in a second mode to connect the same hydraulic motors in parallel; and said first and second hydraulic circuits being operable to drive the hydraulic motors on one side of said frame in one direction and the hydraulic motors on the opposite side of said frame in an opposite direction to effect turning of said vehicle and, when in the second parallel mode, enable the vehicle to turn in a shorter radius than when in the first series connected mode. 14. The all terrain vehicle of claim 13 wherein in the second parallel mode of the first and second hydraulic circuits, the hydraulic motors secured to the wheel axles to one tandem suspension system on one side of the vehicle may be caused to rotate while the hydraulic motors secured to the wheel axles of a second tandem suspension system on the same side of the vehicle are caused to remain substantially stationary during turning movement of the vehicle. 15. The all terrain vehicle of claim 12 which further comprises a resilient spring located between the frame and each control arm to bias the control arms away from the frame. 16. The all terrain vehicle of claim 12 wherein each friction element comprises a friction plate mounted upon each control arm to limit movement of each pair of control arms toward one another and prevent the pneumatic wheels on each pair of control arms from coming into abutting contact with one another. 17. A low surface impact, skid steered, all terrain vehicle comprising: a rectangular frame; a pair of sets of tandem mounted, independently movable control arms suspended from opposite sides of the frame such that there are at least four control arms suspended from each side of the frame; a hydraulic motor driven wheel axle mounted on a lower end of each control arm; at least one wheel mounted upon each wheel axle; a pair of hydraulic control circuits each having its own separate motor driven pump operable to drive hydraulic motors on each wheel axle on each side of the vehicle; each hydraulic control circuit being connectable in either a series connected mode or a parallel connected mode and in the series connected mode, providing substantially equal fluid flow and pressure to all of the hydraulic motors on one side of the vehicle so as to obtain substantially equal wheel speed and minimize wheel slippage with a surface upon which the vehicle is supported; and each hydraulic control circuit, when operating in the parallel connected mode, driving the hydraulic motors on front and rear sets of wheels with differing fluid flow and pressure so that when the wheels on opposite sides of the vehicle are driven in opposite directions, skid steering of the vehicle is improved over that obtainable when the hydraulic control circuits are in the series connected mode, said hydraulic control circuits, when in the parallel connected mode, including proportional flow control valves operable to prevent all fluid flow from flowing to the hydraulic motor of the wheel axle which encounters the least resistance to wheel rotation. 18. The all terrain vehicle of claim 17 wherein when the hydraulic control circuits are operating in the parallel connected mode and are operated so as to drive the hydraulic motors and wheels driven thereby on opposite sides of the frame in opposite directions, the one set of wheels on each side may be caused to rotate while another set of wheels on the same side may be caused to remain substantially stationary during turning movement of the vehicle. 19. The all terrain vehicle of claim 18 wherein there are a pair of tandem connected front wheel axles and a pair of tandem connected rear wheel axles on each side of the vehicle. 20. The all terrain vehicle of claim 19 wherein the hydraulic motors drivingly secured to each of the pair of tandem connected front wheel axles are connected in parallel and the hydraulic motors drivingly secured to the pair of tandem connected rear wheel axles are connected in parallel so that when the hydraulic motors are connected in a series connected circuit, each hydraulic motor receives approximately equal flow from one of said motor driven pumps. 21. The all terrain vehicle of claim 20 wherein the proportional flow control valves comprise 50-50 flow control valves operably connected in the hydraulic control circuits to the hydraulic motors drivingly secured to each pair of tandem connected wheel axles. 22. The all terrain vehicle of claim 21 which further includes an engine for driving each of said first and second motor driven pumps, said engine also being operable to drive an auxiliary pump, said auxiliary pump being connected in a hydraulic circuit to an auxiliary valve for controlling flow of hydraulic fluid from said auxiliary pump to auxiliary equipment mounted upon said vehicle.