Earth-based vehicle

Abstract

A vehicle is provided including a main frame structure, a track assembly mounted to the main frame structure and having an single, endless ground-engaging track extending in a longitudinal direction. A pair of steerable ground-engaging wheels flank the track, constructed and arranged to exert a ground bearing pressure sufficient to change a direction of travel of the track in response to turning of the wheels to steer the vehicle. Steering structure is operatively associated with the wheels to turn the wheels. Power drive structure is mounted with respect to the main frame structure and is constructed and arranged to drive the wheels and the track simultaneously so as to move the vehicle along the ground. The wheels are constructed and arranged to be moved with respect to the main frame structure so as to change a position thereof with respect to the main frame structure, thereby permitting driving, steering and ground pressure of the vehicle to be adjusted in accordance with ground conditions.

1. A vehicle comprising:
 a main frame structure,    a track assembly mounted to said main frame structure and having an endless ground-engaging track extending in a longitudinal direction,    a pair of steerable ground-engaging wheels mounted with respect to the main frame structure such that each said wheel of said pair flanks said track, said wheels being constructed and arranged to exert ground bearing pressure sufficient to change a direction of travel of said track in response to turning of said wheels so as to steer the vehicle,    steering structure operatively associated with said wheels to turn said wheels, and    power drive structure mounted with respect to said main frame structure and constructed and arranged to drive said wheels and said track simultaneously so as to move the vehicle along the ground.    
     
     
       2. The vehicle according to  claim 1 , wherein said wheels are constructed and arranged to be moved with respect to said main frame structure so as to change a position thereof with respect to the main frame structure, thereby permitting driving, steering and ground bearing pressure of the vehicle to be adjusted in accordance with ground conditions. 
     
     
       3. The vehicle according to  claim 1 , wherein said wheels are coupled to an axle assembly at opposing ends of said axle assembly, said axle assembly being mounted with respect to said main frame structure so as to be disposed generally transverse to the longitudinal extent of said track. 
     
     
       4. The vehicle according to  claim 3 , wherein bounds of said track define an interior space, said axle assembly being mounted with respect to said main frame structure such that a portion of said axle assembly extends through said interior space. 
     
     
       5. The vehicle according to  claim 4 , wherein said axle assembly is constructed and arranged to be movable with respect to said main frame structure so as to change a position of said wheels with respect to the main frame structure, thereby permitting driving, steering and ground bearing pressure of the vehicle to be adjusted in accordance with ground conditions. 
     
     
       6. The vehicle according to  claim 5 , wherein said axle assembly is movable generally vertically with respect to said frame structure to adjust a vertical position of said wheels. 
     
     
       7. The vehicle according to  claim 6 , wherein said axle assembly is movable an amount such that said wheels lift at least a portion of said track from ground contact. 
     
     
       8. The vehicle according to  claim 6 , further comprising an air bag device operatively associated with said axle assembly for moving said axle assembly generally vertically. 
     
     
       9. The vehicle according to  claim 1 , wherein said frame structure has fore and aft ends and said track assembly is mounted centrally with respect to said main frame structure between said fore and aft ends. 
     
     
       10. The vehicle according to  claim 4 , wherein said power drive structure includes an engine, at least one hydrostatic pump driven by said engine, at least one hydraulic motor coupled to said axle assembly and at least one hydraulic motor coupled to said track assembly, said hydrostatic pump being fluidly connected to said hydrostatic motors for driving said track and said wheels, said engine and said hydrostatic pump defining a power unit. 
     
     
       11. The vehicle according to  claim 10 , wherein said power unit and said axle assembly are mounted on a movable member, said movable member being mounted with respect to said frame structure so as to be movable fore and aft within said interior space so as to change the fore and aft center of gravity of the vehicle. 
     
     
       12. The vehicle according to  claim 11 , wherein said movable member is movable such that when said movable member is disposed at a fore position, said wheels lift at least a fore end of said track from ground contact. 
     
     
       13. The vehicle according to  claim 11 , wherein said movable member is a flat plate mounted within a guide track so as to be slidable therein, said guide track being fixed to said main frame structure. 
     
     
       14. The vehicle according to  claim 13 , further comprising at least one hydraulic cylinder coupled to said flat plate for moving the flat plate within the guide track. 
     
     
       15. The vehicle according to  claim 11 , wherein said movable member is movable along a track member via bearings, said track member being fixed to said main frame structure. 
     
     
       16. The vehicle according to  claim 1 , wherein said wheels include rubber tires and said track is a rubber track. 
     
     
       17. The vehicle according to  claim 1 , wherein said steering structure is constructed and arranged to be operated hydraulically. 
     
     
       18. The vehicle according to  claim 1 , wherein said steering structure includes a steering unit and a hydraulic cylinder associated with each said wheel to move the associated wheel, said steering unit being hydraulically operated and fluidly coupled to the hydraulic cylinders for controlling turning movement of said wheels. 
     
     
       19. The vehicle according to  claim 1 , in combination with a second vehicle, said second vehicle including a second frame structure, a second track assembly mounted to said second frame structure and including an endless ground-engaging track, and a pair of steerable ground-engaging wheels mounted with respect to said second frame structure so as to flank the second track assembly, said power drive structure being constructed and arranged to drive the track and wheels of the first and second vehicles, simultaneously. 
     
     
       20. The vehicle according to  claim 10 , wherein said hydraulic motors are constructed and arranged to be operated in such a manner that vehicle speed is determined by the number of motors selected to operate at one time. 
     
     
       21. The vehicle according to  claim 1 , wherein said wheels are disposed at a position vertically lower than a position of said track relative to said main frame structure, so that said wheels make ground contact at points deeper into the ground than points of track ground contact. 
     
     
       22. A vehicle comprising:
 a main frame structure,    a track assembly mounted generally centrally with respect to said main frame structure and having a single, endless ground-engaging track extending in a longitudinal direction,    a pair of steerable ground-engaging wheels mounted with respect to the main frame structure such that each said wheel of said pair flanks said track, said wheels being constructed and arranged to exert ground bearing pressure sufficient to change a direction of travel of said track in response to turning of said wheels to steer the vehicle,    steering structure operatively associated with said wheels to turn said wheels, and    power drive structure mounted with respect to said main frame structure and constructed and arranged to drive said wheels and said track simultaneously so as to move the vehicle along the ground,    said wheels being movable with respect to said main frame structure so as to change a position of said wheels with respect to the frame structure, thereby permitting driving, steering and ground bearing pressure of the vehicle to be adjusted in accordance with ground conditions.    
     
     
       23. The vehicle according to  claim 22 , wherein said wheels are coupled to an axle assembly at opposing ends of said axle assembly, said axle assembly being mounted with respect to said main frame structure so as to be disposed generally transverse to the longitudinal extent of said track. 
     
     
       24. The vehicle according to  claim 22 , wherein said steering structure is constructed and arranged to be operated hydraulically. 
     
     
       25. The vehicle according to  claim 22 , wherein said main frame structure has fore and aft ends and said track assembly extends substantially between said fore and aft ends. 
     
     
       26. The vehicle according to  claim 22 , wherein said wheels are mounted for vertical movement with respect to said main frame structure. 
     
     
       27. The vehicle according to  claim 23 , wherein said axle assembly is constructed and arranged to be movable generally vertically to adjust a vertical position of said wheels. 
     
     
       28. The vehicle according to  claim 27 , wherein said axle assembly is movable an amount such that said wheels lift at least a portion of said track from ground contact. 
     
     
       29. The vehicle according to  claim 27 , further comprising an air bag device operatively associated with said axle assembly for moving said axle assembly generally vertically. 
     
     
       30. The vehicle according to  claim 23 , wherein said power drive structure includes an engine, at least one hydrostatic pump driven by said engine, at least one hydraulic motor coupled to said axle assembly and at least one hydraulic motor coupled to said track assembly, said hydrostatic pump being fluidly connected to said hydrostatic motors for driving said track and said wheels, said engine and said hydrostatic pump defining a power unit. 
     
     
       31. The vehicle according to  claim 30 , wherein said hydraulic motors are constructed and arranged to be operated in such a manner that vehicle speed is determined by the number of motors selected to operate at one time. 
     
     
       32. The vehicle according to  claim 30 , wherein bounds of said track define an interior space, said power unit and a substantial portion of said axle assembly being disposed within said interior space. 
     
     
       33. The vehicle according to  claim 32 , wherein said power unit and said axle assembly are mounted on a movable member, said movable member being mounted with respect to said frame structure so as to be movable fore and aft within said interior space so as to change the fore and aft center of gravity of the vehicle. 
     
     
       34. The vehicle according to  claim 33 , wherein said movable member is movable such that when said movable member is disposed at a fore position, said wheels lift at least a fore end of said track from ground contact. 
     
     
       35. The vehicle according to  claim 32 , wherein said movable member is a flat plate mounted within a guide track so as to be slidable therein, said guide track being fixed to said main frame structure. 
     
     
       36. The vehicle according to  claim 35 , further comprising at least one hydraulic cylinder coupled to said flat plate for moving the flat plate within the guide track. 
     
     
       37. The vehicle according to  claim 33 , wherein said movable member is movable along a track member via bearings, said track member being fixed to said main frame structure. 
     
     
       38. The vehicle according to  claim 22 , wherein said wheels include rubber tires and said track is a rubber track. 
     
     
       39. The vehicle according to  claim 25 , further comprising a dozer blade mounted with respect to said frame structure at the fore end thereof. 
     
     
       40. The vehicle according to  claim 22 , wherein said steering structure includes a steering unit operatively associated with said wheels for controlling steering of the vehicle. 
     
     
       41. The vehicle according to  claim 40 , wherein said steering structure includes a hydraulic cylinder associated with each said wheel, said steering unit being hydraulically operated and fluidly coupled to the hydraulic cylinders for controlling steering of said wheels. 
     
     
       42. A tandem vehicle comprising:
 a first vehicle including; 
 a main frame structure,  
 a track assembly mounted generally centrally with respect to said main frame structure and having a single, endless ground-engaging track extending in a longitudinal direction,  
 a pair of steerable ground-engaging wheels mounted with respect to the main frame structure such that each said wheel of said pair flanks said track, said wheels being constructed and arranged to exert ground bearing pressure sufficient to change a direction of travel said track in response to turning of said wheels to steer the first vehicle,  
 steering structure operatively associated with said wheels to turn said wheels,  
 power drive structure mounted with respect to said main frame structure and constructed and arranged to drive said wheels and said track simultaneously so as to move the first vehicle along the ground,  
 said wheels being movable with respect to said main frame structure so as to change a position of said wheels with respect to the frame structure, thereby permitting driving steering, and ground bearing pressure of the first vehicle to be adjusted in accordance with ground conditions,  
   a second vehicle coupled to an aft end of said first vehicle, said second vehicle including a second frame structure, a second track assembly mounted to said second frame structure and including an endless ground-engaging track, and a pair of driven and steerable ground-engaging wheels mounted with respect to said second frame structure so as to flank the second track assembly, said power drive structure being constructed and arranged to drive the track and wheels of the first and second vehicles, simultaneously.    
     
     
       43. A tandem vehicle comprising:
 a first vehicle including: 
 a main frame structure,  
 a track assembly mounted to said main frame structure and having an endless ground-engaging track extending in a longitudinal direction,  
 a pair of steerable ground-engaging wheels mounted with respect to the main frame structure such that said wheels flank said track, said wheels being constructed and arranged to exert ground bearing pressure sufficient to change a direction of travel of said track in response to turning of the wheels to steer the first vehicle,  
 steering structure operatively associated with said wheels to turn said wheels, and  
 power drive structure mounted with respect to said main frame structure and constructed and arranged to drive said wheels and said track simultaneously so as to move the first vehicle along the ground, and  
   a second vehicle coupled to an aft end of said first vehicle, said second vehicle including: 
 a second main frame structure,  
 a second track assembly mounted to said second main frame structure and having an endless ground-engaging track extending in a longitudinal direction,  
 a pair of steerable ground-engaging wheels mounted with respect to the second main frame structure such that said wheels flank said track, said wheels being constructed and arranged to exert ground bearing pressure sufficient to change a direction of travel of said second track in response to turning of the wheels of the second track,  
   said track and said wheels of said second vehicle being operatively coupled to said power drive structure of said first vehicle such that said power drive structure of said first vehicle drives said wheels and track of said first vehicle together with said wheels and track of said second vehicle.    
     
     
       44. A vehicle comprising:
   a main frame structure;        a track assembly supporting said main frame structure and having an endless ground - engaging track extending in a longitudinal direction of said vehicle;        a pair of ground - engaging wheels mounted with respect to said main frame structure such that said wheels are disposed in flanking relation on opposing sides of said track, said wheels and said track assembly being mounted within said vehicle so as to enable said wheels and said track assembly to be moved generally vertically relative to one another to shift a distribution of vehicle weight between said wheels and said track assembly;        a power drive assembly constructed and arranged to move said wheels and said track in driving engagement with the ground so as to drive said vehicle along the ground; and        steering structure operatively associated with said wheels, said steering structure being constructed and arranged to control operation of said wheels so as to affect a vehicle steering operation wherein said power drive structure moves said wheels in driving engagement with the ground to steer said vehicle;        power - operated structure constructed and arranged to affect the generally vertical relative movement between said wheels and said track assembly during said vehicle steering operation to shift said distribution of vehicle weight from said track assembly to said wheels to provide said wheels with increased traction during said vehicle steering operation.      
     
     
       45. A vehicle according to  claim 44 , wherein said power- operated structure is connected to said wheels and is constructed and arranged to move said wheels generally downwardly relative to said track assembly to shift said distribution of the vehicle weight.    
     
     
       46. A vehicle according to  claim 45 , wherein said power- operated structure is communicated to a supply of pressurized fluid and is constructed and arranged to move said wheels generally downwardly relative to said track assembly using said pressurized fluid.    
     
     
       47. A vehicle according to  claim 46 , wherein said supply of pressurized fluid is a supply of pressurized hydraulic liquid and wherein said power- operated structure includes hydraulic cylinders operatively connected to said wheels.    
     
     
       48. A vehicle according to  claim 47 , wherein said power drive assembly includes a hydraulic pump constructed and arranged to pressurize said supply of pressurized liquid.  
     
     
       49. A vehicle according to  claim 46 , wherein said supply of pressurized fluid is a supply of pressurized air and wherein said power- operated structure includes an air bag operatively connected to said wheels.    
     
     
       50. A vehicle according to  claim 44 , wherein said power- operated structure is constructed and arranged to affect the generally vertical relative movement between said wheels and said track assembly to an extent sufficient to lift a substantial portion of said track assembly out of ground contact about a longitudinal end portion thereof during vehicle steering operation to thereby distribute the weight of said vehicle over three spaced supporting points including said longitudinal end portion of said track and each of said wheels.    
     
     
       51. A vehicle according to  claim 50 , wherein said longitudinal end portion of said track assembly is a rear end portion of said track assembly.  
     
     
       52. A vehicle according to  claim 50 , wherein said power- operated assembly is connected to said wheels and is constructed and arranged to move said wheels generally downwardly relative to said track assembly to shift said distribution of the vehicle weight.    
     
     
       53. A vehicle according to  claim 52 , wherein said power- operated structure is communicated to a supply of pressurized fluid and is constructed and arranged to move said wheels generally downwardly relative to said track assembly using said pressurized fluid.    
     
     
       54. A vehicle according to  claim 52 , wherein said supply of pressurized fluid is a supply of pressurized hydraulic liquid and wherein said power- operated structure includes a hydraulic cylinder operatively connected to said wheels.    
     
     
       55. A vehicle according to  claim 54 , wherein said power drive structure includes a hydraulic pump constructed and arranged to pressurize said supply of pressurized liquid.  
     
     
       56. A vehicle according to  claim 55 , wherein said supply of pressurized fluid is a supply of pressurized air and wherein said power- operated structure includes an air bag operatively connected to said wheels.    
     
     
       57. A vehicle according to  claim 44 , wherein said wheels are pivotally mounted to said frame for pivotal steering movement about a pair of generally vertical axes and wherein said steering structure is constructed and arranged to pivot said wheels about said generally vertical axes so as to affect said vehicle steering operation.  
     
     
       58. A vehicle according to  claim 50 , wherein said wheels are pivotally mounted to said frame for pivotal steering movement about a pair of generally vertical axes and wherein said steering structure is constructed and arranged to pivot said wheels about said generally vertical axes so as to affect said vehicle steering operation.  
     
     
       59. A vehicle according to  claim 44 , further comprising a single axle extending transversely of said frame, said wheels being respectively mounted on opposing ends of said axle assembly.  
     
     
       60. A vehicle according to  claim 59 , wherein said power- operated structure is connected between said axle and said frame, said power - operated structure being constructed and arranged to move said axle assembly generally downwardly relative to said frame so as to move said wheels generally downwardly relative to said track assembly to thereby shift said distribution of the vehicle weight.    
     
     
       61. A vehicle according to  claim 60 , wherein said axle is hingedly connected to said frame.  
     
     
       62. A vehicle according to  claim 60 , further comprising a movable member mounted within track assembly for movement in an inclined manner, said axle being mounted to said movable member such that movement of said movable member in said inclined manner moves said axle generally vertically relative to said track assembly, said power- operated structure being connected between said frame and said movable member.    
     
     
       63. A vehicle according to  claim 60 , wherein said power- operated structure is communicated to a supply of pressurized fluid and is constructed and arranged to move said axle generally downwardly relative to said track assembly using said pressurized fluid.    
     
     
       64. A vehicle according to  claim 59 , wherein said wheels are pivotally mounted to said axle for pivotal steering movement about a pair of generally vertical axes and wherein said steering structure is constructed and arranged to pivot said wheels about said generally vertical axes so as to affect said vehicle steering operation.  
     
     
       65. A vehicle according to  claim 50 , further comprising a single axle extending transversely of said frame, said wheels being respectively mounted on opposing ends of said axle.  
     
     
       66. A vehicle according to  claim 65 , wherein said power- operated structure is connected between said axle and said frame, said power - operated structure being constructed and arranged to move said axle generally downwardly relative to said frame so as to move said wheels generally downwardly relative to said track assembly to thereby shift said distribution of the vehicle weight.    
     
     
       67. A vehicle according to  claim 66 , wherein said axle is hingedly connected to said frame.  
     
     
       68. A vehicle according to  claim 67 , wherein said power- operated structure is communicated to a supply of pressurized fluid and is constructed and arranged to move said axle assembly generally downwardly relative to said track assembly using said pressurized fluid.    
     
     
       69. A vehicle according to  claim 44 , further comprising an axle assembly having wheel mounting portions disposed on opposing sides of said track assembly, said wheels being rotatably mounted to said wheel mounting portions and said axle assembly being constructed and arranged such that said wheel mounting portions are movable generally vertically relative to said track assembly so as to allow the generally vertical relative movement between said wheels and said track assembly;
 said power- operated structure being operatively connected between said frame and said axle assembly and being constructed and arranged to move said wheel mounting portions generally downwardly relative to said track assembly so as to shift said distribution of vehicle weight from said track to said wheels.      
     
     
       70. A vehicle according to  claim 69 , wherein said axle assembly has a pair of arms extending away from each of said wheel mounting portions, respectively, said arms being hingedly connected to said frame to enable said wheel mounting portions to be moved generally vertically relative to said track assembly.  
     
     
       71. A vehicle according to  claim 70 , wherein said power- operated structure is communicated to a supply of pressurized fluid and is constructed and arranged to move said wheels generally downwardly relative to said track assembly using said pressurized fluid.    
     
     
       72. A vehicle according to  claim 71 , wherein said supply of pressurized fluid is a supply of pressurized hydraulic liquid and wherein said power- operated structure includes hydraulic cylinders.    
     
     
       73. A vehicle according to  claim 72 , wherein said power drive assembly includes a hydraulic pump constructed and arranged to pressurize said supply of pressurized liquid.  
     
     
       74. A vehicle according to  claim 73 , wherein said axle assembly comprises a single axle extending transversely of said frame, said wheel portions being provided on opposing end portions of said axle and said axle, said arms being connected with said axle such that hinging movement of said arms moves said axle and said wheels together generally vertically relative to said track assembly.