Vehicle frame assembly and split-frame vehicle

Abstract

A split-frame vehicle in which the front and rear sub-frames may rotate relative to one another along a longitudinal axis that runs generally parallel to the ground. In one embodiment, the vehicle includes a locking mechanism operatively coupled between the front and rear sub-frames. The locking mechanism is operative between a locked position in which the sub-frames are rigidly coupled and an unlocked position in which the sub-frames are free to rotate relative to one another. In a second embodiment, the vehicle includes an axial rotator joint connected between the sub-frames. The joint includes a first bearing plate connected to the front sub-frame and a second bearing plate connected to the second sub-frame. The faces of each bearing plate bear on one another and define the rotational interface between the sub-frames. A drive shaft extends through an opening in the center of each bearing plate. The bearing plates are oriented so that the face of each plate is perpendicular to the longitudinal axis that runs generally parallel to the ground and the drive shaft extends along this longitudinal axis. In a third embodiment, rear steering is incorporated into a split-frame four-wheel drive vehicle.

What is claimed is:  
     
         1 . A vehicle frame assembly, comprising: 
 a first sub-frame;    a second sub-frame rotatably coupled to the first sub-frame; and    a locking mechanism operatively coupled between the first and second sub-frames, the locking mechanism operative between a first position in which the sub-frames are rigidly coupled and a second position in which the sub-frames are free to rotate relative to one another.    
     
     
         2 . The frame assembly according to  claim 1 , wherein the locking mechanism comprises an opening in the first sub-frame and a pin movably attached to the second sub-frame, the pin movable between an extended position in which the pin extends into the opening in the first sub-frame to rigidly couple the sub-frames and a retracted position in which the pin does not extend into the opening in the first sub-frame and the sub-frames are free to rotate relative to one another.  
     
     
         3 . A vehicle frame assembly, comprising: 
 a first sub-frame having a first cross member;    a second sub-frame having a second cross member positioned parallel and adjacent to the first cross member, the second cross member rotatably coupled to the first cross member at a center portion of the cross members; and    a locking mechanism operatively coupled between the first and second cross members at a location away from the center portion of the cross members, the locking mechanism operative between a first position in which the cross members are rigidly coupled and a second position in which the cross members are free to rotate relative to one another.    
     
     
         4 . The frame assembly according to  claim 5 , wherein the locking mechanism comprises an opening in the first cross member and a pin movably attached to the second cross member opposite the opening in the first cross member, the pin movable between an extended position in which the pin extends into the opening in the first cross member to rigidly couple the cross members and a retracted position in which the pin does not extend into the opening in the cross members are free to rotate relative to one another.  
     
     
         5 . The frame assembly according to  claim 5 , wherein the locking mechanism comprises: 
 a first opening in the first sub-frame on one side of the center portion and a first pin movably attached to the second sub-frame opposite the first opening;    a second opening in the first sub-frame on the other side of the center portion and a second pin movably attached to the second sub-frame opposite the second opening;    the pins movable between an extended position in which the pin extends into the openings in the first cross member to rigidly couple the cross members and a retracted position in which the pins do not extend into the openings in the first cross member and the cross members are free to rotate relative to one another.    
     
     
         6 . A vehicle frame assembly, comprising: 
 a first sub-frame;    a second sub-frame;    a first bearing plate connected to the first sub-frame, the first bearing plate having an opening therethrough and a face;    a second bearing plate connected to the second sub-frame, the second bearing plate having an opening therethrough and a face, the second bearing plate face bearing on the first bearing plate face;    a drive shaft having a longitudinal axis which lies substantially perpendicular to the bearing plate faces, the shaft rotatable in and extending through the bearing plate openings.    
     
     
         7 . The frame assembly according to  claim 6 , further comprising a retainer operatively coupled between the shaft and the bearing plates, the retainer configured to retain the shaft in the bearing plate openings while allowing the shaft to rotate about the longitudinal axis.  
     
     
         8 . The frame assembly according to  claim 6 , wherein the longitudinal axis is positioned along a mid-line of the sub-frames.  
     
     
         9 . The frame assembly according to  claim 6 , further comprising a first yoke disposed at a forward end of the drive shaft and a second yoke disposed at a rearward end of the drive shaft, the first yoke connectable to a front drive line of a vehicle and the second yoke connectable to a rear drive line of the vehicle.  
     
     
         10 . The frame assembly according to  claim 7 , wherein the retainer is configured to apply a compressive force between the first bearing plate and the second bearing plate.  
     
     
         11 . The frame assembly according to  claim 9 , further comprising a joint connecting one end of the drive shaft to one of the yokes.  
     
     
         12 . The frame assembly according to  claim 11 , wherein the joint comprises external splines on the one end of the drive shaft and mating internal splines on one of the yokes.  
     
     
         13 . A vehicle frame assembly, comprising: 
 a first sub-frame;    a second sub-frame;    a center bearing rotatably coupling the second sub-frame to the first sub-frame at a center portion of the sub-frames; and    a locking mechanism operatively coupled between the first and second sub-frames, the locking mechanism operative between a first position in which the sub-frames are rigidly coupled and a second position in which the sub-frames are free to rotate relative to one another.    
     
     
         14 . A frame assembly according to  claim 13 , further comprising an outboard bearing slidably interposed between the first sub-frame and a second sub-frame at a location away from the center portion of the sub-frames.  
     
     
         15 . The frame assembly according to  claim 13 , wherein each of the center and outboard bearings comprise: 
 a first bearing plate connected to the first sub-frame, the first bearing plate having a face; and    a second bearing plate connected to the second sub-frame, the second bearing plate having a face and the second bearing plate face bearing on the first bearing plate face.    
     
     
         16 . A vehicle frame assembly, comprising: 
 a first sub-frame;    a second sub-frame;    a first bearing plate connected to the first sub-frame, the first bearing plate having an opening therethrough and a face;    a second bearing plate connected to the second sub-frame, the second bearing plate having an opening therethrough and a face, the second bearing plate face bearing on the first bearing plate face;    a front sleeve extending forward from the first bearing plate along a longitudinal axis which lies substantially perpendicular to the bearing plate faces;    a rear sleeve extending rearward from the second bearing plate along the longitudinal axis;    a tubular bushing extending through the sleeves;    a drive shaft rotatable in and extending through the bushing;    a first yoke disposed at a forward end of the drive shaft, the first yoke connectable to a front drive line of a vehicle; and    a second yoke disposed at a rearward end of the drive shaft, the second yoke connectable to a rear drive line of the vehicle.    
     
     
         17 . The frame assembly according to  claim 16 , further comprising a retainer operatively coupled to the shaft and the bushing, the retainer configured to retain the shaft and the bushing in the sleeves.  
     
     
         18 . A split-frame vehicle, comprising: 
 a frame including a first sub-frame rotatably coupled to a second sub-frame;    an engine supported by the frame;    a transmission operatively coupled to the engine;    a first set of wheels connected to one of the sub-frames;    a second set of wheels connected to the other of the sub-frames;    a drive line operatively coupled between the transmission and at least one of the sets of wheels; and    a locking mechanism operatively coupled between the first and second sub-frames, the locking mechanism operative between a first position in which the sub-frames are rigidly coupled and a second position in which the sub-frames are free to rotate relative to one another.    
     
     
         19 . The vehicle according to  claim 18 , wherein the locking mechanism comprises an opening in one of the sub-frames and a pin movably attached to the other one of the sub-frames, the pin movable between an extended position in which the pin extends into the opening to rigidly couple the sub-frames and a retracted position in which the pin does not extend into the opening and the sub-frames are free to rotate relative to one another.  
     
     
         20 . A split-frame vehicle, comprising: 
 a frame including a first sub-frame rotatably coupled to a second sub-frame;    an engine supported by the frame;    a transmission operatively coupled to the engine;    a first set of wheels connected to one of the sub-frames;    a second set of wheels connected to the other of the sub-frames;    a first drive line connected to the transmission;    a second drive line connected to one of the sets of wheels;    a first bearing plate connected to the first sub-frame, the first bearing plate having an opening therethrough and a face;    a second bearing plate connected to the second sub-frame, the second bearing plate having an opening therethrough and a face, the second bearing plate face bearing on the first bearing plate face; and    a drive shaft having a longitudinal axis which lies substantially perpendicular to the bearing plate faces, the drive shaft coupled between the first and second drive lines and rotatable in and extending through the bearing plate openings.    
     
     
         21 . The vehicle according to  claim 20 , further comprising a retainer operatively coupled between the shaft and the bearing plates, the retainer configured to retain the shaft in the bearing plate openings while allowing the shaft to rotate about the longitudinal axis.  
     
     
         22 . The vehicle according to  claim 20 , wherein the longitudinal axis is positioned along a mid-line of the sub-frames.  
     
     
         23 . The vehicle according to  claim 20 , further comprising a first yoke disposed at a forward end of the drive shaft and a second yoke disposed at a rearward end of the drive shaft, the first yoke connectable to a front drive line of a vehicle and the second yoke connectable to a rear drive line of the vehicle.  
     
     
         24 . The vehicle according to  claim 21 , wherein the retainer is configured to apply a compressive force between the first bearing plate and the second bearing plate.  
     
     
         25 . A more than two wheel drive split-frame vehicle, comprising: 
 a frame including a front sub-frame and a rear sub-frame;    an engine supported by the front sub-frame;    a transmission operatively coupled to the engine;    a front set of steerable wheels drivingly coupled to the transmission through a front drive train;    a front steering linkage connected to the front wheels    a rear set of steerable wheels drivingly coupled to the transmission through a second drive train, the second drive train having a first drive line connected to the transmission and a second drive line connected to the rear set of wheels;    a rear steering linkage connected to the rear wheels;    an axial rotator joint rotatably coupling the front sub-frame to the rear sub-frame, the axial rotator joint including a rotatable drive shaft connected between the first and second drive lines; and    a locking mechanism operatively coupled between the front and rear sub-frames, the locking mechanism operative between a first position in which the sub-frames are rigidly coupled and a second position in which the sub-frames are free to rotate relative to one another.    
     
     
         26 . The vehicle according to  claim 20 , wherein steering force is delivered to the rear wheels by a hydraulic system comprising: 
 a hydraulic cylinder connected to the rear steering linkage;    a hydraulic pump connected to the hydraulic cylinder; and    a controller connected to the hydraulic pump.