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You are an expert at summarizing long articles. Proceed to summarize the following text: 
FIELD OF THE INVENTION 
       [0001]    The present invention is directed to an earth-working vehicle, such as a backhoe loader, having an implement, such as a backhoe, in which the implement is capable of being shifted transversely of the vehicle. 
       BACKGROUND OF THE INVENTION 
       [0002]    For many years, it has been common to mount the backhoe support structure or swing tower on a frame and utilize a pair of hydraulic cylinders to pivot the tower with respect to the frame. In such a unit, the hydraulic cylinders are usually connected to the boom support or swing tower on opposite sides of the vertical pivot axis between the swing tower and the frame. For example, in one type disclosed in Long U.S. Pat. No. 3,047,171, the free ends of the piston rods of the hydraulic cylinders are connected to the frame structure at spaced locations while the cylinder barrels are connected at transversely spaced points to the swing tower or mast. 
         [0003]    In more recent years, an earth-working vehicle of the type disclosed in the Long patent has also been mounted in a manner that the entire unit can be shifted transversely with respect to the vehicle. The frame supporting the mast or tower is supported on transversely extending rails that are secured to the rear end of the vehicle. This allows the operator to position the frame in any one of an infinite number of positions with respect to the fixed rails and readily lock the unit with respect to the rails. 
         [0004]    A side-shift backhoe incorporates a frame which supports the backhoe mechanism and which is mounted for lateral, transverse movement with respect to the tractor or the like on which the backhoe is mounted. This type of backhoe was developed primarily for trenching in confined spaces, such as in close proximity to a house or other obstruction and enables operation closer to the obstructions than if the backhoe were mounted centrally of the rear of the tractor. 
         [0005]    Traditionally, an implement bucket has been repositioned by uncontrolled movement of the backhoe while supporting the backhoe bucket teeth on the ground to one side and pushing the slide carrying the backhoe out on the other side using hydraulic cylinders. Some of the side-shift backhoes required complex components including hydraulically or manually operated clamps or pins. 
       SUMMARY OF THE INVENTION 
       [0006]    In one preferred embodiment, an earth-working vehicle, such as a backhoe loader, has an elongated main frame and an implement support slidingly mounted to the main frame. The implement support is mounted at one end of the main frame and is capable of sliding transversely with respect to the elongated main frame. The vehicle also includes a motive means to slide the implement support with respect to the elongated main frame. The motive means includes a hydraulic motor mounted to one of the main frame and the implement support and either a chain having both ends secured to the other of the main frame and the implement support or the rack of a rack and pinion secured to the other of the main frame and the implement support. The hydraulic motor has a driving sprocket to drive the chain or a pinion to drive the rack and slide the implement support. 
         [0007]    Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a fragmentary perspective view of a vehicle having an earth-working implement attached to the rear end thereof; 
           [0009]      FIG. 2  is an enlarged fragmentary sectional view, as viewed along line  2 - 2  of  FIG. 1 ; 
           [0010]      FIG. 3  is an enlarged fragmentary sectional view, as viewed along line  3 - 3  of  FIG. 2 ; and 
           [0011]      FIG. 4  is a schematic illustration, as viewed along line  4 - 4  of  FIG. 3 , showing structural support components. 
           [0012]      FIG. 5  is a schematic illustration, similar to  FIG. 4 , showing a second embodiment of the slidable implement support. 
           [0013]      FIG. 6  is a schematic illustration, similar to  FIG. 4 , showing a third embodiment of the slidable implement support. 
           [0014]      FIG. 7  is a schematic illustration, similar to  FIG. 4 , showing a fourth embodiment of the slidable implement support. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]      FIG. 1  of the drawings generally shows an earth-working vehicle  10  including rear wheels  13  with an earth-working implement  14  secured to the rear end of the vehicle  10 . The vehicle  10  has a pair of horizontally oriented, vertically spaced rails  16  secured to the rear end of the vehicle  10 . Each of the rails  16  is substantially rectangular in cross section (see  FIG. 3 ) and includes a rear vertical implement support plate  18 , with the rails releasably connected to vehicle  10  through quick release frame  17 . However, other rail and plate arrangements may be used. As most clearly shown in  FIG. 3 , tower frame  20  consists of upper and lower plates  22  and  24  that are interconnected by a pair of vertical beams  26 . The transversely spaced vertical columns or beams  26  each have a pair of lock members or means  28  supported thereon for securely locking the tower frame  20  in any one of a plurality of adjusted positions with respect to rails  16 . These lock members or means may be of the type disclosed in Magee U.S. Pat. No. 3,494,636 or may be hydraulically actuated assemblies well known in the art. 
         [0016]    Upper and lower plates  22  and  24  each have a pair of transversely spaced abutments  27  secured thereto by bolts and the abutments engage the forward surfaces of plates  18  while the lower surface of upper plate  22  is supported on the edge of upper plate  18 . Thus, the entire tower frame  20  may be laterally shifted with respect to rails  16  and locked in adjusted positions by lock means  28 . 
         [0017]    Mobile tower frame  20  supports a swing tower  40  that has a substantial C-shaped configuration with upper and lower portions  42  and  44  respectively pivotally supported on upper and lower plates  22  and  24  by pivot pins  46 . Pivot pins  46  define a vertical tower pivot axis for supporting swing tower  40  for pivotal movement on tower frame  20 . Swing tower  40  supports an implement, such as backhoe  48  for pivotal movement about a horizontal pivot  49 . The backhoe  48  is well known in the art. 
         [0018]    The swing tower  40  is pivoted with respect to the tower frame  20  by a pair of hydraulic cylinders that are mounted in order to allow the tower frame  20  to be moved along the sliding rails  16  while still having the center of gravity for the backhoe  48  as close as possible to the rear axle for the vehicle  10 . As most clearly shown in  FIGS. 2 and 3 , the tower frame  20  has a support portion consisting of three plates  50  extending between rails  16  and the plates  50  terminating forwardly of the rails  16 . The two hydraulic cylinders, which define the swing mechanism for swing tower  40 , each include a cylinder barrel  52  and a piston rod  54  that extends from one end of the cylinder barrel  52 . Each of the cylinder barrels  52  has a trunnion mounting bracket  56  secured to the cylinder barrel  52  intermediate opposite ends with a pair of trunnions  58  carried by the bracket  56 . The trunnions  58  are received in openings  60  in the plates  50  so that the two cylinder barrels  52  are mounted in vertically spaced relation to each other and are located between an adjacent pair of plates  50 . Also, the openings  60  are positioned so that both cylinder barrels  52  are supported on a common vertical pivot axis at the forward ends of the plates  50 . It will be noted in  FIG. 2  that the common pivot axis defined by openings  60  and trunnions  58  are located on a plane P, which extends through the pivot axis defined by pins  46  and this plane is generally parallel to the longitudinal axis of the vehicle  10  and the pivot axis may be located forward of rails  16  and between the rear edges of wheels  13 . 
         [0019]    Piston rods  54  of the hydraulic cylinders are connected to an intermediate portion of the swing tower  40 . This connection consists of brackets  66  extending from the body of the swing tower  40  with pins  68  extending through the apertures in the brackets and apertures in the end of piston rods  54 . As shown in  FIGS. 2 and 3 , the piston rods  54  are connected to the intermediate portion of the swing tower  40  at laterally and vertically spaced points, both of which are spaced from the vertical pivot axis defined by pins  46 . 
         [0020]    As shown in  FIG. 4 , a hydraulic motor  72  is supported on mounting bracket  73  that is securely mounted on the rear end of the vehicle main frame  74 . The hydraulic motor  72  provides the motive power to slide the implement support plate  18  and the attached backhoe  48  transversely of the vehicle  10 . The hydraulic motor  72  may be a low speed high torque hydraulic motor (LSHT motor). A driving sprocket  76  is mounted on the shaft of the hydraulic motor  72 . 
         [0021]    The ends of a roller chain  79  are secured to a pair of yoke end connectors  80  that are mounted on the implement support plate  18 . See  FIG. 4 . One end of the roller chain  79  is secured to one of the yoke end connectors  80 . The roller chain  79  passes around a chain sprocket  82  mounted to one side of the quick release frame  17  at one end of the rails  16 , around the driving sprocket  76 , around tensioner sprocket  84  mounted to the mounting bracket  73 , around a second chain sprocket  82  mounted to the other side of the quick release frame  17  at the opposite end of the rails  16 , and is secured to the second yoke end connector  80 . The tensioner sprocket  84  deters the roller chain  79  from jumping out from the sprockets. 
         [0022]    The LSHT motor  72  rotates under applied hydraulic pressure from the vehicle hydraulic circuit at very low speeds without need for an intermediate speed reducer, and directly moves the roller chain  79 , which moves the backhoe  48 . The mechanism is simple with very few parts. Hence, frictional losses are minimal and the system is easy to maintain. The steel roller chain  79  is designed to operate without an enclosure. Due to the short duration and extent of movement, as well as the low speed of operation, the roller chain  79  runs efficiently without lubrication. 
         [0023]    By using the present system, movement of the backhoe  48  is controlled. Safety is improved since the controlled movement is without jerking that is prevalent in the prior systems. The present system is compact and improves vehicle maneuverability. 
         [0024]    A second embodiment of the slidable implement support is shown in  FIG. 5 . In this embodiment, the mounting bracket  73 , on which the hydraulic motor  72  is secured, is mounted on the implement support plate  18  and the yoke end connectors  80  are secured to the main frame  74 . One end of the roller chain  79  is secured to one of the yoke end connectors  80  and passes around a chain sprocket  82  mounted to one side of the quick release frame  17  at one end of the rails  16 , around the driving sprocket  76 , around tensioner sprocket  84  mounted to the mounting bracket  73 , around a second chain sprocket  82  mounted to the other side of the quick release frame  17  at the opposite end of the rails  16 , and secured to the second yoke end connector  80 . A third chain sprocket may be mounted on the mounting bracket  73  opposite the tensioner sprocket  84  to guide the roller chain  79  more parallel to the movement of the implement support plate  18 . 
         [0025]    In  FIG. 6 , the mounting bracket  73  and hydraulic motor  72  are mounted on the implement support plate  18  and the roller chain  79  is replaced with a rack  86 . The hydraulic motor  72  drives the pinion  88  moving the implement support plate  18  transversely with respect to the vehicle main frame  74 . 
         [0026]    The mounting bracket  73 , hydraulic motor  72  and pinion  88  may be mounted on the rails  16 , as shown in  FIG. 7 . In that case, the rack  86  is mounted on the implement support plate  18 . 
         [0027]    While the invention has been described with reference to a number of preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Summary:
An earth-working vehicle, such as a backhoe loader, has an implement, such as a backhoe, mounted in a manner that the implement can be shifted transversely with respect to the vehicle. A hydraulic motor and roller cable or rack are secured to the vehicle main frame and implement supporting plate to position the implement transversely of the vehicle without the jerky movements of prior backhoe loaders.