Abstract:
A linkage support system and method for mounting and supporting a linkage on a work vehicle. The linkage support system includes a load bearing support and a removable linkage pin support rigidly attached to the load bearing support. The work vehicle is, typically, an earthmoving vehicle which includes a frame, a work tool such as a bucket, and a linkage for manipulating the work tool. The load bearing support may be a portion of the frame of the vehicle.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to supports for linkages for manipulating work tools such as, for example, buckets on loaders and other work vehicles. More specifically, it relates to a system and method of attaching the linkages to work vehicles.  
       BACKGROUND OF THE INVENTION  
       [0002]     On many work vehicles such as, for example, loaders, the mechanical performance of the linkage mechanism for manipulating a work tool, such as a bucket, is optimized, in part by the anchor position of the linkage on the frame, i.e., linkage pin location. It is sometimes difficult to gain the necessary optimal linkage pin location on the conventional frames on which these linkages are attached as the required locations may not be conducive to ease of frame manufacture.  
       SUMMARY OF THE INVENTION  
       [0003]     In order to gain a desired or optimal performance from a linkage mechanism of a work vehicle it is sometimes necessary to place linkage pin supports in positions that are less than optimal with respect to the manufacturing process for a conventional frame. This, can lead to undesirable increases in the time and cost for manufacture of the frame with less than optimal linkage performance. Additionally, during the life of the work vehicle, there may be occasions when an alternate linkage pin location may be desired for optimal performance of the same or of a different linkage. With conventional vehicles, such a change would require another frame or another vehicle either of which would significantly increase costs.  
         [0004]     The inventors recognize that the problems above have resulted from the use of conventional one-piece frames which include the linkage pin supports and have solved the above problems by providing a removable linkage pin support. This arrangement makes it possible to achieve optimal linkage performance without the concomitant increases in the time and cost for manufacture associated with conventional frames. The invention replaces the complex linkage pin support area of the conventional frame with a linkage pin support system which includes a removable linkage pin support and a load support area of the frame suitable for the rigid attachment of the removable linkage pin support to the frame. In practice, the frame and the removable linkage pin support are separately manufactured and, afterwards, rigidly assembled using attaching bolts or some other suitable method of attachment.  
         [0005]     During the life of the work vehicle conditions may arise where changes in linkage pin support locations are desirable such as, for example, a change in terrain or a desire to use a linkage of a different configuration. As noted earlier, the costs for such a change on a work vehicle with a conventional frame would be substantial as a change of vehicle or, at the least, a change of frame would be required. The invention makes it possible to modify linkage pin locations on a work vehicle without incurring the associated time and cost difficulties of replacing the entire frame or vehicle as the removable linkage pin support may be replaced by another removable linkage pin support of a different configuration. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     Embodiments of the invention will be described in detail, with reference to the following figures, wherein:  
         [0007]      FIG. 1  is a view of a work vehicle in which the invention may be used;  
         [0008]      FIG. 2 . is a view of an exemplary embodiment of a front portion of the work vehicle illustrated in  FIG. 1 ;  
         [0009]      FIG. 3  is a view of an exemplary embodiment of a removable linkage pin support from the front frame illustrated in  FIG. 2 ;  
         [0010]      FIG. 4  is a view of an exemplary embodiment of the removable linkage pin support of  FIG. 3  with associated linkage pins assembled in place;  
         [0011]      FIG. 5  is a detailed view of the front frame illustrated in  FIG. 2  showing load bearing areas having a hole pattern that matches that of the removable linkage pin support shown in  FIG. 4 ;  
         [0012]      FIG. 6  is an exploded view of the exemplary embodiment of the front frame, the removable linkage pin support, and other associated parts illustrated in  FIG. 2 ; and  
         [0013]      FIG. 7  is a detailed sectional view of attachment hole  121   b  shown in  FIG. 6 .  
     
    
     DETAILED DESCRIPTION  
       [0014]      FIG. 1  illustrates a work vehicle in which the invention may be used. The particular work vehicle illustrated in  FIG. 1  is an articulated four wheel drive loader having a main frame or body  10  that includes a front frame  20  pivotally connected to a rear frame  30  by vertical pivots  40 , the loader being steered by pivoting of the front frame  20  relative to the rear frame  30  in a manner well known in the art. The front and rear frames  20  and  30  are respectively supported on front drive wheels  22  and rear drive wheels  32 . An operator&#39;s station  34  is provided on the rear frame  30  and is generally located above the vertical pivots  40 . The front frame  20  includes a mast  21  having a right mast portion  21   a  and a left mast portion  21   b . The front and rear drive wheels  22  and  32  propel the vehicle along the ground and are powered in a manner well known in the art.  
         [0015]     Mounted on the front frame  20  is a boom  50  that is partly formed by right and left arms  50   a  and  50   b  respectively. The right and left arms  50   a  and  50   b  are connected by a transverse cross tube  52  that is welded to each of the right arm  50   a  and the left arm  50   b . The rear end of the boom  50  is connected to the mast  21  by transverse pivots  61  and  63  and a loader bucket  70  is mounted on the forward end of the boom  50  by transverse pivots  62  and  64 . The boom  50  is rotated about transverse pivots  61  and  63  by hydraulic lift cylinders  65   a  and  65   b , first ends of which are, respectively, connected to the front frame  20  at transverse pivots  65  and  67 . Second ends of hydraulic lift cylinders  65   a  and  65   b  are, respectively, connected to the right and left arms  50   a  and  50   b  at transverse pivots  66  and  68 .  
         [0016]     The rotational location of the bucket  70  about the pivots  62  and  64  is controlled by a linkage  80  which, in this particular configuration, includes: a hydraulic tilt cylinder  81 ; left and right leveling links  82   a  and  82   b ; a bell crank  83 , a guide link  84 ; and a bucket link  85 . The hydraulic tilt cylinder  81  powers the linkage  80  and is connected to the bucket by the bell crank  83  which is mounted on a transverse pivot  90  at the front end of the leveling links  82   a  and  82   b . The hydraulic tilt cylinder  81  is connected to a first end of the bell crank  83  by a transverse pivot  91  and a second end of the bell crank  83  is connected to a first end of the bucket link  85  by a transverse pivot  92 . The bucket link  85  is mounted on a transverse pivot  93  at a second end of the guide link  84  and a first end of the guide link  84  is connected to the cross tube  52  via a transverse pivot  94  carried in a support  54  welded to the cross tube  52 . A second end of the bucket link  85  is pivotally connected to the loader bucket  70  via a transverse pivot  95 . As shown in  FIG. 2 , a first end of the entire linkage  80 , including the first end of the hydraulic tilt cylinder  81  and the first end of the leveling links  82   a  and  82   b , is operatively mounted to a removable linkage pin support  100  via linkage pins  110  and  111 . The removable linkage pin support  100  is rigidly connected to the front frame  20  at load bearing areas  120  and  122 , which are portions of the mast  21 , via bolts  130   a  and  130   b . Linkage pins  110  and  111  are attached to the linkage pin support  100  via screws  103   a  and attachment holes  103  and  106 .  
         [0017]      FIG. 3  is a detailed view of the removable linkage pin support  100  which includes leveling link support areas  101  and  102 , each having a threaded linkage pin attachment hole  103  and a linkage pin insertion hole  104 . The removable linkage pin support  100  also includes a tilt cylinder support area  105  having a threaded linkage pin attachment hole  106  and linkage pin insertion holes  107 . Included in each leveling link support area are access holes  108  for assembling the linkage pin  111  to the tilt cylinder support area  105 . In practice, the linkage pin  111  is assembled to the tilt cylinder support area  105  by inserting it into the insertion holes  107  via one of the access holes  108 . Also included are attachment holes  109   a  and  109   b  for rigidly attaching the removable linkage pin support  100  to the front frame  20  via screws  130   a  and  130   b  respectively. Finally, a hydraulics access hole  108   a  is provided for supplying hydraulics to the hydraulic tilt cylinder  81  via hydraulic tubes or pipes (not shown). Linkage pins  110  and  111  are assembled as shown in  FIG. 4  after the first ends of the leveling links  82   a  and  82   b  and the hydraulic tilt cylinder  81  are in place for mounting to the removable linkage pin support  100 .  
         [0018]      FIG. 6  is a detailed view of the load bearing areas  120  and  122 . In this particular configuration, the load bearing areas  120  and  122  contain threaded attachment holes  121   a  and  121   b  for rigidly attaching the removable linkage pin support  100  to the load bearing areas  120  and  122 . The attachment holes  121   a  and  121   b  are configured in a pattern that matches that of attachment holes  109   a  and  109   b . Each of the attachment holes  121   b  includes a countersunk portion  121   b ′ and a threaded portion  121   b ″ for receiving the attachment bolts  130   b . The threaded portions  121   b ″ are smaller than, parallel to, and concentric with the countersunk portions  121   b ′. The countersunk portions  121   b ′ have diameters equal to those of the attachment holes  109   b  and are sized to fit the outer diameter of locator bushings  123 . The inner diameters of the locator bushings  123  are sized to fit the outside diameter of the shanks or threaded areas, i.e. the inserted portion, of the bolts  130   b.    
         [0019]     In practice, the locator bushings  123  are placed in the countersunk portions  121   b ′ and the linkage pin support  100  is assembled to the front frame  20  by placing the matching attachment holes  109   b  directly over the exposed areas of the locator bushings  123  and pressing the linkage pin support  100  down. The linkage pin support  100  is then rigidly attached to the front frame  20  via bolts  130   a  and  130   b.    
         [0020]     Having described the illustrated embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.