Patent Document

BACKGROUND 
   The present invention relates to a quick coupler for attaching an implement to a vehicle such as an agricultural tractor. 
   Different sized tractors are normally provided with different sized implement hitches. For example, standards require that larger tractors be provided with a larger category 4N hitch, whereas smaller tractors are normally provided with a smaller category 3 hitch. It is also known to mount a quick coupler to a tractor hitch and then couple an implement to the quick coupler. A larger category 4 quick coupler is normally mounted on a larger category 4 hitch. Yet, there are many hitch-coupled implements which are designed to be coupled with a category 3 hitch. Therefore, it would be desirable to have a quick coupler which can be mounted on a category 4 hitch and which can be modified or adapted to be coupled to either a category 3 or category 4N implement. 
   SUMMARY 
   Accordingly, an object of this invention is to provide an adjustable quick coupler mechanism. 
   A further object is to provide a quick coupler which can be converted to different standard dimensions. 
   These and other objects are achieved by the present invention, wherein a quick coupler mechanism includes a frame having a cross member and left and right side members projecting from the cross member. A first set of hook members having a first type of dimensional characteristics may be mounted on the frame to form a first category of coupling mechanism. A second set of coupling members having a second type of dimensional characteristics may be mounted on the frame to form a second category of coupling mechanism. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a quick coupler frame according to the present invention; 
       FIG. 2  is a perspective view from the front of a portion of the frame of  FIG. 1 ; 
       FIG. 3A  is a perspective of a category III top hook; 
       FIG. 3B  is a perspective partially exploded detail view of the hook of  FIG. 3A  mounted to the cross member of  FIG. 1 ; 
       FIG. 4  is a perspective view of a category IV top hook which may be used in place of the hook of  FIG. 3A ; 
       FIG. 5  is a perspective exploded view showing a category 4NL lower hook mounted to the side member of  FIG. 1 ; 
       FIG. 6  is a top view of the hook of  FIG. 5 ; 
       FIG. 7  is a side view of a category 3 lower hook which may be used in place of the hook of  FIG. 5 ; 
       FIG. 8  is a top view of the hook of  FIG. 7 ; 
       FIG. 9  is a perspective view of a center portion of an alternate embodiment cross member; and 
       FIG. 10  is a perspective detail view showing the top hook of  FIG. 3A  mounted to the cross member of FIG.  9 . 
   

   DETAILED DESCRIPTION 
   Referring to  FIGS. 1 and 2 , a quick coupler assembly includes a quick coupler frame  10  having upper cross member  12  and right and left downward extending side members  14  and  16 . A pair of upper mounting tabs  18  and  20  are spaced apart and project upwardly from a top surface of cross member  12 . A pair of lower mounting tabs  22  and  24  are spaced apart and project downwardly from a bottom surface of cross member  12 . Tabs  18  and  20  include a forward pair of aligned bores  26  and  28  for use in coupling the frame  10  to a tractor (not shown). Tabs  18  and  20  also include a pair of rear aligned hook coupling bores  30  and  32 . Tabs  22  and  24  include a pair of aligned hook coupling bores  34  and  36 . 
   Right side member  14  includes a rear plate  40  and a pair of spaced apart side plates  42  and  44 . Rectangular slot  46  extends upwardly from the lower end of plates  40 . Left side member  16  includes a rear plate  50  and a pair of spaced apart side plates  52  and  54 . Rectangular slot  56  extends upwardly from the lower end of plates  50 . Each side member preferably includes a conventional hook latching mechanism, including handle portion  58  and latch lever portions  60  which are shown in FIG.  1 . Since left side member  16  is a mirror image of right side member  14 , the following description will be directed only to right side member  14 . 
   A forward pair of aligned bores  62  and  64  for use in coupling the frame  10  to a tractor hitch draft link (not shown) extend through a lower end of plates  42  and  44 . A pair of aligned upper rear hook coupling bores  66  and  68  extend through the lower end of plates  42  and  44 . A pair of aligned lower rear hook coupling bores  70  and  72  extend through the lower end of plates  42  and  44 , spaced apart from and below bores  66  and  68 . 
   Referring now to  FIG. 3A , a category III center hook  80  includes a base member  81  and a hook member  83  which projects from a lower end of member  81 . Base member  81  includes an upper mounting bore  77  and a lower mounting bore  79 . Referring now to  FIG. 3B , hook  80  is mounted to the tabs  18  and  20  of cross member  12  by pins  82  and  84  which extend through bores  30 ,  32  and  34 ,  36 , respectively, and through corresponding bores  77  and  79  in the member  81 . 
   Referring now to  FIG. 4 , a category IV center hook  90  includes a base member  91  and a hook member  92  which projects from a central portion of member  91 . Base member  91  includes an upper mounting bore  94  and a lower mounting bore  96 . Hook  90  may be mounted to the tabs  18  and  20  of cross member  12  by pins  82  and  84  which extend through bores  30 ,  32  and  34 ,  36 , respectively, and through corresponding bores  94  and  96  in the member  91 . By comparing  FIGS. 3A and 4 , it is apparent that the vertical distance between hook member  83  and upper mounting bore  77  of hook  80  is larger than the vertical distance between hook member  92  and upper mounting bore  94  of hook  90 . 
   Referring now to  FIGS. 5 and 6 , a category IV lower hook  100  includes a base member  102  and a hook member  104  which projects from a lower end of member  102 . Base member  102  includes an upper mounting bore  106  and a lower mounting bore  108 . Referring now to  FIG. 5 , hook  100  is mounted side member  14  by pins (not shown) which extend through bores  66 ,  68  and  70 ,  72 , respectively, and through corresponding bores  106  and  108  in the member  102 . 
   Referring now to  FIGS. 7 and 8 , a category III lower hook  110  includes a wider base member  112  and a narrower hook member  114  which projects from a lower end of member  112 . Base member  112  includes an upper mounting bore  116  and a lower mounting bore  118 . Hook  110  may be mounted to the side member  14  by pins (not shown) which extend through bores  66 ,  68  and  70 ,  72 , respectively, and through corresponding bores  116  and  118  in the member  112 . By comparing  FIGS. 6 and 8 , it is apparent that the lower hook  100  is wider than the lower hook  110 . 
     FIGS. 9 and 10  show an alternate embodiment of the central portion of the cross member and an alternate upper hook member  130  for use therewith. Referring to  FIG. 9 , a pair of upper mounting tabs  120  and  122  are spaced apart and project upwardly from a top surface of cross member  12 . A pair of lower mounting tabs  124  and  126  are spaced apart and project downwardly from a bottom surface of cross member  12 . Tabs  120  and  122  include, respectively, a pair of aligned bores  121  and  123  for use in coupling the frame  10  to a tractor (not shown). Tabs  124  and  126  also include a pair of rear aligned hook coupling bores  125  and  127 . 
   Referring now to  FIG. 10 , hook  130  includes a base member  132  with an upper end  134  received by a forked end of an upper hitch draft link  142  and by tabs  120  and  122  and held in place by pin  144 . A lower end of base member  132  is held in place between tabs  124  and  126  by pin  146 . A hook prong  140  projects generally upwardly from base member  132 . 
   With this invention, the upper and lower hooks may be exchanged to allow for different mast height (vertical distance between lower hooks and upper center hook), pin sizes, and hook widths such as are required by the standards for category III and IVNL implements and quick couplers. The user can easily change the quick coupler implement side from a category III to a category IVN depending on what implement they are working with. Because the hooks are separate parts, the material properties of each can be chosen to allow for better strength and wear without significant cost increase. 
   While the present invention has been described in conjunction with a specific embodiment, it is understood that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, this invention is intended to embrace all such alternatives, modifications and variations which fall within the spirit and scope of the claims.

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