referring to fig1 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 fig1 . 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 fig3 a , 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 fig3 b , 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 fig4 , 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 fig3 a 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 fig5 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 fig5 , 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 fig7 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 fig6 and 8 , it is apparent that the lower hook 100 is wider than the lower hook 110 . fig9 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 fig9 , 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 fig1 , 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 .
an implement quick coupling mechanism for a work vehicle includes a frame having a cross member and left and right side members projecting from the cross member . the cross member and side members have mounting parts which permit different implement coupling parts to be mounted thereon . 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 .