Quick coupler

Claim 1

A quick coupler for detachably attaching an implement to an earthworking vehicle which is provided with a pair of lift arms and a pair of tilt links, said coupler comprising: a hitch assembly including a pair of transversely spaced hitch members one of which hitch members having upper and lower end portions thereof rotatably linked to one of said tilt links and one of said lift arms, respectively, and the other one of said hitch members similarly having upper and lower end portions thereof rotatably linked to the other one of said tilt links and the other one of said lift arms, respectively, said hitch members each having upper and lower coupling elements respectively in the upper and lower end portions thereof; a hook assembly fixedly mounted on the back of said implement and including a pair of transversely spaced hook members each having upper and lower end portions, an upper receiving portion in the upper end portion shaped to receive from beneath one upper coupling element of said hitch assembly for engagement with the front, top and rear surface portions thereof and a lower receiving portion in the lower end portion shaped to receive from behind one lower coupling element of said hitch assembly for engagement at least with the front surface portion thereof, a locking member rotatably mounted in the vicinity of the lower receiving portion of each hook member and normally having at least one portion thereof disposed in a normal position interfering with a path of movement taken by said lower coupling element of said hitch member when moved toward said lower receiving portion of said hook member for engagement therewith, said locking member being rotatable into a released position clear of said path of movement when engaging said lower coupling element of said hitch member with said lower receiving portion of said hook member and into a locking position same as or proximal to said normal position as soon as said lower coupling element is engaged by said lower receiving portion of said hook member, said locking member being adapted to be held in said locking position by a force transmitted thereto from said lower coupling element of said hitch member and acting in a direction to disengage said lower coupling element from said lower receiving portion; and an unlocking mechanism linked to each locking member of said hook assembly to rotate said locking members from said locking position to said released position; wherein said unlocking mechanism is provided with a stopper member rotatably mounted on said lift arm and including means operable at the operator's station of said earthworking vehicle for rotating said stopper member between a nonoperative and an operative position thereof, the fore end of said stopper member being abutted against said locking member of said hook assembly when moved into said operative position, whereupon said implement is tilted forward to cause said locking member to rotate from said locking position into said released position under the influence of the force applied thereto by the abutment of said stopper member.