Patent ID: 6978701
Filing Date: 2005-12-27
Classification: B25B

Abstract:
1. A wrench having a head portion adapted to engage and apply torque to a workpiece, and turning means for turning said head portion, the wrench further comprising: a flexible ring portion included in said head portion and attached to said turning means at one end and free at its other end, said ring portion having an inner working surface for engaging the workpiece; clamping means included in the turning means for clamping the free end of the ring portion against the workpiece when the turning means is turned in a predetermined direction; a portion of the flexible ring portion at or adjacent the free end thereof having an external, first cam surface which defines a wedge shape with the inner working surface of said portion; said wedge shape increasing in thickness towards the free end of the flexible ring portion; and said clamping means having a second cam surface arranged to cooperate with said wedge-shaped portion so that when torque is applied to said head portion in said predetermined direction, said wedge-shaped portion is urged in such a peripheral direction relative to the workpiece as to tend to close the flexible ring portion around said workpiece.