US Patent 7509895 Self-adjusting locking pliers

The self-adjusting locking pliers include a body having a fixed jaw supported at one end. A moveable jaw is pivotably supported on the body at a slidable pivot connection. A linkage transmits a force applied to the handles of the pliers to the jaws and locks the jaws in the clamping position. The linkage allows the angle between the links to be preset to thereby control the clamping force applied to the work piece. The movable jaw is selectively attached to the linkage in one of two positions such that the jaw span may be adjusted without affecting the geometry of the linkage.