US Patent 8950299 Locking pliers

A locking pliers includes a fixed handle supporting a fixed jaw, a movable jaw, a movable handle pivotally connected to the movable jaw about a pivotal axis, and a movable pivot unit disposed on the fixed handle and the movable jaw. The pivot unit includes a pivot pin and a pivot hole configured to loosely receive the pivot pin such that, when a manual turning force is applied to the movable handle, the movable jaw is turned clockwise to a locking position. As a result of abutting engagement between the pivot pin and a leading region of the pivot hole, a friction force is generated to hold the movable jaw in a tightening position. The gripping force between fixed and movable clamping surfaces of the jaws can be firm and stable.