US Patent 7637753 Ground clamp

A clamping device utilizing the mechanism of conventional vise-grip or locking pliers comprises a L-shape fixed arm and a L-shape movable arm, an insulating U-shape clamping jaw which is connected to the ground cable of an arc welding system; and a floating pad attached to a threaded rod so that the effective clamping size of the clamping device is adjustable. With the U-shape clamping jaw, the clamping device is capable of clamping firmly flat workpieces of various thicknesses as well as workpieces with curved or angled surfaces and providing a good electrical contact between the ground cable of the arc welding system and the workpiece.