Locking pliers

The first locking pliers, with the trade name Vise-Grip, were invented by William S. Petersen in De Witt, Nebraska, United States in 1924.

[1][2] Later, in 1955, in the United Kingdom, M K Mole and Son, a hand tool manufacturing company, under the managing direction of Thomas Coughtrie, began making nearly identical pliers.

Locking pliers remain clamped to an object without requiring continuous pressure on the handles based on the "over-center" principle.

After being properly adjusted using a threaded screw, the pliers are brought to bear by cam action.

Locking pliers have four advantages: A typical use would be to hold metal parts in place for welding.