Machine tool vise

Claim 1

A precision machine vise comprising: an elongate body including an elongate base having a pair of laterally spaced, upstanding slide structures secured thereto and projecting therefrom, a stationary jaw mounted on said slide structures and having an inner face and an outer face, a movable jaw mounted on said slide structures for sliding movement towards and away from the said stationary jaw, an actuating nut being shiftable relative to said body for moving said movable jaw, interlocking inclined surfaces on said movable jaw and actuating nut whereby the nut imparts a downward component of force on the movable jaw as the latter is urged into gripping relation with a work piece gripped between the jaws, a cylinder housing secured to one end of said body and having bearing engagement only with the outer face of said stationary jaw and one end of said base, said housing having a cylindrical chamber therein connected in communicating relation with a source of fluid under pressure, an elongate revolvable actuating screw extending through said body and said cylinder housing and threadedly engaging said actuating nut for shifting the same, a piston mounted on said screw and positioned in said chamber, a control valve connected in communicating flow controlling relation with said source of fluid pressure and said cylinder and when operated supplying fluid to the cylinder to axially shift the screw in a forward direction toward said stationary jaw, a resilient means engaging the screw and returning the same in a rearward direction when the valve is rendered inoperative.