Abstract: A fluid driven piston and cylinder includes a pair of wide opening jaws for gripping relatively thick workpieces. The jaws are mounted on a head which is linearly displaceable by a piston rod powered by the piston and cylinder. An actuating plate on the head actuates closure of the jaws when the head reaches its maximum outward position of displacement. The actuating plate displaces a U-shaped yoke reciprocably mounted on the head. The jaws are pivotally mounted on the head and are squeezed into gripping relationship to a workpiece by rollers mounted on the extremities of the yoke.

Abstract: A pair of actuatable gripping jaws are secured to a mounting head which is slidably mounted on a support by a pair of guides. The mounting head is of unitary construction and includes a fluid operated motor integral therewith for actuating the jaws at any point along the stroke of the mounting head. One of the guides is defined by the drive shaft of a fluid operated piston and cylinder which reciprocably drives the mounting head. A rigid fluid conduit coupled with the mounting head for supplying fluid to the motor defines the other guide.

Abstract: A clamping assembly is operated by a piston and cylinder assembly rotatably mounted on a support. A mounting bracket rotatably mounted on the support is provided with a pair of pivotally mounted plates each having a clamping arm and a cam track. The mounting bracket includes an annular shoulder engaging the support; a flange draws the shoulder against the support, thereby selectively locking the bracket and the piston and cylinder against rotation in any of a plurality of rotational positions. A drive rod connected to the piston extends through the support and into an elongate slot in the bracket. A pair of rollers secured to the outer end of the rod are disposed in the cam slots and drive the plates to pivot. The cam slots are specially configured to lock the clamp in a locking position in the event that fluid pressure is lost in the piston.