Abstract: An apparatus for providing a reciprocating motion. The apparatus has a housing block that contains twin piston guides in spaced apart relationship to one another. The piston guides each contain a piston that has a gear rack. The gear racks are connected by a pinion gear so that the movement of one piston will cause an equal and opposite movement of the other piston. The movement of the pistons is controlled by the application of a fluid pressure to one or both of the pistons. The travel of the pistons is limited by a mechanical stop at one end and a fluid cushion device at the other end. Tools for the altering of a workpiece may be attached to one or both ends of the pistons. In one embodiment, the apparatus is subjected to a rotary displacement achieved through the linear motion of one of the pistons.

Abstract: An apparatus for providing a reciprocating motion. The apparatus has a housing block that contains two movable arms in spaced apart relationship to one another. The movable arms are each controlled by independently attached fluid driven actuator cylinders that are mounted externally of the housing block. Tools for the altering of a workpiece may be attached to one or both ends of the movable arms. An embodiment utilizes a rack and pinion gear arrangement to immobilize any imbalance in forces that may exist when the movable arms are biased against a workpiece.

Abstract: An apparatus for providing a reciprocating motion. The apparatus has a housing block that contains two movable arms in spaced apart relationship to one another. The movable arms each contain a rack gear connected to a common pinion gear. One movable arm is driven by a fluid actuated cylinder. The driven movable arm then produces an equal and opposite motion in the other arm because of the interconnection of the pinion gear. Tools for altering of a workpiece may be attached to one or both ends of the movable arms. An embodiment utilizes the rotation of the pinion gear shaft to cause a translation of the entire apparatus away from a workpiece.