Richard B Freeman, Alfred W Schmidt: Vacuum-pneumatic power tool. Isler and Ornstein, April 7, 1981: US04259858 (19 worldwide citation)

A power tool in the form of a fluid pressure cylinder utilizing multiple movable pistons coupled for contemporaneous pressure-responsive working movement, as well as for return to no-load position. Individual pressure buildup on each pressure chamber is controlled by pre-selected imput and exhaust o ...

Alfred W Schmidt, Douglas G Reed: Power operated gripper. Fabco Air, Charles A Bevelacqua, April 28, 1987: US04660877 (6 worldwide citation)

A power operated gripper in which both the gripping and releasing movements of the gripping elements are made under power. The gripper comprises a thrust member which is extended and retracted in a linear motion by the power means, gripper arms which swing in an arc to grip and release a workpiece, ...