GB1328842A - Gas powered drive unit - Google Patents

Abstract

1328842 Pneumatic actuators UNITED STATES SURGICAL CORP 25 Aug 1970 [25 Aug 1969] Divided out of 1328841 18260/73 Heading F1D In a pneumatic actuator downward movement of a spring-returned piston 112, Fig.1, is initiated by a trigger 136, Fig.2. This permits a spool 104 to move down and open an input port 102 to admit gas under pressure into a chamber 132. Gas pressure acting on a seal 106 now overcomes the force of the return spring 117 and forces the spool and piston down until the position shown in Fig.2 is reached. In this position the spool closes on exhaust port 126. Gas now passes through a transfer port 110 and forces the piston down as shown in Fig.3. As the pressure rises in a chamber 134 the spool is raised by pressure on its underside which is of greater area than that of the diaphragm 106. Gas now passes into a chamber 130 where it acts on the underside of a diaphragm 108 and returns the spool to its original position and closes the inlet port 102. The gas from above the piston 112 is vented through the exhaust port 126 and the spring 117 raises the piston to its original position as shown in Fig.1. A port 124 prevents from pressure building up in a chamber 128 due to flexing of diaphragm 108.