Force-multiplying pneumatic device

Claim 1

A force-multiplying pneumatic device including a body which is divided into front and rear chambers by a diaphragm, and a power piston which is secured to the diaphragm, whereby the application of a pressure difference between the two-chambers by operation of an input shaft, applies a frontward thrust the power piston, which thrust is transmitted to an output shaft through an elastic and pressure deformable reaction disc, the reaction force from the output shaft being transmitted partially to the input shaft through the reaction disc, characterised in that said reaction disc (10) is received in a recess (3e) formed in the front side of the power piston (3) for receiving therein the deformable reaction disc (10), the front end portion of the input shaft .(6) being adjacent to the rear surface of the reaction disc (10), and in that, a cylindrical retainer (11) is removably secured to the power piston (3) and is received in the recess (3e) to engage the reaction disc (10) by an annular end (11c) thereof, a large diameter rear end portion (12a) of the output shaft (12) being slidably inserted in the retainer (11), and said retainer (11) having radially inwardly projecting stop means (11a) to limit the frontward displacement of the large diameter rear end portion (12a) of the output shaft (12).