PNEUMATIC SERVOMOTOR AND METHOD ITS CONTROL Russian patent published in 1997 - IPC

FIELD: braking devices of transport facilities. SUBSTANCE: pneumatic servomotor has housing divided into front chamber and rear chamber by piston. Front chamber is constantly connected with vacuum source and rear chamber for mounting the hollow-piece of piston with build-in valve distributor consisting of spring-loaded valve, first seat on movable plunger and second seat on piston; piston skirt embracing the tail-piece is secured in housing over periphery by means of diaphragm; movable plunger is articulated with control rod loaded with return spring; it is mounted in tail-piece of piston for engagement with counter-acting disk made integral with pushing rod. Plunger is provided with threaded bush and active spring-loaded bush mounted on it in succession; on side of rear chamber, piston is provided with diaphragm rigidly secured to skirt and intermediate diaphragm over inner surface of diaphragm; distributor valve is made in form of section of surface of intermediate diaphragm; first seat is made on active bush and second seat is made on piston skirt. Method of control of servopiston consists in control of required clearance between plunger and counter-acting disk through preliminary application of force to pushing rod corresponding to mode of change-over of distributor; motion of plunger is effected through screwing it together with threaded bush till it gets in contact with counter-acting disk. EFFECT: enhanced reliability and efficiency. 11 cl, 1 dwg