PNEUMATIC SERVOMOTOR Russian patent published in 1995 - IPC

FIELD: braking follow-up pneumatic servomotors. SUBSTANCE: servomotor has housing 10 accommodating piston 20 formed by rear cylindrical section 22 which carries skirt 14. The latter, by means of turnable diaphragm 12, forms front chamber 16 constantly communicating with vacuum source, and rear chamber 18 selectively coupled either with front chamber 16 or with atmosphere through valve (20a, 32a, 40) set into action by means of control rod 34 which can thrust through plunger 32 against one of surfaces of reaction disk 53 rigidly coupled with pusher 56. Valve (20a, 32a, 40) has shutoff member 40 engaging with valve first seat 32a formed on plunger 32 and with valve second seat 20a formed on piston 20. Plunger 32 and piston 20 carry second shutoff valve (65, 70). EFFECT: enhanced quality of operation. 4 cl, 1 dwg