Pneumatic servomotor for assisting braking in motor vehicle, has blocking key axially located against transmission piece such that groove arrives at key and key is inserted in groove for permitting sensors to act on piece

摘要

The servomotor has a sensor piston (103) and a sensor (103') comprising a transversal blocking groove (104) formed at a cylindrical peripheral surface of the piston and the sensor. A blocking key (102) is supported against the surface. A force transmission piece (109) surrounds the sensors and is supported on a reaction disk (32). The key is axially located against the piece such that the groove arrives at the key and the key is inserted in the groove for permitting the sensors to act on the piece, when the sensor and the piston (103) forward with respect to a piston (22).