Assembly of a pneumatic brake booster and of a master cylinder

An assembly of a pneumatic brake booster of a motor vehicle and of a master cylinder, the booster including a casing fixed to a wall separating the passenger compartment from a front compartment of the vehicle, said brake booster having a casing which is divided in leaktight fashion by a movable wall structure into a front chamber permanently connected to a source of partial vacuum and a rear chamber connected selectively to said front chamber or to the atmosphere by a valve means actuated by a control rod, said control rod being capable of bearing, by means of a front face of a plunger on a rear face of a reaction disk secured to a push rod, said master cylinder including a body having an axial bore for receiving at least one piston and formed with at least first and second flanges, said first flange interacting with a first screw and first nut and said second flange interacting with a second screw and second nut for fixing said body with said casing to form a mechanical link between said piston of said master cylinder and said push rod of said booster, characterized in that said push rod of the booster includes at least first and second parts which are joined together to form said mechanical link, said mechanical link having a ball free to rotate in a housing formed on an end of said first part, said ball being capable of rolling over a planar face formed on an end of the second part, said planar face being inclined with respect to an axis of said first part, such that an angle formed between said first and second parts allows a force to be transmitted between said first and second parts and means are provided so that with a rotation of said master cylinder with respect to said booster in response to a rotational torque developed when said master cylinder is pushed substantially breaks the mechanical link between said piston of the master cylinder and said push rod of the booster.

An assembly of a pneumatic brake booster of a motor vehicle and of a master cylinder, the booster including a casing fixed to a wall separating the passenger compartment from a front compartment of the vehicle, said brake booster having a casing which is divided in leaktight fashion by a movable wall structure into a front chamber permanently connected to a source of partial vacuum and a rear chamber connected selectively to said front chamber or to the atmosphere by a valve means actuated by a control rod, said control rod being capable of bearing, by means of a front face of a plunger on a rear face of a reaction disk secured to a push rod, said master cylinder including a body having an axial bore for receiving at least one piston and formed with at least first and second flanges, said first flange interacting with a first screw and first nut and said second flange interacting with a second screw and second nut for fixing said body with said casing to form a mechanical link between said piston of said master cylinder and said push rod of said booster, characterized in that said push rod of the booster includes at least first and second parts which are joined together to form said mechanical link, said first flange of said master cylinder is situated outside the casing of the booster and said second flange of said master cylinder is situated inside the casing of the booster and means are provided so that with a rotation of said master cylinder with respect to said booster in response to a rotational torque developed when said master cylinder is pushed substantially breaks the mechanical link between said piston of the master cylinder and said push rod of the booster.