Patent ID: 7555902
Filing Date: 2009-07-07
Classification: B60T,F15B

Abstract:
1. A tandem master cylinder ( 1 ) for an automotive hydraulic brake system including a housing ( 2 ) having a bore ( 3 ), a first and a second piston ( 4 , 5 ) slidably arranged in the bore ( 3 ) to define a first pressure chamber ( 29 ) between the first and second pistons ( 4 , 5 ) and a second pressure chamber ( 35 ) between the second piston ( 5 ) and one end ( 38 ) of the bore ( 3 ), first and second stops ( 32 , 37 ) in the housing ( 2 ) respectively engageable with the first and second pistons ( 4 , 5 ) to define respective rest positions, first and second valves ( 25 , 26 , 27 ; 40 , 41 , 42 ) located respectively inside the first and second pistons ( 4 , 5 ) for hydraulically connecting the first and second pressure chambers ( 29 , 35 ) to an unpressurized supply chamber ( 8 , 9 ) when the first and second pistons ( 4 , 5 ) are engaged with their respective first and second stops ( 32 , 37 ) and movable to respective closed positions sealing the first and second pressure chambers ( 29 , 35 ) upon movement of the first and second pistons ( 4 , 5 ) out of engagement with the first and second stops ( 32 , 37 ), wherein at least one of the first and second valves (