GB697509A - Improvements in or relating to hydraulic braking systems - Google Patents

Abstract

697,509. Hydraulic brakes. KORBER, F. Sept. 18, 1951, No. 21926/51. Class 103 (i). A master cylinder assembly for hydraulic brakes includes both an auxiliary piston 6, for counteracting leakage that may occur past the main piston 1, and also a sealing piston 23 for cutting off a defective pipe or pipes. The auxiliary piston 5 has a central passage 6 through which liquid is forced by the main piston 1 during normal operation. The piston is held in position by the engagement with a projection 5a of a stop member 13 pressed outwardly by a spring 14. In the event of substantial leakage past the main piston 1, this piston in moving down the cylinder first closes the passage 6 in piston 5 with its end valve projection 16 and in moving also the auxiliary piston 5 releases the stop member 13 which is urged outwardly by the spring 14 so that electrical contacts 18, 19 are closed to actuate a circuit controlling a warning light indicating to the vehicle driver that the brakes are defective. The main and auxiliary pistons 1 and 5 acting together, however, are still effective to apply the brakes. When any brake conduit connected to connection 22 is still effective, the sealing pistons 23 are moved only part of the way down cylinder 24. If, however, the pipe leaks, the piston 23 moves right to the end of the cylinder and by engagement with clamps 25a seals off the pipe. After repair of the pipe it may be vented by means of screw 30 acting on ball valve 29.