GB393581A - Improvements in brakes - Google Patents

Abstract

393,581. Fluid-pressure brakes. BENDIX BRAKE CO., 401, North Bendix Drive, South Bend, Indiana, U.S.A. Dec. 3, 1931, No. 33517. Convention date, Dec. 4, 1930. [Class 103 (i).] In a hydraulic master cylinder movement of the piston 38 to apply the brakes draws fluid into a chamber 48 behind it and the return movement of the piston puts the fluid under pressure and into communication with the fluid lines. The piston of the master cylinder operated by the brake pedal rod 32 comprises two parts 38, 40 of different diameter, movement of which on brake application enlarges the chamber 48 between them and produces a suction to draw reserve fluid into this space from the reserve reservoir connected to a port 30, through a chamber 64 and a passage 68 controlled by a ball check valve. When the brake is released this fluid is forced past a check valve 66 into a passage 62 and into the chamber 78 below a piston 70, which is moved against a spring 72 until a predetermined pressure is attained when a spring-controlled valve 76 opens to allow excess liquid to return to the reservoir. This fluid pressure is communicated to the pipe lines connected to port 36 by passages 62, 60 when the piston 38 has returned to its release position. Pistons 38, 40 .engage each other by projections 44, 46, and in a modified form of piston, the pistons are of the same diameter and the piston 40 is positively connected to the brake pedal rod so that it is quickly returned on brake release and thus creates a suction between the pistons between which liquid is accordingly drawn.