GB513639A - Improvements in or relating to master cylinder units for liquid pressure control systems - Google Patents

Abstract

513,639. Hydraulic transmission of power. CLEVELAND, F. J. (Bendix Aviation Corporation). March 8, 1938, No. 7286. [Class 69 (ii)] [Also in Group XXXIV] In a hydraulic master cylinder comprising a main piston and one or more floating pistons which divide the cylinder into compartments each of which is connected to a set of brakes or other devices, means are provided whereby a pair of adjacent pistons become joined when pressed together through failure of the hydraulic pressure between them. The end piston may become similarly attached to the cylinder end. The length of the connection between the operating pedal and the main piston may be automatically adjusted when the pistons connect. A floating piston 32 divides the working space of the cylinder into compartments 33, 34 which as shown, are connected through outlets 19, 15 to the rear and front brakes respectively of a vehicle. The main and floating pistons 23, 32 are positioned respectively by pins 55, 46 which enter grooves in the pistons. Chambers 33, 34 are normally connected to the reservoir 11 by passages through the pins 46, 55 and the pistons, mushroom valves 50, 54 which close the piston passages when the pistons are moved being normally held open by engagement of the valve stems with the pins. Each valve has a rubber skirt 53 to form a seal. If in applying the brakes, the pipe line connected at 15 to the front brakes fails, a socket 40 on the piston 32 is forced on to a tapering spigot 41 on the cylinder end 14 thus preventing return of the piston. Similarly it the pipe line connected at 19 to the rear brake fails the pistons 23, 32 are joined by the socket and spigot 38, 37. To permit return of the pedal 57 to the normal position in this case, the thrust connection between it and the piston 23 is automatically extensible and comprises balls or rollers 66 adapted to wedge between a tapered part 65 of the member 63 and a socket member 62 to transmit the thrust, while during the return stroke, after the piston 32 has engaged the pin 46, the socket 62 slides on the member 63.