GB336140A - Improvements in and relating to brakework for vehicle wheels - Google Patents

Abstract

336,140. Bendix-Perrot Brakes, Ltd., and Clark, H. Nov. 22, 1929. Fluid-pressure; blocks acting on drums. - For setting and adjusting the relative position of shoes in vehicle brakes of the type in which adjacent ends of shoes which are fully floating with a drum are separated by a cam or other shoe-actuating device to apply the brakes, an hydraulic setting device h, j is arranged between the ends of the shoes remote from the cam &c., liquid being admitted to the hydraulic device to separate these ends of the shoes to anv desired extent. Between the ends of the brake shoes a, b remote from the operating cam is arranged a floating cylinder h open at one end and a piston j working within the cylinder, each connected to the shoes by part-spherical heads engaging sockets l in the shoes, the parts being maintained in engagement by a coiled spring m connecting the shoes. A light spring p arranged between the piston and the closed end of the cylinder urges the piston outwardly and lugs n projecting from the back of the cylinder slide on the back plate c. Pipes s lead from the cylinders on each wheel to a single controlling means comprising a cylinder u, Fig. 6, with a piston v adjusted by a screw rod working through a boss w on the cylinder. To adjust the brakes the piston is screwed down until all the brakes are fully applied and then screwed back a certain amount and secured by a locking device y. A pump may be provided in the hydraulic system beyond the regulating cylinder with stop cocks between the pump and cylinder and between the cylinder and pipe lines, adjustment being effected by opening the cocks, pumping up the pressure in the system to apply the brakes, closing the cock leading to the pump, turning back the regulating piston to give the desired clearance and finally closing the cock between the regulating cylinder and the pipe lines. Air release valves may be provided adjacent the cylinders u, h and a catch plate for leakage may be arranged beneath each cylinder h, or a flexible sleeve may be fitted over the open end of the cylinder and around the piston rod. A device z for returning the shoes to a central position as described in Specification 339,505 is fitted. The piston rod of the piston j may be pivoted, and separate bosses may be provided for the cylinder and the piston rod slidable under guides on the back plate c.