GB1205294A - Improvements in or relating to brake force regulators - Google Patents

Abstract

1,205,294. Load-dependent brake-force regulators. AUTOBRZDY JABLONEC NARODNI PODNIK. 28 Aug., 1968 [30 Aug., 1967], No. 41127/68. Heading F2F. In a load-dependent brake-force regulator incorporating a differential piston and a regulating piston, the regulating piston being subject to a force dependent on the vehicle load, the regulating piston is coaxial with the differential piston, and the distribution space, connected to the brake cylinders and defined in part by the shoulder formed between the larger and smaller heads of the differential piston, is connected by a passage in the smaller head with the regulating space, which is formed between the smaller head and the regulating piston. As shown, a differential piston 8 has a larger head 9 accommodated with clearance in a bore 5 provided in a body 1 attached to a sprung portion of the vehicle (e.g. the frame). The larger head 9 has a resilient packing 10 for engagement with a seat 11 formed where the bore 5 joins a bore 7 of less diameter. The differential piston 8 has a reduced central portion 12 forming, with part of the bore 7, a distribution space 20 having connections at 21, 22 to brake cylinders (preferably for the rear wheels). Finally the piston 8 has a smaller head 13 slidable in bore 7, an axial hole 25 and a transverse hole 26 to connect the distribution space 20 with the region 24 below the smaller head 13, and a central protuberance 17 at the top of the larger head surrounded by a cup spring 18. Below the piston 8 is a regulating piston 14 having at the top a central protuberance 23 and, at the bottom, a recess 28 for accommodation of a rod 29 pivoted to an arm 31 attached to a helical torsion spring 32 which is connected with the axle. On application of the brake, master-cylinder fluid entering at 4 depresses piston 9, 13 slightly, then flows via 19, 11, 20, 21, 22 to the rear brake cylinders. Some fluid passes via 26, 25 to the regulating space 24, depressing regulating piston 14 against the force of torsion spring 32 until head 9 reaches seat 11; thereafter, no more fluid flows to the rear brake cylinders. If, at the moment of braking, the rear axle is relieved of load by movement of the vehicle weight towards the front axle, the effective force of spring 32 is reduced, so the volume of the regulating space is increased, with consequent reduction in rear brake pressure and less tendency to wheel locking. If, on braking, the rear axle load is on the other hand increased, the spring force is increased, and the rear brake pressure is consequently increased. If the increase in spring force is large, piston 9, 13 is raised until head 9 is lifted off seat 11, so inlet space 19 is connected to the rear brake cylinders again, until equalization of pressures occurs. On brake release the parts resume the positions shown.