GB1508614A - Fluid pressure-medium brake systems for motor vehicles - Google Patents

Abstract

1508614 Load-responsive brakes ROBERT BOSCH GmbH 16 May 1975 [25 July 1974] 20784/75 Heading F2F In a fluid pressure vehicle braking system with a braking regulator 1 with a triple valve 2 providing a ratio of input to output pressure which is varied in response to vehicle loading a device 12 is provided to produce an intermediate ratio in case of failure of the load response linkage 9. The ratio may be varied by an adjustable fulcrum 16 of a balance beam 17 or by an adjustable effective-area diaphragm (Fig. 4). As shown in Fig. 1 the linkage normally adjusts the fulcrum 16 through a resilient link 10 but on failure of the linkage to a rear axle 6 a spring 13 pushes a member 14, which abuts linkage pivot 11, against a stop 15 intermediate the limits of the normal travel of the pivot 11. In Fig. 2 (not shown) a prestressed tension spring (19) is coupled to the housing by a link (20) permitting the spring to rise on suspension movement above the coil bound condition assumed on linkage failure. In Fig. 3 the fulcrum is adjusted normally by a piston 24 acted on by pneumatic suspension pressure from a spring bellows 22 but on failure of the pressure a spring 10 displaces the piston 25 and, through a stop 28 on the pistonrod, the piston 24 to the right together with a valve 27 which communicates inlet brake pressure P E as shown or outlet brake pressure P A to a chamber 26 between the pistons. The pressure herein holds the piston 24 to the right against a stop 29 and displaces the piston 25 to an intermediate position to the left. Fig. 4 shows a practical variable-area-diaphragm triple valve with an internal passage 36 from the brake outlet 3 to the valve 27 which may communicate through a hollow stem of the piston 24 with the chamber 26 and a sintered metal pressure damping disc 35 in the part 34 for the air suspension connection.