GB985888A - Improvements relating to motor vehicles - Google Patents

Abstract

985,888. Anti-skid brake control. ROLLSROYCE Ltd. Nov. 8, 1963, No. 44272/63. Heading F2F. A motor vehicle is equipped with means responsive to sideways acceleration of the vehicle for controlling means for reducing the braking load on the rear wheels of the vehicle so as to prevent skidding when a predetermined amount of sideways acceleration is exceeded during braking, as when braking on a corner. As shown, the means responsive to sideways acceleration comprises a pendulum formed by a mass 10 carried by an arm 11 which is pivotally mounted on the vehicle for swinging in a plane transverse of the vehicle, the extent of swinging being limited by adjustable stops 33, 34 and controlled by adjustable springs 31, 32. The adjustment is such that when a predetermined sideways acceleration is reached, the pivotal movement of the pendulum rotates a control spindle 12. In the embodiment of Fig. 3, spindle 12 has recesses 14, 15 (Fig. 1) open to atmosphere, and on rotation of the spindle air is admitted via one of the recesses to a passage 18 communicating with a brake control chamber 20 of an hydraulic pressure limiting valve comprising a ball 28 normally lifted off a seat 26<SP>1</SP> by a stem connected to a diaphragm 22 which has a perforation 24 communicating chamber 20 to a chamber 21 which is connected to the engine inlet manifold. The stem has a balloperating portion 29 of small diameter and a large diameter portion 30 the top of which is disposed in a pressure-relieving chamber 27 connected by conduit 27<SP>1</SP> to the rear wheel brake cylinders. Hydraulic fluid from a master cylinder enters at 26 and normally flows unrestricted to the rear brake cylinders. When air enters chamber 20 the vacuum therein is partially destroyed so that stem 29, 30 descends, closing the ball valve 28 and by the retraction of portion 30 expanding chamber 27 to relieve pressure in the brake cylinders. In the embodiment of Figs. 4, the spindle 12 rotates a valve member 41 having recesses 43, 44 normally communicating hydraulic fluid under pressure from a power source via inlet 42 to outlet pipes 45, 46, the rotation causing inlet 42 to be blocked off. At the same time further recesses 47, 48 move to positions where one of them communicates one of the pipes 45, 46 with a respective one of two exhaust pipes leading to a return reservoir for the hydraulic fluid.