Anti-skid braking systems for vehicles

Abstract

An anti-skid braking for a vehicle comprises a wheel having an hydraulic brake applicable by supplying thereto fluid under pressure from a master cylinder, a sensor to sense the presence of skid conditions at the wheel during braking and thereupon to produce a skid signal, a dump valve operative to cause fluid to be displaced from the brake in response to a skid signal so as to relieve the brake pressure, and a flow-control regulator valve arranged to regulate flow of fluid to the brake so as to re-apply the brake pressure at a controlled rate. The flow-control valve comprises a first restriction of predetermined size connected in series with a second restrictor defined between two relatively movable members and located upstream of the first restriction. The first restriction is defined at least in part by the member of which that member is biassed by a valve spring against the action of the pressure difference across the first restriction. Fluid is exhausted by the dump valve in response to the skid signal into a dump chamber and that fluid is adapted to displace an expander piston in a direction to increase the biassing effect of the valve spring whereby to increase the rate of flow of fluid through the regulator valve, and a scavenger pump is arranged to withdraw fluid from the dump chamber and return it to the master cylinder on the said upstream side of the second restrictor.

Dependencies are inferred from the claim text.