Anti-skid vehicle braking systems

A fluid pressure-operated anti-skid braking system for vehicles comprising at least one actuator for applying a wheel brake, a supply of operating fluid for operating said actuator, fluid-flow control valve means interposed between said supply and said brake and through which pressure fluid from said supply is supplied to said actuator, deceleration responsive means responsive to a skid signal for operating said valve means to relieve pressure of said pressure fluid applied to said actuator at a skid point when the deceleration of said wheel is excessive and exceeds a pre-determined value, a memory for storing a memory pressure dependant on said pressure of said pressure fluid at said skid point, an orifice through which said memory pressure decays by leakage while said deceleration of said wheel exceeds said pre-determined value, said memory pressure directly operating said control valve means throughout a first stage of brake re-application, and providing a changeover point between said first stage and a second stage of brake re-application, said first stage comprising re-application of said operating fluid from said supply until an intermediate pressure less than said pressure of said pressure fluid is attained at said changeover point, and said second stage comprising continued re-application of said supply of said operating fluid at a reduced rate of pressure increase.