Control valve assembly

A control valve assembly for a vehicle braking system, comprising an inlet, an outlet, a valve to control communication between said inlet and said outlet, a control member movable to open and close said valve, and inertia-responsive means responsive to deceleration of the vehicle to effect operation of said control member to reduce the pressure at said outlet after said valve has closed, said inertia-responsive means comprising an inertia responsive device which supplies a signal in dependence upon deceleration, and a force-applying means which applies a force to said control member in response to said signal to move said control member in a direction to reduce said outlet pressure, said force applying means comprising a servo-system for amplifying said signal from said inertia responsive device, wherein said servo system comprises an auxiliary valve operable in response to movement of said inertia responsive device, a pressure operable member subjected to a pressure in dependence upon operation of said auxiliary valve, and means coupling said pressure operable member in force-transmitting relation with said control member, whereby said control member is subjected to a force which is dependent upon said deceleration.