Valve for force-reversing modulator

Claim 1

In an adaptive braking system for a vehicle having a fluid pressure operated brake, means for sensing an incipient skidding condition and generating a control signal in response thereto, a modulator responsive to said control signal for effecting a brake pressure reduction compRising: a housing defining a chamber therewithin, a diaphragm slidably mounted in said chamber dividing the latter into a pair of compartments, said diaphragm being movable between neutral and actuated positions wherein fluid communication to said brake is first terminated and the fluid pressure level at said brake is thereafter reduced as said diaphragm is moved from said neutral position to said actuated position, one of said compartments being communicated to a higher fluid pressure source and the other compartment being communicated to a lower fluid pressure source when the diaphragm is disposed in said neutral position, and valve means responsive to said control signal to reverse communication of said compartments so that said one compartment is communicated to said lower pressure source and said other compartment is communicated to said higher pressure source to thereby shift the diaphragm to the actuated position; said valve means including a housing, piston means slidable in said housing to define a first cavity therewithin between the face of said piston means and the wall of the housing, said first cavity being communicated to said other compartment, an electrically actuated valve member responsive to said control means to communicate said first cavity, and therefore, the other compartment, to a higher pressure source, said piston sliding in response to the pressure admitted into said first cavity by actuation of the electrically actuated valve member, and another valve member responsive to sliding of said piston to communicate said one compartment with said lower pressure source.