US 3,937,527 A · Fluid pressure relay valve

Abstract

A fluid pressure relay valve particularly for the electro-pneumatic control of vehicle brakes has a piston displaceable within a valve housing to define a control chamber on one side of the piston and on the other side of the piston there is a second chamber which is connected to the braking device. The pressure within the control chamber is controlled by inlet and outlet solenoid valves. The piston actuates valve means for controlling the pressure in the second chamber by venting the chamber or by connecting the chamber to a source of fluid pressure. An additional volume of pressure medium is connected to the control chamber for the purpose of increasing the pressure in the control chamber subsequently to the release of the signal "hold the pressure." The increase in pressure is to a predetermined level which is a function of a controlled lowering of pressure in the additional volume.

Claims8

Dependent claims

A fluid pressure relay valve for the electro-pneumatic control of vehicle brakes comprising a housing having a control chamber therein, inlet and outlet solenoid valve means connected to said control chamber for controlling the control pressure therein, a piston displaceable within said control chamber and defining one wall of said control chamber, there being a second chamber on the other side of said piston connected to a braking device, first and second valve means actuable by said piston for venting said second chamber and for connecting said second chamber to a source of pressure medium, and means defining an additional volume of pressure medium connected to said control chamber for increasing the pressure in said control chamber to a predetermined level by a lowering of the pressure in said additional volume means subsequently to a "hold the pressure" signal.

Dependencies are inferred from the claim text.

Fluid pressure relay valve

Life of this patent

Fluid pressure relay valve

Life of this patent

Abstract

Claims8