Compressed air brake systems for vehicles

Claim 1

A compressed air brake system for vehicles, comprising brake circuits and brake-actuating means for supplying compressed air to the brake circuits, a double check valve comprising a valve body, a chamber formed in said valve body, two inlet ports each connecting said chamber to one of said brake circuits, said inlet ports being substantially axially aligned, an outlet port connecting said chamber to a utilization circuit, flat valve seats defined within said chamber and entirely encompassing each of said inlet ports, and a flexible flap pivotally mounted within said chamber between said valve seats and having flat opposite faces each of which can contact a said flat valve seat entirely about a said inlet port thereby selectively to obturate one of said inlet ports under the action of compressed air supplied through the other inlet port, said flap extending in a direction substantially perpendicular to the axis of said inlet ports and having one end inserted in said valve body, said opposite faces of said flap being disposed at an acute angle to each other whose apex is remote from said inserted end of said flap, said flap tapering in thickness over all the portion of the flap that contacts said valve seats.