PRESSURE CONTROL DEVICE
A pressure control accumulator for hydraulic brake systems includes a housing (12) having a brake fluid port (36) and a cavity (46) communicating with the port. A staged series of resilient membranes is disposed within the cavity for nullifying hydraulic brake fluid pulsations over a wide range of pressures. The staged series preferably includes a resilient diaphragm (80) disposed adjacent the port for nullifying hydraulic brake fluid pulsations at low and normal pressures by itself and maintaining the brake fluid on one side of the diaphragm, and a resilient membrane disposed remote from the port and normally spaced from the diaphragm, the diaphragm and the remotely-disposed membrane cooperatively nullifying hydraulic brake fluid pulsations at high pressures by providing a plurality of resilient resistances in series. The remotely-disposed membrane may be a second diaphragm (90).