WHEEL BRAKE CYLINDER ASSEMBLY FOR A HYDRAULIC TWIN BRAKE SYSTEM

摘要

A wheel cylinder in a braking system is provided with first and second pistons slidable therein and protruding from opposite ends to actuate the brake elements. An intermediate piston is slidably disposed in the cylinder between the first and second pistons to define first and second fluid pressure chambers disposed in communication with a high pressure system and low pressure system respectively. A third pressure chamber is formed between the intermediate piston and the first piston. A valve in the intermediate piston provides communication between the third pressure chamber and one of the first and second pressure chambers and is normally open when both pressure systems are operative. Upon failure of the high pressure system movement of the intermediate piston in the opposite direction by the low pressure system will close the valve thereby trapping the fluid therein to provide a fluid link between the intermediate piston and the first piston to prevent an increase in stroke when the low pressure system takes over.