Improvements in actuators warning systems autore-position for dual brake circuit

摘要

A self-resetting warning actuator (42) for a vehicle brake system includes a housing (27) having a bore (44) which defines a recess (58). A pair of pressure responsive pistons (50, 54) are received in the housing bore and each is exposed to the pressure in one brake circuit. A roller member (48) is disposed in the housing recess and between the pistons. When the brake system is operating normally, the pressures in the two brake circuits are substantially equal and the pistons define a neutral position. Should one of the circuits fail, the pistons are shifted from their neutral position by the resulting pressure difference between the circuits. The housing recess defines a ramp which forces the roller member between the pistons when the pistons shift from their neutral position. A signaling device, by its response to the movement of the pistons, provides a warning to the vehicle operator. When the brake system is repaired, and the pistons are once again exposed to equal pressures, the roller member is forced from between the pistons. Movement of the roller member along the recess ramp returns the pistons to their neutral position.