Spreading type multiple disc brake

Claim 1

A multiple disc brake comprising: a brake housing having spaced braking surfaces in a chamber, a pair of pressure plates mounted together in the chamber and each having a braking surface facing a housing surface, actuator means for rotating the pressure plates relative to each other, cam means mounted between the pressure plates for forcing the pressure plates apart and toward the housing surfaces upon relative rotation, a shaft extending through the chamber and rotatable relative to the chamber and the pressure plates, a pair of brake discs interposed between each pressure plate and its adjacent housing surface, the discs being rotatably fixed to the shaft and axially movable relative thereto, a servo disc interposed between each pair of brake discs and being rotatably fixed to and axially movable relative to the pressure plates, and stop means mounted on the brake housing and engageable with one of the pressure plates for limiting the rotation thereof, the cam means effecting axial separation of the pressure plates upon relative rotation thereof to frictionally interengage the brake discs with the housing surfaces, the pressure plate suRfaces and the servo discs to retard relative rotation of the shaft and the brake housing, the frictional engagement of the brake discs with the servo discs enhancing relative rotation and axial separation of the pressure plates upon engagement of the one pressure plate with the stop means to increasingly retard the relative rotation of the shaft and the brake housing.