Abstract: A hydraulic or fluid-power brake is disclosed. The brake comprises a stationary housing, and a rotor shaft journaled in the housing. A number of rotor discs are carried on the shaft for rotation therewith, but they are adapted for axial sliding motion on the shaft, as by a spline arrangement. A number of stator discs are interleaved with the rotor discs and are carried on torque pins mounted in the housing for sliding motion in the direction of the rotor shaft axis, but are secured against rotational movement with the rotor shaft and rotor discs. Biasing means such as springs urge the stator discs into braking engagement with the rotor discs. To relieve this braking action and permit free shaft rotation, a primary piston, having an annular skirt surrounding the rotor discs, engages one stator disc to apply a force urging that stator disc in a direction opposite to the force applied by the biasing means so as to release the braking action.

Abstract: An auxiliary release apparatus for use with a hydraulic pressure releasable brake having a principal source of hydraulic pressure comprises an auxiliary source of hydraulic pressure selectively connectable to the brake for releasing the brake when the principal source of hydraulic pressure is not operating. The auxiliary release apparatus includes a shuttle valve and a relief valve for automatically disconnecting the auxiliary source and reconnecting the principal source of hydraulic pressure from the brake when the principal source of hydraulic pressure is operating. The auxiliary source of hydraulic pressure includes a cylinder, a hand pump comprising a handle and a piston connected to the handle and disposed in the cylinder, a fluid supply reservoir and suitable connection lines between the fluid supply and the cylinder. The relief valve also regulates the amount of pressure provided to the brake by the hand pump.