Abstract: A drum brake (10) having first (14) and second (16) brake shoes retained on a backing plate (20) and moved into engagement with a drum (18) to effect a brake application corresponding to a desired braking input supplied to a actuator member (28) is disclosed. The actuator member (28) has a housing (50) with a first bore (54) therein connected to a cross-bore (56). A pinion (58) located in the first bore (54) has a shaft with first end (60) and a second end (62). The shaft has teeth (58) thereon adjacent the first end (60) and a gear (64) connected to the second end (62). First (74) and second (76) racks which are located in the cross-bore (56) have teeth (67,67') thereon which mesh with the teeth (68) on the pinion (58). A first linkage member (28) connects the first rack (74) with the first brake shoe (14) while a second linkage member (28') connects the second rack (76) with the second brake shoe (16).

Abstract: The hydraulic and electric powered parking brake system (10) comprises a redundant or simultaneous operation of the system (10) to meet Federal Safety Standards. A dash mounted control knob (24) operates a hydraulic brake application mechanism (20) which transmits a hydraulic pressure to a hydraulically operated pilot piston (70). The control knob (24) also operates a switch (30) to send an electrical signal to an electrical control unit (100) which sends an electrical signal to a solenoid (80). The solenoid (80) and hydraulic pilot piston (70) can be operated, independently or simultaneously, to displace a control valve (60) located within a parking actuator assembly (114) and effect the release of hydraulic pressure from spring apply and hydraulic release actuators (16, 90) connected to vehicle brakes (18). The hydraulic fluid is released past the control valve (60) and to a reservoir (52).