Patent ID: 7506573

Claim:
A mid-power spring brake actuator comprising: first, second, and third actuator housing portions, the first actuator housing portion interposed between the second and third housing portions, a parking brake release actuator received within the third housing portion, a connecting shaft attached at a first end to the parking brake release actuator and extending through a dividing wall defined by the first housing portion, a service brake apply actuator received within at least one of the first and second housing portions, a brake actuator spring interposed between the dividing wall defined by the first housing portion and a second end of the connecting shaft, a service brake actuation chamber provided between the brake actuator spring and the service brake apply actuator, and a parking or emergency brake de-actuation chamber defined between the parking brake release actuator and the first housing portion, wherein travel of the connecting shaft as a result of force applied by the brake actuator spring upon failure of an interconnection between the connecting shaft and the parking brake release actuator is limited so as to inhibit undesired expansion of the brake actuator spring.