摘要 |
A spring-applied, air-released parking brake, having a manual release mechanism with an automatic reset feature. To release a spring-applied parking brake, in the absence of air, a torsion bolt having a cam member formed on it is manually rotated to a position aligning the cam with an elongated slot in the piston push rod of the parking brake cylinder. This allows the piston to be extended in a direction to extend the spring, thus relieving the spring force. Reapplication of air pressure moves the piston push rod out of the elongated slot to permit angular rotation of the bolt by its torsion spring, so as to prevent its entry in the elongated slot until the bolt is again rotated manually. |