Patent ID: 7926628

Claim:
A spring-applied parking brake with manual release and reapply comprises: a pneumatic cylinder having a cylinder wall and front and rear walls; a piston sealed relative to the cylinder wall; a parking brake spring or springs extending between the piston and rear wall for biasing the piston to the front wall; a gear box fixed relative to the rear wall, said gear box having a manual crank; a pushrod extending through the cylinder, front and back walls, piston and gear box for being connected to provide braking force when in a position extending outward from the front wall, said pushrod having a key or rack on the end thereof extending through the gear box and helical threads on a portion through the piston; a threaded collet surrounding the helical threads having flexible radially expandable tines, said collet captured by the piston and secured from rotation relative to the piston; and such that when the gear box is manually cranked, the pushrod is rotated and due to the threads on the inside of the collet, the pushrod is moved axially relative to the piston and, such that when pneumatic pressure is applied to the cylinder to move it against the parking brake spring, the collet tines can expand and release to permit the pushrod to move to a reset position relative to the piston.