Spring applied brake mechanism

摘要

A brake mechanism is mounted on a vehicle and includes a housing having a slot for receiving a rotatable disc to be braked. The upper portion of the housing includes a chamber for receiving pressurized fluid from a source. A spring actuated piston is slidably and sealingly disposed within the chamber. A removable spring assembly is positioned forwardly of the actuating piston and exerts a preselected spring force thereon. When the fluid pressure acting against the piston is less than the spring force applied to the piston, the piston moves axially in the chamber and a rod portion thereof contacts a lever that is pivotally mounted to the housing. The lever pivots on the housing to axially displace a brake applicator piston that is movably positioned in the housing adjacent to the rotatable disc. A plurality of braking pads are secured to the end portion of the applicator piston and additional braking pads are secured to the brake housing opposite the disc. Displacement of the applicator piston moves the braking pads into braking engagement with the disc to overcome rotation of the disc and stop the vehicle. In the event fluid pressure in the chamber diminishes, the spring assembly is automatically actuated to exert a parking brake force and move the braking pads into braking engagement with the disc. The spring assembly may be locked in a compressed state for efficient removal from the housing for maintenance or replacement and includes a device for visually indicating the wear condition of the braking pads.