Automatic brake clearance adjuster

A brake for retarding rotation of a rotatable member about a longitudinal axis, comprising:

• a brake housing including a fluid receiving chamber;
• a piston element disposed partially within the fluid receiving chamber, the piston element being movable by pressurized fluid in the chamber longitudinally in an extend direction outwardly with respect to the fluid receiving chamber for applying a pressure for retarding the rotation of the rotatable member, the piston element including a pressure plate having a longitudinal hole therethrough;
• a longitudinally extending rod mounted to the brake housing external to the piston element;
• and
• an automatic clearance adjuster mechanism located in the longitudinal hole of the pressure plate, including a split ring sleeve element disposed about the rod and having a longitudinally tapered outer surface, a biasing element disposed for releasably holding the sleeve element against the rod for preventing movement of the sleeve element along the rod to limit the retraction of the piston element to a predetermined distance relative to the sleeve element and having a longitudinally tapered inner surface positioned for slidable engagement with the tapered outer surface, and a release element disposed to release the biasing element when the piston element is moved in the extend direction to allow the sleeve element to be moved by the piston element to an advanced position along the rod and allow the biasing element to hold the sleeve element against the rod in the advanced position through action of the slidably engaged tapered inner and outer surfaces compressing the split ring to hold the sleeve element around the rod when the piston element is retracted, when the movement in the extend direction is stopped or the piston element is moved in the opposite direction, the sleeve element when held against the rod in the advanced position limiting the retraction of the piston element to the predetermined distance to the advanced position.