Collet style tread brake unit

A brake actuator for use in railway transit and similar vehicles to adjust for wear of braking components located on such vehicles, said brake actuator comprising:

• (a) an exterior housing member;
• (b) a power collet housing disposed for axial movement within said exterior housing member;
• (c) a slack adjusting collet housing axially aligned with and spaced from said power collet housing disposed in said exterior housing member;
• (d) an elongated rod member at least partially disposed within said external housing member and extendable therefrom in a first direction, said elongated rod member having at least one of an externally threaded surface and a serrated surface extending along a length thereof;
• (e) a power collet disposed on said elongated rod member for non rotational movement therealong and within said power collet housing, said power collet having integral fingers for each of gripping and sliding on a surface of said elongated rod member;
• (f) a slack adjusting collet disposed on said elongated rod member for non rotational movement therealong and within said slack adjusting collet housing, said slack adjusting collet having integral fingers for each of gripping and sliding on a surface of said elongated rod member;
• (g) a yoke member disposed about and in engagement with said power collet housing at an end thereof disposed closely adjacent an end of said integral fingers of said power collet;
• (h) an axially translatable bearing disposed on said yoke member;
• (i) a fixed bearing secured within said external housing member and spaced from said axially translatable bearing;
• (j) a piston member disposed in said external housing member for longitudinal movement in a second direction which is generally perpendicular to said first direction;
• and
• (k) a fork-shaped wedge member secured to said piston member disposed astraddle said elongated rod member and in engagement between and with each of said axially translatable bearing and said fixed bearing, said fork-shaped wedge being effective to axially translate said axially translatable bearing and said yoke member and said power collet and said elongated rod member in said first direction.