Ratchet bolt assembly

Abstract

This invention provides a self-retracting and self-locking bolt assembly for fixed attachment to a workpiece to removably secure the workpiece to a second workpiece containing a mating internally threaded fastening device. A bolt has a shank with rolled threads on its outer end and an exterior shank shoulder, adjacent the head, which faces the threaded section. A collar circumscribes the shank and is slidably retained on the shank, by the rolled threads, between the shoulder and the rolled threads. The head is axially spring-biased away from the collar. The collar is in turn slidably and nonrotatably retained coaxially within the longitudinal passage through a cylindrical ferrule. The collar is also axially spring-biased, within the ferrule, towards the shank shoulder with a force greater than the head-biasing force. As the bolt is pressed axially through the collar and ferrule, the shoulder enters the ferrule passage, contacts the collar and presses it through the passage against the spring force upon the collar. During rotational tightening of the bolt, mating ratchet teeth upon the contacting surfaces of the shoulder and collar slip past one another. After tightening, the spring-enforced contact between the mating ratchet teeth precludes rotational bolt loosening from vibration and the like but permits subsequent loosening with the wrench. When the bolt is disengaged from its mating fastening device, and the wrench removed, the bolt and collar are spring-returned to their fully biased positions.