This invention relates to an improved captive screw and assembly, and particularly a screw which may be held loosely captive in the threaded hole of a support member. The invention comprises a machine screw or cold formed fastener with an unthreaded interrupted mid-section that separates two spaced-apart...http://www.google.com/patents/US4877364?utm_source=gb-gplus-sharePatent US4877364 - Captive screw and assembly
