Lock cylinder with a pivotable closure

Claim 1

A lock cylinder comprising: a lock cylinder body formed with a passage adapted to receive a key, a head at one end of said body, a rectangular recess provided in an end of said head in line with said passage and having a pair of extensions along one edge of said recess, and a slot formed axially in said head and communicating with said edge between the interior of said recess and the exterior of said head along the outer periphery thereof; a torsion spring received in said recess and having one leg received in said slot and projecting outwardly from said head therethrough, and another leg lying within said recesss; a rectangular flap received in said recess and having a pair of lugs projecting into said extensions for pivotally mounting said flap in said recess whereby said other leg lies along an inner surface of said flap; a cover plate affixed on said head, registering with and covering only said end, overlying said recess and said flap, and having a window aligned with said passage so that insertion of a key through said window deflects said flap inwardly against the force of said spring said cover plate being affixed to said head by a tab bent over said head; and a circumferentially projecting hook formation provided on said head adjacent said slot, said one leg having an axially bent end exposed along said periphery underlying said formation and braced thereagainst to stress said spring whereby said spring can be stressed only after it has been affixed on said head to cover said spring by the bending of said one leg beneath said formation.