| 摘要 |
<p>A bolt is conventionally reciprocal in a stationary casing with each being formed of longitudinally telescoped parts and with the parts of each being bayonet joint connected. Each bayonet joint connection is comprised of a projection of one part selectively movable in a pair of longitudinally spaced, transverse slots separated by a longitudinal slot in the other part, whereby each may be selectively longitudinally adjusted the same determined amount for increasing or decreasing the backset distance between the forward extremities of the casing and the latch operator transverse axis the same determined amount. The transverse cross sections of certain slidably reciprocal mating parts of the bolt and casing are formed generally mutually rectangular so that rotational movements of one during the backset adjustment will positively require the same rotational movements of the other. A spring-pressed friction member between the casing telescoped parts frictionally resists movement therebetween minimizing any danger of non-planned, accidental backset adjustment.</p> |
