公开(公告)号：US3876236A

公开(公告)日：1975-04-08

申请号：US39084773

申请日：1973-08-23

申请人： BEST LOCK CORP

发明人： BEST WALTER E ,  MCCULLUM R GENE

IPC分类号： E05B55/00 ,  E05B55/12 ,  E05C1/16

CPC分类号： E05B55/12 ,  E05B55/005 ,  Y10S292/57 ,  Y10T292/098

摘要： A latch bolt mechanism for use with a cylindrical lock set has a main latch bolt and an auxiliary bolt to control deadlocking of the main bolt, all mounted in a tubular housing. The main bolt has a tubular stem telescopically received over a tailpiece in the form of a round rod with a retraction head at the rear. The tailpiece is slidable in the stem through lost motion which is limited by engagement between a stop ring on the stem and a timing groove in the tailpiece, and the tailpiece is biased to forward position by a spring acting between a cap at the front end of the tailpiece and a reaction washer pressed into the bolt stem. A deadlocking dog is pivoted on a rear support with its forward end positioned to block rearward movement of the bolt stem. The tailpiece also has a cam groove to receive the dogging end of the dog, and the cam of such groove releases the deadlocking dog when the tailpiece is first retracted through its limited lost motion in the stem and thereafter retracts the latch bolt. The bolts are urged forward by springs which seat on a foot lever fulcrumed against the end closure of the tubular housing and engaged at its end with a lug on the deadlocking dog to bias that dog toward its deadlocking position. The auxiliary bolt carries a dog release finger which normally holds the deadlocking dog in release position, but which, when the auxiliary bolt is retracted relative to the bolt, lets the locking dog move to bolt-blocking position. The tailpiece spring is weaker than the bolt spring so that when the bolt is deadlocked retraction of the tailpiece first moves it through its lost motion to where its cam will release the locking dog, and then moves it to retract the latch bolt.