MORTISED BAR LOCK

The invention concerns a lock bolt mechanism actuable by a two-bit key (12) which can be placed into a rebate chiselled out for this purpose in a door, which has a lock casing accommodating a bolt head which is pushed out on closure, tumblers (10) fitting to the notches of the two-bit key which together with tumbler supporting springs (13) are threaded on to a common tumbler pin (11) for assuring a two-stage locking, as well as a spring-supporting pin (9) furthermore a guide pin (4) fixed into the lock casing for assuring the locking of the tumblers, and wherein on one side of the bolt head (8) there is a lower bolt body plate (6) and on the other side of the bolt head (8) there is an upper bolt body plate (7), the plates being fixed together by way of the spring-supporting pin (9) and which are fixed to the bolt head (8) by way of permanent connecting element(s) (15), further in that of the lower bolt body plate (6) and the upper bolt body plate (7) at least one, but preferably both, is/are formed with a first bolt tooth (7a) corresponding to the first stage of locking and the second bolt tooth (7b) corresponding to the second stage of locking.