Safety lock with two keys - has cylinder acting with notched guides pushed into plane of tumbler by key

摘要

The safety lock can be partially locked with one key and completely locked using another key consecutively. To partially operate the lock the first key has to be rotated, one half-turn in one direction, and then back one quarter turn in the other. To completely operate the lock, the first key is rotated one half-turn and then removed, the second key is then inserted and also rotated one half-turn. It is then impossible to free the lock without both keys, giving double security. The lock consists of a drum turning in a tubular housing and acting with guides (3, 12) provided with notches, which are pushed into the plane of the tumbler (6) by the key.