Locking mechanism for a door of an elevator shaft

摘要

A locking mechanism for an elevator shaft door has a housing 20 and a barrel 22 mounted in the housing to receive a drop release key 10 having a release lever 14 pivotably mounted on the end of a shaft 12 such that, after insertion into the barrel 22, the release lever 14 is drops under its own weight into a position inclined relative to the shaft 12 and rotation of the shaft 12 brings the release lever 14 into a contact with an actuator arm 24 for operating a latch of the elevator shaft door, the locking mechanism including an electromagnetically operable disabling device 30, 50 to prevent the release lever 14 from coming into contact with the latch actuator arm 24 when the key 10 is rotated. The electromagnetically operable disabling device 30 may retain the release lever 14 aligned with the shaft 12, i.e. preventing pivoting. This may be done by magnetic attraction of a ferromagnetic release lever 14 or by the use of a solenoid (40 fig. 4) whose armature (42 fig. 4) obstructs pivoting of the release member 14. Alternatively the armature 52 of a solenoid 50 may deflect the release member 14, the armature 52 preferably including a ramp.