| 摘要 |
A mechanism for locking the back cover of a combination lock to the lock housing is described having two sequentially and phased moveable parts, each having an aperture through which a locking member may be inserted, the apertures are disposed in parts moveable in parallel and adjacent planes and a portion of each aperture is at all times aligned with the other aperture such that a third member may extend through the apertures. The apertures have enlarged portions which will pass the third member and channel portions which prevent withdrawal of the third member while permitting movement of the moveable parts. The third member is carried by the back cover of the lock and can only be withdrawn by sequentially withdrawing from a first moveable part, shifting the moveable parts to a second position and withdrawing from the second moveable part. The back cover may thus be only removed by starting with the bolt in an extended position and locked condition and prior to final withdrawal of the third member, withdrawing the lock bolt to an unlocked position, necessitating possession of authorization to unlock the lock in order to remove the back cover.
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