| 摘要 |
A lock includes a running plate formed integrally with a locking bar and provided with a fence adapted to cooperate with a plurality of tumblers so as to alternatively block and allow retraction of the locking bar, and this mechanism is mounted together with the cooperating components within a lock housing. The tumblers allow retraction of the locking bar when moved by a prescribed key to a unlocking position and this prescribed key, which can move the tumblers to the unlocking position, can be exchanged with another prescribed key by displacing the rotational axes of the tumblers. The rotational axes of the tumblers are rotatably released or fixed by a conversion shaft extending through an opening formed in the tumblers and rotatably supported in the lock housing. The conversion shaft is provided with a stop piece and a locking piece. An operative association is established among the conversion shaft, the running plate and a key guiding member rotatably supporting the prescribed key so that it is impossible to release the rotational axes for its displacement or to fix the rotational axes thus released unless the tumblers have been moved to the unlocking position and are held at this unlocking position.
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