| 摘要 |
PROBLEM TO BE SOLVED: To provide a crime preventive thumb-turn mechanism for preventing unauthorized operation of a thumb turn. SOLUTION: The crime preventive thumb-turn mechanism is obtained by inserting a cam mechanism and a clutch 15 into a gap between a rotary body linked to a lock member and an inner cylinder of a thumb-turn cylinder lock 7. The cam mechanism consists of a ratchet cam 10 and a slide cam 13 and it is rotated by rotation of the inner cylinder. The clutch 15 is connected to or separated from rotation of the thumb turn. Thus by inserting a key into the thumb-turn cylinder lock 7 to angularly rotate the inner cylinder, the cam mechanism is operated to alternately switch the relationship between the clutch 15 and the thumb-turn rotation to connection and separation, and when the connection between the clutch 15 and the thumb-turn rotation is released, the thumb-turn rotation is rendered idle. COPYRIGHT: (C)2004,JPO
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