| 摘要 |
PROBLEM TO BE SOLVED: To prevent a malfeasant unlocking operation that burglarproofness is deteriorated, a thumb-turn is operated by inserting a tool, a hand or the like and a thumb-turn lock is unlocked easily regarding the thumb-turn lock mainly used as a door lock. SOLUTION: In the thumb-turn lock, by which a dead bolt is projected or retracted to or from an end face on the door side by operating the thumb-turn on the indoor side and which is used for locking/an unlocking, the thumb-turn lock 1 in which a cylindrical indicator 10 rotatable in the periphery of the axial center of the thumb-turn lock is installed between the inner-peripheral wall surface of the cylindrical thumb-turn and the outer-peripheral wall surface of an external cylinder for a cylinder lock and the front end face of the indicator is exposed to the outside while a display means 10a capable of visually recognizing the rotation of the indicator is mounted to a part of the front end face is provided. COPYRIGHT: (C)2004,JPO
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