| 摘要 |
PROBLEM TO BE SOLVED: To provide a cylinder lock which can make it impossible to find out a code altered site from an unlocking key before code alteration. SOLUTION: A plug 5, which can be moved between first and second positions and is freely rotatable, is provided within a cylinder case 4. An optimal number of first tumbler pins 2, which advance towards and retreat from a key insertion part 1, and an optimal number of second tumbler pins, which advance towards and retreat from a key insertion part 1, are placed on different bus bars on the plug 5. A first driver pin 6, which coincides with the position of the first tumbler pin 2 when the plug 5 is located at the first position, and a second driver pin, which coincides with the position of the second tumbler pin when the plug 5 is located at the second position, are placed in the cylinder case 4. The cylinder lock is constructed so that locking and unlocking operations can be performed in such a manner that, when the plug 5 is located at the first position, a first unlocking key 10 is used while, when the plug 5 is located at the second position, a second unlocking key is used. Each unlocking key is provided with an unlocking code forming concave part 8, which coincides with the corresponding tumbler pin position, and a relief groove 9 that permits the passage of the uncorresponding tumbler pin when the key is inserted into the plug 5. COPYRIGHT: (C)2009,JPO&INPIT
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