| 摘要 |
PROBLEM TO BE SOLVED: To avoid possibility, in which a password number is changed carelessly, by installing a retaining-ring holder engaged with the side end section of a notch for release in the retaining wall of a retaining ring at a place excepting a locking place and a release place. SOLUTION: A plurality of concentrically disposed lock rings 6 are composed of dial rings 61, on which symbols are marked, and retaining rings 62 rotatably fitted to the dial rings 61. Lock members 8, 8 with lock sections 81, 81 abutted against the peripheral surfaces of the retaining walls 12 of the retaining rings 62 are mounted. A lock is locked and released by reciprocating the lock members 8 in the radial direction by a knob 7. The lock rings 6 can be turned at the locking places and release places of the lock members 8 at that time, and retaining-ring holders are engaged at the side end sections of notches 13 for release in the retaining walls 12 at places excepting the locking places and the release places. Accordingly, rotation is not prevented in the lock rings 6 at the release places, and there is no possibility that a password number is changed carelessly. |
