| 摘要 |
PROBLEM TO BE SOLVED: To enable a key for operation to be pulled out even in an unlocked state and realize the performance of work with a high degree of efficiency. SOLUTION: In a locking state, a locking piece 45 is rotated with a cylindrical drive member 40 in the direction of the arrow (a) by the energizing force of an energizing coil spring, and is brought into engagement with the interior of a locking groove 17. In order to switch to an unlocking state, the key for operation is inserted into a key insertion hole, and is rotated in the right direction. After that, a drive shaft 32 is rotated, and its double-side D cut part 33 drives the cylindrical drive member 40 through the medium of a projection 43 of a communicating hole 42. Then the double-side D cut part 33 drives the locking piece 45 as shown in (b), and the locking piece 45 is drawn in and is disengaged from the locking groove 17. When a hand is taken off the key K for operation in a state where a movable unit has been lowered, the locking piece 45 is rotated in the direction of the arrow (c) by the energizing force of the energizing coil spring, and is pushed back until it is brought into contact with the wall surface of a movable unit storage hole. In this state, a margin of rotating the drive shaft 32 in the left direction is provided as shown in (d). Thus, the key for operation can be returned to the angle position at the time of insertion, and can be pulled out. COPYRIGHT: (C)2011,JPO&INPIT
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