| 摘要 |
<p>A key 3 rotatably supported in a mounting 1 and capable of being brought into engagement with a lock 6 is held in the correct orientation for engaging the lock by being locked to the mounting 1 by a retractable sleeve 9. Only when the mounting is brought into engagement with the lock does a portion 14 of the lock engage the sleeve and push it back relative to the mounting to free the key for rotation. The mounting may be on a movable part of a machine guard 2 with the lock on a fixed part 7 and controlling operation of the machine.</p> |
