| 摘要 |
<p>The lock is operated by a key, which turns an eccentrically mounted disc through 180 deg. The key can normally only be withdrawn from the keyhole when the espagnolette is in the locked position in the conventional lock. The hub of the eccentric disc is made in two parts, with a peg in one fitting into a semicircular slot in the other. Of a full turn of the key, the first half is spent in moving the peg through the slot, and only the second half turns the eccentric disc, through 180 deg., as before. A similar modification can be made to a lock operated by turning a key through 90 deg.</p> |
