Читать книгу Rudimentary Treatise on the Construction of Locks онлайн

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Mr. Partington, in his edition of the marquis’s singular work, makes a few comments on these lock-and-key contrivances. He says that the lock is evidently intended to operate on the principle of applying a screw for the purpose of moving the bolt, instead of using a key as a lever for this purpose. That such a plan might be applied to locks generally, he observes, there can be no doubt; and by a similar contrivance the large keys at present in use for outer doors, iron chests, &c. might be advantageously reduced by this means. By employing the escutcheon mentioned by the marquis, much additional security would be obtained. It must be confessed, however, that many of the marquis’s statements are difficult to credit.

The escutcheon has been a favourite resource with lock-makers. Mr. Mordan’s escutcheon, for instance, introduced before the Society of Arts in 1830, is a contrivance to be placed temporarily over the keyhole of a door, to prevent the picking of the lock during the owner’s absence. The escutcheon, or “protector,” has a short pipe which, after the door has been locked, is thrust into the keyhole; attached to the pipe is a small lock, on Bramah’s or any other convenient principle, so contrived that, on turning its key, two lancet-shaped pieces fly out laterally and bury themselves in the wood. The escutcheon cannot be removed until the small key has reacted upon the small lock; and until this removal has taken place, the large key cannot reach the keyhole.