Appleton's dictionary of machines, mechanics, engine-work, and engineering : illustrated with four thousand engravings on wood ; in two volumes (1873)
D. Appleton and Company · New York : D. Appleton and Co. · leaf 243
at takes the pressure, being behind the iron wall I K, which is fixed completely across the lock,prevents the possibility of its being reached through the key-hole, and the first tumblers B B are quitedetached at the time, thereby making it impossible to ascertain the position of the parts in the… … L is the drill pin on which the keys fits; and M M is a revolving rmg or curtain, which turns roundnth the key, and prevents the possibility of inspecting the interior of the lock through the key-hole;and should this ring be turned to bring the opening upward, the detector plate is immediately…
Mechanical engineering · Mechanics · Engineering
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