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On the Construction of Locks and Keys by John Chubb
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10 CONSTRUCTION OF LOCKS AND KEYS.
key. The pick-lock E, also, by passing round the wards, will easily open the lock.*
Not only is the principle of these locks faulty, but many thousands are made yearly for the same keys to pass, and sold to different persons; it is, therefore, quite possible, that twenty skeleton keys might be made, which would open the majority of the street doors in London. Moreover, vast numbers of common locks are made with keys so cut as to represent intricate wards, and on being opened, nothing but the bolt, and perhaps a single tumbler, will be found, without any wards in the case.
3rd. Locks having a single tumbler in addition to fixed wards.— A tumbler is a sort of spring latch for detaining the bolt of the lock, so as to prevent its motion, until the key, in turning, first lifts the tumbler out of contact with the bolt, before moving it. Tumbler locks certainly afford more security than warded locks, but the former, as usually made, can be lifted by a picklock, or false key.
4th. The Egyptian lock.—The essential principle of this lock is, that of having moveable pins, or nails, dropping into, and securing the bolt, each pin falling by its own weight, independently of the others, but all of them requiring to be raised together to the proper height, by corresponding pins in the end of the key, before the bolt can be unfastened. anvilfire.com!
This lock, although unknown in Europe until the latter end of the last century, contains the true principle of security, viz., that of several independent moveable detainers of the motion of the bolt, any one of which would alone prevent that motion; the key was adapted to move and arrange all those detainers simultaneously, and into such positions as would alone permit the bolt to be moved.
Most of the ingenious inventions of late years have been based on a like principle of security. The forms of these moveable obstructions to the bolt, in locks of modern date, are of course various, some acting vertically, others horizontally, some with a revolving motion about a fixed centre, and, in fact, in almost every way it is possible to conceive. Without intending in any way to depreciate the numerous inventions for the improvement of locks (many of which possess great merit), it will be sufficient to describe particularly the three principal locks which are well known and generally appreciated, namely, Barren's, Bramah's, and Chubb's. _____________
* The original lock, key, and picklocks were exhibited, and also a few picks, selected from about a ton weight of such instruments, captured by the police, and deposited in Scotland Yard.
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On the Construction of Locks and Keys by John Chubb