|
|
|
On the Construction of Locks and Keys by John Chubb
|
CONSTRUCTION OF LOCKS AND KEYS. 35
right angles to it, the notches in the spring keys being brought in a line with the plane of the plate, or diaphragm of the lock, the rod and weight turned the false key, or pipe, opened the lock, and stopped the further motion of the automaton. In that state, the slides indicated the exact depth of the grooves of the proper key, and gave the form of a matrix, by which to make a key similar to the original one.
In order to ascertain the result of friction on Chubb's detector lock, one of them was subjected to the alternate rectilinear motion of a steam engine, in the Portsmouth dock-yard, and was locked and unlocked upwards of four hundred and sixty thousand times consecutively, without any appreciable wear being indicated by a gauge applied to the levers and the key, both before, and after this alternate action.
He believed Chubb's lock had never been picked; the detector was the main feature of its excellence ; and additional precaution, therefore, was only departing from its simplicity, and adding to the expense without any commensurate advantage.
Mr. FAREY said, before closing the discussion he desired to direct attention to the importance of the means of securing iron chests, or safes. The bolts should be so arranged as to shoot out from all the four sides of the door (Fig. 8, p. 22), by the action of a handle, which should be secured from being opened by one, or two small locks; this was a much safer plan than having large keys, capable of throwing the bolts, as the large keyholes and greater space within the locks, afforded facilities for tampering with them.
The letter locks, which had been only cursorily alluded to, were invented by Cardon, who advanced no further than using one word ; they were improved by Kegnier, who placed the letters on moveable rings, so as to permit a great extent of permutation. These locks were, however, not safe, as they might be easily picked, by sus-ending a weight on the hasp, and turning round the rings seriatim, until it was felt, that the combination was arrived at, by the pin holding in the notch of the ring.
Mr. STEPHENSON, M.P., V. P., said it might be assumed as proved from the discussion, and therefore it was the duty of the Institution to express the conviction, that no locks really made by Chubb, had ever been picked, either in Great Britain or on the other side of the Atlantic; that they did, in fact, combine that strength, simplicity, easy action, and security, without which the most ingenious locks were utterly useless.
Notwithstanding the circumstantial description of the ingenious method, employed in the United States, for taking an impression of
|
|
|
On the Construction of Locks and Keys by John Chubb