When the American locks became known in England, Mr. Hobbs undertook the superintendence of their manufacture, and their introduction into the commercial world. Such a lock as that just described must necessarily be a complex piece of mechanism; it is intended for use in the doors of receptacles containing property of great value; and the aim has been to baffle all the methods at present known of picking locks, by a combination of mechanism necessarily elaborate. Such a lock must of necessity be costly; but in order to supply the demand for a small lock at moderate price, Mr. Hobbs has introduced what he calls a protector lock. This is a modification of the ordinary six-tumbler lock. It bears an affinity to the lock of Messrs. Day and Newell, inasmuch as it is an attempt to introduce the same principle of security against picking, while avoiding the complexity of the changeable lock. The distinction which Mr. Hobbs has made between secure and insecure locks will be understood from the following proposition, viz. “that whenever the parts of a lock which come in contact with the key are so affected by any pressure applied to the bolt, or to that portion of the lock by which the bolt is withdrawn, as to indicate the points of resistance to the withdrawal of the bolt, such a lock can be picked.” [Fig. 47] exhibits the internal mechanism of this new patent lock. It contains the usual contrivances of tumblers and springs, with a key cut into steps to suit the different heights to which the tumblers must be raised. The key is shewn separately in [fig. 48]. But there is a small additional piece of mechanism, in which the tumbler stump shewn at s in [figs. 46] and [47] is attached; which piece is intended to work under or behind the bolt of the lock. In [fig. 47], b is the bolt; t t is the front or foremost of the range of six tumblers, each of which has the usual slot and notches. In other tumbler-locks the stump or stud which moves along these slots is riveted to the bolt, in such manner that, if any pressure be applied in an attempt to withdraw the bolt, the stump becomes pressed against the edges of the tumblers, and bites or binds against them. How far their biting facilitates the picking of a lock will be shewn further on; but it will suffice here to say, that the movable action given to the stump in the Hobbs lock transfers the pressure to another quarter. The stump s is riveted to a peculiarly-shaped piece of metal h h ([fig. 46]), the hole in the centre of which fits upon a centre or pin in a recess formed at the back of the bolt; the piece moves easily on its centre, but is prevented from so doing spontaneously by a small binding spring. The mode in which this small movable piece takes part in the action of the lock is as follows: when the proper key is applied in the usual way, the tumblers are all raised to the proper heights for allowing the stump to pass horizontally through the gating; but should there be an attempt made, either by a false key or by any other instrument, to withdraw the bolt before the tumblers are properly raised, the stump becomes an obstacle. Meeting with an obstruction to its passage, the stump turns the piece to which it is attached on its centre, and moves the arm of the piece p so that it shall come into contact with a stud riveted into the case of the lock; and in this position there is a firm resistance against the withdrawal of the bolt. The tumblers are at the same moment released from the pressure of the stump. There is a dog or lever d, which catches into the top of the bolt, and thereby serves as an additional security against its being forced back. At k is the drill-pin on which the pipe of the key works; and r is a metal piece on which the tumblers rest when the key is not operating upon them.
fig. 47. Hobbs’s Protector Lock.
fig. 48. The key.
Another lock, patented by Mr. Hobbs in 1852, has for its object the absolute closing of the key-hole during the process of locking. The key does not work or turn on its own centre, but occupies a small cell or chamber in a revolving cylinder, which is turned by a fixed handle. The bit of the movable key is entirely separable from the shaft or stem, into which it is screwed, and may be detached by turning round a small milled headed thumb-screw. The key is placed in the key-hole in the usual way, but it cannot turn; its circular movement round the stem as an axis is prevented by the internal mechanism of the lock; it is left in the key-hole, and the stem is detached from it by unscrewing. By turning the handle, the key-bit, which is left in the chamber of the cylinder, is brought into contact with the works of the lock, so as to shoot and withdraw the bolt. This revolution may take place whether the bit of the movable key occupy its little cell in the plate or not; only with this difference—that if the bit be not in the lock, the plate revolves without acting upon any of the tumblers; but if the bit be in its place, it raises the tumblers in the proper way for shooting or withdrawing the bolt. It will be understood that there is only one key-hole, namely, that through which the divisible key is inserted; the other handle or fixed key working through a hole in the cover of the lock only just large enough to receive it, and not being removable from the lock. As soon as the plate turns round so far as to enable the key-bit to act upon the tumblers, the key-hole becomes entirely closed by the plate itself, so that the actual locking is effected at the very time when all access to the interior through the key-hole is cut off. When the bolt has been shot, the plate comes round to its original position, it uncovers the key-hole, and exhibits the key-bit occupying the little cell into which it had been dropped; the stem is then to be screwed into the bit, and the latter withdrawn. It is one consequence of this arrangement, that the key has to be screwed and unscrewed when used; but through this arrangement the key-hole becomes a sealed book to one who has not the right key. Nothing can be moved, provided the bit and stem of the key be both left in; but by leaving in the lock the former without the latter, the plate can rotate, the tumblers can be lifted, and the bolt can be shot.
CHAPTER VIII.
THE LOCK CONTROVERSY: PREVIOUS TO THE DATE OF THE GREAT EXHIBITION.
It must be evident, even on a cursory glance at the past history of the lock-manufacture, that the prime motive for the introduction of novelties and improvements in construction is the desirability of producing a lock which no one can open without the proper key. From the earliest and simplest lock, down to the latest and most complex, this object has been constantly held in view; and every clear proof or evidence that this object has not been attained has led to the invention of some new contrivance. It has been a succession of struggles—to attain security—to shew that this security has not been attained—to make a further and more ingenious attempt—to detect the weak point in this renewed attempt—and so on. We need not repeat here, what was stated in an early chapter, that benefit must ultimately result from a candid discussion of this question. When M. Réaumur proposed to explain how the locks of his day could be picked or opened without the true key, his object was to shew to persons who were not locksmiths how far they could depend upon the principle of security offered by locks. But before proceeding on his inquiry, the illustrious naturalist asks, “Ne craindra-t-on pas que nous ne donnions en même tems des leçons aux voleurs?” And he replies, “Il n’y a pas grande apparence qu’ils viennent les chercher ici, et qu’ils en aient besoin; ils sont plus grands maîtres que nous dans l’art d’ouvrir les portes. Apprenons donc l’art d’ouvrir les portes fermées, afin d’apprendre celui de les fermer d’une manière qui ne laisse rien ou qui laisse peu à craindre.”[5]
[5] “But is there not this danger, that at the same time we shall be giving lessons to the thieves? It is not very probable that they will seek instruction of us, or that they have any need of it; they are greater masters in the art of opening doors than we can pretend to be. Let us then learn the art of opening locked doors, in order that we may acquire that of securing them in such a way as to leave little or nothing to be feared on account of their security.”