Rudimentary Treatise on the Construction of Door Locks For
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Digitized by Google RUDIMENTARY TREATISE CONSTRUCTION OF LOCKS. FAINTED BY LEVEY, BOBSOJf, AND F11ABJU.TK, Great New Street and Fuller Line. Digitized by Google RUDIMENTARY TREATISE CONSTRUCTION at DOOR LOCKS, tax COMMERCIAL AND DOMESTIC PURPOSES. SECOND ISSUE. WITH MR. SMYTH'S LETTER ON THE BRAMAH LOCE3. LONDON < JOHN WE ALE, 59, HIGH HOLBOSN. M.DCCCLTOI-IX. Digitized By Google PREFACE. The reader is entitled to know the origin of the Bmall work which he holds in his hands. In August 1852, being about to write a short article on Locks for a Cyclopaedia of Useful Arts, of which I am the editor, I consulted my esteemed and lamented friend, the late Professor Cowper, of King's College, as to the desirability of explaining to the general reader the defects of some of our English locks, which, previous to the celebrated "lock controversy" of 1851, had borne a high character for Bkilful construction, beauty of workmanship, and undoubted security. Professor Cowper expressed his strong conviction that by exposing the defects of our locks, the cause of mechanical science, as well as the public in general, would be benefited ; that if our locks were defective, inventors would be stimulated to supply the defects, and the art of the locksmith would be raised accordingly. He considered that Mr. Hobbs had made a considerable step in advance in the constructive details of his art, not only in having detected the weak points of some of our best English locks, but also in having introduced two or three new locks, which appeared to be more secure than any of those previously produced. Professor Cowper gave me an introduction to Mr. Hobbs, who placed at my disposal a variety of literary materials relating to the history and construction of locks, and stated his intention at some future time of bringing out a small book on the subject, if ho could meet with a publisher. I recom- mended him to offer the work to Mr. Weale, for insertion in his series of Rudimentary Works. This was accordingly done, and I was invited to prepare the work j but as my engagements did not leave me sufficient leisure to write the book, I requested my friend Mr. George Dodd to put the materials together, and to search for PREFACE. more. Mr. Dodd acceded to my request ; and having completed his part of the work, I subjected it to a careful revision, and added various details which seemed to be necessary to completeness, at least so far as the narrow limits of a small rudimentary work would admit of completeness. The manuscript was then sent to press : each sheet as it was received from the printer was submitted to Mr. Hobbs, who read it with care, and made his annotations and corrections thereon. Mr. Hobbs and I then had a meeting, when the additions and corrections were read and discussed, and ad- mitted or rejected as the case might be. The sheet having been thus corrected was sent to press. It should also be stated that, during the progress of the work, Mr. Weale, at my request, wrote to Messrs. Braraah, and also to Messrs. Chubb, informing them that a Rudimentary Treatise on the Construction of Locks was being prepared, and requesting them to state in writing what alterations or improvements they had made in their locks since the date of the Great Exhibition. The communications which we have received from these celebrated firms are inserted verbatim, in their proper places, in the present work. Such is the mode in which this email volume has been prepared. I have endeavoured to perform an editor's duty conscientiously, without entertaining the feeling of a partisan in the matter. My chief object in superintending the production of this book (an ob- ject in which the Publisher fully participates) is to advance the cause of mechanical science, and to supply a deficiency in one of the most interesting portions of its English literature. C. TOMLTNSOH. Bedford Placi, AnjjOdU Sguart, July 1853. L'.'i j I 2 :3 !:, CONTENTS. T. On T^cks and LocV-liternhim I H. Ancient Locks: Grecian, Bomaii, Egyptian 8 TTT. Lock nkflsincat.inn. The Pnzzlo-Loek and thfl Dial-Lock 16 IV. Warded Locks, with their varied appendages 21 V. On Tumbler, or Lever Locks 41 TL The Bramak Lock 64 1 Vn. Amerinan Locks 82 VIII. The Lock Controversy : previous to the date of the Great Exhibition 102 IX. The Lock Controversy: during and since the time of the X, Effects of the Great Exhibition of 1851 in improving English Locks . IAQ XI. The Lock and Key Manufacture ISA XTI. English PiiLi'iiis fi>r Licks, Aubin's Lock trophy. Con- clusion . IE* DigdlicODy Google Digitized By Google ON THE CONSTBUCTION OF LOCKS. CHAPTER L ON LOCKS AND LOCK- LITERATURE. The manufacture of locks, and a consideration of the me- chanical principles involved in their construction and security, have never yet been treated with any degree of fulness in an English work. Lock-making has occupied a large amount of ingenuity, and lock-patents have been obtained in considerable number, though not always, we are satisfied, with a commen- surate return for the expense incurred,—but lock-philosophy (if so it may be designated) has not been largely attended to. And yet it may safely be said that much which is both mechanically and commercially important is comprised in a lock. Every improvement in the manufacture of iron, steel, and brass — that is, in the tool-making and machine-making processes —may be made to reflect its light on the lock- manufacture ; the stamping, the casting, the planing, the slotting, the screw-cutting, the polishing of metals, — all, in proportion as they are improved, impart some of their aid to the lock-maker. Then, in the finer kinds of locks, the works are so delicate as to approach to the nicety of clock- talented work ; thereby combining the manipulative skill of a fiigiiizod By Google 2 ON LOCKS. artisan with the rougher mechanical work of the smith. The principles of mechanical science are also appreciated by many lock-makers. The lever, the inclined plane, the eccentric, the cam, the screw, the wheel and pinion, the ratchet, the spring, — all arc brought to bear on the internal mechanism of locks, frequently in many novel combinations. The commercial importance of locks —though of course never seriously questioned when once fairly brought before one's attention —has been recently rendered so apparent as to have risen to the position of a public topic. If a strong room, containing gold and silver, notes and bills, books and papers—if such a room be necessarily shielded from intrusion, it becomes no less necessary that the shield should be really worthy of its name, trusty and reliable: a good lock is here nearly as indispensable as a faithful cashier. And without dwelling on such an auriferous picture as a room full of gold, we shall find ample proof of the commercial importance of lock-making in the ordinary circumstances by which we are every day surrounded. Until the world becomes an honest world, or until the honest people bear a larger ratio than at present to the dishonest, the whole of our movables are, more or less, at the mercy of our neighbours. Houses, rooms, vaults, cellars, cabinets, cupboards, caskets, desks, chests, boxes, caddies,— all, with the contents of each, ring the changes between meum and tuum pretty much according to the security of the locks by which they are guarded. A commercial, and in some respects a social, doubt has been started within the last year or two, whether or not it is right to discuss so openly the security or insecurity of locks. Many well-meaning persons suppose that the discussion respect- ing the means for baffling the supposed safety of locks offers a premium for dishonesty, by shewing others how to be dis- honest. This is a fallacy. Rogues are very keen in their profession, and know already much more than we can teach them respecting their several kinds of roguery. Rogues knew a good deal about lock-picking long before locksmiths dis- Oigiiizod By Google — ON LOCKS AND LOCK-LITERATURE. 8 cussed it among themselves, as they have lately done. If a lock — let it have been made in whatever country, or by whatever maker— is not so inviolable as it has hitherto been deemed to be, surely it is to the interest of honest persons to know this fact, because the dishonest are tolerably certain to be the first to apply the knowledge practically; and the spread of the knowledge is necessary to give fair play to those who might suffer by ignorance. It cannot be too earnestly urged, that an acquaintance with real facts will, in the end, be better for all parties. Some time ago, when the reading public was alarmed at being told how London milk is adul- terated, timid persons deprecated the exposure, on the plea that it would give instructions in the art of adulterating mi lk ; a vain fear — milkmen knew all about it before, whether they practised it or not ; and the exposure only taught purchasers the necessity of a little scrutiny and caution, leaving them to obey this necessity or not, as they pleased. So likewise in respect to bread, sugar, coffee, tea, wine, beer, spirits, vinegar, cheap silks, cheap woollens — all such articles as are suscep- tible of debasement by admixture with cheaper substances < much more good than harm is effected by stating candidly and scientifically the various methods by which such debase- ment has been, or can be produced.