In England, because the doors are provided with a lock rail, or style, below the middle line of the door, horizontal rim and mor tice locks (usual size 6" longX34"X2") are generally used.
The three most common actions employed in medium quality door locks are the Palace motion (fig. 9), the Easy action and the Scotch spring (fig. 1o) types. The action in figure 12 is termed "Easy," because the striking plate on the door post pushes back the bolt against only one of the springs, but when the knob is turned both the feather and the coil springs come into operation. The Scotch spring in figure io is riveted at the end further away from its point of operation, so that the movement of the spring being very small, its life is long.
On the Continent of Europe and in South America doors are made with one large panel, and so the type of lock in use to meet this style is a high upright lock, the usual size being 3"X6" highX r. The latch bolt is operated in this lock by spiral springs and can be made easy or hard as required.
In America the doors are made with six or more panels, and the rails, or stiles, are too small to take a lock, so that a small upright lock, usually 3"X31" highXi" is fitted inside the frame. The American action is as a rule of the "Easy" type, involving the use of two or more coil springs. A typical action is illustrated in figure 12.
The three principal lock producing countries of the world are England (6,000 operatives), United States of America (9,000 operatives), and Germany (7,500 operatives). Each country has her own special types of padlocks and cabinet locks, as well as of door locks.
Locks Arranged in Groups.
—It has been estimated that there are upwards of i50 locks of all kinds in use in and about a loth century house of average size. Locks are also required for many other purposes, involving a large variety of patterns. For the sake of cataloguing they are divided into four main groups.
I. Rim locks—all locks in this group are fixed to the surface of door.
2. Mortice are, as the name implies, fixed in the door.
3. Padlocks—the origin of this word being descriptive of their function. The word "pad" is taken from "foot-pad," as this type of hanging lock was used to secure packages being transported on the old fashioned pack-horse, when road thieves abounded.
4. Cabinet locks—which term includes the whole range of locks used on household furniture.
some extent manufacturers are endeavouring to standardize their products. It may be that an action is fitted into several differ ent cases, and that one type of case may be suitable for several different actions. Costs of pro duction are reduced in this way, fewer parts being made and a greater quantity of each part, this lending itself to mass produc tion methods. In some locks there are as many as fifty sep arate parts, each of which must be accurately made, in order that it may successfully perform its function.
Until the end of the 19th cen tury almost all locks were hand made by skilled craftsmen, whose title of "locksmith" con veys the true idea that his art is a branch of the ancient art of blacksmithing of earlier times. The skilled men of the trade are now, to a large extent, located in the toolroom, which has become the heart of the modern factory. The drawing office also plays an important part. Not only is it responsible for the design of the lock, both as regards its external and internal parts, but it is there that the charts of numbers are prepared from which the keys of a suite of locks are made, so that very little responsibility rests upon the operator of the machine making the parts, or on the assembler. Unskilled labour is employed in assembling the machined parts but there are, nevertheless, a considerable num ber of skilled craftsmen in the trade who make the heavier types of locks. Their labours are, however, lightened by machines Which perform many operations for them which until recently were done by hand. Owing to the comparatively small sale of these heavier locks, the cost of manufacture of tools for their production would more than counter-balance the resultant saving in assemblers' wages.
The materials used in the manufacture of locks vary with the type, quality and the purpose for which the lock is required. Medium quality rim and mortice locks are of cast iron or steel cases, with brass bolts, wards and levers. Padlocks are made of steel, pressed brass, cast brass, bronze, grey iron or malleable iron, and cabinet locks of steel, pressed brass or cast brass.
Suites or sets of locks are made in several different ways, three of the most important being :— I. All to pass, i.e., all keys and locks identical.
2. All with different keys.
3. All to differ and yet controlled by a master key. A variation of this is often employed for flats, the front doors of the flats having locks with keys all different from each other but each key opening the street door lock.
There are many methods adopted in the trade for making such suites as these, depending on the types of locks used.
The selling price of a lock varies from the cheapest padlock at 2d. each, to a lock used on a Banker's strong-room door worth perhaps I ioo, but the price of an average household door lock is about 3/– to 4/– each. It has been estimated that there are 50,000,000 locks produced in the world every year. (A. J. PA.)