This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol6", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
It should be noted that some of these hinges have special outer boxes for fixing in floors other than wood. Fig. 189, A, is a sketch of Smith's floor spring, showing the shoe for door, and is typical of this type of hinge. Fig. 189, B, shows a plain and C an adjustable top centre.
Of spring hinges other than floor springs, one of the best known is Gerish's. The single-action hinge is shown at Fig. 190, A, and the double action at B. The spring is contained in a cylinder, and is let into a circular mortice in the door frame. A chain is attached to the spring and passes through a hole in the hinge-plate attached to the frame, and in the case of double-action hinges through the middle plate also, and is attached to the plate screwed to edge of door. The double-action hinge consists of two knuckles, one of which comes into play when the door is opened in one direction, and the other when it is opened in the other direction. A pair of double-action spring hinges is usually considered to consist of one spring hinge and one blank. Single and double-action helical spring butts are illustrated at C and D, and the double blank hinge at E. The helical spring or springs are contained in the cylinders. These hinges can be had with capstan heads for regulating the strength as illustrated, or non-regulating. The action of the single-acting hinge will be obvious from the illustration; the double-action hinge consists of two cylinders, and three plates corresponding to the two knuckles and three plates of Gerish's hinge, the only difference being that in the one case the spring is contained in the hinge joint and in the other it is separate. F and G illustrate an improved double-action spring hinge and blank manufactured by Messrs. Nettlefold & Sons, the advantages claimed for it being rapidity of fixing, neater appearance than the three leaf var eties, and that, unlike them, it prevents sagging of the door. The blanks are on similar principles to the hinge.
The " Victor " butt spring for single-acting doors, as shown in Fig. 190, H, manufactured by Robert Adams, is made with a silent check action, and the door can be thrown fully back. This hinge is fixed near the bottom of door, and an ordinary butt is used at the top.
Most of these hinges are without check action, but an independent door check such as the " Magic" (I), can be used in the case of single-action doors, or one of the many door slams on the market, such as that shown at J, may be used.
Fig. 190, K, represents the special "sympathetic" door gear for opening and closing double-hung doors simultaneously. It can be adapted to open both leaves at the same time either in the same or opposite directions.
The many varieties of hinges which are specially made for fittings and cabinet purposes are scarcely within the scope of this paper. They can be selected from the catalogue of any first class firm dealing with this class of goods.
In dealing with furniture and fastenings, money will be well spent in selecting the best. Where economy is a point to be considered it may be obtained by simplicity of construction, but the workmanship and material should be of the best. Where the very cheap locks fail most is in the inferior workmanship and materials, and the extreme lightness of the working parts.
Locks must be chosen according to their position and use. In many situations the mechanism of a very elaborate lock would be quite thrown away.
Ordinary door locks are divided into two kinds as regards the method of fixing them in the door, namely, "Rim locks," which are fixed on the face of the door; and " Mortice locks," which are let into a mortice on the edge of the door. Each of these two kinds is again divided into "Dead - shot locks," or "Dead locks," as they are often called, "Latching locks," and "Two-bolts locks." A "Dead-shot lock" consists of one bolt actuated only by a key. A latching lock consists of a spring bolt actuated by a handle, but such that it can be locked by means of a key, rendering the handle inoperative. A two-bolt lock consists of a spring bolt actuated by a handle and a dead-shot bolt. A third variety is the ordinary night latch for street doors, which consists of a spring bolt actuated by a handle on the inside and a key without, - generally speaking, however, the key in no sense locks this bolt, the locking being done by means of a small catch or pin on the inside, which renders both handle and key inoperative.
A stock lock is a rim lock in a hard wood instead of a metal case. It is used for stable, coach-house, and similar doors. The angles are sometimes iron bound for strength and protection. This lock is also largely used on church doors, the iron or metal corners generally being ornamental.
A draw-back lock for street doors consists of a spring bolt actuated by a draw-back knob on the inside, with a hook or catch to hold the knob back when it is not required, and a key to lock the spring. Such are made as rim, mortice, or stock locks.
Fig. 191 illustrates, at A, B, C, D, and E respectively, a single-bolt iron-bound stock lock (A), a rim dead lock (B), a two-bolt rim lock (C), a two-bolt mortice lock (D), and a rim night latch (E). Mortice locks can also be had of an upright form, suitable for doors with narrow stiles, and centre bit mortice locks are made to fit into the cavity drilled by a centre bit.