Fuze, Tape. So called from its shape. May be quick or slow burning.
Fuzes, Combination. Are fuzes combining the principles of the simple fuzes. The term is specially applied to time-percussion fuzes, which are so arranged as to burst either at the end of a certain time or upon striking the object. No very exact classification of fuzes has ever been made. If we consider all the operations necessary to the action of the fuze, only certain time fuzes can be considered simple. Concussion fuzes usually depend for their action upon some operation which takes place between the discharge and the time of impact, which bestows a character of sensitiveness which would, if existing at the time of loading, make them too dangerous to handle. Percussion fuzes, also, must have a similar supplementary operation, but this usually takes place at the time of discharge, or upon impact. It is by this means that the safety-pin, screw, or wire holding the plunger is removed or broken. For these reasons these fuzes are ordinarily time-concussion and concussion-percussion, respectively. A fuze, however, usually takes its name from the immediate cause of the explosion. If this is due to the explosion of a fulminate by a direct blow, it is a percussion fuze. If the shock acts in a different way, it is called concussion. If the explosion takes place at the end of a given time, we have a time fuze. There are also fuzes which may be called centrifugal-percussion, concussion-chemical, concussion-friction, etc., examples of which will be given. It is readily seen that it is difficult to make a classification which will cover all the ingenious devices which have been invented.
The simplest time fuze is one which is ignited by the flame of discharge. In the U. S. field and siege service the paper fuze is used for rifle projectiles, both shells and case-shot, and in the field service the Bormann for spherical. For larger spherical projectiles, the paper case is inclosed in a hollow plug of wood, as in mortar-shells, and in a brass plug in the sea-coast service. In the latter the outer end of the plug is closed with a brass cap having a crooked chaume, to prevent the burning composition from being extinguished in striking water. In the U. S. service percussion fuzes are used only for rifle-shells. The fuze ordinarily employed is, strictly speaking, a concussion-percussion, since the safety wire must be ruptured by the shock of impact before the cap can be exploded.
The time fuze already described can be used in smooth-bore guns and in muzzle-loading rifles; but in breech-loading guns or guns without windage, the fuze composition cannot be ignited directly by the flame of discharge,—one of the strongest arguments in favor of muzzle-loaders. The time fuze for breech-loading guns is ignited by an interior contrivance, usually a plunger and cap; it is, consequently, a percussion-time fuze. Such is the nature of the Armstrong time fuze and the time fuzes used in Germany and Russia. Time fuzes are absolutely necessary to the successful use of case-shot or shrapnel, which must be burst in the air. The latest invention in time fuzes is the substitution of clock-work for the column of burning composition as a time-keeper,—a Yankee idea which has not yet received any official recognition, or been subjected to public test.
The Boxer fuze, used extensively in England, is a time fuze consisting of a column of composition driven in a wooden plug, which is closed at the lower end. In some forms of the fuze small longitudinal channels filled with rifle-powder communicate with the bursting charge. The time-scale is a row of holes in the side of the plug, one of which is bored through to the composition in setting the fuze. The flame communicates with the charge either through the side hole directly, or by the side channels downwards through the end of the plug. Two kinds of fuzes are used,—the simple time fuze for muzzle-loaders, and the percussion-time for breech-loaders.
The Splingard fuze, invented by Captain Splingard, of the Belgian service, is a good example of a time-concussion fuze. It consists of a column of pure composition surrounding a hollow spindle of plaster of Paris. The composition is ignited by the flame of discharge, and burns away, leaving the spindle unsupported. When the projectile strikes, the part of the spindle above the unburned composition breaks off, and the flame fires the bursting charge through the hole in the stump. If the spindle fails to break, the charge is fired when the entire column has been consumed. This fuze is specially applicable to spherical projectiles.
The concussion fuze formerly used in Prussia was a time-concussion-chemical fuze. The burning of a column of composition left a glass tube containing sulphuric acid to be broken, by a lead ball, by the shock of impact. The acid coming in contact with a mixture of chlorate potash, sulphur, and white sugar, produced a flame which fired the bursting charge.
The Beebe concussion fuze for spherical projectiles, invented by Captain Beebe, U. S. Ordnance Corps, was a concussion-friction fuze. A contrivance equivalent to a friction-primer buried in the bursting-charge, and offering great resistance to motion in the powder, was fired by the sudden movement of an attached weight upon impact. The shock of discharge also played a part in detaching the fuze from the fuze-plug.
The German percussion fuze, now commonly used in Krupp guns, may be called centrifugal-percussion. The safety-pin passes through a hole from the outside of the shell. This pin is thrown out by the rotation of the shot, leaving but slight resistances to the motion of the plunger.
In the English cap-percussion fuze the corresponding safety-pin is pulled out by a tape by hand just before loading.