Description of Capt. C. A. McEvoy’s Circuit-closing Arrangement for Harvey’s Sea Torpedo.
Fig: 1. Fig: 2.
London: E. & F. N. Spon, 48, Charing Cross.
Kell Bros. Lithrs.
Fig. 1.—An exterior tube, a a; screw-head, [= a]; interior tube, b; intermediate tube, d; firing bolt, e; spindle, f; long brass spiral spring, g; short spiral spring, h; socket for spindle, i i; insulated wire from battery, k k; insulated terminal, l; electric fuze, m; priming space, n n; charging hole, o; insulated bridge, p; metal bridge, u.
The electric wire k k passes through the screw-head [= a] of external tube a a, and winding spirally around the intermediate tube d, terminates in a connection with the insulated bridge p at s. The intermediate tube d is attached to the head of the spindle f at t. When pressure is brought to bear on the firing bolt e, the spindle f is forced down, and carries with it the insulated bridge p, until the bridge touches the insulated terminal l. It will be seen that the long spiral spring g and short spiral spring h serve to support the spindle f, and keep the bridge p off the terminal l until they are forced into contact. Whilst the insulated bridge p remains above the insulated terminal, the former is in constant contact with the metal bridge u; but this contact is broken when the metal bridge moves downward and before it makes contact with the insulated terminal l. When the insulated bridge p is in contact with the metal bridge u, the electric fuze is out of circuit; and a current sent through the torpedo will return by way of the earth without firing the torpedo; but when contact with the metal bridge u is broken, and contact with the insulated terminal l is made, the current is directed through the electric fuze, and the torpedo fired.
The priming in the tube is sufficient to rupture the tubes and ignite the charge in the torpedo.
Fig. 2 shows a section of the circuit-closer, with the spiral spring slightly compressed, and the insulated bridge in contact with the insulated terminal, and the circuit closed. By dispensing with the electric fuze, and using in its place a piece of copper wire, any number of experiments may be made with an uncharged torpedo without adjustment or manipulation of any kind; it only being necessary to attach to the return wire near the battery a galvanometer or electric fuze to indicate the time of the impact.
The torpedoes here described are manufactured by J. Vavasseur and Co., at the London Ordnance Works; at which establishment the inventor has every facility in the supervision of the various details in the construction of the torpedoes, buoys, and brakes. Such supervision of the torpedoes and their equipments is highly essential to secure safety and efficiency.