A Recording Annunciator Target
In rifle practice it is often desirable to provide a target which will indicate to the marksman when the bull’s-eye is struck. The device shown in the sketch, arranged behind an ordinary card target, has given satisfactory results on a private range, and can easily be adapted for other uses.
Fig. 1
Fig. 2
Fig. 3
The Bullet Forces the Hinge against the Thumbscrew, Causing the Bell to Ring
Referring to Fig. 1, A indicates a wooden base, 4 by 8 by ¹⁄₂ in., on which is mounted a strap hinge, B, 6¹⁄₂ in. long, by means of a block, 1³⁄₈ in. high. An opening, C, 1¹⁄₂ in. in diameter, is provided in the base, and a plate, D 1³⁄₄ in. square, is riveted to the strap hinge opposite to the opening. An electromagnet, E, obtained from an electric bell, is mounted upon the base under the small end of the hinge. A standard, F, provided with a cross arm, G, is secured upon the base between the opening and the magnet. A thumbscrew with a locknut extends through the cross arm, engaging the rear side of the strap hinge, and permits an adjustment of distance between the core of the magnet and the surface of the hinge. A bell or buzzer, H, is connected as indicated, through the battery circuit. The electromagnet is connected through the battery and push button J.
The strap hinge normally rests against the electromagnet. The force of any projectile passing through the opening against the plate closes the bell circuit and indicates to the marksman that the bull’s-eye has been hit. By the closing of the magnet circuit, the strap hinge is drawn again into normal position and the bell circuit is broken. Figure 2 shows a front view of the circuit-closing device. The device may be mounted in any suitable box, as suggested in Fig. 3. The front of the box is covered with sheet metal, ¹⁄₁₆ in. thick, and the standard target card is mounted thereon.—John B. Brady, Washington, D. C.
¶A convenient method of holding paper in a roll is to fasten a wire clip at each end near the edge of the piece.