A New or Improved Instrument for Indicating and Recording the Aiming of Naval Guns at the Moment of Firing.

摘要

18,955. Dick, C. J. A. Sept. 23. Gunnery practice, teaching.-The object is to provide a device for recording the direction of the aim of the gun at the moment of discharge, and for recording the direction of motion of the ship at the same instant. Figs. 1 and 2 show vertical sections, taken at right-angles to one another, of an instrument in which the registering-surface is stationary. A photographic camera is employed, the axis of which is parallel to the sighting-axis of the gun. The axis of the camera is marked in the apparatus by a cross-wire y, and the gun is correctly aimed if the picture of the target a coincides with the point y. The position of the ship is shown by pointers c, c', which are pivoted to heavy pendulums d, d1, and are included in the photograph. To indicate whether the ship was moving upwards or downwards at the moment of firing, two pivoted arrows b, b1 are provided with rollers, which are pressed by the friction sectors d2, d3 mounted on the upper ends of the pendulums. The two pendulums may be replaced by one doubly-suspended pendulum with a single pointer, which can swing up and down parallel to its position of rest, and can also stand at different angles to the same. The pointer may be replaced by a line of light formed by a screen with a horizontal slit in it fastened to a single pendulum carried in gymbals. The pointers b, b1 may be dispensed with, by taking a second photograph of the pointer c, c1. If the registering-surface is a steadily-moving one, consisting, for instance, of a sensitive film which is wound off one roller on to another, the points c, c1 carry screens each provided with an aperture for light, the movements of the pointers being then registered by curved lines, as shown at x, z in Fig. 3. The surface of a liquid may be used instead of the pointers c. c1. In the form of apparatus shown in Fig. 7, a U-shaped tube p is filled with mercury, and one arm is provided with vertical slits q for the passage of the light on to the moving film f. The surface of the liquid will then trace a curve.