GB190022127A - Improvements in Sighting Devices for Guns. - Google Patents

Abstract

22,127. Grubb, Sir H., Dawson, A. T., and Buckham, G. T. Dec. 5. Telescopes.-Consists of improvements upon the sighting apparatus for ordnance described in Specification No. 12,108, A.D. 1900. Fig. 1 shows a vertical longitudinal section, and Fig. 2 an end view, of one form of the invention. A horizontal tube c is provided at its front end with a glass sight-piece d, covered with some opaque material, through which a design, such as the cross e, is cut. An object-glass f renders the luminous rays from the sight e parallel to one another, and a piece of thick glass a, silvered at its lower back part and inclined at an angle of 45‹, receives the image and reflects it upon the front surface s<1> of the glass, whence it is reflected back to the eye of the gunner. The distant target, when viewed by the gunner, will hence be seen with a phantom image of the sight e superposed thereon. The sight e must be strongly illuminated, and, to increase the briliiancy of the reflected image while reducing that of the target, a neutral-tinted glass h may be arranged near to, but not in actual contact with, the glass surface s', or, instead of the glass h, the surface s' may have a semi-transparent reflecting coating deposited thereon. In the modification shown in Fig. 3, the upper part of the glass a consists of two prisms u, v of crown glass. With this arrangement the prism u may be made separate from the lower prism k, which is then made of flint glass and without the silvered reflecting surface s<1>. In the modification shown in Fig. 4, the luminous image of the sight is seen direct, while the image of the target is seen reflected from the prism m upon the semi-transparent reflecting surface a<1>. Instead of rendering the luminous rays proceeding from the sight parallel by refraction through the convex lens f, they may be rendered parallel by reflection from a concave reflecting surface, as shown in Fig. 5. In this arrangement, both the target and the image of the sight are seen direct, the glass a having a semi-transparent reflecting surface a<3>, and the illuminating light entering the tube b through the opening d*, and being reflected upon the surface a<3> by the prism d', or by an ordinary mirror.