GB437444A - Improvements in or connected with optical sights - Google Patents

Abstract

437,444. Gun sights. BARR & STROUD, Ltd., and MACGILL, C. D., Caxton Street, Anniesland, Glasgow. April 26, 1934, Nos. 12564/34 and 12140/35. [Class 92 (ii)] Relates to sights in which the target is viewed through a transparent screen 9 and an image of an illuminated or luminous ring is reflected from the screen whereby the sighting of the gun may be corrected for the speed of the target. According to the invention, the image of the ring is obtained by an annular optical member such as a parabolic reflector 2, Fig. 1, or an annular series of inclined optical members such as a ring of parabolic mirrors K, Fig. 3, or a ring of lenses P, Fig. 7, the source of light in the form of an illuminated ring or a ring of illuminated points being at the foci of the optical members, whereby an annular beam of light is projected on to and reflected from the screen. In Fig. 1, the surface of revolution forming the mirror 2 is generated by the arc of a parabola, the axis of which is inclined to the central axis A B. The source of light 4 illuminates an adjustable circular slit 3, embracing the foci of the parabolic arcs, and a central hole 7, the image of which is thrown on to the screen by a lens 6 to form the ring centre. In Fig. 3, the source of light 4 illuminates from below a ring of points 15 at the foci of a series of inclined parabolic mirrors K attached to a plate L. In Fig. 7, light reflected from a surface 16 illuminates a series of holes 17 at the foci of a ring of inclined lenses P.