GB578958A - Improvements in or relating to gunsights - Google Patents

Abstract

578,958. Gyroscopes. CUNNINGHAM, L. B. C., FORD, H., BARNES, J. W., SYKES, B., HANCOCK, M., and ROBINSON, B. W. Aug. 22, 1942, No. 11861. [Class 97 (iii)] [Also in Group XXI] Relates to means, employing the processional movement of a gyroscope, for instantaneously and automatically applying a lag to the sight line in following a target to obtain the required deflection angle to correct for the relative speed of gun and target. According to the invention, the lag is obtained by an eddycurrent drag applied by a member spinning with the gyroscope. Fig. 2 shows the invention applied to a reflex-sight illuminated by a lamp 59 with a graticule 57-58 viewed by reflection from a gyroscopically-mounted disc 17 through mirror 61, lens 62 and a reflective semitransparent target view-plate 63. The disc 17 with its gyroscopic mounting and controlling electromagnets is shown in Fig. 3 mounted in a box 50. The rotor comprises the disc 17 driven by a belt pulley 42 through a Hooke's joint 45, the spindle 15 and an aluminium dome 18. The balance of the rotor may be adjusted by bendable tabs 64 on the disc 17. Coils 23-24 and polepieces 21-22 produce a magnetic flux through the dome, the eddycurrents in which 'constrain the processional movement of the rotor. Adjustable air gaps are provided by screws 53. The currents through the coils are adjusted to suit the data such as range, height, air speed, gun azimuth and elevation, and the lead for relative angular velocity of gun and target is continuously applied by the processional deflection of the rotor. In a modification, the deflection of the rotor is conveyed through linkage to a graticule in a telescopic lens and prism system through which the target is continuously followed. Specification 480,185, [Group XXI], and U.S.A. Specification 1,936,442 are referred to.