GB138376A - Improvements in or relating to ordnance - Google Patents

Abstract

138,376. Dawson, Sir A. T., and Buckham, Sir G. T. July 31, 1918. Sights.-Relates to gun-elevating gear of the kind provided with vertical deflexion gear for adding or subtracting the vertical deflexion angle to or from the angle of tangent elevation, and consists in means whereby the operation of the vertical deflexion gear causes the reading of the tangent elevation indicator to vary by an amount proportional to the vertical deflexion, so that the required vertical deflexion may be imparted by operating the tangent elevation gear until the leading of the indicator is the same as it was prior to the operation of the vertical deflexion gear. In the form shown in Fig. 1, as applied to a gun having an independent line of sight, the operation of the pointing crank-handle F imparts elevation to the sight through the shafts e, e<1>, simultaneously with elevation to the gun through gearing comprising a worm on an extension ex, Fig. 2, of the shaft e, adapted to actuate one bevel wheel of a differential gear the pinions of which rotate, the shaft F<x> carrying a pinion F' gearing with the elevating arc F<2>. The operation of the tangent elevation hand-wheel B<1> causes a worm b to rotate a worm-wheel b<1> solid with (1) the other bevel-wheel of the aforementioned differential gear for imparting elevation to the gun, and (2) a bevel-wheel bx adapted to rotate the range dial A with respect to the fixed pointer A<1> through one member of a differential gear D. The operation of the vertical deflexion hand-wheel C<1> mounted on the opposite side of the gun is adapted, through the shaft C, to actuate, the second member of the differential gear D, whereby the range dial A is rotated by an amount proportional to the vertical deflexion. By actuating the ranging hand-wheel B<1> until the reading of the range dial opposite the fixed pointer A<1> is the same as it was before the vertical deflexion gear was operated, the required vertical deflexion is imparted to the gun. A clock-spring may be provided between the casing and one of the bevel wheels of the differential gear D to take up backlash. A modification is described showing how the invention may be applied to a gun not having an independent line of sight.