GB190822703A - Improvements in Sighting Apparatus for Ordnance. - Google Patents

Abstract

22,703. Dawson, A. T., and Buckham, G. T. Oct. 26. Sights. -A uniformly-graduated range dial, similar to that described in Specifications No. 24,703, A.D. 1903, and No. 23,727, A.D. 1907, is obtained, according to the present invention, by interposing a mechanism between the range dial and the sight-elevating gear so that the movement of the dial is augmented at short ranges and diminished at long ranges. Fig. 1 shows a side elevation of the range dial, and Fig. 2 shows a section on the line 1-1, Fig. 1. A range pointer B is rotated by a motor B' controlled from a distance, and its indications are corrected for changes in muzzlevelocity and charge-temperature by moving the casing of the motor B<1> by means of an adjustable link C<3>, and a bellcrank C, C<x> having its arm C engaging with a spiral groove A x on the range dial A. The sight is elevated, and at the same time the range dial A is rotated to bring a fixed mark thereon into line with the pointer B, by turning a handwheel A<2> which rotates a pinion D through a worm and worm wheel A<1>, A<5>. The pinion D engages with a pinion D' on the same spindle as the sightelevating pinion, and also with a sector d. This sector is pivoted at dx to an arm d<1> attached to the range dial, and has a roller d<3> engaging with a stationary cam groove e formed in the dial casing, and so shaped as to give the necessary compensating movement to the dial. When the pinion D is rotated by the sight-setter, the movement of the range dial is increased at short ranges and diminished at long ranges owing to the motion of the sector d. A modification is described in which the arm d' extends from the pinion D, the sector d engaging with a second toothed wheel attached to the range dial.