GB190920243A - Improvements in and relating to Sighting Apparatus for Ordnance. - Google Patents

Abstract

20,243. Dawson, Sir A. T., and Buckham, G. T. Sept. 3 Sights. - Relates to sighting - apparatus for ordnance adapted to fire at objects above the horizon, of the type in which the firing-angle is automatically corrected by means of a cam according to variation in the angle of site of the object aimed at. According to the present invention, the cam-surface is composed of a series of curves based on the firing-angles for various altitudes ; during the elevation of the gun, the cam is moved transversely, and, by means of a movable arm, corrects the position of the range-pointer. Range corrections are made by rotation of the cam. In the construction shown in Figs. 1 and 4, a casing K is bolted to an extension of the boss of the quadrant that brings the gun to the loading position, and a sight-elevating quadrant K<Î> carries the sight F, and is operated from the spindle k<2> of the range dial J<1>, the spindle being operated by worm and bevel gearing from the band-wheel L. An extension K<ÎÎ> of the boss of the quadrant K<Î> is hexagonal and carries the cam H free to slide thereon. Bolted to the cam is a square-threaded screw H<1>, the nut H<1Î> of which is attached to the gun carriage. The segment j, pivoted to the casing K and engaging teeth on the boss of the pointer J, is operated from the cam H by the roller h<Î> and arm h. The sight is first set to the desired range, and the gun is then elevated until the object is sighted. The pointer J having moved during the elevation of the gun, the sight F must be operated until the desired range is registered at the same time that the object is sighted. The range dial is readily removable by means of screws j<Î> and elongated slots j<1x>. Back-lash between the sight F and the range dial J<1> is minimized by making the sightelevating pinion in two parts, relatively rotatable and capable of being locked in the adjusted position. Springs l, obviate back-lash in the correcting-gear. Fig. 5 shows the invention applied to sighting-apparatus, and with ranging and pointing gear similar to that described in Specification 21,299/09. The cam H is mounted on a screw connected to the carriage, and operates the pointer J through the arm h. During the pointing operation, the cam moves transversely and corrects for altitude. During the ranging operation, the cam is stationary, the ranging shaft d<2> and consequently the pivot of the arm h moves, and hence the cam corrects for range.