GB191102923A - Improvements in or relating to the Sighting Apparatus of Ordnance. - Google Patents

Abstract

2923. Dawson, Sir A. T., and Horne, J. Feb. 6. Sights and methods of sighting.-Relates to telescope sights of the kind in which the eyepiece does not move in elevation with the gun, but a prism or reflector at the object glass end of the telescope is rotated about an horizontal axis for the range-adjustment independently of the gun, and is rotated in the reverse direction when the gun is elevated. The invention consists in lever mechanism arranged between the gun and the holder for the prism or reflector, comprising a lever attached to the holder and connected either directly, or through an intermediate link, with a second lever which is movable relatively to the gun for the rangeadjustment, and with the gun when this is elevated. In the construction shown in Figs. 1 and 3, as applied to a periscope sight, the upper prism a<1> is carried in a rotatable holder a<1Î> journaled in the end of the vertical tube A of the periscope A, A'. The periscope is rotatable, for lateral corrections, about its vertical axis in bearings in the fixed bracket A<0>. Two arm A<1Î> are connected at their upper ends to the prism-holder a<1Î>, and are joined together at their lower ends to form a lever (the " periscope lever ") for rotating the holder. A second lever AX (the " gun lever "), pivoted co-axial with the gun trunnions c‹ and connected by a universal joint to a radial pin a<2> at the lower end of the periscope lever A<1Î>, is of such length that, if rotated sufficiently, its outer end would pass through the axis of rotation of the prism-holder. The lever A<Î> has an arm A<3> carrying the range-dial C and the sightelevating gear C<0>, C<1>, c<1>, c, c<2Î>, C<2>, whereby the lever is adjusted for range relatively to a member C<2Î> fixed to the gun trunnion c<0>, and transmits to the prism a<1> an angular adjustment equal to one-half that of the lever A<Î> relatively to the member C<2Î>. The elevation of the gun moves the member C<2Î>, and with it the levers A<Î>, A<1Î>, and turns the prism-holder back again, to bring the line of sight on to the target. The worm spindle C' of the sight-elevating gear carries a second worm C<3> which drives a wormwheel B'. The rotation of this worm-wheel effects, through a screw-and-nut device, a lateral displacement of the shaft b' of a worm b which is geared with a toothed sector A<3Î> on the periscope A, and thereby effects the drift correction. The worm b and deflexion dial B are rotatable by hand to effect the corrections for speed of ship &c. The member C<2Î>, or an equivalent part, may be mounted in a position remote from the trunnion c<0>, in which case it is connected to the trunnion by a parallel motion.