GB191125844A - Improvements in or relating to the Sights or Ordnance and Small Arms. - Google Patents

Abstract

25,844. Hardcastle, J. H. Nov. 20. [Cognate Application, 7021/12.] Telescope systems; micrometer systems.-The invention comprises telescope sights for use in systems of sighting such as that described in Specification 8038/11, [Class 119, Small-arms], according to which the aim at all ranges is taken at a point a constant distance below the target base, the line of sight having a fixed relationship to the gun-barreh and no range estimation being required. The improved sighting-devices are employed to measure the angle through which the sight - line must be depressed, and to apply that angle between the sight-line and the target base. Fig. 1 is a part sectional plan of a sight constructed so that the aim may be taken at a point about twice the height of the target below the target base. The object-glass is divided vertically, in known manner, into two halves O<1>, O<2>, of which O<1> is displaceable relatively to the other by toothed-gearing P<1>, P<2> operated by a rod R. A lens L' is combined with the half-lens O<1> and produces an image of the target, described as a 'ghost,' in the plane of the cross-wires CW, which cross-wires constitute the ' principal ' line of sight. A lens L<2> is also combined in the manner shown with the fixed half O<2> of the object-glass, and this combination also produces a target-image in the plane of the cross-wires CW. The relative sizes of the target - image T<1> and the ' ghost ' G thus produced are shown diagramatically in Fig. 3 (a), but side by side instead of superposed as in the actual apparatus. The half-lens 0' and lens L' are then displaced vertically until the head of the ' ghost ' registers with the base of the target-image T<1>, as shown in Fig. 3 (b). Finally, or simultaneously, the gun is elevated until the cross-wires CW intersect upon the base of the ' ghost ' G as shown in Fig. 3 (c). The ' principal ' line of sight is thus directed to the desired point below the target. The telescope may be arranged to permit simultaneous observation by two persons, one of whom elevates the gun while the other adjusts the position of the two images. If the line of sight is to be depressed through a, ' negative ' angle equal to the angle subtended by the target, the lenses L<1>, L<2> are omitted, and the target image T<1> and ' ghost ' G are of equal heights. The second Provisional Specification describes constructions differing slightly from those above described, for example, a telescope with fixed and adjustable fiduciary marks, and an adjusting-device for moving simultaneously the telescope out of the principal line of sight and the adjustable fiduciary mark relatively to the fixed one.