Patent GB-664596-A (GB)
Abstract: 664,596. Sighting devices. CONTRAVES AKT.-GES. Jan. 19, 1949. [Jan. 19, 1948] No. 1550/49. Class 92 (i). Relates to sighting devices in which the aiming off triangle is reproduced as at TSM, T representing the gun site and M and S respectively the present and future positions of the target, the vector TS being variable, and in which the point T is fixed in relation to a carriage 37 slidable along a guideway 38 pivoted in a vertical plane parallel to the axis of the gun barrel and participating in the elevating movements of the gun barrel. According to the invention, the elevation of the guideway differs from the elevation of the gun barrel by a variable angle so that the vector corresponding to the distance of the gun to the future point of impact is inclined to the gun barrel at the superelevation angle, means being provided for adjusting the variable angle in the dependence on the elevation of the gun barrel. In the construction shown, the mechanism is carried by a casing 5 pivoting about a horizontal shaft 6 and moved, by linkwork, to follow the barrel in elevation. The point S is determined by the intersection of the axis of a shaft 9 carried by the casing and of the axis a-a of a housing 15 rotatably mounted on a ring 13 carried by the shaft 9. The point M is located at the bottom of a shaft 17 carried by the housing 15 and is set by the combined rotation of the housing about axis a-a and of a bar 21 on the housing so that SM is parallel to the path of the target, and by setting a knob 22 to move shaft 17 radially so that the length SM is made proportional to the target's velocity. The point T lies on the axis 24 of a device slidable along a rod 31 which has a universal connection 18, 19, with the shaft 17 at the point M. The adjustment of the point T, to vary the vector ST in accordance with the mean velocity of the projectile, is effected by a handle 52 on a shaft 48 which carries a pointer 54 movable over a range scale 57, and a gear 47 which through a gear 46 and threaded shaft 42 positions the carriage 37 on the guideway ; the carriage is connected by a beam 26 and shaft 25 to the device 28, 29 by which point T is positioned on the rod 31. A sighting device 27 is suitably connected to the parts 25, 28, whereby the line of sight is maintained parallel to the line TM. Superelevation. This is applied to the sighting system by a cam 69 in the form of an eccentrically mounted disc on the shaft 9. The latter is made to rotate during elevational movements of the gun by parallel links 59, 61 and bar 62, and serves to position the arm and also to maintain the ring 13 in a horizontal position. A fork 68 on the guideway embraces the disc, and thus the guideway pivots about shaft 67 when the gun is elevated thereby imparting a movement to the point T. It is shown in the Specification that with the disc cam the movements of the part T can be made such as to impart the required degree of superelevation for all elevations of the gun barrel. The housing 15 may, by shaft 66 and worm 64, be given a rotation opposite to the azimuth movements of the gun, thus avoiding constant alterations to the bar 21 when following a target, Specification 358,901 is referred to.