GB631347A - Improvements relating to gun fire-control instruments - Google Patents

Abstract

631,347. Gun-fire control. AKTIEBOLAGET BOFORS. March 18, 1947, No. 7498. Convention date, Dec. 21, 1943. [Class 92 (ii)] Relates to predicting mechanism of the kind in which the target's present and future positions, the position of the sighting instrument, and the lines and angles between these points are mechanically represented on a scale inversely proportional to the present range. According to the invention the apparatus is so constructed that the points representing the sight and the target's present position are fixed. Space diagram.-As shown in Fig. 1, point I represents the sighting instrument, M the target, T the target's future position, MS a perpendicular to IM in the plane MIT, IQ a line parallel to MS, IG a horizontal line perpendicular to IM, and IH a horizontal line perpendicular to IT. IF is a perpendicular through the apparatus. The angles between these lines, to one another and to the horizontal, are indicated, and the present and future ranges are given as L and LT respectively. Apparatus.-In Fig. 3 the apparatus reproduces the data of Fig. 1, the corresponding points bearing the suffix 2; thus I 2 represents the position of the apparatus, and the distance I 2 M 2 represents the target's present range. Certain data, referred to below, which is set into the mechanism can be obtained by any appropriate means. The mechanism includes a rotatable yoke 1 carrying, on a transverse pivot 4, a rotatable yoke 3, in which pivots at 14 a frame 13 carrying a pivoted block 15. The axes I 2 F 2 of frame 13 and I 2 G 2 of frame 3 pass through the point I 2 , and through this point also passes the axis I 2 T 2 of a shaft 16 connected to the block 15 and to a sleeve 28 movable radially on a rotatable ring 21. In setting the apparatus to correspond to the space diagram, the yoke 1 is rotated from the horizontal by gearing 5, 6, 7, through the angle K, the angle between MS and MR, and the frame 3 is so set that angle F 2 I 2 M 2 equals angle FIM, M 2 being at the centre of ring 21. Further settings consist in the rotation of the ring 21 by gearing 22, 23, through an angle such that angle I 2 M 2 T 2 equals angle IMT when the sleeve 28, which is on a spring-controlled carriage 26, is radially displaced by a rod 30 acting on a cam 29 of the carriage, by an amount proportional to v/l.tT, v being the target velocity, l the present range and tT the projectile's time of flight. The displacement of rod 30 is obtained from mechanism to which data is fed from a device 33 controlled by the effective length of rod 16. With the parts correctly set, devices 17, 18, measure the azimuth and training angles and transmit them electrically to the gun.