Patent GB-152630-A (GB)
Title: Improvements relating to fuse setting apparatus for anti-aircraft artillery
IPC: F42C17/00
Filed: 1920-05-05
Abstract: 152,630. Morse Instrument Co., (Assignees of Morse, R. V.). Oct. 10, 1919, [Convention date]. Gunnery calculators; computing by plotting.-Consists mainly in the use of a two-dimensional cam the angular position of which is made to depend on the altitude of the target and the angle of quadrant elevation or the line of sight of the gun, the cam being connected by gearing to the fuse - setter proper. As shown, the fuse-setter 78 which is carried by the door 25, Figs. 1 and 2, of the apparatus receives its adjustment for time of fuse through pinion 77, chain 74, cam 70, gear-wheels 65, 62, and pinion and rack 83, 60, Figs. 2 and 4, when the gun is elevated. The setting depends upon the elevation of the gun and the height of the target as follows. The spindle 61 of the pinions 62, 83 is carried by a block 50 which moves in elevation with the gun; and the rack 60, which is kept in fixed angular alinement with the gun by a guiding-frame 51, 52, and block 50, is connected at its lower end by a pivot 58 to a saddle 55 free to slide on a bar 45, which is adjusted by means of screws 31, 32 and gearing 34, 33, 36, 37 by a hand-wheel 38 according to the height of the target indicated by a pointer 46 on a scale 47. The effective length of the rack between the pivot 58 and the centre of the spindle 61 thus depends on the height of the target as well as on the elevation of the gun. The cam 70 is designed to give the correct setting for varying elevations of gun for a given height of target; and the pitch or relative speed of the screws 31, 32 and the scale 47 are designed to correct the setting for varying heights of target. By a process of trial and error with the use of curves representing the firing data and the calculations of the mechanism described, it is possible to obtain such a mechanism with a single cam 70 which will give sufficiently approximate fuse settings for all heights of target and elevations of gun within reasonable limits. The cam 70 and the gear-wheel 65 are coupled together by a clutch 71 which can be disengaged and rotated by means of a hand-wheel 72 to change the angular position of the gear-wheel 65 relatively to the cam 70 in order to modify the setting by an amount indicated by the angular distance between a pointer 66 moving with the gear-wheel 65 and a pointer 73 moving with the cam 70. This angular correction is to provide for the change in position of a moving target during the time that elapses from the setting of the fuse to the burst of the projectile, and is adjusted by observation of fire. Part of the mechanism described above is mounted in a casing 23 attached to the gun mounting, and part by the door 25 of the casing which is provided with a window 82 for the scale 47. To prevent damage to the gear-wheels 65, 62, one of which is carried by the door and the other mounted in the casing, the door is arranged to be closed in a slightly lowered position and then to be raised to bring these gear-wheels into engagement, a peep-hole 68 in the door allowing the pinion 62 to be seen for this purpose. A stop 69 depending from the top of the casing over the door prevents the closing or opening of the door except when it is in the lowered position.