Patent GB-147084-A (GB)
Title: Improvements in anti-aircraft gunnery
IPC: F41G5/08
Filed: 1920-07-07
Abstract: 147,084. Girardelli, R. May 3, 1919, [Convention date]. Speed indicators operating by sighting aerial objects.-Consists in apparatus controlled by a range-finder and a sighting telescope for determining the azimuth and elevation angles and the fuse time necessary in order to lay an anti-aircraft gun on a moving target, corrections being made for the change of these quantities during the time of flight of the shell, and in means for imparting the corrected angles and the fuse time to the gun and fuse-setting instrument respectively. In the form shown, three surface cams 1, 2, 3 shaped respectively to give the variation with range and angle of sight of tangent elevation, time of flight, and fuse length, are mounted on a shaft 4 which may be (1) slidden axially in proportion to the range of the target by a motor 5, actuated from a range finder, and acting through a planet gear 10 on a rack and pinion gear 12, 13, and (2) rotated through a planet gear 63, and bevel gear 39, 40, in proportion to the angle of sight by a motor 6, controlled by the movements in elevation of the sighting telescope. The motor 5 drives through bevel gearing a governor 14, the collar 34 of which is therefore displaced by an amount proportional to the instantaneous rate of change of range, and this displacement is communicated by links 15<d> to a sliding frame 16<d> having a groove in which works a roller 17<d> on an oscillating rod 18d against which rests a sliding rod 20d. The rod 18<d> is carried on a sliding rod 8 having a roller 37 working on the time of flight cam 2. The displacement of the rod 20<d> by the rod 18<d> will thus be a function both of the rate of change of range and of time of flight t, and thus will be proportional to the change of range in that time. Identical devices are actuated by the motor 6, through the shaft 4. gears 42, 45, 48, governor 24 and links 15
, and by the motor 27, which receives the azimuth angle, through gears 53, governors 55 and' links 15<b>, so that the two rods of these devices that correspond to the rod 20d are displaced respectively by amounts proportional to the change in the angle of sight and in the azimuth angle during the time of flight t. The displacements of these three rods are adapted respectively to actuate motors 22, 25, and 30, of which the motor 22 through gears 59, 60 displaces the shaft 4 by an amount proportional to the change of range in time t, the motor 25 through gears 62, 64, 65 rotates the shaft 4 through an angle proportional to the change in the angle of sight in time t, and the motor 30, through gears 68, 70 71, communicates the change of azimuth in time t to the commutator 29 which transmits the azimuth angle to the guns. The corrected angle of sight is transmitted from shaft 4 through a differential gear to a transmitter which communicates it to the gun, the corrected tangent elevation, transmitted from the roller 50 through its rod being superimposed on the angle of sight through the same differential gear; and the corrected fuse time, transmitted from the roller bearing on the cam 3 is communicated to the fusesetting device to determine the displacement of the member which regulates the setting of the fuse.