Patent GB-186335-A (GB)
Title: Improvements in apparatus for effecting gunnery calculations
IPC: G01C3/04
Filed: 1922-09-15
Abstract: 186,335. Soc. Anon la PrÚcision Moderne. Sept. 24, 1921, [Convention date]. Calculating-apparatus for mechanically and continuously determining the corrections, in elevation and deflection, to be applied to gun sights on account of the directions and speeds of the firing and enemy vessels and the wind, comprises a box 1 containing pointers, dials and setting and operating devices which are inter-related and connected by cam, differential gearing and other mechanism so as to show upon dials the corrections and the required total elevation and deflection. The medial line 18 represents in plan the line of tire and connects the axes of three dials 11, 12, 13 and pointers 5, 6, 7 which are respectively allotted to the firing vessel, the wind, and the target. Each pointer carries a cursor 8, 9, 10 which can be radially adjusted in accordance with the observed speeds of the three elements and a pin on each cursor 8, 10 engages in two slots 44, 46 arranged at right angles and made in two superposed plates 43, 45 movable respectively parallel and at right angles to the plane of fire. The dials and pointers are first set by rotation of cranks 14, 24, 29, 36 in order that the pointers may take up their correct orientations with reference to the plane of fire. The dials are rotated by connecting their common actuating shaft 25 with the cranks through differential gear. The cursors 8, 9, 10 are next radially adjusted according to the speeds and the upper plates 43 are consequently moved proportionally to the speed of approach. The movements of the plates are additively conveyed by means of a cord 49 to a pointer 54 movable around the exterior of a speed-indicating instrument 53. A crank 56 has now to be rotated at such a speed as to ensure agreement between the speed indicator hand 52 and the pointer 54, and the consequent rotations of the shaft 55 are transmitted to pointers 60, 62 to show the instantaneous value of the range. The connection between shaft 55 and the pointers may be broken by throwing out a clutch 58 in order tc allow preliminary or extensive adjustments of the pointers. In order to correct the range in respect of the movements in the plane of fire the displacements of the three carriages 43 are conveyed through pins 63, slotted arms 64 and pins 70 to other carriages 66 each slidable parallel to the line of fire 18 and connected through pin 70 with a subjacent plate which can slide only at right angles to this line and has a pin co-operating with a suitably-shaped cam 71, rotated through a shaft 75 from the shaft 55, and therefore set according to the instantaneous range. The movements of the carriages 66 due to the combined motions of the carriage 43 and cam 71 are conveyed through cord 80 and pulleys 77, 78, 79 to one element of a differential gear the other element of which is driven by the distance shaft 55. The resulting movements affect one wheel of a second differential gear controlled also by a crank 85 for imposing large changes in elevation as called for from observation of fire. The driven shaft of this latter differential gear carries the pointer 60' which in conjunction with an intergeared pointer 62<1> gives the corrected range. Lateral allowance due to the speeds of the vessels and the wind is obtained by mechanism similar to that just described, the displacements of the under-carriages 45 being utilized for this purpose. Each carriage 45 conveys its movements through a bell-crank lever 90 to a slotted carriage 94 overlying another carriage which is controlled by a cam 101 driven from the distance shaft 55, the arrangement of these parts being identical with that described above in connection with the carriage 66, and its subjacent plate. The motions of the carriages 94 are combined and conveyed by a cord 110 to a pointer 114 through a differential gear and corrections for drift are super-added at this gear by a cam set from the range shaft 55 through shaft 105 and worm 104'. The dial 115 may be turned directly by means of a shaft 118 and crank 119 in order to impose large changes in deflection, these being indicated by a pointer 121. The wind conditions may be observed or given in terms of apparent speed and direction, in which case an additional dial 122 may be arranged below the wind dial 12 and may be set in accordance with the bearing of the firing vessel, this setting being effected automatically by the dial 2 through gearing 124, 124'..