Patent GB-200798-A (GB)
Title: Apparatus for applying corrections in the laying of artillery pieces from a distance
IPC: F41G3/14
Filed: 1923-06-05
Abstract: 200,798. Schneider et Cie. July 17, 1922, [Convention date]. Methods of sighting. - In a gunnery-control system for obtaining convergence of fire from a number of guns controlled from a single station and particularly applicable to ships, corrections. are applied to each gun for parallax in altitude and azimuth, difference of range, platform inclination, and individual gun data such as muzzlevelocity and wear. The system provides two pairs of pointers at each gun to be brought into coincidence for correct laying, one pair being operated by electric transmitters from the control station and making the corrections in training and elevation for parallax, the other pair operated by the actual movements of the gun and embodying in addition corrections for difference of range, platform inclination and gun particulars. For convenient approximation purposes, the guns are considered as in groups and each group is represented by an imaginary gun placed on a straight line passing through these guns and the control station. Correction for parallax in azimuth is obtained by means of a drum 1, Fig. 2, bearing curves D<1>, D<2>, &c. expressing, for the separate imaginary guns, the relation between the range and the function sin a/range where a is the angle between the line of sight and the imaginary base line. The drum is turned in accordance with this angle a. A screwed spindle 4 carries a nut 5 bearing a pointer 8 and prevented from rotating by a guide 7. Bevel wheels 9, 10, 12, 13 and 15, 16 convey the rotations of spindle 4 to shafts 11, 14, 17 respectively in the proportion of the distances of the imaginary guns from the control station and these converted movements are added to the bearing received from the control station through shaft g and are conveyed to the individual gun stations through transmitters t<1>, t<2>, t<3>. To facilitate setting the pointer 8 at points when the curves are close together, the movements of the pointer are multiplied by means of the rack and pinion 24, 23, pulley 22, and band 20 and the setting indications taken over by a pointer 18 co-operating with correspondingly enlarged curves on the drum. For parallax in altitude the guns are considered again as grouped according to heights and the correction for each gun is applied by means of a suitably contoured cam introduced into the elevating mechanism of the sighting telescope when the guns are at one level different from that of the control station. If not, cams are introduced between the telescope elevating mechanism and that for transmitting the elevation to the gun layers, the cams being driven as a function of the distance. To correct for gun platform inclination the inclination of each platform is taken with reference to a plane midway between the extreme inclinations (the necessary correction for this 'being applied to the sighting instrument at the control station) and the correction for the gun is effected by means of the mechanism shown in Fig. 3. A plate 103 fixed to a shaft 101 turned proportionately to the bearing of the line of greatest slope is adjustably secured at 107 to a second plate 105 the spindle of which supports pivotally at 110 a plate 108 geared at 113 with an adjusting screw 112. By this means the plate 108 can be inclined proportionally to the inclination of the gun platform concerned, and this displacement is conveyed through screw 115 gearing as a rack with pinion 46 to one element of a differential gear 49, the other of which i is turned according to the elevation of the gun. Consequently the corrected angle is given by pointer 52, which is mounted coaxially with the hand of the receiver driven from the control station. By adjusting so as to secure coincidence of reading of the two pointers therefore, the corrected gun elevation can be determined. In order to correct for difference of range a camoid 53 turned proportionally to the bearing of the target and displaced axially according to the range supports the whole of the mechanism so far described, as'shown at 54. The correction for muzzle-velocity is also introduced to this mechanism by means of a camoid 55 rotated proportionally to the range and moved axially as a function of the muzzlevelocity. The resultant movement of the spring- controlled rack 56 produces a rotation of the screw 115 and thus modifies the position of the pointer 52. A simplified apparatus, only semiautomatic in character, is described, comprising a drum bearing graphs giving the relation between bearings and the sum of the various cor. rections and turned proportionally to the bearing, a screwed spindle similar to 4, Fig. 2, being used to actuate manually by setting from this drum one element of a differential gear the other element nf which is driven bv the shaft 1, as in Fig. 3. Specification 177,146 is referred to.