Patent GB-138944-A (GB)
Title: Improvements in apparatus for calculating gun elevations, deflections, fuse settings& other quantities used in gunnery
IPC: F41G11/00
Filed: 1918-01-03
Abstract: 138,944. Cahen, H. Jan. 3, 1918. Methods of sight. ing.-Relates to apparatus for calculating gun elevations, deflexions, fuse settings, and quantities used in gunnery wherein a series of charts are employed corresponding to the fire area of the gun, and consists in mounting the charts on cylinders used in combination with a deflection rod, an angle of sight bar. a height bar, and an enemy bar which latter is rotatable according to direction of travel of target and extensible according to the time of flight or fuse time. A chart is shown in Fig. 3 wherein the bars B<1>. B<2> are graduated for height, the bar E for horizontal range and the pivoted angle of sight bar C for range along the line of sight, the chart being marked with curves of times of flight which are read at the intersection of C, E for any particular adjustment of height and angle of sight. Similar charts may be prepared for elevation and fuse setting, and three such charts may be superposed as in Fig. 17. The line of sight CA being set off on the lowest chart, the intersection of this line with the height line gives the position of the target. If AD be set off in the direction of movement of the target equal to the time of flight multiplied by the speed of the target, the point D is the corrected target position. A vertical line from D through the other charts gives at the intersections D<1>, D<2> with the height lines on those charts, the corrected elevation and fuse settings. Fig. 20 illustrates in plan a target moving along a line ED at an angle to the line of sight CA. If D is the new position, then if the chart be swung from CA to CD the point L where CL = CD will coincide with D. The verticals through L on the chart will give the corrections. The three charts are combined in an instrument shown in Figs. 4, 7, 8, and 9. Fig. 4 shows a bar k-the enemy bar-moved longitudinally a distance corresponding with AD. A cam m<5> the section of which corresponds to different speeds of target is moved axially by pinion and rack n<1>, n<3> to adjust for speed, and angularly by the wheel m<6> for time of flight, the movement being transmitted through a bar m<4> and a rack m<3> to pinions operating rack-teeth under the bar h. The rack is carried in a sleeve sliding on the shaft l<1>, which, together with the gear case l and bar k is rotated through skew gear from the handle l<3> an amount corresponding to the horizontal deflection. The bar k carries at its end a fitting s sliding on a bar o and carrying pointers e<1>, f<1>, the pointer support engaging in a camgroove in a sleeve p<3> sliding in a bar q (Fig. 7) parallel to the bar o and swinging with it about the pivot o<1>, which motion, through the gearing r, s, rotates the shaft g and cam sleeve p<3> to move the pointers horizontally an amount corresponding to AL, Fig. 20. The apparatus is carried on a stand a rotatable on a turntable a<2> by the handle j<3>. The charts for time of flight, elevation, and fuse-setting are formed on rollers d, e, f, the lower roller having a height scale g<5>, and all three being adjustable according to the height scale from a hand-wheel g<4> by similar worm-gears. The bar o is pivoted at o', and a horizontal deflection scale o<2> and pointer o<3> are provided. Pointers d<1>, e<1>, and f<1> move horizontally over the drums. A sighting-bar h pivoted at h<1> in the plane of the axis of the cylinder d is kept trained on to the target. The vertically-guided height-bar i is pivoted to a slide on the rod h carried on a guiderod i<3>, and is adjustable vertically from the roller d by gearing and a rack, and is adjusted horizon. tally by a load-screw operated from a hand-wheel j<3> through gear j<4> and passing through a nut in the sliding mounting j, on which the present-position pointer d' is carried.