Patent GB-226494-A (GB)
Abstract: 226,494. Schneider et Cie. Dec. 17, 1923, [Convention date]. Disc recording - apparatus. - In firing from ship to ship, in order to correct the range or the. time of flight to allow for the distance travelled by the objective vessel during the time of flight of the projectile, the curve of actual times of flight plotted in a discontinuous manner on a moving paper band from range finder readings is extrapolated by eye in a continuous manner in order to ascertain the further position of the objective. The upper curve D, Fig. 1, is a curve of distances plotted against time horizontally and may be replaced by a times of flight curve T for a given type of gun and projectile. If a shot is fired at time t0, the corresponding time of flight will be T0, a point on the curve T. But during the time of flight To the objective vessel has moved such a distance that t0 m is the new interval of time between the firing of the gun and the moment when the projectile hits the objective in its new position, and since m M is the actual time of flight for the new position, t0 m=m M if the projectile is to hit the objective. This gives a point T showing the corrected time of flight from which the corrected range is deduced. A paper band A, Fig. 2, is moved to the left at a uniform rate by clockwork mechanism and a rod 5 at right-angles to this direction of motion is carried in fixed guides 6 and may be moved longitudinally by handoperated mechanism so that the distance of a style 7 thereon from the lower edge a of the band is proportional to the corresponding actual time of flight of the projectile. The rod 5 is also rotated from time to time as range finder readings are taken so that the style 7 plots the points constituting the times of flight curve. A cursor 9 having an index is moved along a rod 8 fixed at 45‹ to the band A by a screw 10 operated by a handle 11 which is connected either with a needle, moving over a dial graduated in times of flight, distances, or angles of elevation, or with a distant transmission mechanism from the gun. The paths of the style 7 and cursor index 9 meet at the point taken as origin for the times of flight. This apparatus being connected to one range finder, at' the moment of taking each measurement the rod 5 is displaced axially and rotated so that the corresponding time of flight is plotted. The curve thus indicated on the paper in a discontinuous manner by these points is continuously extrapolated by the operator turning the handle 11 so as to keep the index 9 on the extension of the curve, this extension being estimated by eye. Thus the distance M t0 from the index 9 to the point of time t0 will give at every moment the value M m and, therefore, the corrected time of flight. Style-operating device for several range finders. Where there are several, say two, range finders directed on the same objective there are parallel rods 5, 5<1> ... Fig. 3, one for each finder and these rods are rotated to plot the points by toothed sectors on the rods meshing with racks E, E<1> .. , moved axially when magnets F, F<1> .. are energized. Suitable mechanism is provided for moving the rods 5 axially. In order that the two styles B<1> on the rods 5, 5<1> may not be lowered simultaneously a contact stud g permanently connected by a brush g<1> to the negative of a battery H wipes past brushes f, f<1> connected to magnets F, F<1>, Fig. 3. When the telemetrist is sure of his readings he depresses a switch I or I<1> at the range finder and on contact of g with f or f , F or F<1> is energized to drop a style B'. In a modification, Fig. 7, three finders M<1> - - M<3> are connected to one rod 5 by brushes L<1> - - L<3>, switches I<1> - - I<3>, battery H, and a magnet F. Also brushes O<1> - - O<3> of a second and coaxial rotary distributor, and battery H<1> connect the range finders with actuating mechanism J for displacing the rod 5 axially, the brushes O<1> - - O<3> being angularly displaced relatively to the brushes Ll - - L<3>, so that when a switch I is depressed the rod 5 is first fed axially and then rotated to plot the point.