Patent GB-417697-A (GB)
Abstract: 417,697. Anti-aircraft fire-control. SOC. LA PRECISION MODERNE, 162, Rue St. Charles, Paris. Sept. 28, 1933, No. 26733. Convention date, Oct. 20, 1932. [Class 92 (ii).] Relates to apparatus for transmitting at a distance the position in space of an arm which has been set by a predicting device, for example as described in Specification 365,083, to the position required for a gun shooting at an aerial target, the apparatus being of the kind in which this " gun parallel arm " is carried by three axes of rotation. According to the invention, the gun parallel arm 8, is pivoted at 10 on the shorter axis of symmetry of a flat rectangular frame 81 whose longer axis 82 is pivoted horizontally in a forked member 83 adjustable about a vertical axis on a pillar 12. The rotation of the arm 8 about the axis 10 relatively to the frame 81 is transmitted by a rack and pinion 87, 88 to a needle 89 moving opposite a dial 90; and the rotation of the frame 81 about the axis 82 relatively to the forked member 83 is indicated by a pointer 86 on a dial 85. For direct firing the two angles transmitted to the gun are one, the difference between the angle of sight elevation and the angle indicated by the pointer 86 and the other, the angle indicated by the pointer 89. The pointer 86 is followed by a pointer 91 driven by a hand-wheel 92 ; the angle of sight elevation is applied to a sighting device 1 by a hand-wheel 17; and these two angles are subtracted one from the other by a differential 94, and the difference is sent to the gun by mechanical means or an electric transmitter 97. The pointer 89 is followed by a pointer 101 driven by another hand-wheel which also operates means for transmitting the angle to the gun. For indirect firing, the forked member 83 is rotated about its vertical axis until the horizontal axis 82 is at right-angles to the arm 8 as indicated by the pointer 89, being on zero, and the two angles transmitted to the gun are one, the angle of elevation of the arm 8, and the other the algebraic sum of the horizontal deflection of the sight and the horizontal rotation of the forked member 83. The pointer 86 is as before followed by the pointer 91 driven by the hand-wheel 92, but in this case, the angle of rotation of the pointer is transmitted to the gun without modification by the operation of the handle 17, a clutch being provided to uncouple the mechanism of the handle 17 from the transmitting device. The forked member 83 is rotated by a handwheel 103 and its rotation is combined by a differential with the horizontal deflection of the sight for transmission to the gun. Automatic follow-the-pointer devices may be provided instead of the handles described above. For use on board ship, two toothed sectors at right-angles to each other are interposed between the forked member 83 and its vertical pillar, and these sectors are controlled by gyroscopes to maintain the axis 82 horizontal. When this control apparatus is situated in a place where the target cannot be seen, an observing station is used to transmit the angle of sight to the control apparatus and the azimuth direct to the guns, and in this case the control apparatus has no vertical axis of adjustment but only the two axes 10, 82.