Patent GB-146324-A (GB)
Title: Improvements in and relating to apparatus for the determination of the direction of the axis of rotation of a body
IPC: F41A31/02
Filed: 1920-07-02
Abstract: 146,324. Krupp Akt.-Ges., F. Dec. 30, 1918, [Convention date]. Naval mountings.-Consists in optical apparatus for determining the axis of rotation of a body such as a gun mounting on a ship and further for measuring the angle between two such axes. Provision is also made whereby the relative change of position of these axes due to the elastic deformation of the ship may be observed. A collimator G' with an illuminated graticule as shown in Fig. 8 is mounted on a plate G rotating in a plate F which can be adjusted by screws f<1>, the whole being supported by a staging c<2> fixed to the gun B. A staging e' on a fixed part of the ship carries a sighting-apparatus for the collimator G<1>, comprising a telescope K<2>, with a simple cross-wire graticule k<3>, Fig. 7, mounted on a plate K rotating in a plate J provided with adjusting screws i'. A second telescope M mounted on trunnions m<1> is also mounted on the plate K. The lines of sight of these two apparatus are placed approximately in the axis of rotation a-a of the gun mounting A A<1>, and the collimator G<1> is adjusted by the screws f<1> till, on traversing the gun, the image of the intersection of the cross-wires g<2> remains stationary in the field of vision of the telescope K<2>; the axis a-a and the line of sight of the collimator G' are then coincident. By adjusting the screws i' the intersection of the cross-wires g<2> can be made to coincide with the intersection of the cross-wires k<3> of the telescope K<2>, the lines of sight of both devices then coincide with the axis of rotation a-a. To measure the angle between two such axes as in Fig. 2, the axes are determined as before by two sets of apparatus; the telescope M of the left-hand gun is sighted on to the telescope M of the right-hand gun which is provided with an illuminated graticule, Fig. 10. The left-hand telescope M is provided with a graticule, Fig. 9, and is so adjusted by the screws i<1> that the cross-wires m<6> of the right-hand telescope coincide with the cross-wires m<2>; the line of sight of the left-hand telescope K<2> is stated to be now parallel to the line of sight of the right-hand telescope K<2>. Fig. 11 shows the field of vision in the telescope K<2>. By turning the collimator G<1> on its plate F till the scale g<3> on the graticule passes through the centre of the cross-wires k<3>, as shown in Fig. 12, the angle W, being the angle between the axes, can be read on the scale g<3>, and by a scale f<3> on the plate F the angle W<1> through which the collimator G' has been rotated may be read. If the two telescopes M cannot be used to view directly, a third one is used in a position such that both are visible and this intermediate telescope is adjusted to the right-hand telescope M as before. The left-hand telescope M is then adjusted to the intermediate telescope, which is now used as a collimator, and consequently the axes of the two telescopes K<2> are now parallel, and can be compared with the line of sight of the left-hand collimator G' as before. The change of position of the gun mountings due to elastic deformation of the ship will be shown by the cross-wires m<2> and m<6> in the field of vision of the left-hand telescope M not coinciding, as shown in Fig. 13; the parallel wires m<7> in conjunction with the scale m<4> measure the angle W<4>, and the angles W<2> and W<3> can be estimated by means of the scale m<3>.