Patent GB-580335-A (GB)
Title: Improvements in instruments for controlling gunfire
IPC: F41G5/08
Filed: 1944-06-30
Abstract: 580,335. Calculating-apparatus. ABBEY, A. (Arenco Aktiebolag.). June 30, 1944, No. 12529. [Class 106 (i)] In an instrument for controlling gunfire at aerial targets, an arrangement for determining the course angle (i.e. the angle between the line of aim at the target and the direction of movement thereof) comprises distinct devices for reproducing a horizontal and a vertical projection of the target path, and adjustable implements for indicating the target direction in the two projections, these implements, and a further device representing the angle of elevation, being coupled to an apparatus for deducing the course angle. A representation of the horizontal projection of the target path is scribed 'on a disc 1 (the surface of which is coated with a non-drying colouring material) by a stylus 6 radially adjustable with respect to the disc 1 so that its distance from the centre represents the horizontal range Ah. The disc 1 is rotated by a worm 2 from a device sV representing the angle of traverse. Pivoted about the point 6 an arm 7 is rotated by a worm 8 and is manually adjusted from a control 9, through a differential 10, to a position representing the horizontal projection of the direction of movement of the target (kVh) (as observed from the curve drawn by the stylus 6). A second stylus 11 is adjustable along the arm 7 by a device Tfh representing the horizontal projection of the distance of aiming ahead of the target. Thus, the stylus 11 traces out the path of the impact point. An arm 12 is slotted to receive the stylus 11 and follows its movements. The vertical projection of the target path is drawn by a stylus 22 on a paper strip 17 which is wound on to a roller 19 by a device 20 at a speed representing the horizontal target velocity, the stylus 22 being mounted on a rack 21 which is adjusted by a device H representing the height of the target. A second rack 23 is moved relative to the rack 21 to set an arm 25 tangentially to the target path, this rack being set by a manual control 27 which therefore represents the diving angle (dV) of the target. The resultant of the angle dV and the angle kVh is obtained by a parallelogram linkage 37 which is turned about an axis 40 under the influence of the control wheel 9 (kVh) (the interposition of a heart-shaped cam 49 being necessitated 'to provide for the fact that the linkage 37 cannot turn through a complete revolution). The arm 38 of the parallelogram is turned about its centre by a worm 52 driven from the control wheel 27 representing the angle dV. Thus, the arm 36 of the parallelogram assumes a position representing the direction of the target in space. A device hV representing the angle of elevation of the target, rotates a support 33 for a disc 30 to the centre of which the arm 36 is pivoted, and thus the required course angle is represented on the disc 30 by the position of the arm 36. The disc 30 may be graduated to enable the course angle to be read directly or a transmitting device may be used for indicating the angle on a remote dial 66. The angle Ssv, representing the bearing to'the impact point, is indicated on a scale 16.