Patent GB-124791-A (GB)
Title: Method and Apparatus for Measuring Angular Velocities especially for Directing Artillery Fire.
Inventor: WILSON JOHN SIGISMUND
IPC: F41G5/08
Filed: 1916-03-29
Abstract: 124,791. Wilson, J. S., and Dalby, W. E. March 29, 1916. Sights and methods of sighting. - Relates to means for directing anti-aircraft gun-fire, of the kind described in Specification 6801/15, and consists in moving a sighting-device to follow the target either in the vertical plane of the sight or in azimuth, the sighting-device being connected to an electric generator generating a current proportional to the speed of the following movement, the generated current actuating a pointer or the like, which forms one of the elements of the sights on the gun or indicates the deflexion on a suitable volt-meter scale. A variable resistance may be provided in the circuit to be set for " time of flight." The corrections may be simultaneously transmitted to a number of guns. As shown in Fig. 1, two sighting-instruments a, b, constructed substantially as described in the above-mentioned Specification, are provided, one a for following the target in azimuth, the other b to follow the target in the vertical plane of the sight. Each instrument is provided with a small generator, as shown in Fig. 3, for generating an electric current proportional to the speed of the following movement. The currents pass through a resistance box c set according to the " time of flight " and serve directly to adjust an element of the sighting- telescopes 9, 19 provided on the gun for vertical and lateral deflexions. Alternatively, the required deflexions may be shown on volt-meter indicators located near the gun. The electric generator 41, as shown in Fig. 3, is added to the sighting- instrument described in the above-mentioned Specification, and is actuated by the handle 20 by means of which the sighting-telescope c is moved to follow the target. A two-speed gear-train 83, 85 is provided between the handle 20 and the armature 42 for use alternatively, according to whether the target is moving fast or slowly. The resistance box, as shown in Figs. 1 and 10, contains a set of resistances 70 for each circuit, adapted to be adjusted according to the '' time of flight," by means of a handle 72. In order to maintain the total current in the circuit constant, whilst varying that passing through the indicating- dial or galvanometer, a shunt 73 is provided to each resistance series 70. By adjusting the arm 73<a> of the shunt 73, compensation may be made for any variation in the total current due to electrical conditions. The two sets of resistances 70 may be coupled by a slidable pinion on a spindle 75 provided with a thumb-lever 75<a>, thus permitting of simultaneous or independent control. In the form in which the correction is imparted direct to the gun-sight, as shown in Figs. 1 and 6, the foresight of the gun is the optical centre of the lens combination 51, whilst the back-sight is constituted by a wire 53 carried on the pointer 54 of a galvanometer having a movable armature 55 and magneto 56. The sighting- telescope 52 is secured to the cover 59 of the box 57, the cover being connected by a ring joint 60 to the box so as to permit of rotary movement. The wire 53 and galvanometer may be adjusted by means of screws 66, 67. A modification is described in which two sighting-wires subtending a definite angle are used instead of the single wire 53 shown in Fig. 6, to enable the field of view to be extended.