Patent GB-663988-A (GB)
Title: A device for training an aiming mechanism such as a gun, a sighting telescope, an acoustic detector or a searchlight on a moving target
IPC: F41G5/08
Filed: 1949-08-05
Abstract: 663,988. Control of several A.C. motors. HOLZER, D. M. de, [Representative of HOLZER, R. C. DE]. Aug. 8, 1950. [Aug. 5, 1949] No. 20451/49. Class 38 (iii). [Also in Group XXXV and XXXVIII.] The movement of aiming mechanism which is trained upon a moving target is controlled by a combination of two synchronous motor units, one supplied at a constant frequency and the other at a variable frequency, the two units being so mechanically coupled as to provide a drive at a speed equal to the difference between the synchronous speeds of the two units, the variable frequency being derived from an electronic oscillator having inductive and capacitive parts to constitute a frequencydetermining resonant circuit in which one of the parts is variable to vary the frequency and with it the speed. The first motor unit is shown as having a stationary armature 1 and a rotating field 2. The armature is supplied at terminals 3, 31 from a source of standard frequency, and the field is either energised with direct-current through slip-rings 4 or is of the permanent magnet type. The second motor unit comprises an armature 7 mounted on the same shaft 6 as the field 2 and having its winding energised at a variable frequency through slip-rings 9. The permanent magnet rotor 10 of the second motor unit is thus driven at a speed corresponding to the difference between the fixed and variable frequencies. A number of motorcombinations of the type described may be used for training a telescope, range finder, and anti-aircraft gun, capacitors forming part of the resonant circuit comprised in the oscillator pertaining to each motor being manually adjusted for this purpose. When it is necessary to allow for the speed of the target and other factors, the motor-combinations which drive the gun are adjusted by having in the corresponding resonant circuits a plurality of capacitors so as to embody all the required corrections, some of the capacitors being driven by motor-combinations of the type described and controlled in a similar manner. As shown in Fig. 6 a motor-combination 101 of the type described is supplied from an electronic oscillator circuit 81 and has capacitors 30 to 37 mounted upon its shaft, the capacity-variation of the capacitors being approximately, sinusoidal. The motor-combination 101 also drives shafts 39 to 42 at different speeds through gearing, each of those shafts carrying two capacitors similar to the capacitors 30 to 37. A searchlight 57 is movable to change its bearing by motor-combination 102 and its elevation by motor-combination 103. The carbons 58 can be moved in a small circle to swing the beam by means of motor-combinations 104 and 105 which are both supplied from electronic oscillator circuits 82, which, when operative, include one of the pairs of capacitors such as 49, 50. Each pair of capacitors are arranged so that their capacity-variations are 90 degrees out of phase and the carbons 58 accordingly carry out a circular movement. Motor-combinations 106, 107 are respectively connected in parallel with motor-combinations 102, 103, and are coupled to a telescope which thereby follows the movement of the searchlight. Hand-operated capacitors 64, 65, are connected in the control circuits of motorcombinations 102, 106, and 103 and 107. A motor-combination 108 is connected in parallel with motor-combination 101 and actuates a shutter in the telescope synchronously with the rotation of the searchlight. When an arm 66 is moved on to the first row of studs 68, a cam member 69 releases lever 70 and connects capacitors 30, 34, 49, 50, in the control circuits of motor-combinations 102 to 107. The searchlight and telescope are given a rotary movement about the bearing and elevation found approximately by an acoustic detector. Further movement of the arm reduces the area of search until the telescope is fixed towards the target. A capacitor 72, 73, is adjusted so that when the arm 66 leaves the last row of studs the motorcombination 101 is stopped and the telescope can then be moved by means of capacitors 64, 65. The telescope and searchlight are directed towards the area including the target found by the acoustic detector by means of selector switches 74 which connect capacitors 75 in the control circuits 82 for the motors 102, 106 and 103, 107.