GB606876A - Improvements in or relating to gun-fire control or like apparatus for similar purposes - Google Patents

Abstract

606,876. Photo-electric control of follow-up systems. VICKERS-ARMSTRONGS, Ltd., INGOLDBY, M. K., and SPAINK, J. H. ABBINK-. April 21, 1938, Nos. 11996 and 36227. [Class 40 (iii)] [Also in Groups XXXVII and XXXVIII] In a follow-up system for controlling, e.g. a gun in correspondence with the movements of, e.g. a sighting device, the usual follow-up switches are replaced by pairs of photoelectric cells co-operating with shutters. As shown, a telescope 33 via a selsyn transmission system controls the movements of shutters 66, 48, corresponding to the primary members of coarse and fine follow-up switches, the parts of the secondary members being taken by pairs 45, 46 of photo-electric cell-lamp combination carried by frames driven by the servo-motor 58 which through a hydraulic follow-up system drives the gun. Lag in the hydraulic system is measured by a differential gear 83 the cage of which is geared to the stator of the fine selsyn receiver 44. The follow-up assemblies control the armature current of the servomotor, the coarse arrangement being normally ineffective. The field current depends on the speed of the fire receiver, which is measured by means of a photo-electric cell 61 co-operating with a radially slotted disc 59 on the shaft of the fine receiver. The cells may be partially exposed in the balanced position. Specifications 586,589, [Group XXI], and 586,590 are referred to circuit arrangements. The armature current.-of the servo-motor 58 is normally controlled by the fine photo-cells 91 which render one or other of the gas-filled tubes 101, 102 effective for a variable portion of a halfcycle of the A.C. supply and these tubes control further gas-filled tubes 112, 113 in the armature circuit. When the error is so large that the coarse photo-cells 92 come into play, a relay 119 in the anode circuit of one or other of associated pentode tubes interrupts the grid circuit of one of the tubes 112, 113 to cause it to become conductive to the maximum extent. At the'same time, the grid circuit of a tube 123 in the field circuit is interrupted to give the maximum field current. At other times the conductivity of tube 123 is controlled by the potential drop across a resistor 133 fed by a rectifier supplied with amplified pulses produced in the photo-cell 61 by rotation of the slotted disc 59. The amplifier characteristic is such that the potential drop across 133 increases with the frequency of the pulses. Modifications are referred to in which the armature current is varied in accordance with the speed of the receiver and the field current is reversed to give a reversal of direction.