GB450878A - Improvements in or relating to wind direction indicators for aerodromes - Google Patents

Abstract

450,878. Electric signalling systems. CHANCE BROS. & CO., Ltd., and HALLETT, L. B. H., Glass Works, Smethwick, Birmingham. Feb. 1, 1935, No. 3280. [Class 40 (i)] A remotely controlled wind-direction indicator for aerodromes comprises a motor-driven rotary indicator, the motor being controlled by slip-rings or cams and electromagnetically operated switches, the magnets being less in number than the number of positions the indicator may take and operated in varying combinations by rotatable selective means at the control position.. The indicator may be a T-shaped member rotatable on a circular track and illuminated at night. In the circuit arrangement shown in Fig. 4, the selective means at the control position comprises three slip rings 24-26 rotatable by a handle and engaging brushes 27-29 to operate magnets A-C at the indicator in combinations dependent on the angular position of the handle. The magnets select a particular slip ring 1 ... 8 and operate magnet D which closes the circuit of motor M including a brake magnet E to release the indicator which is thereupon rotated until the circuit of D is open at the slip ring. The slip-rings at the transmitter and indicator may be replaced by cam controlled switches. In a modification giving a finer setting, the transmitter and indicator are provided with two sets of slip rings, one set, for fine control, being geared to the other coarse control, so that it makes a complete revolution for oneeighth of a revolution of the other. Each set at the transmitter has a corresponding set of magnets such as A,B,C, at the indicator, each of which selects a further magnet of respective groups controlling the circuits over the coarse and fine control slip-rings or cam-operated contacts at the receiver. The direction of rotation of the motor may be controlled by the direction of rotation of the handle by the provision of a reversing relay. Provision may also be made for opening the current supply circuit during rotation of the handle by arranging that the handle, when at rest, is pressed into engagement with a notched circular member, disengagement of the handle causing the opening of a main switch.