GB489532A - Improvements in or relating to aerial beacon lights - Google Patents

Abstract

489,532. Visible signalling apparatus. SVENSKA AKTIEBOLAGET GASACCUMULATOR. Oct. 18, 1937, No. 28360. Convention date, Oct. 31, 1936. [Class 118 (ii)] [Also in Group XI] In a beacon light for aerial navigation in which a projector is rotated constantly in one direction, or oscillated within an angle of approximately 180‹ wholly or mainly above the horizontal plane through the projector so that the preferably fan-shaped beam 3 moves in a plane, or along a conical surface, intersecting that horizontal plane, the angular velocity of the beam may be varied to provide an intensified impression of light in desired areas, or the main rotating, or oscillating, movement may be interrupted, e.g. in the horizontal or vertical position of the beam, and the beam be oscillated one or more times within a small angle, signals of different character being obtained by letting the beam pass, e.g. zenith, without oscillation during certain periods. The main rotating, or oscillating, movement of the fan-shaped beam 3 about the axis 4, in, or parallel to, the focal line of the projector, may be interrupted and the beam be rotated, or oscillated, about its axis 8 to obtain signals of different character on course and off course. As shown, the beam is oscillated through 180‹ about its axis 8 at the end of each main oscillation. Alternatively, the beam may be rotated through 180‹ or a multiple of that angle. To obtain signals of different character along the flying route and on either side thereof whilst avoiding different signals at different heights, a high frequency oscillation within a comparatively small angle about the axis 8 is superimposed upon the main rotating or oscillating movement. The projector may comprise a reflector 1 of parabolic cross section, or a Fresnel lens, with one or more high pressure mercury vapour lamps 2 in the focal line and an auxiliary reflector may be provided on the other side of the lamps.