US 1961116 A
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May 29, 1934. P. 'VAN BRAAM VAN VLOTEN 1,961,116
LIGHT BEACQN FOR AIR TRAFFIC AND FOR NAVIGATION PURPOSES Filed Feb. 1, 1952 Patented May 29, 1934 UNITED STATES LIGHT BEACON FOR AIR-TRAFFIC AND FOR NAVIGATION PURPOSES Pieter van Braam van Vloten, The Hague, Netherlands, assignor to N. V. Philips Gloeilampenfabricken, Eindhoven, Netherlands Application February 1, 1932, Serial No. 590,260 In the Netherlands February 5, 1931 4 Claims.
This invention relates to a light beacon for air-trafilc, navigation and similar purposes.
According to the invention such a light beacon comprises a bar-shaped light source arranged in 5 the focal line either of a cylindrical reflector having preferably a parabolic section or of a cylindrical lens, said light source and the reflector or lens being movable about a vertical axis. In this manner a fan-shaped light beam of great in-.
tensity is obtained which may turn about the vertical axis, thus covering the whole air space or a large part thereof. The beacon may be used, for instance, as a flashing light, a fixed light serving as boardor sector light.
Preferably, the light source and the reflector or lens are arranged in such a manner that the light source is at an acute angle with the axis of rotation. Due to this arrangement the light beam is directed obliquely upwards thus enabling the covering of the whole space.
If it is desired to readily distinguish the light beacon from ordinary white lights then colored light sources are employed. The use of such light sources in combination with the cylindrical reflector or lens offers particular advantages. In fact, the light beacon satisfies the requirement of a. fair luminous intensity in the visual field being obtained by a not exceedingly high consumption of energy also when emitting colored light.
As a red light source it is advantageous to use a low tension neon tube of high efficiency. The comparatively small surface brightness of barshaped light sources has, to a certain extent, the
advantage that the light destined for indicating flying grounds does not daze the pilot on landing. The amplification of the light substantially corresponds to the ratio between the diameter of the luminous gas column and the aperture of the cylindrical mirror or the width of the cylindrical lens.
The invention will be more clearly understood by reference to the accompanying drawing, representing, by way of example, some forms of construction thereof.
Fig. 1 is a vertical section through a beacon according to my invention, while Figs 2-4, respectively, are fragmentary sectional details of various modifications of lamp and reflector, and
lamp and lens combinations.
Fig. 1 shows a stationary fixed lantern 1 having essentially glass walls and in which is mounted a vertical shaft 2 which is uniformly rotated through the intermediary of a transmitting gearing and a motor 3. The shaft 2 has secured to it a frame work 4 in which are mounted the low tension neon tubes 5 and the cylindrical mirrors 6 having a parabolic cross section (see Fig. 2). The collector rings 7 are connected to three anode connections provided at the top of the tubes. The
collector rings 8 serve for supplying the heating current for the incandescent cathode of the neon tubes.
The neon tubes are so arranged that they are at an acute angle with the axis of rotation 2 in such a manner that the point at which the axes of the tubes intersect the axis of rotation 2 lies higher than the neon tubes. Due to this the fanshaped light source is used as economically as possible, it being even possible to observe the light in the zenith. In fact, the fanning of the light in the symmetry plane of the reflectors is so great that an angle of more than 90 is easily covered. Since the axes of the light sources are given an inclined position they have a great efliciency. It is possible to choose such an inclination that the line of maximum luminous intensity has the required elevation.
Fig. 3 shows a cylindrical mirror 9 having a circular cross section and which is placed behind the bar-shaped light source 5. The cross-section of the lens 10, which must emit a more or less parallel flat beam of light, has a shape which is well-known with circular lenses for coast and other lights, this shape being shown in Fig. 3. In this case the cross sections in planes which are parallel to the plane of drawing, are equal.
Fig. 4 shows how the bar-shaped light source 3 may be surrounded by a cylindrical lens constituted by four similar parts 10.
What'I claim is:-
1. A light beacon comprising a rotatable support, an elongated lamp mounted on said support in a substantially upright position, its axis forming an acute angle with the vertical, and means for concentrating the light rays emitted by said lamp into a fan-shaped beam extending from at least the vertical to the horizontal.
2. A light beacon comprising a rotatable support, at least one elongated lamp and a reflector both mounted in a substantially upright position on said support, the axis of said lamp forming an acute angle with the vertical, said reflector concentrating the light rays emitted by said lamp into a fan-shaped beam.
3. A light beacon comprising a rotatable support, a bar-shaped light source and a cylindrical reflector both mounted in a substantially upright position on said support, the axis of said light source forming an acute angle with the vertical, said reflector being parabolic in section, and said light source being disposed in the focal line of said reflector.
4. A light beacon comprising a rotatable support, an elongated lamp mounted on said support in a substantially upright position, its axis forming an acute angle with the vertical, and a lens concentrating the light rays emitted by said lamp into a fan-shaped beam.
PIETIER VAN BRAAM VAN VLOTEN.