US2219019A - Method and means for emitting sig - Google Patents

Description

Oct. 22, 1940. v PARSBERG 2,219,019

umaon AND MEANS FOR EMITTING SIGNALS WITH vmnue smrm. CHARACTER Original Filed Dec. 22, 19:2

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WITNESS I W flTTGRN) Patented Oct. 22, 1940 UNITED STATES PATENT OFFICE METHOD AND MEANS FOR EMITTING SIG- NALS WITH VARYING ACTER SIGNAL CHAR- Jersey Original application December 22, 1932, Serial No.

Divided and this application Septem-- ber 30, 1937, Serial No. 166,538. In Sweden December 24, 1931 8 Claims.

Application was. filed in Sweden December 24, 1931, and in the United States December 22, 1932, Serial No. 648,348. The present application is a division of United States application Serial No. 648,348, on which Patent No. 2,096,755 issued October 26, 1937.

It has become the general practice in arranging the illumination of air routes to use powerful revolving searchlights projecting beams of condensed light which sweep the horizon. When these beams of light sweep past a certain point, the impression obtained in the said point is that of a flashlight character, usually single flash. The period between the separate flashes varies in length in different countries. In America, for instance, it is considered suflicient with one flash every ten seconds, whereas in Germany they have generally gone in for a period of about three seconds. If it is taken into consideration that it has been the practice for years to provide one flash every five seconds for marine traffic, which moves much slower, the conclusion is easily arrived at that for aviation the period should be quicker and not slower, and consequently that a period of three seconds would be more in accordance with the requirements of air traflic.

Flashes at shorter intervals may be obtained by increasing the rotary speed of the apparatus or by dividing the available light energy into several beams. In both cases the efficiency of the beacon will be reduced. In the first case the light impression will be diminished, owing to the reduced duration of the flash (according to the Blondel and Rey law), while in the latter case the light efficiency of the beacon will be reduced by the division of the light energy.

The Frenchmen Blondel and Rey have scientifically proved that, in order to obtain a flashlight of a light range equivalent to that of fixed light, the light power of the flashlight must be larger and consequently, in order to express its equivalent in terms of a fixed light, the light power of a flashlight must be multiplied by a factor which is less than 1. This factor is dependent on the duration of the flash and diminishes quickly as this is reduced. The factor in question is, for instance, approximately .2 for a flash of .03 second, .48 for a flash of .1 second, and rises to .84 for a flash of .3 second.

From this point of View, it would be advantageous in order to obtain a good light impression or a good signal effect, to have a long duration of the flash, which can be attained by increasing the width of the light beam or by reducing the rotary speed of the beacon. From the point of view of light economy the first-mentioned way of solving the question is not to be recommended. On the other hand, a reduction of the rotary speed will mean that the interval between the separate flashes will be longer. As stated above, it is desirable that this interval should be comparatively short.

It is evident that the two requirements which thus present themselves, particularly in the technique of airway beacons, i. e., long duration of the flash on the one hand and short intervals between the separate flashes on the other, are at variance with each other, inasmuch as compliance with one of the requirements requires a low rotary speed, whereas, the other requires high rotary speed of the beacon.

This invention refers to an arrangement by means of which the above-mentioned features are both attained simultaneously, the lens or reflector system of the beacon being soarranged O as to provide a two-part beam, one part of which rotates while the other part oscillates with a revolving motion in such a way that the signal character of the beam or beams of light will be difierent in diiferent directions. Preferably, according to the invention, the rotating lens or reflector system of the beacon is not allowed to revolve uniformly as has been the practice hitherto, i. e., withan approximately constant speed in the same direction, but is instead given a nonuniform revolving motion. By non-uniform revolving motion is to be understood in this connection that in certain sections of the revolution the system revolves at a slower speed. than in other sections.

The intention with such a non-uniform revolving motion is to improve the light impression in certain sections of the revolution at the expense of the light impression in the other sections. When the beacon is intended as an airway beacon, the flying direction is suitably laid through the first-mentioned sections because the beacon light should be most visible in that direction, whereas the other sections donot as a rule require full light power.

In one form of employing the invention the rotating lens or reflector apparatus is, as mentioned above, given a lower angular speed when the beam or beams of light sweep past the flying two lens panels. arranged at an angle of 180 between their optical axis, and giving at a constant revolving speed and a period of, say, five seconds, a flash of a duration of .10 second, thus will be arranged successively to alter the revolving speed. When beams of light from the lens panels pass the flying direction, the speed of the beacon has been reduced to one-third, whereas the speed has been increased three times when the 1 same light beams pass directions which are at right angles to the flying direction. Then the light efficiency of the beacon in the flying direction will successively be-increased by about 80%, whereas the light efiiciency in directions which are at right angles to the flying direction will successively be reduced to about half.

Fig. 1 of the drawing is'a diagrammatic illustration of the invention utilizing two lens or reflector devices, one revolving, and the other oscillating within an angle of the rotation of the first;

Fig. 2 is a vertical sectional View through the apparatus. for use in practising the invention;

Fig. 3 is a transverse sectional view taken on the line G-H of Fig. 2; and

Fig. 4 is a similar view taken on the line IK of Fig. 2.

In the present form of employing the invention, two lens or reflector apparatus are co-operating, one of which revolves, whereas the other turns back and forth within an angle of any size, as is shown by the curves e and .2 respectively, Fig. 1. Within the revolving angle to of the last mentioned apparatus and outside this angle, respectively, different light characters may be obtained by adjusting the motion of the revolving lens apparatus in relation to the oscillating motion, as shown to the left and to the right, respectively, in the diagram. From the diagram to the left is seen that the aviator receives a mixed single and double flash character furthest out towards starboard, and three-flash character furthest out towards the port side. Outside the revolving angle w a slow single-flash character is obtained in relation to the character within the said angle. The revolving angle is the limit of the flying route. If the connecting line between two successive beacons is laid along one of the legs of the revolving angle and the two opposing flying angles of two such successive beacons are on opposite sides of this connecting line, there can be no collision of aeroplanes coming from op posite directions, provided that the pilots always keep inside the angle to of the beacon in front of them.

In this form of employing the invention, the character of the signal within the flying angle to can be very rapid, and alterations in the character are thus easily noticed.

Lights of the description in question make the use of special so-called course lights unnecessary, because the aviator will notice an alteration in the flying character as soon as he deviates from the flying course.

The above-described forms of arranging the light may naturally also be used for maritime beacons, or for maritime and airway beacons combined.

In the arrangement of apparatus shown by Figs. 2, 3 and 4, the lens system is divided in two parts, one of which revolves, and the other turns back and forth within an angle of any size, corresponding to the diagram of Fig. 1. Fig. 2 shows a form of employing the invention wherein a source of light 5 cooperates with two lens apparatus arranged one on top of the other, one of them revolving and the other oscillating. The upper part 74 is supported by the rods 66, which are secured to a table 6'! revolving around the shaft 65. The lower lens part 13 rests on the disk 64 placed :on the shaft65. The table 6? and the upper lens part 14 are caused to revolve at a periodically varying revolving speed :by means of the elliptic gear 76, TI driven by the shaft 15. The lower lens part 13, on the other hand, is caused to move back and forth by means of the cam 18 arranged on the shaft 15 for sooperating with the arm 79, secured on the shaft 65.

It will be apparent from this structure that uniform rotary motion applied to the shaft I5 will be transformed into non-uniform motion by the elliptic gears TB, 11, and that the upper lens part 14 will have a lower speed when the beam sweeps through the angle forming the flying direction. It will also be apparent that the cam 18 in cooperation with the arm 19 will cause the lower lens part 13 to oscillate within the angle forming the flying direction. The result of the operation of such an arrangement of lenses is Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. The method of producing signals with different signaling character in difierent directions, comprising the directional emission of two beams of radiant energy from a source, continuously rotating one of said beams in a plane around said source at uniform time intervals, and oscillating the other beam around said source substantially in the same plane through a predetermined angle at uniform time intervals.

2. The method of producing signals with different signaling character in diflerent directions, comprising the directional emission of two beams of radiant energy from a source, continuously rotating one of said beams in a plane around said source at uniform time intervals and substantially decreasing the angular speed of said beam through a .pre-determined angle of its rotation,.and oscillating the other beam around said source through said angle inv substantially the same plane.

3. The method of producing signals with different signaling character in dilferent directions, comprising the emission of two pairs of oppositely directed beams of radiant energy from a source, continuously rotating one of said pairs of beams in a plane and around said source at uniform time intervals, and oscillating the other pair of beams substantially in the same plane and around said source through pre-determined angles at uniform time intervals.

4. The method of producing signals with different signaling character in different directions, comprising the emission of two pairs of oppositely directed beams of radiant energy from a 2.

source, continuously rotating one of said pairs of beams in a plane at uniform time intervals and substantially decreasing the angular speed of said beams through ore-determined angles of th ir re el io and os at t he a beams through said angles in said plane at uniform time intervals.

5. In route signaling apparatus, the combination of a source of radiant energy, separate projecting means for producing from said energy two beams independently movable substantially in the same plane, a rotatable support for each of said projecting means, mechanism for continuously rotating one of said supports to thereby rotate one of said beams in said plane around said source at uniform time intervals, and mechanism tor continuously oscillating the other support to thereby oscillate the other beam through a pre-determined angle in said plane at uniform time intervals.

6. In route signaling apparatus, the combination of ;a source of radiant energy, separate projecting means for producing from said energy two beams independently movable substantially in the same plane, a rotatable support for each of said projecting means, mechanism for continuously rotating one of said supports to thereby rotate one of said beams in said plane around said source at uniform time intervals, means for substantially decreasing the rotary speed of said support through a pre-determined angle of its movement, and mechanism for continuously oscillating the other support to thereby oscillate the other beam through said angle in said plane at uniform time intervals.

7. In route signaling apparatus, the combination of a source of radiant energy, separate projecting means for producing from said energy two beams independently movable substantially in the same plane, a rotatable support for each of said projecting means, a continuously rotating driving shaft, motion transmitting means between said driving shaft and one of said supports to rotate said support at uniform time intervals and with substantially decreased speed through a certain angle of its movement, and motion transmitting means between said driving shaft and the other support to oscillate the latter support within said angle at uniform time intervals.

8. In route signaling apparatus, the combination of a source of radiant energy, separate projecting means for producing from said energy two beams independently movable substantially in the same plane, a rotatable support for each of said projecting means, a continuously rotating driving shaft, apair 'of intermeshing elliptical gears between said driving shaft and one of said supports to rotate said support with substantially decreased speed through a certain angle of its movement, a cam arm on the other of said supports, and a cam on said driving shaft for cooperating with said cam arm to oscillate the latter support within said angle at uniform time intervals.

ERIK ROBERT PARSBERG.

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