US3435286A - Plural lamps for simulating a candle flame - Google Patents

Description

March 25, 1969 P. J. KAYATT PLURAL LAMPS FOR SIMULATING A CANDLE FLAME Filed Sept. 17, 1965 INVENTOR. Rf/JP 4Z ZQYTI' United States Patent O M 3,435,286 PLURAL LAMPS FOR SIMULATING A CANDLE FLAME Philip J. Kayatt, Bronx, N.Y., assignor to Duro-Test Cor- ]orallion, North Bergen, NJ., a corporation of New Filed Sept. 17, 1965, Ser. No. 488,117 Int. Cl. H01j 1/00; H01k 1/14 U.S. Cl. 315-47 8 Claims ABSTRACT F THE DISCLOSURE The present invention relates to light sources of the incandescent filament type which simulate the flickering illumination of a candle.

The device comprises at least two light sources one of which is steady and the other of which changes its intensity periodically at a frequency which approximates rthe flicker frequency of a candle. Such a frequency is in the range from one to ten cycles per second and preferably about three or four cycles per second. A combination of three light sources of which one is steady and the other two of which change their intensities at different repetition rates will produce a very satisfactory simulation of a candle. The incandescent filaments may be formed either of tungsten or carbon. The non-steady filaments are flashed by thermosensitive switch elements in conventional manner and the switching may be either to fully ofi or partially ofi, as circumstances may render preferable.

The filaments may be enclosed in a common evacuated glass envelope or in individual envelopes. Additionally, a translucent flame-shaped covering formed of a suitable plastic applied to the common envelope or the group of individually enclosed light sources will prevent direct observation of the filaments and enhance the simulation of an actual candle flame.

Various objects, features and advantages of the invention will become apparent upon reading the following specification with reference to the accompanying drawing forming a part hereof.

Referring to the drawing:

FIGURE 1 is a side elevational view of a lamp embodying the invention.

FIGURE 2 is an enlarged elevational View partly broken away and shown in section taken along the line 2f-2 of FIG. 1.

FIGURE 3 is a schematic view of the lamp shown in FIGS. 1 and 2 illustrating the electrical circuitry.

FIGURE 4 is a view similar to FIG. 3 showing a modification in which all of the light sources are enclosed in a common glass envelope.

Referring to the drawing, the lamp designated generally as comprises a flame-shaped covering 11 formed of a translucent plastic material such as a silicone rubber which may be conveniently applied as by dipping, for example. Molding and other techniques may be employed -where suitable. The lamp is shown provided with the usual screw-type base 12 for insertion in a complementary socket (not shown) connected to a suitable power supply.

In the embodiment shown in FIGS. 2 and 3, light sources 14, 15 and 16 are enclosed in individual en- 3,435,286 Patented Mar. 25, 1969 velopes 17, 18 and 19, respectively. The light sources are connected in parallel -by conductors 20 to the terminals of the base 12. Light source 14 is of the continuously energized or steady type and is illustratively shown as comprising a carbon filament. A tungsten filament may, of course, be substituted for the carbon filament shown. Light source 15 is of the tungsten filament type and is shown connected in series with a bimetallic thermally responsive flasher switch 21 which lautomatically flashes the light source 15 from fully on to fully off at a repetition rate of about two to six flashes per second. The on and oil times are about equal. A ratio of on time to off should be in the range from 2:1 to 1:2 for best results.

Light source 16 is a tungsten filament connected in series with a further tungsten filament 22. A bimetallic flasher 23 periodically short circuits the further filament 22 thereby bringing light source 16 to full brilliancy. With flasher 23 open, the temperature of light source 16 may drop to a dull red or lower. The rate of rise to full brilliancy is accelerated by starting from a dull red temperature. The flasher 23 may thus operate at a more rapid repetition rate than flasher 21 which brings light source 15 to a fully off condition.

The arrangement of FIG. 4 is similar to that of FIGS. 2 and 3 except that the steady light source 24 is constituted by a tungsten filament instead of a carbon filament as for light source 14. Additionally, all three light sources are enclosed in a common glass envelope 25. The common envelope 25 is enclosed in a translucent flame-shaped covering 11 as described above.

In operation, the steady light source 14 or 24 provides a predetermined minimum illumination independently of the flashing sources 15 and 16. The flashing sources produce intermittent illumination which varies the total light output from the three sources as in the total light output of a candle flame. By having two different repetition rates -for the two flashing sources, the effect of a candle flame is further accentuated. The lateral spacing of the light sources produces an optical effect which simulates the lateral movement of a candle flame. Although one of the two flashing light sources may be omitted, a better simulation is obtained by the use of at least two flashing sources with different repetition rates. All of the flashin-g sources may be of the same type, such as the type of source 15 or source 16, if desired. The flame effect will be obtained with the covering 11 omitted. Its use is desirable, however, because the translucency distorts the appearance of the light sources and combines their illuminative effects in a manner which strengthens the optical illusion of an actual flame.

While I have shown and described what I believe to be the best embodiments of my invention, it will be appa-rent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. A flame-simulating illumination device for operation from a source of voltage comprising: a steady light source, first and second intermittent light sources, a respective means for connecting said steady and said first and second intermittent light sources in parallel to said voltage source, said respective means connecting the first and second intermittent light sources to the voltage source operating to vary the intensity of the output of each of said sources at a different repetition rate within the range from one to ten cycles per second While still permitting current to pass through the steady light 4source at all times, said means for connecting the steady light source to the voltage source operating the steady source continuously, and means for mounting all of said light 3 sources in close proximity to each other for simultaneous observation by a user of the device, said device producing a visual flame-like effect.

2. A device according to claim 7, wherein said light diffusing means is a flame-shaped covering of translucent material at least partially surrounding all of said sources.

3. A device according to claim 2, wherein each of said sources is constituted by an incandescent filament, said means for connecting said intermittent sources to the voltage source each comprising thermally actuated flasher means for varying the intensity of illumination of its associated filament.

4. A device according to claim 3 wherein one of said thermally actuated asher means alternately connects and disconnects the filament of one of said sources from the voltage source.

5. A device according to claim 3 wherein the filament of one of the intermittent sources is `formed of two parts and the flasher means associated with said one intermittent source periodically shorts out one of the parts of said filament.

6. A device according to claim 4 wherein the filament of the other of said intermittent sources is formed of two parts and the flasher means associated with said other source periodically shorts out one of the parts of said lament of said other intermittent source.

7. A device according to claim 1, further comprising 4 `light diffusing means common to and at least partially covering all of said light sources.

8. A device according to claim 2, lucent material is a silicone rubber.

wherein said trans- References Cited UNITED STATES PATENTS 2,235,360 3/1941 Davis 315-65 2,442,845 6/ 1948 Davis 315-72 2,760,120 8/ 1956 Fisher-man 315-72 X 2,901,646 8/1959 Plagge et al. 313-31 2,976,450 3/1961 Benoliel et al. 315-75 X 3,077,022 2/ 1963 Cullis 313-315 3,138,737 6/1964- French 315-50 2,862,145 11/1958 Davis 315--47 3,218,500 11/1965 Wright 313-116 3,327,162 6/1967 Wright 315-47 3,047,773 7/ 1962 Morton 315-205 FOREIGN PATENTS 937,825 9/ 1963 Great Britain.

JOHN W. HUCKERT, Primary Examiner.

A. I. JAMES, Assistant Examiner.

U.S. Cl. X.R.

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