US2627590A - Flashing incandescent lamp with bimetallic filament support - Google Patents

Description

Feb. 3, 1953 s. G. OHLUND 2,627,590

FLASHING INCANDESCENT LAMP WITH BI-METALLIC FILAMENT SUPPORT Filed June 5, 1951 7 l ii 46 lNVEN ATTORNEY Patented Feb. 3, 1953 UNITED STATES PATENT OFFICE Selfrid Gunnar fihlund, Enskede, Sweden Application June 5, 1951, Serial No. 229,888 In Sweden June 11, 1949 7 Claims.

This invention relates to an electric incandescent lamp or discharge lamp with an incandescent body supported by a lead-in wire and one or several supporting wires, the lamp being provided with a built-in bimetal breaker in order to obtain short-circuiting of one or several parts of the incandescent body.

Arrangements with such thermic relays are known, as a matter of fact, for obtaining flashing lamps. Ehe invention aims at a simple arrangement, by means of which a breaking device operating with utmost reliability is obtained. The invention is characterized by a construction in which on at least one of the lead-in or support wires of the lamp a bimetal strip connected with the incandescent body is mounted and so arranged that when heated it will bend downwardly to another lead-in or supporting wire to shcrtcircuit the intermediate incandescent body portion.

In accordance with the present invention heat from the incandescent body portion, transmitted to the bimetal strip substantially by conduction, causes the latter to make a contact movement, whereas in previous devices of the same general character heat has been transmitted to the bimetal elment by radiation. Since the tempera ture difference between the incandescent body or filament of the lamp when the latter is energized and when it is cold is very great, a very strong and reliable action of the bimetal relay is obtained with the present invention.

The invention is further illustrated by a few examples of design shown in the accompanying drawing.

Fig. 1 shows an incandescent lamp with an incandescent body arranged in inverted V-shape, one leg of which is induced to light periodically.

Fig. 2 shows a similar lamp with both legs of the incandescent body provided with twinkling devices.

Fig. 3 shows a body arranged in inverted U- shape with twinkling devices on each leg.

The examples shown in Figs. 1 and 2 are incandescent lamps intended for use in connection with Christmas tree illumination. The usual series 11- lumination sets for this purpose contain sixteen series-connected lamps. It is sufficient for obtaining a good imitation of burning candles to let a few, for instance three of the series-connected lamps consist of lamps with twinkling devices. With the arrangement shown in Fig. 2 it may happen, of course, that both legs are short-circulted at the same time; but this will not do any harm in series-connection together with lamps without twinkling relays.

The Christmas tree lamp shown in Fig. 1 consists of an envelope 3 elongated to a point and closed at the bottom by fusion 9, through which lead-in wires I and i2 pass. The lead-in wires are downwardly connected with a socket Ill and at the top surrounded by a pearl foot I! and bridged by a so-called supporting bridge 8, which, for instance, consists of an oxidized aluminum ribbon. To'lead-in wire I is welded a bimetal strip 6. The incandescent body of the lamp consists of a tungsten coil arranged in inverted V- shape. The top 2 of the incandescent body is carried in an eye I on a supporting wire 5, attached to foot H by fusing. One of the ends of the incandescent body is fastened to lead-in wire [2, and the other one to bimetal strip 6. To the supporting wire 5 is fused by welding a small piece of wire I 3 directed towards bimetal strip 6. When the lamp is turned on, the leg of the incandescent body attached to bimetal strip 6 conveys its heat to bimetal strip 6, which thereby is induced to bend inwardly against contact l3, when the leg in question will become extinct. The bimetal strip is cooled down and draws away from contact i3, and the procedure described is repeated.

In the case of the Christmas tree lamp as shown in Fig. 2, both lead-in wires are fitted with bimetal strips 6, each connected to one end of incandescent body 4. Supporting wire 5 is provided with an eye I4 serving as a counter-contact for bimetal strips 6.

In the case of the incandescent body arrangement shown in Fig. 3 the incandescent body is of inverted U-shape. The central part l5 of the in candescent body hoop rests in eyes I of the two supporting wires 5, and the legs l5 of the yoke are attached to the ends of bimetal strips 6, which in turn are attached to lead-in wires 1. Supporting wires 5 are provided with outward bends i'l directed towards the respective bimetal strips and serving as a counter-contact for the bimetal strips during their closing movements.

The designs shown are only to be regarded as examples, and the fundamentally new arrangement disclosed by this invention may, of course, be employed in a much greater number of arrangements than has been described here. Although the invention has been primarily described with regard to electric incandescent lamps, it can be used for incandescent bodies in electric discharge tubes.

What I claim is:

1. An electric lamp comprising a flexible filament, fixed leads for conducting current to and away from the filament, a heat sensitive element constructed to fiex in response to variations in temperature rigidly fixed to one of said leads and connected in series between said one of said leads and said filament to form a part of the current carrying circuit through the lamp during the normal operation thereof, and means located to be contacted by said element upon fiexure thereof in response to predetermined temperature change to provide a shunt across at least a portion of said filament.

2. An electric lamp comprising a flexible filament, fixed leads for conducting current to and away from the filament, supporting means engaging said filament intermediate its ends, a bimetallic element fixed at one end to one of said leads and connected at its other end to one end of said filament, said element being located with reference to said supporting means to flex into contact with a portion thereof to provide a shunt through said supporting means across the portion of the filament to which said element is connected.

3. A lamp as defined in claim 2 in which said 4 tact located to be engaged by said bimetallic element.

5. A lamp as defined in claim 4 in which a bimetallic element is connected between each of said leads and the adjacent ends of the filament and said supporting wire is provided with two contact parts projecting in laterally opposite directions and disposed to be respectively engaged by different ones of said bimetallic elements.

6. A lamp as defined in claim 2 in which said filament is in the form of an inverted U the upper portion of, which is supported by supporting means comprising two spaced wires, one of which provides a contact part located to be engaged by said bimetallic element.

7. A lamp as defined in claim 6 in which each REFERENCES crrsn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,994,620 Putt v v Mar. 19, 1935 2,361,485 MacGregor Oct. 31, 1944 2,442,845 Davis June 8, 1948

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