US3734678A - Photoflash lamp - Google Patents

Abstract

A mechanically ignitable photoflash lamp in which an igniter tube containing a percussive type igniting material is sealed into the lamp bulb. The bulb has a filling of combustible material and a combustion supporting material. To prevent displacement of the combustible material due to the resulting pressure wave, when the igniting material is ignited, the combustible material is a physically stable web, mesh or network of foil or wire designed as a hollow body fitting the shape of the bulb and bearing against the bulb wall.

Description

0 United States Patent 1191 1111 3,734,e7a Liepert 1 May 22, 1973 s41 PHOTOFLASH LAMP 2,238,780 4/1941 Reiter ..431 95 2,611,255 9/1952 Poelma et al ..43l/95 [751 wemngen 3,586,471 6/1971 McDonough ..431/93 many [73] Assignee: Patent-Treuhand Gesellschait fur Primary Examinercal'l'oll y, JR

elektrische Gluhlampen mbH, Mu- Attorney- Robert D. Flynn. Stephen H. Frishauf and nich, Germany Leonard Holtz [22] Filed: June 15, 1971 ABSTRACT [21] Appl' 153312 A mechanically ignitable photoflash lamp in which an igniter tube containing a percussive type igniting [30] Foreign Application Priority Data material is sealed into the lamp bulb. The bulb has a July 10 1970 Germany ..P 20 34 328.6 fining of mbustible material and a combustion porting material. To prevent displacement of the com- 52 us. c1 ..431/93 hushhle material due to the "Suiting F wave, 51 1111. C1 ..F2lk 5 02 when the igniting material is ignited, the combustible [58] Field of Search ..431/93, 94, 9s material is a P y y Stable web, mesh or network of foil or wire designed as a hollow body fitting the shape [56] R fere Cit d of the bulb and bearing against the bulb wall.

UNITED STATES PATENTS 3 Claims, 4 Drawing Figures 2,057,583 10/1936 Mey ..43l/95 I: Q Q. a

PATENTEU 3 3 I I I INVI'LN'I'OP Reinhold Liepert PHOTOFLASH LAMP CROSS REFERENCE TO RELATED APPLICATION:

U.S. Ser. No. 838,758 filed July 3, 1969 and now US. Pat. No. 3,624,824.

The present invention relates to mechanically ignitable photoflash lamps as disclosed, for example, in application U.S. Ser. 838,758. Such photoflash lamps have a metallic igniter tube sealed into the lamp envelope, which is in communication with the interior of the envelope. The end of the tube projects externally of the envelope and is closed and contains a percussionsensitive igniting material. When imparting a blow with a percussive tool on the igniter tube in place which is filled with igniting material, the igniting material reacts and the flame generated thereby and accompanied by a pressure wave, initiates the process of combustion in the lamp. The light-generating combustible material in the lamp envelope consists preferably of finely divided zirconium, and the gaseous atmosphere is oxygen.

The pressure wave generated by ignition of the igniting material may cause an irregular distribution of the combustible material within the lamp envelope; in particular, it may be propelled into the dome of the bulb. This results in irregular light distribution and reduced light output during flashing of the lamp.

It is an object of the invention to provide a lamp in which the detrimental influence of the pressure wave can be avoided. Subject matter of the invention:

The combustible material is designed as a physically stable web or network which has the shape of a hollow body with at least one aperture; it is fitted to the shape of the lamp envelope and is located adjacent to, preferably bearing against the wall of the lamp envelope.

The invention will be explained in greater detail by means of the drawings.

FIG. 1 shows a lamp in accordance with the invention comprising a physically stable web or network of combustible material in the shape of a hollow cylinder open at both ends.

FIG. 2 shows a lamp in accordance with the invention comprising a physically stable web or network of combustible material in the shape of a hollow cylinder open at one end.

FIGS. 3 and 4, respectively, show a photoflash lamp according to FIGS. 1 and 2, respectively, comprising an igniter tube provided with an ignition capsule.

The photoflash lamp comprises a light-transmissive tubular envelope 1, which is filled with combustible material and oxygen at a pressure of about 7 at. An igniter tube 3 of copper or of an iron-nickel alloy is sealed into one end of the envelope, the igniter tube being in communication with the interior of the envelope and closed at its end 4 projecting externally of the envelope. The portion of the igniter tube 3 projecting externally of the envelope is filled with a percussionsensitive igniting material 5. The igniting material may be loosely filled into the igniter tube (FIGS. 1 and 2). Preferably, the igniting material is contained in a capsule 6 (FIGS. 3, 4) provided with an anvil and disposed within the igniter tube.

The end 4 of the igniter tube 3 may be closed by coldpress welding even after the igniter tube 3 has been sealed into the glass envelope. It is preferred, however, to seal an already closed copper tube into the bulb.

The other end of the lamp envelope comprises an exhaust tip 7, which is formed by drawing the lamp envelope off the exhaust tube.

The combustible material in the lamp envelope consists of a physically stable, that is, form-stable, web, mesh or network of foil or wire, preferably of crimped zirconium shreds, and has the shape of a hollow body 2 fitted to the shape of the lamp envelope. It has an aperture facing the igniter tube 3. With a substantially cylindrical envelope shape, the hollow body 2 has the shape of a hollow cylinder. It may be open at both ends (FIGS. 1 and 3) or open at one end only (FIGS. 2 and 4). The walls of the cylinder are located adjacent the wall of the envelope. They preferably bear against the walls of the envelope over at least a major portion thereof. In a lamp of approximately spherical shape, the shape of the hollow body resembles a hollow sphere provided with an aperture in a place facing the igniter tube.

By forming the combustible material to the shape of a hollow body bearing against the wall of the lamp envelope and with an aperture facing the end of the igniter tube projecting into the lamp envelope, the pressure wave generated by the ignition can freely expand through the aperture into the hollow space devoid of igniting material without causing displacement of the combustible material during ignition.

I claim:

1. Photoflash lamp comprising a light-transmitting envelope,

combustible material and a combustion-supporting material located in the envelope, an igniter tube sealed into the envelope having one end in communication with the interior of the envelope and the other end projecting externally of the envelope, the other end being closed and containing a percussion-sensitive igniting material,

wherein the combustible material is a physically stable web or network in the shape of a substantially cylindrical hollow body provided with at least one axial aperture facing the one end of the igniter tube, the web or network forming said body being shaped to fit the shape of the lamp envelope and located adjacent the wall of the lamp envelope, so that a pressure wave generated by ignition of said percussion-sensitive igniting material can freely expand through said aperture into the hollow space within the hollow body and devoid of igniting material, and without causing displacement of the combustible material during ignition.

2. Photoflash lamp as set forth in claim 1, wherein at least a major portion of the web or network of combustible material bears against a major portion of the lamp envelope.

3. Photoflash lamp as set forth in claim 1, wherein the physically stable web or network comprises crimped zirconium shreds.

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Claims (3)

1. Photoflash lamp comprising a light-transmitting envelope, combustible material and a combustion-supporting material located in the envelope, an igniter tube sealed into the envelope having one end in communication with the interior of the envelope and the other end projecting externally of the envelope, the other end being closed and containing a percussion-sensitive igniting material, wherein the combustible material is a physically stable web or network in the shape of a substantially cylindrical hollow body provided with at least one axial aperture facing the one end of the igniter tube, the web or network forming said body being shaped to fit the shape of the lamp envelope and located adjacent the wall of the lamp envelope, so that a pressure wave generated by ignition of said percussion-sensitive igniting material can freely expand through said aperture into the hollow space within the hollow body and devoid of igniting material, and without causing displacement of the combustible material during ignition.

2. Photoflash lamp as set forth in claim 1, wherein at least a major portion of the web or network of combustible material bears against a major portion of the lamp envelope.

3. Photoflash lamp as set forth in claim 1, wherein the physically stable web or network comprises crimped zirconium shreds.

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