US3897196A - Photoflash lamp with sealed bead - Google Patents

Photoflash lamp with sealed bead Download PDF

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Publication number
US3897196A
US3897196A US444343A US44434374A US3897196A US 3897196 A US3897196 A US 3897196A US 444343 A US444343 A US 444343A US 44434374 A US44434374 A US 44434374A US 3897196 A US3897196 A US 3897196A
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United States
Prior art keywords
wires
lead
bead
filament
envelope
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US444343A
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English (en)
Inventor
John P Saunders
Burleigh H Leach
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GTE Sylvania Inc
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GTE Sylvania Inc
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Filing date
Publication date
Application filed by GTE Sylvania Inc filed Critical GTE Sylvania Inc
Priority to US444343A priority Critical patent/US3897196A/en
Priority to US524605A priority patent/US3919750A/en
Priority to JP50020429A priority patent/JPS50152723A/ja
Application granted granted Critical
Publication of US3897196A publication Critical patent/US3897196A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K5/00—Light sources using charges of combustible material, e.g. illuminating flash devices
    • F21K5/02—Light sources using charges of combustible material, e.g. illuminating flash devices ignited in a non-disrupting container, e.g. photo-flash bulb

Definitions

  • ABSTRACT A photoflash lamp having an hermetically sealed enve- [52] U.S. Cl. 431/95 [53] Field f H 431/94 95 p ntaining a pair of filament-supporting lead-1n wires spaced apart by a glass bead which has been [56] References Cited stretched toward the filament to prevent post-ignition UNITED STATES PATENTS short circuits by isolating the melting lead-in wires.
  • This invention relates to the manufacture of photoflash lamps and, more particularly, to flashlamps containing filament lead-in wires and means for preventing post-ignition short circuits therebetween.
  • Photoflash lamps generate an actinic light output by the burning of an energetic fuel, such as finely shredded zirconium, hafnium or aluminum metal foil, in a combustion supporting atmosphere, such as oxygen.
  • the ignition means comprises a pair of lead-in wires sealed through one end of the tubular glass envelope and supported in a spaced side-by-side relation by a glass bead fused about the wires.
  • a tungsten filament is mounted across the inner ends of the two lead-in wires with the ends of the wires at their junctions with the filament being coated with a primer material, such as a powdered zirconium mixture.
  • the filament glows to incandescence, causing the primer material to ignite, which in turn ignites the finely shredded metallic combustible in the lamp to produce a predetermined quantity of light output.
  • Certain other lamp types additionally employ a glass sleeve disposed about a portion of one of the lead-in wires as an insulating shield extending from the glass bead toward the filament for preventing post-ignition short circuits across the lead-in wires.
  • a glass sleeve disposed about a portion of one of the lead-in wires as an insulating shield extending from the glass bead toward the filament for preventing post-ignition short circuits across the lead-in wires.
  • the lead wires are initially provided in the fonn of a hairpin with the closed end facing downward.
  • the glass bead is then melted and fused about the lead wires to retain the spacing therebetween; this is a conventional beading operation.
  • the closed end of the hairpin is trimed off, in the normal manner.
  • the mount structure is then rotated 180, and a glass tube is placed over one of the lead wires so that it rests on the bead.
  • the end of the tube in contact with the bead is then heated just enough to fuse it to the bead but without distorting its upper portion.
  • the mount structure must then again be rotated by 180 to make it ready for further processing.
  • this method requires turning the mount structure head 180 at two separate locations. It also requires a tube feeder and loader, a device to locate one of the wires so that the glass tube can be fed over it, and a great deal of skill on the machine attendants part.
  • one of the principal objects of this invention is to provide an electrically ignitable photoflash lamp having improved means for preventing post-ignition short circuits across the lead-in wires.
  • a further object is to provide an improved and more economical method of manufacturing an ignition mount structure for a photoflash lamp which maintains a suitable isolation between the lead-in wires to prevent post-ignition short circuits.
  • FIG. 1 is an elevational view, partly in section, of a photoflash lamp having an ignition mount structure in accordance with the invention
  • FIG. 2 is an enlarged diagram illustrating the shaped bead employed in the mount structure of FIG. 1 and the manner in which the bead prevents post-igintion short circuits;
  • FIGS. 3-5 are sequential representations of the steps of a method in accordance with the invention which may be employed for making the mount structure of HO. 1.
  • an electrically ignitable photoflash lamp comprising an hermetically sealed, light-transmitting envelope 10 of glass tubing having a press 12 defining one end thereof and an exhaust tip 14 defining the other end thereof.
  • a quantity of filamentary combustible material 16 such as shredded zirconium or hafnium foil, is located within the lamp envelope.
  • the envelope is also provided with a filling of combustion-supporting gas, such as oxygen, at a pressure of several atmospheres.
  • the ignition mount structure comprises a pair of lead-in wires 18 and 20 extending through and sealed into the press 12.
  • a filament 22 spans the inner ends of the lead-in wires, and beads of primer 24 and 26 are located on the inner ends of the lead-in wires 18 and 20, respectively, at their junctions with the filament.
  • the lead-in wires are supported in a spaced side-by-side relation by a glass bead 28 fused about the wires.
  • the glass bead is uniquely shaped by a distortion of its midportion 30 between the lead-in wires to protrude toward the filament 22.
  • the filament 22 glows to incandescence, causing the primer material 24, 26 to ignite, which in turn ignites the finely shredded metallic combustible material 16 in the lamp to produce the desired flash of light output.
  • the intense heat of this combustion process causes the top portion of the lead-in wires 18 and 20 to melt away down to the top surface of the glass bead 28.
  • the upwardly protruding portion of the glass bead serves to isolate the molten portions 32 of the two lead-in wires so that a short circuit conductive path is not inadverently effected by a chance fusion of the two melting wires subsequent to flashing.
  • FIGS. 3-5 illustrate a method of making the mount structure of FIG. 1, in accordance with the invention, which has been found to result in a highly reliable flashlamp structure with protection against post-ignition shorting, while at the same time being particularly suited to automated assembly and providing a significantly more convenient and economical mode of manufacture.
  • the method comprises: providing a pair of lead-in wires 18 and 20 closed at one end 21 in the form of a hairpin; next, placing a glass bead 28 between the lead-in wires and fusing the bead to the wires to retain a spacing therebetween, as illustrated in FIG.
  • a blade 34 is inserted between the pair of wires from the open end and pushed downwardly against the midpoint of the fused bead to stretch and displace the midportion 30 so that it protrudes toward the closed end 21 of the hairpin, as illustrated in FIG. 4.
  • the closed end 21 of the lead-in wires 18 and 20 is trimmed off, as illustrated by FIG. 5, and the filament 22 is attached across the wires near the trimmed ends thereof, whereby the stretched midportion 30 of the bead 28 protrudes toward the filament (as in FIG. 1).
  • FIGS. 3-5 all take place with the mount structure held in an inverted position. No 180 rotations of the mount are required.
  • the cost of the glass tube, previously employed on mount structures with post-ignition short protection, has been eliminated.
  • the process also eliminates the previously required bead feeder, bead loader, wire gatherer, two turn-over devices, extra burner to melt the glass tube, tube detectors and mount ejector.
  • the unstretched bead 28' had an initial height dimension of about 0.080 inch, and the stretching operation to produce the protruding midportion 30 extended the height to about 0.165 inch. Hence, the bead was stretched to approximately double its initial height. In other words, the height of the stretched bead is preferably at least about twice the height of the bead portions fused about the lead-in wires.
  • Such a stretched bead ignition structure has proved to be extremely reliable in preventing post-ignition short circuits, as several thousand lamps of this type have been test flashed without a post-ignition short failure.
  • bead 28 may be formed of other meltable insulating materials in lieu of glass, and the original and stretched dimensions of the bead may vary for different lamp parameters.
  • a photoflash lamp comprising:
  • an ignition mount structure disposed in said envelope in operative relationship with respect to said combustible material, said mount structure including a pair of lead-in wires sealed through one end of said envelope, a filament connected across said lead-in wires, and an insulating bead fused about said leadin wires and located between said filament and the end of said envelope through which said wires are sealed for supporting said wires in a spaced side-byside relation, the midportion of said insulating head between said lead-in wires being stretched to protrude toward said filament to provide a raised barrier between locations where the lead-in wires pass through the bead, and a recessed portion immediately below the barrier on the opposite side of the bead, for preventing post-ignition short circuits between said wires.
  • said mount structure further includes beads of primer located on the inner ends of lead-in wires at the junctions between the leadin wires and the filament.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
US444343A 1974-02-21 1974-02-21 Photoflash lamp with sealed bead Expired - Lifetime US3897196A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US444343A US3897196A (en) 1974-02-21 1974-02-21 Photoflash lamp with sealed bead
US524605A US3919750A (en) 1974-02-21 1974-11-18 Method of making photoflash lamp ignition mount structure with shaped bead
JP50020429A JPS50152723A (fi) 1974-02-21 1975-02-20

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US444343A US3897196A (en) 1974-02-21 1974-02-21 Photoflash lamp with sealed bead

Publications (1)

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US3897196A true US3897196A (en) 1975-07-29

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US (1) US3897196A (fi)
JP (1) JPS50152723A (fi)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3947225A (en) * 1975-03-31 1976-03-30 Gte Sylvania Incorporated Photoflash lamp
US4009987A (en) * 1973-05-01 1977-03-01 U.S. Philips Corporation Electric lamp having an internal switching mechanism
US4155736A (en) * 1976-12-01 1979-05-22 General Electric Company Method of making a non-shorting photoflash lamp
US4174944A (en) * 1978-01-30 1979-11-20 Gte Sylvania Incorporated Single lead electrically-activated flashlamp
US4204834A (en) * 1978-01-30 1980-05-27 Gte Sylvania Incorporated Leadless electric flash lamp
US4249887A (en) * 1977-12-30 1981-02-10 Westinghouse Electric Corp. Photoflash lamp having gap-fire ignition mount, and method of making the mount

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2729960A (en) * 1952-01-02 1956-01-10 Gen Electric Flash lamp
US2811846A (en) * 1953-05-29 1957-11-05 Westinghouse Electric Corp Photoflash lamp
US3123993A (en) * 1964-03-10 flash lamp
US3312085A (en) * 1964-03-05 1967-04-04 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Photoflash lamp with primer
US3501254A (en) * 1966-09-30 1970-03-17 Philips Corp Combustion flash lamp which can be arranged in a holder in parallel connection
US3816054A (en) * 1973-05-02 1974-06-11 Gen Electric Photoflash lamp having non-shorting construction

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3123993A (en) * 1964-03-10 flash lamp
US2729960A (en) * 1952-01-02 1956-01-10 Gen Electric Flash lamp
US2811846A (en) * 1953-05-29 1957-11-05 Westinghouse Electric Corp Photoflash lamp
US3312085A (en) * 1964-03-05 1967-04-04 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Photoflash lamp with primer
US3501254A (en) * 1966-09-30 1970-03-17 Philips Corp Combustion flash lamp which can be arranged in a holder in parallel connection
US3816054A (en) * 1973-05-02 1974-06-11 Gen Electric Photoflash lamp having non-shorting construction

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4009987A (en) * 1973-05-01 1977-03-01 U.S. Philips Corporation Electric lamp having an internal switching mechanism
US3947225A (en) * 1975-03-31 1976-03-30 Gte Sylvania Incorporated Photoflash lamp
US4155736A (en) * 1976-12-01 1979-05-22 General Electric Company Method of making a non-shorting photoflash lamp
US4249887A (en) * 1977-12-30 1981-02-10 Westinghouse Electric Corp. Photoflash lamp having gap-fire ignition mount, and method of making the mount
US4174944A (en) * 1978-01-30 1979-11-20 Gte Sylvania Incorporated Single lead electrically-activated flashlamp
US4204834A (en) * 1978-01-30 1980-05-27 Gte Sylvania Incorporated Leadless electric flash lamp

Also Published As

Publication number Publication date
JPS50152723A (fi) 1975-12-09

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