US3413511A - Electric lamp having in situ molded base of foamed plastic - Google Patents

Electric lamp having in situ molded base of foamed plastic Download PDF

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Publication number
US3413511A
US3413511A US554493A US55449366A US3413511A US 3413511 A US3413511 A US 3413511A US 554493 A US554493 A US 554493A US 55449366 A US55449366 A US 55449366A US 3413511 A US3413511 A US 3413511A
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US
United States
Prior art keywords
base
lamp
envelope
plastic
mold
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
Application number
US554493A
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English (en)
Inventor
Vernon L Plagge
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Philips North America LLC
Original Assignee
Westinghouse Electric Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US554493A priority Critical patent/US3413511A/en
Priority to GB29408/66A priority patent/GB1099746A/en
Priority to NL6609215A priority patent/NL6609215A/xx
Priority to DE19661539613 priority patent/DE1539613A1/de
Application granted granted Critical
Publication of US3413511A publication Critical patent/US3413511A/en
Assigned to NORTH AMERICAN PHILIPS ELECTRIC CORP. reassignment NORTH AMERICAN PHILIPS ELECTRIC CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: WESTINGHOUSE ELECTRIC CORPORATION
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K3/00—Apparatus or processes adapted to the manufacture, installing, removal, or maintenance of incandescent lamps or parts thereof
    • H01K3/16—Joining of caps to vessel

Definitions

  • plastic bases for fluorescent lamps by compression molding a suitable resin in a die.
  • These separately-fabricated bases which usually are made from a thermosetting plastic such as a phenolic condensation product or the like, are then provided with one or more hollow metallic contact pins that are staked or riveted to the bottom of the base shell.
  • the lead-in wires are threaded through the pins and the preformed plastic bases are then cemented to the ends of the tubular glass envelope.
  • the protruding ends of the lead wires are then severed and the pins are joined to the leads by welding or soldering.
  • the separate production operations of base forming, cementing, etc., together with the additional transportation costs in transferring the bases from the molding machines to the lamp-basing machines, increase substantially the overall manufacturing cost of fluorescent lamps.
  • the mold assembly is then heated to a suitable temperature so that the contained resin foams and fills the mold cavity, thereby conforming to the contour thereof. At the same time, the resin contacts and adheres to the surface of the vitreous envelope and the contact pins :and finally cures to a rigid cellular structure. The assembly is subsequently allowed to cool and the mold is removed from about the lamp end, leaving a finished base firmly aflixed to the envelope and contact pins.
  • FIGURE 1 illustrates a completed fluorescent lamp provided with a base structure at each end formed and applied thereto in accordance with the present invention
  • FIG. 2 is an enlarged fragmentary crosssectional view of the mold and a sealed end of the fluorescent lamp seated therein just after the plastic has expanded into place around the lamp envelope and the base pins;
  • FIG. 3 is an elevational view of an incandescent lamp having an integrally-formed base according to the invention.
  • a mold 16 of resilient material such as silicone rubber or the like which has a cavity 17 conforming to the shape and dimensions desired for the finished base 12
  • This mold may, if desired, be reinforced by a thin outer metallic casing 18.
  • the mold 16 is provided with a pair of elongated recesses 20 into which the hollow metallic contact pins 14 are inserted with their upper flared ends spaced slightly above the inner surface of the mold, as shown in the drawing.
  • a predetermined amount 22 of a suitable thermosetting plastic resin and a foaming agent are then introduced into the mold cavity 17, after which the end of the sealed and exhausted lamp envelope 6 is inserted into the mold 16 by threading the outer exposed ends of lead-wires 9 and 10 through the respective contact pins 14 until the shoulder of the envelope seats against the peripheral edge of the resilient mold and forms a seal therewith.
  • the lamp and mold assembly is then vertically supported upon blocks 23, or other suitable members, in a surrounding furnace 24 and heated to a temperature rang ing from approximately 50 C. to 0, depending on the type of plastic resin used. Such heating is continued until the resin 22 foams and fills the mold cavity 17 and thereby contacts and covers the ends of the envelope 6 and pins 14 disposed within the mold 16.
  • the gas and excess foamed material are discharged through a vent tube 26 extending from the bottom of the cavity 17 to the outside of the furnace 24.
  • the foamed resin then cures to a rigid cellular structure within a short period of time, the length of which depends upon the temperature and particular type of plastic resin employed, leaving the lamp base 12 of the desired configuration firmly bonded to and locked in place on the sealed end of the glass envelope 6 and with the contact pins 14 firmly anchored therein. Since the foamed resin surrounds the outer ends of the lead-in wires 9 and 10 and partly fills the end of the reentrant stem 11, as shown in FIG. 2, it aso serves as an insulator that locks the wires in spaced apart relationship and thus prevents short circuits from developing within the base.
  • the base 12 can just as readily be formed by using a material that consists of a mixture of resin and a foaming agent which will likewise foam when heated to an elevated temperature.
  • foaming plastics are well known in the chemical art and comprise polyurethane foams, polystyrene foams, epoxy foams, silicone foams, cellulose acetate foams, etc.
  • Foaming plastics of various kinds are described in detail in an article entitled Plastic Foams, May 1966 issue of Materials Engineering magazine (vol. 63, No. 5, pp. 87-102). Any of the materials referred to in the aforesaid article can be used.
  • the plastic be of the type which cures to a hardened rigid cellular structure that is not too porous as to weaken the base 12 to the extent that it will crack when the contact pins 14 are subjected to the strain normally encountered in inserting and removing the lamp from its fixture sockets, and that the plastic be electrically non-conductive to avoid short-circuiting the lead wires.
  • the plastic should also be of a type that will remain sufliciently rigid at the operating temperature of the lamp that it will support the lamp in its socket.
  • the plastic resin whether self-foaming or one which requires a separate foaming agent, is selected so that it is completely cured in a relatively short period preferably within ten to fifteen minutes) to a hardened strong base member having a minimum of voids which, if they do occur, are of minute size.
  • the cooling time should likewise be of short duration to enable removal of the base lamp from the mold 16 as soon as possible preparatory to the formation of a base on another lamp envelope. If the times for curing and cooling the plastic are not excessive, the actual molding of the base 12 directly on the end of the lamp 5 can very readily be done on an automatic lamp-making machine by performing the molding, curing and cooling operations at various work stations to which the lamp-making machinery is periodically indexed.
  • the protruding ends of the lead-in wires 9 and are trimmed and the wires are attached to the pins 14 by welding or the like in the usual manner.
  • the invention can also be utilized in the manufacture of incandescent lamp types with the same functional, cost and manufacturing advantages.
  • a lamp of this type having the usual pear-shaped envelope 26, and filament mount 28 is provided with a screw-type plastic base 30 that is molded in situ directly onto the sealed end of the envelope.
  • one of the lead wires 31 connects with a rivet-like member 32 anchored in the end face of the base to provide an end contact, whereas the other lead 33 is positioned at and is partly exposed by the base threads to provide the necessary side contact.
  • a single-ended incandescent lamp could be based by using a foamable resin as a mean for cementing a metal base shell to the bulb, which resin would also seWe as the insulator member at the bottom of the shell and hold the eyelet or end contact in operative relationship with he shell.
  • a translucent or color-coded base can very readily be provided for fiuorcescent lamps simply by selecting the proper type of plastic resin.
  • the mold can also be made from any suitable material, providing it does not stick to the cured plastic or otherwise interfere with the removal of the formed base.
  • incandescent lamps can be provided with various types and shapes of all-plastic bases simply by altering the configuration of the mold cavity.
  • plastic bases of complex shapes such as those for miniature lamps of the type designed for use in conjunction with panels having printed electrical circuits and disclosed in US. Patents No. 2,892,992 issued June 30, 1959, can also be readily fabricated in situ in accordance with the present invention.
  • vitreous envelope having an end portion that is susceptible to breakage when stressed and has a deformable conductor depending therefrom
  • said envelope contains an incandescible filament
  • said conductor comprises one of a pair of lead wires that are connected to said filament and are sealed through said envelope end portion, and
  • said foamed plastic base member is composed of cured thermosetting resin and is molded in situ onto said envelope end portion.
  • said base member is of the screw-in type
  • one of said lead wires is connected to a terminal anchored in the free end of the base member
  • the other of said lead wires is located in the threaded portion of said base member and constitutes an engageable second contact for the lamp.
  • said envelope is of tubular configuration and the said end portion comprises a sealed end thereof
  • said base member encircles the sealed end of the envelope and is molded in situ thereon
  • said conductor comprises a lead wire that extends from the sealed end of the envelope and is connected to a rigid terminal that is anchored in and protrudes beyond the end face of said base member.
  • said lamp comprises a fluorescent lamp
  • said base member is composed of cured thermosetting resin
  • a second lead wire extends from the sealed end of the envelope
  • said lead wires are connected to a pair of rigid terminals anchored in the end face of said base member.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)
US554493A 1965-07-19 1966-06-01 Electric lamp having in situ molded base of foamed plastic Expired - Lifetime US3413511A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US554493A US3413511A (en) 1965-07-19 1966-06-01 Electric lamp having in situ molded base of foamed plastic
GB29408/66A GB1099746A (en) 1965-07-19 1966-06-30 Electric lamp base and method of manufacture
NL6609215A NL6609215A (US20030204162A1-20031030-M00001.png) 1965-07-19 1966-07-01
DE19661539613 DE1539613A1 (de) 1965-07-19 1966-07-19 Elektrische Lampe und Verfahren zu ihrer Herstellung

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US47302865A 1965-07-19 1965-07-19
US554493A US3413511A (en) 1965-07-19 1966-06-01 Electric lamp having in situ molded base of foamed plastic

Publications (1)

Publication Number Publication Date
US3413511A true US3413511A (en) 1968-11-26

Family

ID=27044010

Family Applications (1)

Application Number Title Priority Date Filing Date
US554493A Expired - Lifetime US3413511A (en) 1965-07-19 1966-06-01 Electric lamp having in situ molded base of foamed plastic

Country Status (4)

Country Link
US (1) US3413511A (US20030204162A1-20031030-M00001.png)
DE (1) DE1539613A1 (US20030204162A1-20031030-M00001.png)
GB (1) GB1099746A (US20030204162A1-20031030-M00001.png)
NL (1) NL6609215A (US20030204162A1-20031030-M00001.png)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3500105A (en) * 1968-02-19 1970-03-10 Sylvania Electric Prod Incandescent lamp having a ceramic screw type base
US4256989A (en) * 1978-09-22 1981-03-17 Duro Test Corporation Incandescent lamp with filament mounting means and socket adaptor
US4622488A (en) * 1983-06-29 1986-11-11 U.S. Philips Corporation Internally fused electric lamp with partially embedded fuse wire
US4854888A (en) * 1988-05-31 1989-08-08 Gte Products Corporation Lamp base
US4878854A (en) * 1988-05-31 1989-11-07 Gte Products Corporation Lamp base
US4949007A (en) * 1987-03-05 1990-08-14 Kabushiki Kaisha Toshiba Low pressure discharge lamp with flat-plate terminal
US5105119A (en) * 1990-09-21 1992-04-14 North American Philips Corporation Electric lamp having a pressure molded base
EP1411542A2 (en) * 2002-10-03 2004-04-21 Star Leader Limited Light bulb and method of forming it
WO2005122205A1 (en) * 2004-06-10 2005-12-22 Koninklijke Philips Electronics N.V. Foamable element for mutually coupling of multiple components of a lamp, and lamp assembly
US20060255707A1 (en) * 2005-05-10 2006-11-16 Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh Lamp base having color coding and lamp having a lamp base
US20150226542A1 (en) * 2014-02-07 2015-08-13 Luceo Co., Ltd. Strain inspection apparatus

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB413127A (en) * 1932-07-29 1934-07-12 British Thomson Houston Co Ltd Improvements in and relating to electric lamps
US2268700A (en) * 1939-03-02 1942-01-06 Guy N Criger Incandescent electric lamp
US2433373A (en) * 1944-01-12 1947-12-30 Raytheon Mfg Co Apparatus for applying reinforcing members to electron discharge tubes
US2771589A (en) * 1954-12-14 1956-11-20 Sylvania Electric Prod End cap for fluorescent lamp
US2884555A (en) * 1958-04-25 1959-04-28 Gilbert Mfg Company Inc Directly attachable electric light bulb
US2983838A (en) * 1959-01-02 1961-05-09 Westinghouse Electric Corp Lamp base and terminal means therefor
US3010045A (en) * 1955-05-27 1961-11-21 Westinghouse Electric Corp Sealed-beam lamp and method of manufacture
US3077022A (en) * 1962-05-03 1963-02-12 Burroughs Corp Lamp and method of manufacture
US3218500A (en) * 1959-06-29 1965-11-16 Hunting Eng Ltd Plastic material covered lamp with panel push-fit mounting means
US3322992A (en) * 1964-02-05 1967-05-30 Penn Keystone Corp Resin encapsulated lamp assembly

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB413127A (en) * 1932-07-29 1934-07-12 British Thomson Houston Co Ltd Improvements in and relating to electric lamps
US2268700A (en) * 1939-03-02 1942-01-06 Guy N Criger Incandescent electric lamp
US2433373A (en) * 1944-01-12 1947-12-30 Raytheon Mfg Co Apparatus for applying reinforcing members to electron discharge tubes
US2771589A (en) * 1954-12-14 1956-11-20 Sylvania Electric Prod End cap for fluorescent lamp
US3010045A (en) * 1955-05-27 1961-11-21 Westinghouse Electric Corp Sealed-beam lamp and method of manufacture
US2884555A (en) * 1958-04-25 1959-04-28 Gilbert Mfg Company Inc Directly attachable electric light bulb
US2983838A (en) * 1959-01-02 1961-05-09 Westinghouse Electric Corp Lamp base and terminal means therefor
US3218500A (en) * 1959-06-29 1965-11-16 Hunting Eng Ltd Plastic material covered lamp with panel push-fit mounting means
US3077022A (en) * 1962-05-03 1963-02-12 Burroughs Corp Lamp and method of manufacture
US3322992A (en) * 1964-02-05 1967-05-30 Penn Keystone Corp Resin encapsulated lamp assembly

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3500105A (en) * 1968-02-19 1970-03-10 Sylvania Electric Prod Incandescent lamp having a ceramic screw type base
US4256989A (en) * 1978-09-22 1981-03-17 Duro Test Corporation Incandescent lamp with filament mounting means and socket adaptor
US4622488A (en) * 1983-06-29 1986-11-11 U.S. Philips Corporation Internally fused electric lamp with partially embedded fuse wire
US4949007A (en) * 1987-03-05 1990-08-14 Kabushiki Kaisha Toshiba Low pressure discharge lamp with flat-plate terminal
US4854888A (en) * 1988-05-31 1989-08-08 Gte Products Corporation Lamp base
US4878854A (en) * 1988-05-31 1989-11-07 Gte Products Corporation Lamp base
US5105119A (en) * 1990-09-21 1992-04-14 North American Philips Corporation Electric lamp having a pressure molded base
EP1411542A2 (en) * 2002-10-03 2004-04-21 Star Leader Limited Light bulb and method of forming it
EP1411542A3 (en) * 2002-10-03 2006-05-31 Star Leader Limited Light bulb and method of forming it
WO2005122205A1 (en) * 2004-06-10 2005-12-22 Koninklijke Philips Electronics N.V. Foamable element for mutually coupling of multiple components of a lamp, and lamp assembly
US20060255707A1 (en) * 2005-05-10 2006-11-16 Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh Lamp base having color coding and lamp having a lamp base
US20150226542A1 (en) * 2014-02-07 2015-08-13 Luceo Co., Ltd. Strain inspection apparatus

Also Published As

Publication number Publication date
GB1099746A (en) 1968-01-17
DE1539613A1 (de) 1969-12-04
NL6609215A (US20030204162A1-20031030-M00001.png) 1967-01-20

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Legal Events

Date Code Title Description
AS Assignment

Owner name: NORTH AMERICAN PHILIPS ELECTRIC CORP.

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:WESTINGHOUSE ELECTRIC CORPORATION;REEL/FRAME:004113/0393

Effective date: 19830316