EP1102310A1 - Filament assembly for an incandescent lamp comprising screw-in end plugs and method of manufature thereof - Google Patents
Filament assembly for an incandescent lamp comprising screw-in end plugs and method of manufature thereof Download PDFInfo
- Publication number
- EP1102310A1 EP1102310A1 EP00310247A EP00310247A EP1102310A1 EP 1102310 A1 EP1102310 A1 EP 1102310A1 EP 00310247 A EP00310247 A EP 00310247A EP 00310247 A EP00310247 A EP 00310247A EP 1102310 A1 EP1102310 A1 EP 1102310A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- filament
- section
- pitch
- plug
- coil
- 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.)
- Withdrawn
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01K—ELECTRIC INCANDESCENT LAMPS
- H01K1/00—Details
- H01K1/18—Mountings or supports for the incandescent body
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01K—ELECTRIC INCANDESCENT LAMPS
- H01K1/00—Details
- H01K1/02—Incandescent bodies
- H01K1/14—Incandescent bodies characterised by the shape
-
- 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
- H01K3/06—Attaching of incandescent bodies to mount
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Resistance Heating (AREA)
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
Description
- This invention relates to a screw-in end plug for use in the filament assembly of an incandescent lamp.
- The use of screw-in end plugs is commonplace in tungsten halogen lamp manufacture. The plugs are short sections of wound tungsten which screw in to the ends of a filament, providing a link between the active filament and the current lead. They are used routinely in monoplane, biplane and other multi-limb studio halogen filaments such as those made by GE Lighting.
- When inserting the plugs into the filament coil to form the filament assembly, the level up to which the plug is screwed is important, since this will determine the active (or lit) length of filament wire in the assembly. This needs to be as closely controlled as possible since it is one of the major input variables which determines the primary lamp performance parameters (power consumption, light output, colour temperature, life etc.). Typically, this dimension is given a tolerance of ± 0.3mm, yet during assembly is controlled visually by judgement with the naked eye, hence is prone to error and demands a very high skill level.
- Another important variable is the length of the end plug which is exposed below the filament. This needs to be controlled to typically ± 0.5mm to ensure that the filament fits the filament support bridge consistently with the correct amount of tension. At present, the length of exposed plug is determined by trimming with wire cutters, again using the naked eye to judge the trimming point.
- Finally, in many cases, it is necessary to use a thick wire as the plug material to fill the space between the filament and the current lead. This is often necessary where there is a mismatch between the current lead diameter and the filament inside diameter. Often, in these cases, it is also necessary to wind the screw-in plug with a very close pitch. This makes processing difficult for two reasons: Firstly, the plug is very difficult to trim accurately without burring, and secondly, it is mechanically very inflexible, which makes it difficult to bend around a pre-bent current lead.
- This invention enables each of the above problems to be addressed.
- According to the present invention, there is provided a filament assembly for an incandescent lamp, including a helically coiled filament and a helically coiled end plug engaging an end of the filament, the end plug comprising a coil having a first section with a diameter and pitch adapted to engage in the end of the filament coil, and a second section having a pitch different from the pitch of the first section.
- The invention also provides a method of assembling a filament assembly in accordance with the preceding paragraph, comprising screwing the first section of the filament plug into the end of the filament until a resistance is encountered as a result of the difference in pitch between the first and second sections of the end plug.
- The end plug comprises a helical coil of wire, which differs from any existing plugs in that it comprises sections having at least two different pitches.
- Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
- Fig 1 is a side view of a screw-in end plug of an incandescent filament lamp in accordance with the invention;
- Fig 2 is a side view of part of a filament assembly of an incandescent lamp, showing one end of a filament mounted on a current lead wire by means of an end plug; and
- Figs 3 and 4 show lengths of coiled wire from which end plugs may be cut.
-
- Fig 1 shows an example of a screw-in
end plug 10 which consists of a helical coil of wire, typically of tungsten, with afirst section 11 have a first, relatively closely wound, pitch, and asecond section 12 having a second, less closely wound pitch. The first and second sections are conveniently of the same diameter, but may be of different diameters. - The screw-in
end plug 10 is used, as shown in Fig 2, to mount afilament 13 on acurrent lead 14. Thefirst section 11 of the end plug has a pitch which enables the plug to screw into the end section of a given helical filament, whereas thesecond section 12 has a pitch which prevents the plug from being screwed beyond a pre-determined length inside the end of thefilament 13. Thus, when the operator is screwing the end plug into the filament, a resistance is encountered as a result of the difference in pitch between the first and second sections of the end plug. Additionally, the pitch of the second section of the plug is such that it can be mounted onto thecurrent lead wire 14 which may be bent up to an angle of more than 60 degrees. - Usually, in a practical manufacturing situation, individual screw-in end plugs are cut from a pre-wound length of coil, typically 150mm long. Such a pre-wound length of coil would, according to the present invention, comprise alternate lengths of coil of different pitches. This would lead to an additional advantage, namely that the operator could easily tell, by the boundary between two sections of different pitch, where to trim the plug once it is inserted into the filament coil. Figure 3 illustrates a typical length of pre-wound
coil 20, where there arealternate sections coil 20 where thesections
Claims (5)
- Filament assembly for an incandescent lamp, including a helically coiled filament and a helically coiled end plug engaging an end of the filament, the end plug comprising a coil having a first section with a diameter and pitch adapted to engage in the end of the filament coil, and a second section having a pitch different from the pitch of the first section.
- The filament assembly of claim 1, wherein said second section of the filament plug has a greater pitch than the first section.
- The filament assembly of claim 1 or claim 2 including a current lead wire engaging in the second section of the filament plug.
- Method of assembling a filament assembly in accordance with any one of claims 1 to 3, comprising screwing the first section of the end plug into the end of the filament until a resistance is encountered as a result of the difference in pitch between the first and second sections of the end plug.
- The method of claim 4 including cutting the end plug from a length of coiled wire having alternating lengths with said first and second pitches, the cut being made at a position where the pitch changes.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9927728 | 1999-11-19 | ||
GB9927728A GB2356488A (en) | 1999-11-19 | 1999-11-19 | Screw-in end plugs for lamp filaments |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1102310A1 true EP1102310A1 (en) | 2001-05-23 |
Family
ID=10865026
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP00310247A Withdrawn EP1102310A1 (en) | 1999-11-19 | 2000-11-17 | Filament assembly for an incandescent lamp comprising screw-in end plugs and method of manufature thereof |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1102310A1 (en) |
JP (1) | JP2001196030A (en) |
GB (1) | GB2356488A (en) |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3535577A (en) * | 1966-11-30 | 1970-10-20 | Philips Corp | Tubular electric incandescent lamp with filament and current supply wires spaced from tube walls |
GB1340778A (en) * | 1971-12-02 | 1974-01-30 | Thorn Electrical Ind Ltd | Filament assejbly for incandescent lamps |
US4812710A (en) * | 1986-03-24 | 1989-03-14 | Patent Treuhand Gesellschaft Fur Elektrische Gluhlampen Mbh | Halogen incandescent lamp with high reliability filament connection, and method of manufacture |
EP0438254A2 (en) * | 1990-01-16 | 1991-07-24 | Ge Lighting Limited | Circular heater lamp |
GB2305585A (en) * | 1995-03-09 | 1997-04-09 | Ge Lighting Ltd | Heat source |
RU2139160C1 (en) * | 1998-06-24 | 1999-10-10 | Мордовский государственный университет им.Н.П.Огарева | Apparatus for cutting filament bodies of light sources |
JP2000106150A (en) * | 1998-09-28 | 2000-04-11 | Ushio Inc | Incandescent lamp |
-
1999
- 1999-11-19 GB GB9927728A patent/GB2356488A/en not_active Withdrawn
-
2000
- 2000-11-17 EP EP00310247A patent/EP1102310A1/en not_active Withdrawn
- 2000-11-17 JP JP2000350343A patent/JP2001196030A/en not_active Withdrawn
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3535577A (en) * | 1966-11-30 | 1970-10-20 | Philips Corp | Tubular electric incandescent lamp with filament and current supply wires spaced from tube walls |
GB1340778A (en) * | 1971-12-02 | 1974-01-30 | Thorn Electrical Ind Ltd | Filament assejbly for incandescent lamps |
US4812710A (en) * | 1986-03-24 | 1989-03-14 | Patent Treuhand Gesellschaft Fur Elektrische Gluhlampen Mbh | Halogen incandescent lamp with high reliability filament connection, and method of manufacture |
EP0438254A2 (en) * | 1990-01-16 | 1991-07-24 | Ge Lighting Limited | Circular heater lamp |
GB2305585A (en) * | 1995-03-09 | 1997-04-09 | Ge Lighting Ltd | Heat source |
RU2139160C1 (en) * | 1998-06-24 | 1999-10-10 | Мордовский государственный университет им.Н.П.Огарева | Apparatus for cutting filament bodies of light sources |
JP2000106150A (en) * | 1998-09-28 | 2000-04-11 | Ushio Inc | Incandescent lamp |
Non-Patent Citations (2)
Title |
---|
DATABASE WPI Section PQ Week 200039, Derwent World Patents Index; Class P52, AN 2000-450115, XP002160585 * |
PATENT ABSTRACTS OF JAPAN vol. 2000, no. 07 29 September 2000 (2000-09-29) * |
Also Published As
Publication number | Publication date |
---|---|
GB9927728D0 (en) | 2000-01-26 |
JP2001196030A (en) | 2001-07-19 |
GB2356488A (en) | 2001-05-23 |
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