JP2001196030A - Screwing end-plug for lamp filament and its assembling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filament structure for incandescent electric bulb including a helical filament and a helical end plug to engage with the end of the filament. SOLUTION: The end plug is composed of a coil, which consists of the first sectionsecond section (12) having a pitch different from that of the first section. By engagingthe second section (12) of the end plug with the outside of a current lead (14), the filamentis mounted on the lead.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw-type end plug for use in a filament assembly of an incandescent lamp and a method of assembling the same.

[0002]

BACKGROUND OF THE INVENTION The use of threaded end plugs is very common in the manufacture of tungsten halogen lamps. These plugs are short pieces of rolled tungsten that are screwed into the ends of the filament, connecting the active filament to the current leads. Plug is GE
Monoplanes, such as products of the Lighting division of the company
It is routinely used in biplane and other multi-leg studio halogen filaments.

When a plug is inserted into a filament coil to form a filament structure, the level at which the plug is screwed in is important because this level determines the active length (ie, emission length) of the filament wire of the assembly. It is. Level is one of the main input variables that determines the main lamp performance parameters (power consumption, fixture efficiency, color temperature, lifetime, etc.) and should be controlled with the utmost care. Usually, there is a tolerance of ± 0.3 mm in this dimension, but since it is controlled by visual judgment during assembly, an error is likely to occur and a very high technical level is required.

[0004] Another important variable is the length of the end plug exposed below the filament. To ensure that the filament fits tightly into the filament support bridge while maintaining a moderate tension, this length typically needs to be controlled to ± 0.5 mm. Currently, the length of the exposed plug is determined by visually re-determining the trimming point and performing trimming with a wire cutter.

Finally, it is often necessary to use thick wires as plug material to fill the gap between the filament and the current leads. This is often necessary when there is a discrepancy between the diameter of the current lead and the inner diameter of the filament. In such cases, it is often necessary to wind the threaded plug at a very tight pitch. Therefore, processing becomes difficult for the following two reasons.
First, plugs are extremely difficult to accurately trim without burring. Secondly, it is difficult to wrap around a pre-bent current lead because the plug is physically very rigid.

[0006]

SUMMARY OF THE INVENTION A filament assembly for an incandescent lamp according to the present invention includes a helically wound filament and a helically wound end plug that engages one end of the filament. The end plug comprises a coil having a first section having a diameter and a pitch for engaging one end of a filament coil, and a second section having a pitch different from the pitch of the first section.

[0007] The method of assembling a filament assembly described in the preceding paragraph includes the steps of assembling the first section of the filament plug until resistance develops as a result of the pitch difference between the first and second sections of the filament plug. Including screwing into one end.

The end plug differs from existing plugs in that it comprises a helical coil of wire, which coil is composed of a plurality of sections with at least two different pitches.

[0009]

Embodiments of the present invention will be described by way of example with reference to the accompanying drawings.

FIG. 1 shows a wire having a first section with a relatively tightly wound first pitch and a second section with a loosely wound second pitch and typically comprising tungsten. 1 shows an example of a screw-type end plug composed of a spiral coil. The first and second sections are advantageously of the same diameter, but may be of different diameters.

A threaded end plug 10 is used to mount a filament 13 on a current lead 14, as shown in FIG. The first section 11 of the end plug has a pitch that allows the plug to be screwed into the end of a given helical filament, while the second section 11
Section 12 has a pitch that prevents the plug from being threaded inward beyond a predetermined length beyond the end of the filament 13. Thus, when the operator screws the end plug into the filament, a resistance develops as a result of the difference in pitch between the first section and the second section of the end plug. Further, the pitch of the second section of the plug allows for mounting on a current lead 14, which may be bent to an angle greater than 60 °.

[0012] Usually, in actual manufacturing situations, the individual screw-type end plugs are of a certain length, usually 1 mm.
It is formed by cutting a pre-wound coil of 50 mm length. In accordance with the present invention, such a pre-wound coil of some length comprises a coil having a length of every other pitch. This has another advantage. That is, once the plug is inserted into the filament coil, the operator can easily know where to trim the plug due to the boundary between the two sections at different pitches. FIG. 3 shows the typical length of a pre-wound coil 20, which comprises approximately equal length sections 21, 2 of every other pitch.
2 FIG. 4 shows another design example of the coil 20,
The coil sections 21, 22 having different pitches have completely different lengths.

Those skilled in the art may make various modifications in structure and / or process and / or function without departing from the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a side view of a threaded end plug of an incandescent filament light bulb.

FIG. 2 is a side view of a portion of a filament assembly of an incandescent lamp showing one end of a filament mounted on a current lead by an end plug.

FIG. 3 is a view showing a long wire coil that can be formed by cutting an end plug.

FIG. 4 is a view showing a long wire coil that can be formed by cutting an end plug.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 End plug 11 1st section 12 2nd section 13 Filament 14 Current lead

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Joan Sasson UK, EL8 8.8 BS, Lester Starshire, Frecknery, Western Avenue, 21st (72) Inventor Anthony John Perrin UK, EL 4.9 FW, Rester, Welham Walk, No. 12

Claims (5)

[Claims] 1. A filament assembly for an incandescent lamp, comprising: a spirally wound filament; and a spirally wound end plug engaged with one end of the filament, the end plug having a coil. An incandescent lamp, the coil having a first section having a diameter and a pitch to engage one end of the filament coil, and a second section having a pitch different from the pitch of the first section. For filament assembly. 2. The filament structure according to claim 1, wherein said second section of said filament plug has a wider pitch than said first section. 3. The method according to claim 1, further comprising a current lead engaging the second section of the filament plug.
A filament structure as described. 4. The method for assembling a filament structure according to claim 1, wherein a resistance is generated as a result of a difference in pitch between the first section and the second section of the end plug. Screwing the first section of the end plug into one end of the filament until the end of the first plug is turned on. 5. The method according to claim 5, further comprising cutting the end plug from a long wire coil having a length of the first pitch and the second pitch alternately, wherein the cutting is performed at a position where the pitch changes. 5. The method of claim 4, wherein the method is performed.