JPH0733367Y2 - Tube incandescent light bulb - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a tube-type incandescent light bulb that is preferably used as a light source for document illumination of a copying machine.

[Conventional technology]

In a tube-type incandescent light bulb used as a light source for illuminating an original in a copying machine, etc., lighting and extinguishing are repeated each time the original is illuminated. The expansion and contraction will be repeated frequently. Therefore, there is a problem that a considerable amount of stress acts on the coil of the light emitting section, which disturbs the coil pitch, disconnects early, and shortens the service life. In particular, in the case of a large-sized copying machine capable of copying A2 or larger sheets, the total length of the tube-type incandescent lamp also becomes long, so that the stress acting on the coil of the light-emitting part becomes large, and the above-mentioned problem is remarkable.

However, as a means for reducing the stress acting on the coil of the light emitting portion, conventionally, there has been proposed a means of forming a single wire coil spring in the non-light emitting portion and bringing the coil spring into contact with the inner wall of the tubular valve.

[Problems to be solved by the device]

However, in the above coil spring, since it is a single wire, its spring coefficient is large, and it is difficult to sufficiently absorb the stress acting on the coil of the light emitting section. More specifically, it is necessary that the non-light emitting portion does not emit light when turned on, and therefore the diameter of the wire must be large. Therefore,
Since the wire diameter of the coil spring is thick, the spring coefficient increases,
The stress absorption effect is reduced. On the contrary, if the wire diameter of the non-light emitting portion is reduced, the spring coefficient can be reduced, but light is emitted, so that the function as the spring is impaired and the light distribution is changed.

Therefore, an object of the present invention is to provide a tubular incandescent light bulb having a small spring coefficient, a high stress absorption effect, and a coil portion that does not emit light.

[Means for Solving the Problems]

In order to achieve the above object, the tubular incandescent light bulb of the present invention has light emitting parts and non-light emitting parts arranged alternately, and a part of the non-light emitting parts has a coil part for absorbing elongation that absorbs expansion in the axial direction. A tube type incandescent light bulb having a filament provided, wherein the extension absorbing coil portion is made of a stranded wire of a high melting point metal, and between the extension absorbing coil portion and a light emitting portion adjacent to the extension absorbing coil portion, A ring anchor for supporting the light emitting unit is present.

[Action]

The extension absorbing coil portion made of a stranded wire has a considerably smaller spring coefficient than the extension absorbing coil portion made of a single wire having the same thickness.

Therefore, the stress can be sufficiently absorbed even if the expansion absorbing coil portion is thickened to the extent that it does not emit light.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a tubular incandescent light bulb according to an embodiment of the present invention. 1 is a tubular bulb, 11 is a seal part, 2 is a filament, 21 is a light emitting part, 22 is a non-light emitting part, 23 is a ring anchor,
Reference numeral 24 is a metal foil, 25 is an external lead, and 3 is an extension absorbing coil portion.

A filament 2 is formed by alternately arranging light emitting portions 21 and non-light emitting portions 22 along the axial direction of the tubular bulb 1. The light emitting portion 21 is made of a coil such as tungsten, and the non-light emitting portion 22 is made of a short-circuit core wire such as molybdenum.

The elongation absorbing coil portion 3 is made of a stranded wire of a refractory metal such as tungsten or molybdenum, is provided in a part of the non-light emitting portion 22, and absorbs the elongation in the axial direction. The outer circumference of the extension absorbing coil portion 3 is in contact with the inner wall of the tubular valve 1, and the extension absorbing coil portion 3 is supported thereby.

In addition, the elongation absorbing coil portion 3 and the light emitting portion 21 adjacent to this
There is a ring anchor 23 between and, and one end of the light emitting portion 21 adjacent to the extension absorbing coil portion 3 is supported by the ring anchor 23.

In the present invention, the short-circuit core wire and the ring anchor 23 constituting the non-light emitting portion 22 function as a support for the light emitting portion 21, and the extension absorbing coil portion 3 absorbs thermal stress acting on the light emitting portion 21. It functions as a body.

As an example of a specific design, the output is 390 W (rated voltage 80
In the case of a tube-type incandescent light bulb with a total length of 352 mm at
Is made of tungsten with a wire diameter of 0.17 mmφ
Is made of molybdenum having a wire diameter of 0.4 mm, and the ring anchor 23 is integrally formed by this molybdenum. The elongation absorbing coil portion 3 is formed by twisting 21 fine tungsten wires each having a diameter of 0.08 mm, and the total thickness is 0.54.
mm, the coil length is 11 mm, and the number of turns is 10. The spring coefficient of the extension absorbing coil portion 3 is about 1 gf / mm.

As is clear from this design example, the extension absorbing coil portion 3 is thicker than the molybdenum wire of the non-light emitting portion 22. Therefore, there is no possibility that the elongation absorbing coil portion 3 emits light.

According to the tubular incandescent light bulb of this embodiment, the expansion absorbing coil portion 3 is a separate body from the short-circuit core wire forming the non-light emitting portion 22, and is formed by a plurality of twisted wires. The spring coefficient can be reduced. Therefore, the expansion / contraction in the axial direction of the filament 2 is sufficiently absorbed by the extension absorbing coil portion 3, and the filament 2
The early disconnection of is effectively prevented. Moreover, since the elongation absorbing coil portion 3 is a separate body from the short-circuit core wire and can be made thicker, there is no possibility of emitting light during lighting and the function as a non-light emitting portion is not impaired.

In the present invention, as shown in FIG. 2, the elongation absorbing coil portion 3 may be provided at the end portion of the filament 2. Further, the elongation absorbing coil portion 3 is not limited to one place, and may be provided in two places as necessary.

[Effect of device]

As described above, according to the present invention, since the spring coefficient of the elongation absorbing coil portion is small and the stress absorbing effect is high, the service life of the tubular incandescent light bulb can be extended.
Further, since the elongation absorbing coil portion can be thickened, there is no fear that the elongation absorbing coil portion will emit light,
The light distribution does not change.

[Brief description of drawings]

FIG. 1 is a sectional view of a tubular incandescent light bulb according to an embodiment of the present invention,
FIG. 2 is a sectional view of a tubular incandescent light bulb according to another embodiment of the present invention. 1 …… Tubular bulb, 11 …… Seal part 2 …… Filament, 21 …… Light emitting part 22 …… Non-light emitting part, 23 …… Ring anchor 24 …… Metal foil, 25 …… External lead 3 …… Extension absorption Coil part

Claims (1)

[Scope of utility model registration request] 1. A tubular incandescent light bulb having a filament, in which light emitting portions and non-light emitting portions are alternately arranged, and a stretch absorbing coil portion for absorbing extension in an axial direction is provided in a part of the non-light emitting portions. The extension absorbing coil portion is made of a stranded wire of a high melting point metal, and a ring anchor for supporting the light emitting portion is provided between the extension absorbing coil portion and the light emitting portion adjacent to the extension absorbing coil portion. A tube-type incandescent light bulb characterized by its existence.