JP2515420Y2 - Filament assembly - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filament assembly incorporated in a tubular incandescent lamp used as a light source for exposure in a copying machine or the like.

[0002]

2. Description of the Related Art In a tube type incandescent lamp used as a light source for exposure in a copying machine, for example, a core wire for short-circuiting is provided in a coiled filament in which dense winding portions and coarse winding portions are alternately arranged. Is inserted and fixed to form a non-light emitting portion. In order to stabilize the exposure amount, it is necessary to connect and fix the short winding core wire and the rough winding portion at the end portion of the shorting core wire, and conventionally, as shown in FIG. 4, welding is performed by resistance heating. Was there. Reference numeral 1 is a coiled filament, 2 is a densely wound portion, 3 is a coarsely wound portion, 4 is a short-circuiting core wire, and 5 is a welding rod.

[0003]

However, with such resistance heating, it is not always possible to weld the end portion 41 of the short-circuiting core wire 4 to the rough winding portion 3, and variations in the welding position occur, resulting in a variation in the exposure amount. There was a problem that something with poor stability could be created.
In addition, since the welding rods 5 and 5 apply a strong pressure to the end portion 41 of the short-circuiting core wire 4 inserted in the rough winding portion 3, the filament 1 is bent and the desired light distribution cannot be obtained. was there. Further, in order to reliably weld at the end portion 41 of the short-circuiting core wire 4 inserted in the rough winding portion 3 by resistance heating, it is necessary to increase the welding power, so that the welded portion recrystallizes and the clamping force causes There was a problem that it was easy to break. Therefore, an object of the present invention is to provide a filament assembly that does not cause problems such as variations in the bonding position, bending of the filament, and breakage of the bonding portion.

[0004]

In order to achieve the above object, in the filament assembly of the present invention, the coiled filament is composed of a densely wound portion and a coarsely wound portion, and the shorting core wire is inserted into the coarsely wound portion. A filament assembly comprising:
Large-diameter portions having a diameter larger than that of the short-circuiting core wire and wider than the pitch of the coarse winding portion are formed at both ends of the short-circuiting core wire, and the large-diameter portion engages with the coarse winding portion of the coiled filament. It is characterized by

[0005]

Since the large-diameter portions are formed at both ends of the short-circuit core wire and the large-diameter portion is engaged with the coarsely wound portion of the coil-shaped filament, the coil-shaped filament is brought into close contact with the coil-shaped filament without applying an excessive force, and therefore, the engagement There is no variation in the mating position, no bending of the filament, and no breaking of the engaging portion.

[0006]

Embodiments of the present invention will be described below. In the embodiment of the present invention, as shown in FIGS. 1 and 2, both ends of the short-circuit core wire 4 have a diameter larger than that of the short-circuit core wire 4 and are wider than the pitch P of the coarse winding portion 3 of the coiled filament 1. The large-diameter portion 42 is formed by, for example, press working. The wire diameter B of the portion of the short-circuit core wire 4 excluding the large-diameter portion 42 is almost the same as the coil inner diameter of the coarse winding portion 3, and the press width A of the large-diameter portion 42.
Is larger than the pitch P of the rough winding portion 3 by, for example, about 0.2 mm, and the press diameter C of the large diameter portion 42 preferably satisfies the following expression 1 in relation to the wire diameter B.

[0007]

[Equation 1]

In the above equation 1, the unit of B and C is m
m and MG represents the weight of a tungsten wire 200 mm.

The coil-shaped filament 1 is made of, for example, a tungsten wire having a diameter of 0.12 mmφ, and the densely wound portions 2 and the coarsely wound portions 3 are alternately provided. The pitch of the tightly wound portion 2 is, for example, 0.21 mm, and the pitch P of the coarsely wound portion 3 is, for example, 0.48 mm. The distance D between the close-wound portion 2 and the large-diameter portion 42 is, for example, 1 mm. The core wire 4 for short circuit is
For example, the wire diameter B of the portion excluding the large diameter portion 42 made of a molybdenum rod is, for example, 0.5 mmφ.

The coarsely wound portion 3 of the coiled filament 1 is screwed into the large diameter portion 42 of the short-circuiting core wire 4 so that they are engaged with each other. That is, since the press width A of the large-diameter portion 42 is slightly larger than the pitch P of the rough winding portion 3, when the pitch P is widened against the elastic force of the rough winding portion 3 and screwed in,
The large-diameter portion 42 is firmly engaged with the pitch of the rough winding portion 3.

FIG. 3 is a schematic view of a tubular incandescent light bulb constructed by using the above filament assembly, in which 71 is a bulb, 72 is a seal portion, 73 is a filament assembly, and 74.
Is an external lead, and 75 is a reduced diameter portion for holding the short-circuit core wire 4. The filament assembly 73 extends along the axial direction of the bulb 1.

In the present invention, the means for forming the large-diameter portion 42 of the short-circuit core wire 4 is not limited to press working, and various other means may be adopted. Further, the means for holding the short-circuiting core wire 4 is not limited to the reduced diameter portion 75, and may be a means such as a ring-shaped supporter.

[0013]

As described above, according to the present invention,
It is possible to obtain a filament assembly that does not cause variations in the engagement position between the coiled filament and the short-circuit core wire, bending of the filament, and breakage of the engagement portion. Therefore,
An incandescent light bulb using this has excellent light distribution characteristics with no change in light quantity and no variation.

[Brief description of drawings]

FIG. 1 is an explanatory view of a core wire for short circuit according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing an engaged state of the short-circuit core wire and the coarse winding portion according to the embodiment of the present invention.

FIG. 3 is a schematic view showing an example of a tubular incandescent light bulb constructed using the filament assembly of the present invention.

FIG. 4 is an explanatory view of a conventional filament assembly.

[Explanation of symbols]

1 Coiled Filament 2 Closely Wound Part 3 Roughly Wound Part 4 Shorting Core Wire 41 End 42 Large Diameter Part 5 Welding Rod 71 Valve 72 Seal Part 73 Filament Assembly 74 External Lead 75 Reduced Diameter Part

Claims (1)

(57) [Scope of utility model registration request] 1. A filament assembly in which a coil-shaped filament includes a close-wound portion and a coarse winding portion, and a short-circuiting core wire is inserted into the rough-winding portion, and the short-circuit is provided at both ends of the short-circuiting core wire. A filament assembly characterized in that a large-diameter portion having a diameter larger than that of the core wire and wider than the pitch of the coarse winding portion is formed, and the large-diameter portion is engaged with the coarse winding portion of the coiled filament.