JP2724531B2 - How to attach a filament shield for fluorescent lamps - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of mounting a filament shield for preventing a filament of a fluorescent lamp from evaporating with heat generation and adhering to an inner surface of a glass tube.

[0002]

2. Description of the Related Art In order to prevent a tungsten filament of a fluorescent lamp from evaporating due to heat generation and adhering to the inner surface of a glass tube and fogging, a filament shield formed by bending a metal band into an annular shape is used for the filament. It is known that the filament shield is placed around the periphery and the filament shield is attached to a metal round wire projecting from a mount supporting the filament by welding.

[0003] In such a case, it is difficult to perform welding with the round wire as it is. Therefore, conventionally, the distal end side of the metal round wire is crushed to a flat portion over a long portion, and the entire flat portion is applied to the outer surface of the shield. Spot welding.

[0004]

However, in such a method of applying a long flat portion, the essential welded portion may not adhere due to the flat portion being bent or bent. Therefore, welding defects often occurred.

In order to avoid this, irregularities are provided on the welding surface on the filament shield side.
There is a drawback that the cost is increased by molding the shield.

[0006]

SUMMARY OF THE INVENTION A method of mounting a filament shield for a fluorescent lamp according to the present invention has been completed in view of the points described above. The bulging part bulging to one side in the radial direction is bent at a plurality of locations spaced apart in the axial direction of the round wire, and a narrow flat surface is formed at the bulging end, and the flat surface is used for the filament shield. Welded to the outer surface.

[0007]

According to the present invention, the flat surface of the tip of the bulge formed in the metal round wire is pressed against the outer surface of the filament shield, and the portion is welded with a laser beam or the like to thereby provide the filament shield. Is attached to the metal round wire.

[0008]

That is, according to the method of the present invention, the narrow flat surface at the tip of the bulging portion of the metal round wire is applied to the outer surface of the filament shield as the welding portion. Even if there is a deformation such as bending, it can be firmly adhered without being affected by it, and when a metal round wire is pressed, the bulging parts on both sides of the flat surface bend and its elasticity is restored. As a result, a uniform pressing force is applied to maintain a close contact state, and the entire surface of the welded portion is uniformly melted, so that stable and favorable welding can be performed.

In addition, as for the formation of the bulging portion and the flat surface of the metal round wire, it is only necessary to perform one forging process as in the case of the conventional flat portion, and it is not necessary to provide an extra process. Since no special molding is performed on the filament shield side, there is no possibility that the cost will be increased.

[0010] In addition, since the metal round wire is literally a round wire in the unformed portion other than the bulging portion and the flat surface, it can be easily positioned and accurately guided to the welding position.
Since the shield side is not particularly formed as described above, it can be supplied stably and has an effect that the welding operation can be performed smoothly and accurately.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the method of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 1 denotes a glass mount welded to the end of a glass tube of a fluorescent lamp, and a tungsten mount is provided between the tips of a pair of lead wires 2 provided through the mount 1. The filament 3 is attached, and the filament shield 5 which is formed by turning the metal strip 6 into an annular shape having an oval cross section as shown in FIG. 2 is covered so as to surround the filament 3.
The filament shield 5 is attached to the tip of a metal round wire 8 protruding from the mount 1 so as to extend to the side of the filament 5.

Next, a method of attaching the filament shield 5 will be described in detail. First, before mounting the filament 3 between the two lead wires 2, as shown in FIG. 3A, a male mold a having a convex portion b and a female mold c having a corresponding concave portion d are formed. In between, the tip side of the shielded metal round wire 8 is inserted, and as shown in FIG. 3B, the metal round wire 8 is forged and formed between the two molds a and c. As shown in (), a bulging portion 9 having a flat surface 10 with a small width at the tip and bulging to the side corresponding to the filament 3 is formed.

After the filament 3 is mounted,
As shown in FIGS. 4 and 5, the mount 1 is supplied to a predetermined welding position, the filament shield 5 is put around the filament 3, the guide e is applied to the lower end of the metal round wire 8, and the bulge 9 is formed. The flat surface 10 of the tip is pressed against the corresponding outer surface of the filament shield 5, and the filament shield 5 is attached to the metal round wire 8 by applying a laser beam from the welding machine g to the welding.

That is, according to the present embodiment, the narrow flat surface 10 provided at the tip of the bulging portion 9 formed on the metal round wire 8 is applied to the outer surface of the filament shield 5 as the welding portion. Even if the metal round wire 8 is deformed such as warp or bend, it can be securely adhered without being affected by the deformation, and when the metal round wire 8 is pressed, both sides of the flat surface 10 are pressed. The bulging portion 9 is bent and a uniform pressing force is applied by the restoring elasticity to maintain the close contact state, and the entire surface of the welded portion is uniformly melted and stable and excellent welding is performed.

The bulged portion 9 and the flat surface 10 of the metal round wire 8 can be formed only by performing a single forging process, and there is no need to perform any special forming for welding on the filament shield 5 side. It does not invite high.

Further, the metal round wire 8 is formed between the bulging portion 9 and the flat surface 1.
Since the unformed portions other than 0 are literally round lines, as shown in FIG.
The filament shield 5 can be supplied stably since the filament shield 5 is not specially formed with irregularities as described above, so that the welding operation can be performed smoothly and accurately. It can be carried out.

When the filament shield 5a such as a mercury plate is attached, as shown in FIG. 7, the same bulging portion 9 and the flattened portion 9 as described above are provided at two places spaced apart in the axial direction of the metal round wire 8. Surface 10 is formed and mercury alloy 1
If welding is performed at two places above and below the two, a stable welding can be performed without damaging the mercury alloy 12. Of course, the bulging portion 9 and the flat surface 10 may be further provided at three or more places.

[Brief description of the drawings]

FIG. 1 is a front view of a mount according to an embodiment of the present invention.

FIG. 2 is an external perspective view of a filament shield.

FIG. 3 is an explanatory view of a step of forging and forming a metal round wire.

FIG. 4 is a partially cut-away enlarged side view showing a filament shield welding process.

FIG. 5 is a sectional view taken along line XX of FIG. 4;

FIG. 6 is a plan view showing a state in which a metal round wire is guided.

FIG. 7 is an explanatory diagram of another embodiment.

[Explanation of symbols]

1: Mount 2: Lead wire 3: Tungsten filament 5: Filament shield 6: Metal strip
8: metal round wire 9: bulge 10: flat surface a: male
c: female type e: guide g: welding machine

Claims (1)

(57) [Claims] 1. A method of attaching a filament shield, which is disposed around a tungsten filament supported on a mount and is formed by bending a metal strip into an annular shape, to a metal round wire protruding from the mount by welding. Then, by forging the metal round wire, the bulging portion bulging to one side in the radial direction is bent at one location or at a plurality of locations spaced apart in the axial direction of the metal round wire. A method for mounting a filament shield for a fluorescent lamp, comprising: forming a narrow flat surface on a bulging end; and welding the flat surface to an outer surface of the filament shield.