JPS58189946A - Manufacturing method of circular fluorescent lamp - Google Patents

Abstract

PURPOSE:To effectively prevent the occurrence of eccentricity out of the axial center of a curvedly formed valve by means of a simple method, by cooling the sealed part of the valve in a way of making full use of air discharged out of a mount pin before the lower part of the valve is curvedly formed by a forming roller in a state of being heated and softened. CONSTITUTION:The upper end of a linear valve 11 is secured tight to a movable body to be intermittently rotated so as to cause the lower end to become a state of freedom. Next, the valve 11 is heated to the extent of a state of being optimum softening conditions for its curved formation. At this time, from the lower side of the valve 11, a mount pin 2 goes up with air discharged out of a slit hole 8 of a mount pin tip 4, and using this air, also the sealed part of the valve 11 is designedly cooled to such a degree that does not interfere with the curved formation simultaneously with the mount pin 2. With this, not only the occurrence of eccentricity out of the axial center of the valve whose stem is curvedly formed can be effectively prevented but also a defective external view attributable to some influence and suchlike from an electrode can be sharply reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing annular fluorescent lamps, and is particularly directed to reducing eccentricity of the stem during bending of the bulb.

Generally, this type of annular fluorescent lamp is manufactured as shown in FIGS. 1 and 2, for example. That is, first, at the stop position [I] of the movable body A which rotates intermittently, the upper end of the linear valve C is held in a free state by the chuck B attached to the movable body A so as to be openable and closable. Fix it so that This valve C is gradually heated and softened as it passes through the heating furnace due to the intermittent rotation of the moving body A. Then, the position in the heating furnace [in the illusion, it will be in a considerably softened state. When the valve C is transferred to position [I] by the intermittent rotation of the moving body A, it is surrounded by an electric oven E that moves forward from both sides of its movement trajectory, and is heated to the optimal softening state for bending. . At this time, the lower end of the bulb O is supported by a mounting pin F that rises within the electric oven E by a certain height. The valve C is moved from position to position by the intermittent rotation of the movable body A, with the lower end supported by the mount pin F. When valve C stops, forming roller G
The lower end is clamped and fixed with a chuck (not shown) attached thereto. At the same time, the mount pin F is lowered. In this state, the forming roller G rolls upward, thereby bending the valve C into an annular shape. Thereafter, an annular fluorescent lamp is manufactured by removing impurity gas from inside the bulb, filling it with inert gas, sealing it with mercury, and so on.

Normally, so-called lead glass, which has a lead content of about 20 to 301%, is widely used as a bulb material for annular fluorescent lamps because it is easy to process. In recent years, due to rising bulb costs due to measures to prevent environmental pollution associated with the manufacture of lead glass, the lead content has been reduced to 10% by weight or less, for example 5% by weight.
The use of so-called low-lead glass or soda glass, which is used in straight tube fluorescent lamps, has been put into practical use in some areas.

However, the softening temperature of soda glass is about 100'C higher than that of lead glass, so the working temperature must naturally be set high, but the stem is made of lead glass, which has excellent workability. It is thought that because of this structure, not only the stem but also the sealing portion between the valve and the stem are in a softer state than the valve.

Therefore, if the bulb C is bent into an annular shape in this state, the stem will be eccentric outward from the axis of the bulb C, as shown in Fig. 3, and the electrode will be shaded when the annular fluorescent lamp is turned on. is projected onto the bulb, significantly impairing its appearance characteristics. In particular, when the electrode comes into contact with the inner surface of the bulb, there are problems not only in terms of appearance but also in that the bulb is easily damaged.

The present invention addresses these points and provides a method for manufacturing an annular fluorescent lamp, which can effectively suppress the eccentricity of the stem from the axis of the curved bulb by a simple means, and can significantly reduce appearance defects. An embodiment will be described below.

In FIGS. 4 and 5, ``■'' is, for example, an electric oven, which is arranged so as to rotate back and forth with respect to the movement locus of the bulb. A mount bin 2 is disposed below the electric oven 1 so as to be movable up and down. The mount bin 2 is composed of, for example, a vibrator 3 and a mount pinch tab 4 which is fitted at the upper end of the vibrator 3. The mount pinch knob 4 integrally forms a seven-lung portion 7 having a notch 6 in a part at the lower end of the conical portion 5, and also forms a pair of slit holes 8, 8 below the conical portion 5. It is configured as follows. On the other hand, a vibrator 9 for supplying a cooling gas such as air is disposed inside the mount bin 2 . There is an air slit hole 8 on the side of the upper end of the vibrator 3.
A screw io is attached to adjust the discharge amount from 8.

Reference numeral 11 denotes a bulb with stems 12 sealed at both ends, and is made of soda glass, for example. and stem]. A strut wire 13 is implanted in 2, and an electrode 14 is connected to the tip thereof. Further, a lead wire 15 extending from the support wire 13 is led out from the outside of the stem 12.

Next, a method for manufacturing an annular fluorescent lamp using this apparatus will be explained. First, the upper end of the linear valve 11 is fixed to a moving body that rotates intermittently so that the lower end is in a free state. When this valve 11 passes through the heating furnace and stops at a fixed position, as shown in FIG.
It is surrounded by electric ovens 1, 1 which move forward from both sides of the locus of movement of oven 1. The bulb 11 is then heated to a softened state that is optimal for bending. At this time, the mount bottle 2 rises from below the valve 11 while discharging air from the slit holes 8, 8 of the mount bottle chip 4. This air cools the mount bin 2 and the sealed portion of the RV valve 11 to an extent that does not interfere with bending. Furthermore, the air discharged from the slit holes 8 forms an air curtain having an inverted V shape, and the position of the valve 11 is adjusted so that the lower end of the valve 11 faces the center of the mount bin 2. and,
The lower end (stem flare portion) of the valve 11 is supported by the camarant pin 2. Thereafter, a mound-shaped fluorescent lamp is manufactured by the usual method π.

In this way, the two parts of the seal between the valve 11 and the stem 12 are heated to a temperature (a little below the strain point temperature) due to the air discharged from the mound pin 2 prior to the bending of the valve 1↓.
Even if the bulb 11 is bent into an annular shape in order to cool the stem 12 to a temperature of 400 to 450''C, the eccentricity of the stem 12 from the axis of the bulb 11 can be significantly reduced, and the appearance characteristics can be improved.

Also, the mount bottle chip 4 has a pair of slit holes 8, 8.
is formed, and the air discharged from it forms an almost inverted V-shaped air curtain. Therefore, even if the axial center of the valve 11 with respect to the mount bin 2 is slightly shifted, the guiding action of the air curtain will keep the valve 11
is automatically adjusted in position relative to the mount bin 2. C
Therefore, the valve 11 can be reliably supported by the mount pin 2, and bending defects caused by incorrect support can be completely eliminated.

In addition, since a pair of notches 6, 6 are formed in the 7-ramp portion 7 of the mount bin tip 4, when the flared portion of the stem 12 is supported by the mount bin 2, the lead @ 15
can be released from the notch 6. Therefore, the stem 12 can be stably supported by the mount pin 2vc.

In particular, there is a screw 10 at the upper end of the vibrator 3 that can reduce the internal space.
By adding this, the amount of air discharged from the slit hole 8 can be arbitrarily adjusted depending on the insertion amount of the screw 10 into the vibrator 3, and the temperature of the sealed portion can be appropriately cooled.

Next, specific examples will be described. Wall thickness is 1.1t @
g. A stem made of ship glass at both ends of Haruzu soda glass with an outer diameter of 29.2φ is sealed so that the weight-bearing length is 96011, and a concave part for gripping with a chuck is molded at the end. Shape. and,
After passing through the heating furnace, the valve was heated to 750~8 in an electric oven.
Heat to 50° (:. At this time, raise the mount pin and at the same time supply air to the vibrator 9 at a rate of Ion per hour. By doing this, the slit hole of the mount bottle is heated to about 2 m! of air is discharged.Then, this air is heated to about 200 to 300"C in the mounting bottle, and the sealed part of the valve is cooled to 400 to 430"C by discharge from the n1 slit hole. Fabricate FOL40 using the usual method.

When this annular fluorescent lamp was turned on and appearance defects caused by the shadow Q of the electrode were measured, the defect rate was 0%, but in the conventional example in which the L part of the seal was not cooled, the defect rate was as high as 5%. Occurred.

Also, the lamp according to the method of the present invention is destroyed to remove the stem.
When the eccentricity of the valve with respect to its axis was investigated, almost no deviation of the axis was observed.

In addition, in the present invention, in addition to soda glass, low lead glass or ship glass can also be used for the bulb. Further, the shape of the mounting bottle and the amount of gas discharged can be changed as appropriate.

As described above, according to the present invention, eccentricity of the stem from the axis of the curved bulb can be effectively prevented by a simple method, and appearance defects caused by electrode shadows can be significantly reduced.

[Brief explanation of drawings]

Fig. 1 is a plan view schematically showing an apparatus for manufacturing an annular fluorescent lamp, Fig. 72 is a side sectional view of an electric oven, Fig. 3 is an enlarged view of main parts of an annular fluorescent lamp, and Figs. The figures are views showing the manufacturing apparatus according to the present invention, in which Fig. 4 is a side sectional view of the main part showing the mounting pin in the electric oven, and Fig. 5 is a plan view of the mounting bin. ■) ↓ Figure 2 Figure 4

Claims (1)

[Claims] The upper end of the linear bulb is fixed to a moving body that rotates intermittently so that the lower end is free, and when the bulb is heated and softened, the lower end of the bulb is supported by a mounting pin and formed into an annular shape by a forming roller. A method for manufacturing an annular fluorescent lamp patented in which the sealed portion of the bulb is cooled with gas discharged from a mount pin prior to bending.