JPS60140631A - Manufacture of circular fluorescent lamp - Google Patents

Abstract

PURPOSE:To sharply shorten time of a bending process by performing bending processing of a straight tubular bulb along the periphery of a bending drum from the center to both end parts of the bulb. CONSTITUTION:When both end parts of a straight tubular bulb 5 are held by the chucks 8 and 8 while being softened by heating in a preprocess and carried in a bending position where a bending drum 6 and bending rollers 7 and 7 are located, the peripheral uppermost part of the bending drum 6 comes closely in contact with the lower periphery of the central part of the straight tubular bulb 5 in a horizontal state, while almost simultaneously the bending rollers 7 and 7 come in contact with two spots at equal distances from the center of the straight tubular bulb 5. The bending rollers 7 and 7 rotatingly come down along the circular orbit with a radius centering around the central line of the bending drum 6 for performing bending processing of the straight tubular bulb 5 by turns.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application This invention is utilized in the process of bending a straight tube bulb into an annular shape in the manufacture of annular fluorescent lamps.

Prior Art Generally, an annular fluorescent lamp is manufactured by a process of applying a fluorescent film to the inner surface of a straight tube bulb, a process of welding a stem having electrodes to both ends of the straight tube bulb, and a process of welding a stem having electrodes to both ends of the straight tube bulb. A process of heating and softening the shaped bulb and bending it into an annular shape, a process of evacuating the inside of the bent annular bulb and activating the electrodes, filling the annular bulb with mercury and a desired inert gas, and then inserting it into an exhaust pipe. It is manufactured through a process such as chip-off. The bending process for the above-mentioned straight pipe valve is performed by holding the straight pipe valve (1) at its upper end with a chuck (2) and suspending it vertically, as shown in Figs. It is usually rolled up from the lower end using rollers (3). That is, the curved roller (3) is a two-part roller consisting of a pair of rollers (3a) (3b), each roller (3a) (3b).
A part of the outer periphery of the straight pipe valve (1) is provided with protruding claws (4) (4) for appropriately gripping the recessed portion of the lower end of the valve (1).
) (3b) is held at the lower end of the suspended straight pipe valve (1) with the claws (4) (4), and then
By rotating and raising the valve, the heated and softened straight pipe valve (1) is bent into an annular shape. After the bending roller (3) has been completely bent, the rollers (3a) and (3b) are separated to the left and right and lowered.

C1 Problems to be Solved by the Invention By the way, in the conventional valve bending method described above, the bending roller is rotated over the entire length of the valve from one end of the straight pipe valve to the other end, so the bending process is performed only once. The time required for the process is long and difficult to shorten, making it difficult to improve the mass productivity of annular fluorescent lamp manufacturing. In addition, straight pipe valves are suspended and bent from the lower end to the upper end, but if this process takes a long time, the upper end of the straight pipe valve, which has been heated and softened, will extend too much under its own weight, resulting in a wall thickness. If the thickness becomes thinner than a predetermined thickness, it may be damaged later, which is a factor that reduces yield.

29 Means for Solving Problems The present invention has been made in view of the above-mentioned conventional problems, and as a means for solving the problems, a two-part curved drum is placed in the center of a straight pipe valve, and the curved drum is Provided is a method for manufacturing an annular fluorescent lamp, which includes a bending step of bending a straight tube bulb from the center to both ends along the outer periphery of the tube.

The straight pipe valve to be bent in this invention may be in either a horizontal or vertical position, and the direction in which both ends of the straight pipe valve are bent may be either horizontal or vertical. It can be executed well. In this way, when bending a straight pipe valve at both ends at the same time with the central part as the starting point, the processing time for one process is equivalent to the time required to bend half of the entire length of the valve. This will reduce the time to about half of that.

E. EXAMPLE A specific example of an apparatus for carrying out the method of the present invention will be explained with reference to FIGS. 4 to 9. Figures 4 to 6 show the basic structure and operation; (5) is a horizontally supported straight pipe valve; (6) is a horizontally supported straight pipe valve;
) is a two-part curved drum with a horizontal center axis, (7) (7)
are two curved rollers whose center axes are horizontal. The straight pipe type valve (5) is held at both ends by chucks (8) (8), and has a bending drum (6) and bending rollers (, 7) ('7) that have been heated and softened in the previous process. When carried into the bending position, the top of the outer periphery of the bending drum (6) comes into contact with the lower outer periphery of the central part of the straight pipe valve (5) in the horizontal state, and the straight pipe valve (5) moves back and forth. ) The curved rollers (7) (7) abut on two positions equidistant from the center. In this state, the curved rollers (7) (7) lower the straight valve (5) along the outer periphery of the fixed curved drum (6) from the center of the valve to both ends of the valve. Then, the straight pipe valve (5) is bent into an annular valve (5') as shown in FIG.

At this time, the bending roller (7) (7) rotates on its own axis in a circular orbit with a radius centered on the center line of the bending drum (6), and descends to sequentially bend the straight valve (5). Process. still,
The movement of the bending rollers (7) (7) is such that, for example, the distance between them is set to about the diameter of the bending drum (6), and the rollers are first lowered vertically to the height of the center line of the bending drum (6), and then the bending rollers (7) are moved. It may be moved inward in a circular orbit centered on the center line of the growing drum (6).

In the above bending process, the chucks (8) (8) at both ends of the valve (5) are in a free state for the valve bending process, and when the bending process is completed, the annular valve (5°) is moved from the bending drum. (6) and the bending roller (7-) When (7) is removed, the annular valve (5") is sent to the next process such as the next exhaust process. Alternatively, the chuck (8) (8) can be moved directly before the bending process. After it is removed from the tubular valve (5) and the bending process is completed, the annular valve (5') is gripped with another chuck.

Next, examples of the ring shapes of the curved drum (6) and curved rollers (7) (7) will be explained from FIGS. 7 to 9. (9a) is a pair of two-piece curved drums (6) Drum (6a) (
6b) is a large diameter gear coaxially fixed to one of the drums (6a), and (10a) is a small diameter gear coaxially fixed or rotatably connected to one of the bending rollers (7); gear (9a). (lla) is a connecting rod whose both ends are rotatably pivoted to the center shafts of both gears (9a) and (loa), and the connecting rod (lla) and both gears (9a)
When the connecting rod (11a) is rotated around the central axis of the large diameter gear (9a) by applying an external force due to the meshing of the gears (10a), the small diameter gear (10a) rotates on the large diameter gear (9a) and forms a curve. The roller (7) accurately rotates in a circular orbit about the center line of the drum (6a). Similarly, the other drums (6b) and curved rollers (7) have large diameter gears (9b) and small diameter gears (1
0b) and the connecting rod (11b).

Both drums (6a) (6b) and curved rollers (7) (7)
are initially separated, and both drums (6a) (6b)
When the center part of the horizontal straight pipe valve (5) is carried in between the drums (6a) and (6b), they come together and come into contact with the center part of the straight pipe valve (5), and both curved rollers (7) (7)
is located near the top of the straight pipe diameter valve (5). Then, when both connecting rods (11a) (11(11b)) are rotated in opposite directions, the curved rollers (7) (7) align the straight valve (5) along the outer periphery of the curved drum (6). It is bent into a ring shape. When the bending is completed, the connecting rod (lla) (
llb) to raise the bending rollers (7) (7) to their original positions, then separate the drums (6a) (6b) and remove them together with the bending rollers (7) (7) from the annular valve (5"). .In addition, the curved roller (7) has two parts like the curved drum (6).
It can also be configured in a split type.

Next, other specific embodiments of the present invention are shown in FIGS. 10 to 13.
The explanation will be given sequentially starting from the figure.

Figure 10 shows the central part of a horizontal straight pipe valve (5) in contact with the bottom of two curved rollers (7) (7). An example is shown in which the combined bending drum (6) is applied from below to the bending process operation.

Figure 11 shows the curved drum (6) and the curved roller (7) (
An example will be shown in which the straight pipe valve (5) is bent upward from the center toward both ends using the same relative motion with the arrangement of (7) upside down.

Figures 12 and 13 show an example in which a curved roller is not used. In Figure 12, a straight pipe valve (5) is held horizontally with chucks (12) (12) gripped at both ends. Place the center part on the curved drum (6) in the fixed position (see (A> in Fig. 12)), then set the chuck (12) (12) free with respect to the straight pipe valve (5). Lower the straight pipe valve (5) along the curved drum (6) and turn it into an inverted U.
12 (see (B) in Figure 12), and then move the chucks (12) (12) inwardly to bend both end portions of the valve along the lower outer periphery of the bending drum (6). Shape into a ring shape (see (C) in Figure 12).

Fig. 13 shows an example of the modified operation shown in Fig. 12, in which the curved tram (6) is placed under the center of the straight pipe valve (5) held horizontally by the chuck (12) (12). Refer to Figure 13 (A>). Next, raise the bending drum (6) and narrow the chuck (12) (step 2) at the same height to bend the straight valve (5) into an inverted U shape. (See FIG. 13(B)), and then move the chucks (12) inwardly to form the valve (5) into an annular shape (see FIG. 13(C)).

In each of the above embodiments, the straight pipe valve is held horizontally and both ends thereof are bent in the vertical direction, but the present invention is not limited to this example. By bending both ends of a straight pipe valve horizontally,
It is also possible to bend both ends of a straight pipe valve, which is vertically suspended by vertically arranging a bending drum, in the vertical direction.

As described in detail, according to the present invention, the central part of the straight pipe valve becomes the bending starting point and both ends are bent simultaneously, so that the bending process required for one bending process is The time required is about half that of the conventional method, and therefore, the time required for the bending process can be significantly shortened, and the mass productivity of ring-shaped fluorescent lamp manufacturing can be easily improved. In addition, by shortening the bending time, the elongation rate of the bulb during bending is reduced (thus, variations in the wall thickness of the bulb are reduced, and troubles such as valve breakage in post-processes are reduced, which improves yield.

[Brief explanation of the drawing]

Figure 1 is a side view of the bulb bending process in the conventional annular fluorescent lamp manufacturing method, Figure 2 is a sectional view taken along line X-X in Figure 1, and Figure 3 is after the operation of Figure 1. 4 is a schematic front view showing an example of an apparatus for implementing the method of the present invention,
Figure 5 is a sectional view taken along line l-Y in Figure 4, and Figure 6 is a cross-sectional view of Figure 4.
7 to 9 are a front view, a right side view, and a plan view for explaining a specific example of the relationship between the bending drum and the bending roller shown in FIG. 4, and FIG. 10 is a front view after the operation shown in FIG. FIGS. 13 to 13 are front views for explaining the four sides of other specific implementation devices of the present invention, and FIGS. 12 and 13 (A), (B), and (C)
indicates each operation process. (5) - straight pipe valve, (6) - curved drum. 1B10 Figure 11 Prisoner Figure 12 (B)

Claims (1)

[Claims] (1) When bending the heated and softened straight tube valve into an annular shape along the outer periphery of the two-part bending drum, the straight tube bulb is bent sequentially from the center to both ends along the bending drum. A method of manufacturing an annular fluorescent lamp characterized by comprising the following steps.