JPH0115977B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to an annular fluorescent lamp tube, and more specifically, to a method for controlling the gas inside the tube after a straight tube is formed into an annular shape. The present invention relates to a tube for an annular fluorescent lamp that facilitates evacuation and thereby speeds up the manufacturing process of the annular fluorescent lamp.

(B) Prior Art Generally, in the manufacturing process of annular fluorescent lamps, there is an annular forming process in which a linear fluorescent lamp tube is heated and softened, and then the tube is wound around a forming drum to form it into an annular shape. In order to prevent the tube from being crushed and deformed when the tube is formed into an annular shape in this annular forming process, an inert gas such as nitrogen gas is filled in the tube prior to forming. After the molding is completed, the gas is exhausted.

By the way, when manufacturing a conventional annular fluorescent lamp, a linear tube a is used as shown in FIG.
An exhaust pipe b is provided only at one end, and a gas supply passage (not shown) is connected to the exhaust pipe to supply nitrogen gas to give a pre-pressure. After the claw e of the tube (which can be divided into two vertically) is applied, the forming drum is rotated in the direction of arrow A and moved in the direction of arrow B to form the tube a into an annular shape. Nitrogen gas inside the tube was evacuated from two exhaust pipes b and sealed.

However, in recent years, there has been a call for speeding up and improving the efficiency of the manufacturing process as described above, and efforts have been made to shorten the processing time in each processing process. Therefore, there was a time constraint, which became the bottleneck for increasing speed and efficiency.

(C) Purpose of the Invention The present invention has been made in view of the above problems in the past, and its purpose is to improve the structure of the tube to facilitate the exhaust of gas inside the tube after it is formed into an annular shape. Therefore, it is possible to speed up the manufacturing process.

(d) Structure of the Invention The tube for an annular fluorescent lamp according to the present invention has exhaust pipes protruding from both ends of the tube body, one of the exhaust pipes is closed, and the outer periphery of the portion on the side of the tube body from the closed portion is closed. A cut line is inserted into the exhaust pipe, and the exhaust pipe can be separated at the cut line.

(e) Embodiments Examples of the present invention will be described below with reference to the drawings.

3 and 4, a tube 1 for an annular fluorescent lamp according to this embodiment is shown. This bulb 1 is constructed by having exhaust pipes 3 and 4 protruding from both ends of a main body 2 having the same structure as the conventional one. The exhaust pipe 3 is bent approximately 90 degrees near the base of the main body and is open, so that nitrogen gas can be filled into the main body 2 through the exhaust pipe.

As shown in FIG. 4, the exhaust pipe 4 is also bent at about 90 degrees near the base of the exhaust pipe 4 with the main body 2. The tip 5 of the exhaust pipe 4 is closed and blind, and a slit or cut line 6 is formed around the entire circumference near the tip. This cut line 6 allows the exhaust pipe 4 to be easily cut at this portion.

When bending the tube 1 into an annular shape, after softening it by heating, as shown in FIG. The gas supply passage (not shown) is connected to the exhaust pipe 3 as in the conventional case. Then, nitrogen gas is filled into the main body from the exhaust pipe 3 to a predetermined pressure, and the forming drum d is rotated in the direction of the arrow X and moved in the direction of the arrow Y to form an annular shape (note that the forming drum d is It is also possible to rotate the main body 2 at a fixed position and move it in the direction opposite to the arrow Y.) During this molding, the nitrogen gas blown through the exhaust pipe 3 is blind at the tip of the exhaust pipe 4 and does not escape to the outside, so that the preload is maintained and the tube will not be crushed or deformed.

Once formed into an annular shape as shown in FIG. 5 in this manner, it is sent to the next step of exhaustion and tip-off, but just before that, the exhaust pipe 4 is cut and opened at the cut line 6. Therefore, main body 2
The nitrogen gas that was filled inside is passed through two exhaust pipes 3,
4 and are simultaneously exhausted. In the embodiment, it was wound around the forming drum d from the exhaust pipe 4 side, but it may be wound from the exhaust pipe 3 side conversely.

(F) Effect As described above, in the tube according to the present invention, exhaust pipes are provided at both ends of the tube body, and the internal gas can be exhausted simultaneously through both exhaust pipes at both ends. The exhaust time can be significantly shortened, contributing to faster fluorescent lamp manufacturing.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a conventional annular fluorescent lamp tube and its annular forming method, Fig. 2 is a side view of a forming drum, and Fig. 3 is an annular fluorescent lamp tube according to the present invention and its annular forming method. FIG. 4 is an enlarged cross-sectional view of a part of one end of the tube shown in FIG. 3, and FIG. 5 is a plan view of the tube after being formed into an annular shape. 1: Tube, 2: Main body, 3, 4: Exhaust pipe, 6: Cut wire.

Claims (1)

[Claims] 1 Exhaust pipes are protruded from both ends of the tube body, one of the exhaust pipes is closed, a cut line is inserted from the closed part to the outer periphery of the tube body side part, and the exhaust pipe is connected at the cut line part. A tube for an annular fluorescent lamp characterized by being separable.