JPH0328771B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Industrial Application Field The present invention is used for manufacturing an annular fluorescent lamp,
In particular, the present invention relates to a method for heating a straight pipe valve in a pre-process of bending the straight pipe valve into an annular shape.

B. Prior art The general manufacturing of annular fluorescent lamps involves an inner surface treatment process such as applying a fluorescent film to the inner surface of a straight tube bulb and firing it.The straight tube bulb is held vertically and electrodes are placed at the openings at both ends. A sealing process of sequentially welding the stems with a straight pipe, a heating process of supplying an inert gas inside to heat and soften the straight pipe valve, and a bending drum to shape the straight pipe valve into an annular shape. This is done through a bending process, which involves evacuating the inside of the bent annular valve to activate the electrodes, and then filling in an inert gas such as argon or mercury, and then chipping off the exhaust pipe. As shown in FIGS. 1 and 2, the above-mentioned heating process and bending process are performed by gripping the upper end of the straight pipe valve 1 with a chuck 3 attached to a horizontally traveling carrier 2. is suspended vertically by its own weight, and in this state is passed through a heating furnace 4 to be heated and softened, and when it comes out of the heating furnace 4, the lower end of the straight pipe type valve 1 is attached to a two-part curved drum 5.
The bending drum 5 is held by a claw 6 protruding from a part of the outer periphery of the valve, and the bending drum 5 is rotated upward along the straight valve 1 to bend the straight valve 1 into an annular shape. After the bending process is completed, the bending drum 5 separates, moves away from the annular valve 1', descends, and returns to the bending position for the next straight pipe valve 1.

C. Problems to be Solved by the Invention Prior to such bending processing, the straight pipe valve 1 is stretched by a certain length in a heating process to ensure a substantially normal ring diameter. However, it is difficult to secure this elongation allowance at a constant rate due to changes in heating conditions within the heating furnace 4 (uneven temperature distribution), and variations occur, causing uneven bending. was. In addition, since the straight pipe type valve 1 is suspended vertically and heated and bent, the upper part of the valve inevitably stretches too much and the wall thickness becomes thinner, which may lead to damage to the valve later, resulting in quality problems. There were also problems with yield.

D. Means for Solving the Problems The present invention provides a means for solving the above problems, in which a straight pipe valve is placed on a rotating roller in a heating furnace and softened by heating while being rotated. First and second carriers are disposed to run parallel to each end of the straight pipe valve on the travel path, and a pair of chucks that can be opened and closed are attached to each of the carriers at a predetermined interval. It is characterized in that both ends of the valve are gripped, and the traveling path of the carrier is expanded outward to stretch the straight pipe type valve to a desired length. By doing this, it is possible to absorb the difference in the elongation rate between the beginning and end of the valve winding during bending, and to set the wall thickness appropriately in advance, making it possible to obtain a substantially uniform valve wall thickness over the entire valve, which results in a good Curving processing can be performed.

E. Example The method of the present invention will be explained using a specific example of the apparatus shown in FIGS. 3 to 7. 7 is a straight pipe valve 1 held horizontally and rotated in a horizontal direction in the direction of the arrow shown in the figure. On a roller conveyor, one straight tube valve 1 is held with its central portion placed between a pair of parallel rotating rollers 8, 8. The rotating rollers 8, 8 are conveyed in one direction and rotated in the same direction to rotate the straight pipe valve 1 while being conveyed in one direction. Reference numeral 9 denotes a heating furnace that surrounds a part of the horizontal conveyance section of the roller conveyor 7, and heats and softens the straight pipe valve 1 held and conveyed by the roller conveyor 7. 10 is a curved drum placed on the exit side of the heating furnace 9, which grips one end of the straight pipe valve 1 coming out of the heating furnace 9 and rotates horizontally to the other end to straighten it. A tubular valve 1 is bent into an annular shape. 11
is a conveying body such as a chain conveyor that has a running path parallel to the section from the middle of the heating furnace 9 to the exit side of the roller conveyor 7, and runs parallel to one end of the straight pipe valve 1 on the roller conveyor 7. First carrier 11
a, and a second conveyor 11b that runs parallel to the other end. 12a, 12a..., and 12b,
12b... are a plurality of chuck holders connected to the first and second conveyors 11a and 11b at predetermined intervals, 1
3a, 13a... and 13b, 13b... are two checks attached to each of the chuck retainers 12a, 12... and 12b, 12b so that they can be opened and closed, and 14a, 14a... and 14b, 14b... are each chuck. Cage 12a, 12a... and 12b, 1
2b...a cam follower rotatably protruding above;
15a and 15b are guide rails that regulate the running direction of the first and second transport bodies 11a and 11b;
Cam followers 14a, 14a..., 14b, 14b
It is a set of two plate cam-shaped rails that sandwich and guide...

When the first and second carriers 11a and 11b approach from above both ends of the straight tube valve 1 that has started to be heated and softened in the heating furnace 8, the chucks 13a, 13
b is closed, and is fitted with a slight gap into gripping recesses 16, 16 previously formed on the outer periphery of both ends of the straight pipe valve 1, thereby rotatably gripping the straight pipe valve 1. From the time of this gripping, the first and second transport bodies 11
a and 11b move parallel to the roller conveyor 7 in the same direction and at the same speed, and when they exit the heating furnace 8, chucks 13a and 13b are opened, and the chucks 13a and 13b are moved away from the straight pipe valve 1 and ascend to return to the original rear position. Do exercise.

The features of the above embodiment are that the first and second transport bodies 11a,
The distance between the running paths running parallel to the roller conveyor 7 of 11b is gradually expanded in the running direction, and as the straight pipe valve 1 is heated and softened, it is actively heated as desired via the chucks 13a and 13b at both ends. It is to stretch it to length. Specifically, the distance between the guide rails 15a and 15b that regulate the traveling direction of the first and second conveyors 11a and 11b in the section where they run alongside the roller conveyor 7 is set as shown in FIG. 4 and FIG. chucks 13a, 13
The distance between the running lines La and Lb of b gradually increases from D and is arranged so that it finally becomes (D+Δd). However, D is the distance between the recesses 16, 16 at both ends of the straight tube bulb 1 at the beginning of heating, and Δd is the extension of the straight tube bulb 1. Also, to widen the distance between the running lines La and Lb, both running lines La and Lb may be expanded outward, but as shown in the drawing, the running line La at one end of the straight pipe valve 1 remains straight. Extend the straight pipe type valve 1 by extending only the running line Lb on the other end side to the outside.
For later bending, it is desirable to stretch more aggressively at the other end than at the other end.

In this way, while the straight pipe valve 1 rotates in the heating furnace 8 and is heated and softened, the chucks 13a and 13b at both ends are caught in the recesses 16 and 16, and gradually stretched in the axial direction to a desired amount. It is accurately stretched by (Δd). Therefore, straight pipe type valve 1
bending is always executed correctly. In addition, since the straight pipe valve 1 is held horizontally by rotating rollers 8, 8, heated, and sent to the bending position, the straight pipe valve 1
The stability during transportation is increased compared to conventional manufacturing, which is suspended vertically, and higher speed operation is possible.

In the bending position of the above embodiment, the bending drum 10 grips the other end of the straight valve 1 and moves to the bending operation, but in order to achieve higher speed, for example, the chuck retainers 12a and 12b are Check 1
3a and 13b are removably installed, chuck 13
While holding the straight pipe valve 1 with the chucks 13b and 13b, the straight pipe valve 1 is sent to the bending position, and the other end of the straight pipe valve 1 is held with the bending drum 10 via the chuck 13b to perform bending. After completion of the process, the chuck 13b may be removed from the bending drum 10 and returned to the chuck holder 12b of the second conveyor 11b.

Further, the present invention is not limited to the above-mentioned embodiment.
As shown in the figure, both ends of the horizontal straight tube type valve 1 are gripped by rotating chucks 17a and 17b, and the straight tube type valve 1 is rotated and fed in orthogonal directions, during which it is heated and softened. Therefore, check 17
It is also possible to stretch the straight pipe valve 1 by the required amount (Δd) using a and 17b and send it to the bending position. In this case as well, the traveling lines of chucks 17a and 17b
The distance between La′ and Lb′ may be regulated using a guide rail similar to the above.

F. Effects of the Invention As explained above, according to the present invention, the elongation of the straight pipe valve can always be stably obtained, so that normal bending can always be performed, and yield and quality can be improved.

[Brief explanation of drawings]

FIG. 1 is a partial front view of a manufacturing apparatus for explaining a conventional method of manufacturing an annular fluorescent lamp, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIGS. 3 to 7 are This shows a specific example of an apparatus for carrying out the method of the present invention, in which FIG. 3 is a schematic front view of the whole, and FIGS.
The figures are a plan view and a front view of the main parts, FIG. 6 is a sectional view taken along the line B-B in FIG. 5, FIG. 7 is a schematic plan view for explaining the operation in FIG. 4, and FIG. 8 is a FIG. 3 is a schematic plan view showing another example of a specific implementation device of the present invention. 1...Straight pipe valve, 1'...Annular valve, 1
3a, 13b, 17a, 17b...Chick, △
d... Growth allowance.

Claims (1)

[Claims] 1 A straight pipe valve is placed on a rotating roller in a heating furnace and heated and softened while being rotated.
disposing first and second conveying bodies that run parallel to each end of the straight pipe valve on a traveling path along the rotating roller;
A pair of openable and closable chucks are attached to each of the conveying bodies at predetermined intervals so as to grip both ends of the straight pipe valve, and the travel path of the conveying body is expanded outward to open and close the straight pipe valve. 1. A method for producing an annular fluorescent lamp, which comprises stretching the material to a desired length.