JPS6116550B2 - - Google Patents

Description

[Detailed description of the invention] This invention forms a metal tube by attaching a metal tape vertically to a running filament, and then performs a diameter reduction process to continuously form a metal tube containing the filament. The present invention relates to a method of forming a seam welded portion of a metal pipe when the metal pipe is welded.

In order to coat a metal tube around a filament such as a group of extremely thin insulated wires, and to hold this filament relatively freely within the metal tube so that it can be replaced if necessary, it is necessary to cover the metal tube. It is difficult to manufacture by extrusion coating methods. The inventors found that the method of rolling metal tape vertically into a circular tube shape, welding the vertical seams (butt ends), and then reducing the diameter to the required diameter has good production efficiency and relatively high quality. We discovered that we can produce good products.

By the way, when we further considered each process, we found that when forming the seam part, if the inner filament has a thermally weak plastic coating such as polyethylene, it is difficult to connect the filament and the metal tube. There is also a relationship with the air gap and linear speed, but due to the heat of welding the seam,
It was found that the internal striatum is affected by temperatures as high as 100-150°C. For this reason, it is conceivable to make the structure of the filament itself a heat shielding structure, but it is preferable that the outer diameter of the filament body is as small as possible, and providing a special coating layer is expensive and cannot be adopted. be.

As a result of various studies, the inventors of the present invention found that by inserting a heat shield between the metal tape seam part to be welded with a torch and the internal linear body, and then performing torch welding, the metal tape continuously incorporates the linear body. They discovered that it is possible to manufacture a product using this method, and the product can be manufactured with good quality and without high costs.

Next, it will be explained with reference to the drawings.

FIG. 1 is a schematic process diagram of a tandem pipe drawing process in which a circular tubular metal coating is provided around a filament using a metal tape. In the figure, a linear body 1 is fed out from a reel 2, and at the same time a metal tape 3 made of aluminum, copper, etc. is fed out from a reel 4 and advanced through a slitter 5. Then, the two are combined, and a metal tube is loosely formed around the linear body 1 through a forming unit 6 including an edge treatment roll, a plate die, and a forming die, and then the seam portion is successively and continuously formed with a welding torch 7. It passes through the first caterpillar traction device 10, enters the first diameter reducing device (die plug) 8 and the triclean cleaning device 9, passes through the second caterpillar traction device 10', and enters the second diameter reducing device ( die) 8', the reel 1 via the triclean cleaning device 9' and the third caterpillar traction device 10''.
1.

In this process, the inventors originally installed a circular tube forming means in which a die 13 was held in a die holder 12 immediately before torch welding, that is, at the final stage of the forming unit, as shown in FIG. A formed metal tape that has been gradually formed into a tubular shape is passed through this, and the tape is finally formed into a circular tube.The mating ends of the tape are welded with a torch 7 to form a seam 15 to complete the process. It was a circular tube. Note 1
4 is a Bakelite plate for thermally protecting the molding die 13, and 1 is a linear body.

However, if the inside of the metal tube is empty, there is no problem.
It must be said that this is a serious problem when a wire body 1 such as an electric wire, etc., whose performance is significantly impaired when affected by heat, is built in polyethylene or other plastic materials. do not have.

As shown in FIG. 3, the present invention focuses on the final stage of the metal tube forming unit, that is, the forming die 13, and the inner surface of the metal tube, which is the torch welding area that follows this, and the seam between the internal linear body 16 and the metal tube. A circular arc-shaped heat-resistant shield 16 made of chrome-plated steel or tetrafluoroethylene resin is inserted between the parts 15, and the inner filament 1 is molded and welded without any thermal influence. can be performed continuously. Further, the heat-resistant shield 16 may be fixed to the end of the forming unit or the like.

In FIG. 3, the same parts as in FIG. 2 are designated by the same reference numerals.

As understood from the above, in the present invention, a heat-resistant heat shield is inserted between the linear body and the seam part of a metal tape formed into a circular tube shape, and the heat shield is inserted into the seam part of the metal tape formed in the shape of a circular tube. The product can be completely protected and manufactured without causing product defects, and the means for that purpose is also very simple and has the advantage of not increasing costs.

[Brief explanation of the drawing]

Fig. 1 is a process diagram for manufacturing a metal tube from a metal tape, Fig. 2 is a partially vertical cross-sectional perspective view showing the final stage of a forming unit according to the prior art and the state of the torch welding stage, and Fig. 3 is a diagram according to the present invention. FIG. 6 is a partially longitudinal cross-sectional perspective view showing the final stage of the forming unit and the state of the torch welding stage. 1...Striatal body, 3...Metal tape, 7...Torch, 13...Die, 16...Heat shield.

Claims (1)

[Claims] 1. When applying metal tape vertically to a running filament to form it into a circular tube shape and welding the seam,
Formation of a seam welded part of a metal tube containing a built-in linear body, characterized by inserting a heat-resistant heat shield between the seam part of the linear body and a metal tape formed into a circular tube shape and performing torch welding. Method.