JPS59126195A - Method of joining tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for joining plastic tubes used to form medical instruments such as catheters.

Conventionally, in most cases of joining this type of duplex pipe, the pipes are butt-joined simply by using an adhesive, or by heating both joint end faces to melt and soften them.

However, in such conventional joining means, due to the pushing action caused by the butt of both tubes during joining,
The adhesive or melted and softened portion protrudes outward and inward, easily deforming the vicinity of the joint, and as a result, annular protrusions are formed on the outer and outer peripheral surfaces of the joint of both duplexes, impairing the appearance.-4 The drawback is that the inner diameter of the tube becomes smaller due to the annular protrusion that is formed inside the tube, making it impossible to make a smooth connection.

The present invention is aimed at overcoming the drawbacks of the conventional art described in "-" and will be explained below based on the illustrated embodiments.

Figures 1 and 2 show how tubes are joined together according to the present invention. In the figures, 1 indicates the inner and outer diameters of tubes 2 and 3 made of nickel, stainless steel, soft iron, etc., which will be described later. It is a core metal forest with equal diameter. The core bar 141 has joint ends 2a, 3ah? of both Chicove tubes 2, 3 to be joined. It is inserted and temporarily joined by abutting both end surfaces against each other. In the figure, reference numeral 4 denotes the shape-retaining frame that surrounds and holds the outer peripheral side of the joined portion of the two tubes 2 and 3 that are temporarily joined together, and is made of heat-resistant material such as Teflon or ceramics. The inner diameter is formed to be approximately equal to the outer diameter of the tube 2.3 depending on the material, and the joint ends 2a and 3a of both the tubes 2.3 can be held between the inner and outer surfaces by the core metal material 1. Further, reference numeral 5 in the figure denotes an electromagnetic coil wound around the outside of the shape-retaining frame 4, and the connecting end 2a of both the L-tubes 2 and 3.

3a, and by applying a high frequency current, the core metal material 1 is heated by induction, and the joint ends 2a, 3a of both L-tubes 2, 3 are heated and melted from the inside. Sa l
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That is, to explain the joining means according to the present invention, first, the ends 2a and 3a of each of the two tubes 2 and 3 to be joined are inserted a little into the core metal material and temporarily joined by butt. . Next, after surrounding and holding the temporarily joined portion of both tubes 2 and 3 with a shape-retaining frame 4, an electromagnetic coil 5 is arranged around it and a high frequency current is applied to induction heat the core metal material 1. At the same time, both the duplex tubes 2 and 3 are pushed in from both sides in the direction of abutting each other, and the joint ends 2a and 3a are melted and joined while being pressed together. After cooling, the core metal material 1 and the shape retaining frame 4 are removed to complete the joining.

The core material used in the above-mentioned embodiments of the present invention is a solid rod-shaped body or a hollow pipe. Particularly, in the case of a pipe-shaped core metal material, it is necessary to allow air or water to pass through during cooling. This will speed up cooling. Further, as the shape-retaining frame, a pipe-shaped frame or a split-shaped frame may be used, and the selection thereof is arbitrary.

As explained above, in joining duplex tubes, the tubes are sandwiched between the inner and outer surfaces of the core metal shape-retaining frame, abutted against each other, temporarily joined, and the core metal material is heated by induction heating. By heating, the joint ends of the di-pipe are butt-joined without melting, so the clamping action of the core metal A and the shape-retaining frame makes it possible to form the inside and outside of the joint of the di-pipe as in the conventional case. There are no annular protrusions that occur on the circumferential surface, and it is possible to make wide joints with equal diameters, and it can also be applied to joining tubes that cannot be joined with adhesives such as polyolefins. It has excellent practical effects.

[Brief explanation of the drawing]

Figure 1 shows the state of connection of the tube according to the present invention.
The explanatory drawing and FIG. 2 are also enlarged sectional views of the main parts. 1... Core metal material, 2, 3... Tube pipe, 2a
, 3a... end, 4... shape-retaining frame, 5... electromagnetic coil.

Claims (1)

[Claims] The respective ends of the two tubes to be joined to each other are inserted into the core metal material to butt and temporarily join, and the outer peripheral side of the temporarily joined portion of the two tubes is surrounded and held by a shape-retaining frame, and then the Winding an electromagnetic coil around the outer periphery of the form frame corresponding to the temporary joint portion of both Chicove tubes and applying a high frequency current to the coil,
At the same time, the core metal material is heated by induction, the ends of both tubes are pushed in the direction of abutting each other, and while avoiding pressure welding, they are melted and joined from the inside, and after cooling, the core metal material and the shape retaining frame are A method of joining tubes characterized by removing the tubes.