JPH0121393B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for inserting an adapter into a universal joint, and is used for manufacturing a universal joint.

<Conventional technology> Conventionally, bent pipe joints are used when constructing curved sections of pipes, but in this construction method, a large number of bent pipe joints are prepared depending on the bending angle of the pipe. Since the number of types of bent pipe joints increases, disadvantages in terms of manufacturing and inventory management of bent pipe joints are unavoidable.

Therefore, as an alternative to the bent pipe joint, the ends of plastic pipe joints 1' and 6' are bulged into spherical shell shapes 2' and 3', respectively, as shown in FIG. A freely bendable pipe has been proposed in which the bulge 3' of the other joint pipe 6' is rotatably fitted into the bulge 2' of the joint pipe via a rubber ring 4'.

In this freely bendable tube, the bending angle can be changed over a fairly wide range, and the above-mentioned difficulties can be alleviated considerably.

<Problems to be Solved by the Invention> By the way, in the above-mentioned universal joint, in order to accommodate the other spherical shell-shaped bulging part 3' within the other spherical shell-shaped bulging part 2', it is necessary to While elastically compressing the maximum diameter part of the bulging part 3' to the diameter of one spherical shell-like bulging part 2', the other spherical shell-like bulging part 3' is compressed to the one spherical shell-like bulging part 2'. It is necessary to press fit the However,
This compressive deformation is mainly due to the hoop stress, which causes only a small amount of deformation overall compared to the external force (external pressure), and moreover, the compressive deformation is due to the hoop stress, which causes only a small amount of deformation overall compared to the external force (external pressure). ' acts as a resistance to compression, requiring a large compression force, and the above press-fitting is impossible with the operator's direct grasping force.
Therefore, it is difficult to fit one spherical shell-like bulge 3' into the other spherical shell-like bulge 2'. Further, due to this aspect, restrictions on the thickness, arc diameter, etc. of the spherical shell-like bulge are unavoidable, and restrictions on the design of the bendable tube are unavoidable.

<Means for Solving the Problems> The present invention proposes a method of forming a plastic pipe socket, which makes it possible to extremely easily manufacture a universal pipe joint whose bending angle can be adjusted over a wide range.

That is, the method for inserting an adapter into a universal joint of the present invention includes forming an end portion of a plastic tube into a spherical shell-shaped fitting bulge, and making the fitting bulge have higher rigidity than the fitting bulge. When inserting the plastic ring-shaped pipe insertion adapter having a shape in which both sides of a sphere are cut out, the axis of the plastic pipe insertion adapter is arranged perpendicular to the axis of the plastic pipe, and then the plastic ring is inserted into the plastic ring. The tube is pressed in the axial direction of the tube, and the fitting bulge opening is expanded and deformed in the diametrical direction by the pressing force to force the fitting.

<Example> The present invention will be explained below with reference to the drawings.

FIG. 2 shows an example of a plastic tube socket manufactured according to the present invention.

In FIG. 2, reference numeral 1 denotes a plastic joint tube, and a fitting bulge 2 in the shape of a spherical shell is formed at one end. The rigidity of this fitting bulge 2 is rather small, and the bulge 2 can be formed by a method such as blow molding the end of the plastic tube 1. Of course, the tube part 1 and the bulging part 2
can also be integrally injection molded; in this case,
The wall thickness of the bulging portion 2 is made slightly thinner than that of the tube portion 1.

Reference numeral 3 designates a plastic tube insertion adapter, the outer surface of which is spherical, and the outer circumferential surface has a groove 4 for attaching a rubber ring, and the inner circumferential surface has a groove 5 for attaching a rubber ring on the tube insertion port side. Each is provided.

This tube insertion adapter 3 has a rigidity greater than that of the above-mentioned bulged portion 2, and is usually injection molded. During this injection molding, in order to eliminate thermal stress distortion as much as possible, it is preferable to perform thinning 6 and 7 on the tube insertion surface and the outer circumferential surface, as shown in FIG. In this case, it is desirable to provide ribs at predetermined intervals in the circumferential direction at the portions of the body where there is excess thickness.
In Fig. 3, 8 and 8 indicate ribs provided in the fillet grooves 7 and 7 on the outer circumferential surface, and Fig. 4 shows an example in which a fillet portion 6 is provided only on the inner circumferential surface and a rib 9 is formed. ing.

The above-mentioned spherical shell-shaped bulge 2 and tube insertion adapter 3 are prepared, and the bulge opening of the plastic tube 1 with the tube end formed into the spherical shell-shaped bulge 2 is made as shown in FIG. 1A. 2A, insert the tube insertion adapter 3 into its central axis a.
-a (see FIG. 1C) is arranged in a direction substantially perpendicular to the central axis bb of the spherical shell-like bulge 2,
In this state, insert the tube insertion adapter 3 into the spherical shell-like bulge 2.
As shown in FIG. At this time, since the outer shape of the tube insertion adapter 3 is a shape in which both sides of a spherical body are cut out, the amount of deformation of the spherical shell-shaped bulging portion 2 is reduced accordingly. This means that the central axis a-a of the tube insertion adapter 3 and the spherical shell-shaped bulge 2
When the tube insertion adapter 3 is press-fitted while aligning the center axis b-b of the This can be easily understood by assuming that.

In this way, the amount of deformation of the entrance of the spherical shell-shaped bulge 2 when press-fitting the tube insertion adapter can be kept to a small amount, and the rigidity of the spherical shell-shaped bulge 2 is relatively small. Therefore, the tube insertion adapter 3 can be easily press-fitted into the spherical shell-shaped bulge 2 shown in FIG. 1B.

As shown in FIG. 1B, after the tube insertion adapter 3 is press-fitted into the spherical shell-shaped bulge 2, the tube insertion adapter 3 is rotated, and as shown in FIG. 3 to coincide with the central axis b-b of the spherical shell-like bulge 2, and then insert the insertion part 11 of the tube 10 into the tube insertion adapter 3 as shown in FIG. In this case, the plastic tube socket shown in FIG. 2 is obtained.

<Effects of the Invention> According to the present invention, a spherical shell-like bulge is formed at the end of a plastic tube as described above, and a pre-formed tube insertion adapter is press-fitted into the tube with its center axis perpendicular to the tube end. Moreover, since the tube insertion adapter can be freely rotated within the spherical shell-shaped bulge after fitting, the orientation of the tube insertion adapter when inserted does not matter at all, and therefore, once inserted, This makes it possible to manufacture a plastic tube socket that has sufficient strength against separation due to external force much more easily than in the past.

[Brief explanation of drawings]

1A, 1B and 1C are explanatory diagrams showing the implementation state of the present invention, FIG. 2 is a sectional view showing an example of a plastic pipe socket formed according to the present invention, and FIG. 3 and 4 are sectional views showing various examples of adapters used in the present invention, and FIG. 5 is an explanatory sectional view of a conventional example. In the figure, 1 is a plastic tube, 2 is a spherical shell-shaped bulge, 3 is a tube insertion adapter, 11 is a tube insertion port,
12 and 13 are rubber rings.

Claims (1)

[Claims] 1. The end of the plastic tube is molded into a spherical shell-shaped fitting bulge, and the fitting bulge has a shape that has higher rigidity than the fitting bulge and has both sides of the sphere cut out. When inserting a plastic ring-shaped pipe insertion adapter, the axis of the plastic pipe insertion adapter is arranged perpendicular to the axis of the plastic pipe, and then it is pressed in the direction of the pipe axis of the plastic pipe, and the pressing force is A method for inserting an adapter into a universal joint, comprising: enlarging and deforming the fitting bulge opening in the diametrical direction and forcibly press-fitting the fitting bulge opening.