JPS6240093B2 - - Google Patents

Abstract

1. A process for forming a collar (11, 11') on the wal of a metal tube (1, 1'), preferably of small thickness, said process being characterized in that the tube (1, 1') being empty of any filling a circular groove (6, 6', 17) delimited by two adjacent sides (7, 8) is formed in per se known manner at the periphery of the tube (1, 1') and on the face opposite to that where the collar is to be produced, by an operation of displacing the metal such as knurling, and that a an axial compression is then applied to the ends of the tube (1, 1') until the two adjacent sides (7, 8) formed in the course of the first phase are brought into contact.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal tube, and more particularly to a method for forming a flange on the inner or outer wall of a thin-walled metal tube that can function as a stop member.

Conventionally, when forming a stopper member on a pipe, a method has been used in which, for example, a metal is notched to form a recess, but this method is only possible when the pipe is thick.

In the case of thin-walled tubes, in order to avoid deterioration in product quality, instead of relying on the method of cutting out a part of the material, for example, roller processing is performed using a roller.

This type of method involves processing the material to form a circular throat on one side and an annular bulge serving as a stop on the other side. The sides of the stop thus formed will be inclined with respect to the vertical section of the tube, which is extremely disadvantageous if a straight stop is required.

The present invention has been developed in view of the above-mentioned drawbacks and seeks to provide a flange consisting of a straight stop member for a pipe by simply deforming the metal.

It is an object of the present invention to provide a method for forming a flange, preferably on the inner wall side of a thin-walled tube, in which, as a first step, a circular throat formed by two adjacent side surfaces is formed on the outer wall surface of the tube. The tube is then deformed so as to form the first
It is characterized by axially compressing the tube until the two adjacent sides formed in the step come into contact with each other.

This method makes it possible to provide a flange with a surface substantially perpendicular to the wall of the tube. The method thus makes it possible to form a straight stop member which can constitute a non-deformable stop device.

A further advantage of the invention is that in the case of an internal stop, the usual conspicuous external throat can be replaced by a simple circular line. Next, embodiments of the present invention will be described with reference to the accompanying drawings.

As mentioned above, in the first step of the method of the invention, an annular throat is formed in the tube 1.

For this reason, by a well-known method, the tube is
Apply the mold pressing roller (MOLETTE) shown by arrow 4 to the tube while maintaining it with the roller shown by , and on the other hand,
Apply rotational motion as indicated by arrow 5. In this way, the metal is machined by the combined action of radial forces and rotational movements to form a circular throat constituted by the side surfaces 7, 8.

Next, in a second step, an axial compressive force as indicated by arrows 9 and 10 is applied to the tube. This compressive force must be large enough to bring the two sides 7, 8 of the throat 6 into contact with each other. In this way, the flange 11 formed by the side faces 7, 8 lies substantially in the vertical section of the tube, thereby forming a straight and undeformable stop member.

FIG. 4 shows yet another preferred embodiment of the invention. In this method, in the first stage of transformation,
The bottom part 15 of the circular throat part 17 is pressed to the position of the wall line 19 (to the position indicated by the line -) to form the flange 21 there.

Thus, a section of material that connects section 23 of the tube to section 25 in a straight line is omitted, thereby:
The resistance portion that directly opposes the axial compressive force applied to the tube in the second stage can be omitted, making the formation of the flange easier.

It goes without saying that the invention can be adapted in various cases without departing from the scope of the invention, such as for example when forming a circular throat by means other than molding rollers (MOLETTE).

Since the method according to the present invention does not rely on notches in the material, it is possible to significantly reduce the wall thickness of the pipe to which the method of the present invention can be applied, which can save up to 50% of the material of the pipe. That will be understood.

[Brief explanation of the drawing]

FIG. 1 is an axial sectional view of a tube at the end of the first stage of the method of the invention applied to the formation of an internal stop. 2 is an axial sectional view of the tube of FIG. 1 at the end of the second stage of the method of the invention; FIG. 3 is a perspective view of the tube of FIG. 2; The figure is a partial axial cross-sectional view of another embodiment. 1'...metal tube, 11'...flange, 17...
Circular throat.

Claims (1)

[Claims] 1. In the first step, a circular throat 6 consisting of two adjacent side surfaces 7 and 8 is formed on the outer circumferential wall of the tube 1 by a grooving operation such as a stamping roller. , the metal tube 1 is formed without any filler, and in the second step, the throat 6 formed in the first step is removed.
A method of forming a flange 11 on the inner wall side of a metal tube 1, characterized in that the end of the tube 1 is compressed in the axial direction until two adjacent side surfaces 7, 8 come into contact with each other. 2. The deformation of the tube in the first step is carried out so that the bottom 15 of the throat 17 reaches at least the wall line 19 and forms a flange there. The method described in Section 1.