GB2260382A

GB2260382A - Flared pipe end

Info

Publication number: GB2260382A
Application number: GB9220504A
Authority: GB
Inventors: Masayoshi Usui
Original assignee: Usui Kokusai Sangyo Kaisha Ltd
Current assignee: Usui Kokusai Sangyo Kaisha Ltd
Priority date: 1991-10-02
Filing date: 1992-09-29
Publication date: 1993-04-14
Anticipated expiration: 2012-09-29
Also published as: DE4232796C2; JPH0532894U; JP2553658Y2; DE4232796A1; GB9220504D0; GB2260382B

Abstract

Herein disclosed is a flared structure (1) which forms one open end 1' of a metal pipe P to be connected to one end of a mating joint 3. The flared structure has at least one deformed elastic wall portion 2 which is formed circumferentially in the vicinity of the open end 1' of the metal pipe P. As the open end 1' is clamped and fastened at the connecting time, the deformed elastic wall portion 2 establishes an elastic force for ensuring a stable connection for a long time. <IMAGE>

Description

FLARED STRUCTURE FOR CONNECTING METAL PIPES The present invention relates

to a structure for connecting a metal pipe and, more particularly, to an improvement in a f lared structure which is formed at an open end of a metal pipe to be connected to one end of a mating joint. The metal pipe preferably has a relatively small diameter and thickness, e.g. J. a diameter of 20 mm and a thickness of 1.5 mm or less and may be used as an oil or air feed passage in an automobile or a variety of other machines and apparatus.

A flared structure of this kind for the connection according to the prior art is shown in Fig. 8. In this structure, an open end 111 of a pipe P' to be connected is flared at 11 so that it is formed of a smoothly opening conical wall 12. To make the connection, the flared structure is fastened and firmly clamped between the pressure receiving seat of a mating joint 13 and the pressure seat of a nut 14.

In this prior art connection, however, the seat of the flare 11 is arranged to abut all over its face against the pressure receiving seat of the partner by the flatness of the conical wall 12, so that its facial pressure is reluctant to rise and it is possible to cause a leakage. Moreover. an excessive fastening pressure is required to prevent leakage at the mating pressure receiving seat due to a dispersion in the bent shape of the pipe P'. On the other hand, concentration of fatigue and stress are caused at the neck of the flare 11 due to structural limitations such as the small thickness of the pipe

2 P' itself and the state of arrangement under vibrations. Thus, the structure of the prior art is disadvantageous in that it is frequently troubled by a cracking or breakage.

The present invention has been conceived in view of the abovespecified problems intrinsic to the prior art and has an object to provide a flared structure for an open end of a metal pipe, which has a deformed elastic wall portion formed in the open end: to establish an elastic force for the connection so that a facial pressure is raised to eliminate any excessive fastening force; and to dispense the concentration of stress at the neck of the f lare and lighten the f atigue thereby to eliminate either cracking or breakage at the neck for a long time.

In order to achieve the above-specified object, according to the present invention, there is provided a f lared structure formed at one open end of a metal pipe to be connected to one end of a mating joint, which structure comprises at least one deformed elastic or resilient wall portion formed circumferentially in said open end for establishing an elastic force as said open end is clamped and fastened for effecting the connection. The deformed elastic wall portion is exemplified by an annular constriction or bulge formed in the vicinity of the open end by an annular rise extending radially outward from the open end, or by one or more annular corrugations formed circumferentially in the vicinity of the open end.

I'll:.1:1 3 Thanks to this construction, i.e., the structure of the deformed elastic wall portion in the open end according to the present invention, the facial pressure is raised by the elastic force which is established as the pressure receiving face of the joint is fastened by the nut. Even if, therefore, a local pressure is built up at the pressure receiving face, no excessive fastening force is required. At the same time, the concentration of stress can be lightened and effectively dispersed at the neck of the flare. Thus, the fear of cracking and breakage of the neck can be eliminated even if the structure is arranged under vibrations, so that the connection can be maintained stably and reliably for a long time.

Structures in accordance with the invention will now be described, by way of example only, with reference to the further accompanying drawings Figs. 1-5 in which:

Fig. 1 is a partially cut-away top plan view showing a flared structure in an open end of a pipe; Fig. 2 is similar to Fig. 1 but shows another embodiment; Fig. 3 is a partially cut-away longitudinal section showing the connection state of Fig. 1; Fig. 4 is similar to Fig. 1 but shows still another embodiment; and 4 Fig. 5 is similar to Fig. 1 but shows a further embodiment.

2 In Figs. 1 to 5, reference numeral 1 designates a flare formed at one end of a metal pipe P. This pipe P is flared at 1 to its open end 11 and is formed circumferentially with an deformed resilient wall portion 2 in the vicinity of the open end 11. This wall portion 2 is exemplified by an annular constriction 21 (as shown in Fig. 1). Alternatively, the wall portion 2 may be exemplified by an annular rise 211 (as shown in Fig. 2) which extends radially outward f rom the open end 1 1. Moreover, the wall portion 2 may be exemplified by one or a plurality of annular bulges 27a formed in the vicinity of the open end 1 1, as shown in Fig. 4. For the connection, the deformed resilient wall portion 2 is resiliently clamped, as it is fastened, between the pressure receiving f ace of a mating joint 3 and the pressure face of a nut 4 assembled. if desired, the wall portion 2 can be exemplified by an annular corrugation or corrugations 21b formed all over the pipe surface toward an open end 11, as shown in Fig. 5.

According to the flared structure of the present invention, as has been described hereinbefore, the flare 1 of the pipe in the vicinity of the open end 11 is merely pressed to form at least one deformed resilient wall portion 2. As a result, the facial pressure of the seat is raised by the elastic force which is established as the open end is fastened. Even if, therefore, a local pressure is built up at the pressure receiving face, no excessive fastening force is required for the nut 4. At the same time, the concentration of stress can be reduced and effectively dispersed at the neck of the flare 1. Thus, the fear of cracking and breakage of the neck can be eliminated even if the structure is subject to vibration in use, so that the connection can be maintained stably and reliably for a long time. Thus, the present invention can provide a remarkably useful flared structure for connecting the open end of a pipe.

6

Claims

1. A flared structure formed at one open end of a metal pipe to be connected to one end of a mating joint, comprising at least one deformed resilient wall portion formed circumferentially in said open end for establishing a resilient force as said open end is connected to the mating joint.

2. A flared structure according to claim 1, wherein the deformed resilient wall portion includes an annular constriction formed circumferentially in the vicinity of said open end.

3. A flared structure according to claim 1 or 2, wherein the deformed resilient wall portion includes an annular bulge formed circumferentially in the vicinity of the open end.

4. A f lared structure according to claim 1, 2 or 3, wherein the deformed resilient wall portion includes an annular rise extending radially outward from said open end.

5. A flared structure according to any preceding claim, wherein the deformed resilient wall portion includes at least one annular corrugation formed circumferentially in the vicinity of the open end.

6. A pipe comprising a flared structure according to any preceding claim.

7

7. A flared structure or pipe substantially as described herein and as illustrated in the accompanying drawings 1 to 5.

cl