GB2312029A

GB2312029A - Fixing a tube to a sheet body

Info

Publication number: GB2312029A
Application number: GB9607557A
Authority: GB
Inventors: Daniel Smith
Original assignee: Newfrey LLC
Current assignee: Newfrey LLC
Priority date: 1996-04-11
Filing date: 1996-04-11
Publication date: 1997-10-15
Anticipated expiration: 2016-04-11
Also published as: GB2312029B; GB9607557D0

Abstract

The tube is secured to the sheet 8 forming part of a body, e.g. a petrol tank, by a die 13 expanding the tube end behind the sheet 8 by a die groove 14, the tube having an intermediate bulge engaged by a split die 15,16 to aid axial compression. The groove has a plurality of ridges 27 to cause indentation of the tube end and wall to prevent rotation of the tube when a hose is subsequently pushed over the other tube end 6. The tube has an O-ring seal or curable epoxy resin adjacent the intermediate bulge to seal against the sheet 8.

Description

IMPROVED TUBE FIXING The present invention concerns an improved method of securing a tube to a sheet body. In particular the present invention concerns an improved method of securing a tube to a sheet forming part of a storage tank, such as a petrol tank.

In the past, metal tubes have been secured to petrol tanks by brazing. There are a number of problems associated with this method. It is environmentally unfriendly. It requires a highly skilled worker. Even so, it is time consuming and a high percentage of joints (up to 30%) still require rework. Also the braze is being used to fill, and seal, gaps between the tube and the sheet metal, a use to which braze material is not well suited.

A solution to this problem is shown in EP 0 268 735 and EP 0 247 586 in which a tubular fixing is connected to a plate by folding of the walls of the tube on opposite sides of the plate. An apparatus for deforming a tube in this way is known from DE 36 11 898 C1.

This has the advantage that a high degree of skill and the need for reworking associated with a brazed joint are eliminated together with the fumes and heat associated with brazing. Since the product is mechanically attached to the sheet metal component this can be done in considerably less time than the brazed method.

However, this solution is not without its own problems.

For example, when securing a flexible hose to a tubular fixing of the kind described, the tubular fixing is subject to a turning force or torque. This is especially the case where the flexible hose is of relatively inflexible material and is forced over an enlarged end of the tubular fixing.

The enlarged end is required to increase the resistance to pull-off even though the hose may be secured to the fixing by a clip. This however increases resistance to pushing the hose on. This immediate problem may be solved by rotating the hose to and fro over the fixing as the hose enlarges over the fixing.

However the fixing then becomes subject to torque applied in opposing directions. This can cause the fixing to rotate. It is a requirement of many applications that the fixing needs to have an effective seal between itself and to the plate to which it is secured. If the fixing rotates it does not have such a seal and cannot be used for such applications. If a sealing member is introduced, for example an O-ring, between a fold of the tubular fixing and the plate, the rotation of the fixing will distort, and may destroy the effectiveness of the sealing member. Thus, this is not a solution for these applications.

According to a first aspect of the present invention, a method of securing a fixing comprising a tubular body having a first smaller axial portion and a second larger axial portion separated by a radially outwardly extending bulge, to a separate sheet body comprises the steps of a) inserting the fixing in a hole in the sheet; b) inserting a spigot of a support die into the first portion of the body, a deforming groove about the spigot being present in the die, the deforming groove being formed with a plurality of angular ridges; c) locking split dies about the second portion of the body; and d) moving the support die and the split die relatively towards one another, thereby causing the fixing to deform.

According to a second aspect of the invention a fixing comprises a tubular body having a first smaller axial portion and a second larger axial portion separated by a radially outwardly extending bulge.

Preferably the second axial portion is provided with an enlarged portion remote from the bulge.

By placing a seal on the first portion facing the bulge, a deformable seal interface may be created thereby providing a seal that ensures that moisture may not pass between the sheet and the fixing.

According to a third aspect of the invention, apparatus for deforming a fixing comprises a support die having a base, a spigot rising from the base, a deforming groove in the base about the spigot, the deforming groove being formed with a plurality of angular ridges, a support jig about the support die; and a pair of split dies, the support die and the split dies being moveable relative to one another.

Preferably the ridges are equispaced about the deforming groove.

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows in partial cross-section a fixing according to the present invention; Figure 2 shows in partial cross-section the fixing of Figure 1 in a first part of the method of the present invention; Figure 3 shows in partial cross-section the fixing of Figure 1, at a later stage than Figure 2; Figure 4 shows the fixing in partial cross-section following installation; and Figure 5 shows a detail of Figure 4.

Turning to Figure 1, it may be seen that a fixing 1 comprises a tubular body 2, with a radially outward extending bulge 3 between first and second axial portions 4, 5. The bulge 3 has been pressed into the tube a predetermined distance from a first end, which in use will be the end to be set.

The fixing 1 of Figure 1 also comprises an enlarged end 6 on the second portion 5, and a seal 7 on the first portion 4 adjacent the bulge 3.

The seal 7 may be in the form of an 0-ring or a dispensed seal, which itself may be a two part epoxy based resin that may be cured subsequent to the setting operation.

The seal may also be applied in the corner of the first portion 4 and the bulge 3 to form a fillet.

The apparatus used for setting the fixing is shown in Figures 2 and 3.

A support die 11 includes a spigot 12 extending from a base 13 of the die 11. A deforming groove 14 surrounds the spigot 12 at a region where it joins the support die and forms a deforming radius 25. A number of angular ridges 27 are disposed in the groove 14. Preferably, these ridges are equispaced. It will be understood that other arrangements of the ridges are possible.

The support die is moveable within a support jig 10.

The jig 10 includes spring biased pads 26.

Split dies 15,16 are provided that are displaceable with respect to one another, and also with respect to the support die 11.

The method of setting the fixing using the apparatus described above will now be described with reference to Figures 2 to 5. In Figure 2 a sheet 8 having a hole is shown supported on the pads 26 of the jig 10. The sheet may form part of a tank, or may subsequently be deformed so to form part of a tank. The spigot 12 extends through the hole. The fixing 1 passes over the spigot 12 and extends between the hole and the spigot, such that the edge of the first portion 4 remote from the bulge 3, is located at or near the deforming radius 25. The fixing rests on the sheet 8 by way of the seal 7 on the bulge 3.

The split dies 15,16 are clamped about the second portion 5 of the body of the fixing as shown by arrows A to grip the second portion by way of an axial pressure. The split dies are then moved towards the deforming die 11 as shown by arrows B. The grip on the second portion 5 of the fixing body forces the fixing down toward the base of the die (Figure 3). The first portion of the fixing is then deformed outwardly by the deforming radius to form a flange 20. The bulge 3 will also be deformed and become somewhat flattened. While being forced into the deforming groove the first portion of the fixing encounters the ridges 27.

Initially the first portion will move around the ridges to form the flange 20. However, during the final stage of the pressing, when the split dies 15, 16 and the support die 11 approach the point where they are closest, the ridges 27 will press into the side of the fixing, and cause the fixing to form protrusions 28 deforming towards and into the sheet.

The sheet itself is correspondingly indented (Figure 5).

The sheet is thus secured between the seal 6 adjacent the flattened bulge 3 and the flange 20. The indentations 29 in the sheet 8 and the protrusions 28 in the fixing form a key to resist subsequent rotation of the fixing.

A plastics pipe or hose 21 may then be secured to the fixing, as shown in Figure 4, by way of a clip 22 located between the flattened bulge 3 and the enlarged end 5.

The bulge 3 illustrated in Figure 1 may be flattened prior to setting. In such an embodiment the fixing method need only deform the first portion to secure the fixing between the formed flange and the flattened bulge and to secure the fixing to the sheet by way of the keyed protrusions and indentations.

Claims

1 A method of securing a fixing comprising a tubular body having a first smaller axial portion and a second larger axial portion separated by a radially outwardly extending bulge, to a separate sheet body comprising the steps of a) inserting the fixing in a hole in the sheet; b) inserting a spigot of a support die into the first portion of the body, a deforming groove about the spigot being present in the die, the deforming groove being formed with a plurality of angular ridges; c) locking split dies about the second portion of the body; and d) moving the support die and the split die relatively towards one another, thereby causing the fixing to deform.

2 A method of securing a fixing substantially as described herein with reference to and as illustrated in Figures 2 to 5 of the accompanying drawings.

3 A fixing comprising a tubular body having a first smaller axial portion and a second larger axial portion separated by a radially outwardly extending bulge.

4 A fixing according to claim 3, characterised in that a seal is provided on the first portion adjacent the bulge.

5 A fixing according to either claim 3 or claim 4, characterised in that the second portion is provided with an enlarged end.

5 A fixing substantially as described herein with reference to and as illustrated in the accompanying drawings.

6 Apparatus for deforming a fixing comprising a support die having a base, a spigot rising from the base, a deforming groove in the base about the spigot, the deforming groove being formed with a plurality of angular ridges, a support jig about the support die; and a pair of split dies, the support die and the split dies being moveable relative to one another.

7 Apparatus according to claim 6 wherein the ridges are equispaced about the deforming groove.

8 Apparatus for securing a fixing substantially as described herein with reference to and as illustrated in Figures 2 and 3 of the accompanying drawings.