GB2263518A

GB2263518A - Joining of two members

Info

Publication number: GB2263518A
Application number: GB9301167A
Authority: GB
Inventors: Thomas David Shon Littlewood
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-01-21
Filing date: 1993-01-21
Publication date: 1993-07-28
Anticipated expiration: 2013-01-21
Also published as: GB2263518B; GB9301167D0; GB9201211D0

Abstract

Clamp members 2, 3 are secured around the ends of a pair of tubes 16 (only one shown) by inserting a flanged bush 7 in aligned holes 6 in the clamp members 2, 3 and the tube ends, the bush 7 being secured in the holes 6 either by expanding a rivet sleeve 27 in the bush 7 by means of a mandrel 23, or by expanding the plain end of the bush itself. <IMAGE>

Description

"Aparatus for Joinina Two Members" This invention relates to apparatus for joining two members and a method of joining two members Tubular steel structures and/or metal plate structures such as those found on off share drilling platforms, occasionally require repair. Frequently, those areas requiring repair are located underwater and a number of methods have been employed to carry out such repairs including, for example, hyperbaric welding. This method has the disadvantage, however, that it is expensive and time consuming. Another method of repair is friction clamping, but this method has limited application in that it is unable to hold significant tensile loads.Cold forging has also been used as a method of repair where access to both sides of the damaged plate is available. KoweTrer, where access is restricted this method is unsuitable.

It is an object of the present invention, therefore, to provide apparatus for the repair of tubular steel structures or any structure fabricated from metal plates, in an environment, such as underwater, where welding is difficult, tine consuming and/or expensive.

In accordance with a first aspect of the present invention, there is provided apparatus for joining a first member to a second member comprising a tube for extending through the first and second members and a fixing device to secure the tube to the first and second members to prevent withdrawal of the tube from the members In accordance with a second aspect of the present invention, there is provided a method of joining two members, the method comprising providing a through passageway through the members, inserting a tube into the through passageway and providing a fixing device to secure the tube to the members to prevent withdrawal of the tube from the members.

Preferably, at least one of the members is tubular, although they could be in the form of plates.

Typically, the first member is a tubular member on an offshore structure and the member could be situated underwater.

Preferably, the second member may be in the form of a sleeve which extends over the first member. Typically, the second member could also be joined to a third member in order to couple the first and third members together.

Preferably, the tube is a metal bush, which extends through the first and second members. Typically, the metal bush comprises a cylindrical section and a flange section.

Preferably, the metal bush comprises an expandable cylindrical section.

Typically, the fixing device comprises a malleable material which can be deformed such that it secures the tube to at least one of the members. Typically the fixing device could comprise a rivet, such as a poprivet which extends through the central aperture of the tube. Alternatively, the rivet could be an extension of the tube.

An example of apparatus in accordance with the present invention will now be described with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a metal bush and a sleeve; Fig. 2 is a cross-sectional view through AAX of the apparatus shown in Fig. 1, in use on the member; Fig. 3 is a cross-sectional view of the apparatus shown in Fig. 2 in a position ready for securing the sleeve to the member; and Fig. 4 is a cross-sectional view of the apparatus shown in Fig. 3, after securing.

Fig. l shows a perspective view of a sleeve 1, when not in use, in the form of a clamp comprising two generally hemi-spherical clamp members 2 and 3, having rectangular extensions 4 and 5 along the length XX1 of each side of the clamp members 2 and 3 respectively.

Extending through the hemi-spherical members 2 and 3 are apertures 6 into which a tube 7, in the form of a metal bush can be inserted. The metal bush 7 is typically in the form of a cylindrical section 8 and a flange section 9 and has a hollow section 10 along the length of the metal bush 7. The flange 9 includes apertures 11 for the insertion of retaining bolts 12 (as shown in Fig. 2). The apertures 6 in the hemi spherical clamp members 2 and 3 have a recess 13 (see Fig. 2) to aid location of a hydraulic milling tool anc for retention of the flange end of the metal bush 7 (see Fig. 2).

In addition, apertures 14 and 15 are located on the rectangular extensions 4 and 5 respectively. In use, the hemi-spherical clamp members 2 and 3 are placed around a tubular member 16 (see Fig. 2) such that the bottom surface of the rectangular extension 4 engages with the top surface of the rectangular section 5 and the apertures 14 coincide with the apertures 15. The top clamp member 2 is then secured to the bottom clamp member 3 by inserting bolts (not shown) through the apertures 14 and 15.

Fig. 2 shows a cross-sectional view through AAl of apparatus as shown in Fig 1 when in use. The clamp member 2 is secured around a tubular member 16 as described above. A through passageway is milled into the tubular member 16 using aperture 6 in the clamp member 2 as a template. A load bearing metal bush 7 is then inserted into the aperture 6 providing a through passageway 10 extending through the clamp member 2 and the tubular member 16.

The flange section 9 of the metal bush is retained in the recess 13 of the aperture 6. The metal bush 7 is secured in position by inserting retaining bolts 12 into the apertures 11 of the flange 9.

Prior to installation of the clamp member 2 around the tubular member 16, it may be possible for "keyway" type grooves 17 to be milled circumferentially into the tubular member 16, into which "keyway rings" (not shown) machined on the inner faces of the clamp member 2 can locate. The keyways can transmit tensile and/or compressive loads from the tubular member 16 to the clamp member 2.

Fig. 3 shows a cross-sectional view of apparatus as shown in Fig. 2 in a position ready for securing the clamp 2 to the tubular member 16. Once the metal bush 7 has been secured in position between the clamp member 2 and the tubular member 16, a pop-rivet which comprises a mandrel 18 and rivet 19 are inserted into the hollow passageway 10 of the metal bush 7 such that the rivet head 20 rests on the flange 9 of the metal bush 7.

A washer 21 and hydraulic jack 22 are then slid down over the top end 23 of the mandrel 18 such that the washer 21 rests on the rivet head 20 and the bottom surface 24 of the hydraulic jack 22 rests on the top surface of the flange 9.

Typically, the washer 21 is saucer shaped in order to transmit the forces from the base 24 of the hydraulic jack 22 to the rivet head 20. in order that the retaining bolts 12 do not interfere with the base of the hydraulic jack 24, the apertures II may be recessed such that the top surface of the retaining bolts 12 is below the top surface of the flange 9.

Once the hydraulic jack 22 is in the correct position, a reaction nut 25 is threaded down on the top end 23 of the mandrel 18, to rest on the top surface 26 of the hydraulic jack 22. Pressure is exerted on the hydraulic jack 22 and in so doing, the mandrel 18 is forced to move in an upwards direction towards the hydraulic jack 22. The bottom section 27 of the rivet 19, called the rivet body, is made of a malleable material and is capable of being deformed under pressure. Thus, when the hydraulic jack 22 is pressurised as described above, movement of the mandrel 18 towards the hydraulic jack 22 causes plastic deformation of the rivet body 27, such that it becomes located along the bottom surface 28 of the metal bush 7 and the bottom surface 29 of the tubular member 16, as shown in Fig 4.

The plastically deformed rivet body 27 thus joins the clamp member 2 and the tubular member 16 together.

Removal of the mandrel 18 from the hollow passageway 10 is prevented due to the hemi-spherical bottom end 30 of the mandrel 18 engaging with the plastically deformed rivet body 27, as shown in Fig. 4. The reaction nut 25, hydraulic jack 22 and washer 21 are subsequently removed and the top end 23 of the mandrel 18 is cut such that it is flush with the rivet head 20. The join is then complete.

Prior to any repair, it is preferable that the tubular member (or plate member) is cleaned of marine growth sufficiently to facilitate installation of the clamp member and, if necessary, pretensioning clamps.

It is preferable that a tubular member (or plate member) be tensioned or a compressive load applied, similar to the load that it was carrying before failure, in order that when the repair is completed and the tensioning or compressing force is released, the repair will be carrying that load. This force will be the design loading for the particular member. Once the tubular member (or plate member) has been tensioned or compressed to the correct loading, then the clamp member can be installed on to the tubular member (or plate member).

As an alternative to the metal bush described in the present example, it is possible to use a metal bush having an expandable cylindrical section and a flange section. The metal bush may be held in position either by bolts as described above, or by exerting pressure on the flange section of the metal bush, for example, by hammering In both instances, the cylindrical section of the metal bush expands to fit the hollow passageway, thus holding it in position.

Typically, the fixing device used in the present invention is a pop-rivet which extends through the central passageway of the metal bush, as described above. Alternatively, the rivet could be an extension of the metal bush The present invention has the advantage that it can be effectively carried out in an environment where welding is time consuming, expensive and/or hazardous.

Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims

1 Apparatus for joining a first member to a second member comprising a tube for extending through the first and second members and a fixing device to secure the tube to the first and second members to prevent withdrawal of the tube from the members.

2. Apparatus according to Claim 1, wherein at least the first member is a tubular member.

3. Apparatus according to Claims 1 or 2, wherein the second member is in the form of a sleeve which extends over the first member.

4. Apparatus according to any of the preceding Claims, wherein the tube comprises a cylindrical section and a flange section.

5. Apparatus according to Claim 4, wherein the cylindrical section is expandable.

6. Apparatus according to Claims 4 or Claim 5, wherein the tube is a metal bush

7. Apparatus according to any of the preceding Claims, wherein the fixing device comprises a malleable material which can be deformed such that it secures the tube to the first and second members.

8. Apparatus according to Claim 7 wherein the fixing device comprises a rivet.

9. A method of joining two members which comprises providing a through passageway through a first member and a second member, inserting a tube into the through passageway and providing a fixing device to secure the tube to the members to prevent withdrawal of the tube from the members.

10. A method according to Claim 9 and further comprising joining the second member to a third member by providing a second through passageway through the third member and the second member, inserting another tube into the other through passageway and providing another fixing device to secure the other tube to the second and third members to prevent withdrawal of the tube from the members, and the second member thereby coupling the first and third members together.

11. A method according to Claim 10, wherein the first and third members are tubular members.

12. Apparatus for joining a first member to a second member, as hereinbefore described with reference to any of the accompanying drawings.

13. A method for joining a first member to a second member, as hereinbefore described with reference to any of the accompanying drawings.