GB2186935A

GB2186935A - Joint

Info

Publication number: GB2186935A
Application number: GB08628240A
Authority: GB
Inventors: John Michael Haynes
Original assignee: Clay Cross Co Ltd
Current assignee: Clay Cross Co Ltd
Priority date: 1985-11-26
Filing date: 1986-11-26
Publication date: 1987-08-26
Anticipated expiration: 2006-11-26
Also published as: GB8628240D0; GB2186935B; GB8529093D0

Abstract

The joint consists of two pipes 30, 31 which are interconnected by a sleeve 32, each end of which is formed internally with frusto-conical recesses 44, 45 occupied by adhesive material bonding the joint parts together. The recesses 44, 45 are shaped such that separating movement of the joint parts stresses the adhesive compressively. In other embodiments, the joint is between a pipe and a flange member and between a sleeve and pipe. In the latter, movement of the pipe relative to the sleeve in either direction tends to stress the adhesive compressively. In another embodiment both joint parts have frusto-conical recesses. The joint is particularly suitable for attachment of the flange to a ductile iron pipe. <IMAGE>

Description

SPECIFICATION Joint description This invention relates to joints comprising a male part received in a female part.

The invention provides a joint comprising a male part received in a female part and an adhesive material bonding the parts together, the adhesive material occupying one or more cavities between the parts and the or each cavity being shaped such that force on the parts tending to produce relative separating movement thereof in at least one direction imposes a compressive stress on the adhesive material.

The male and female parts may each be in the form of a continuous annulus in the region of the joint. However, this need not be the case and one or both of the parts may be interrupted over at least one portion of its respective outer or inner periphery.

Advantageously, the joint has a plurality of cavities in side-by-side relationship along the direction of separation of the joint, each cavity being annular or part-annular and preferably extending over substantially the entire peripheral distance over which the peripheries of the male and female parts are both uninterrupted.

Conveniently, the cavity or cavities are formed by wall portions of one or both of the joint parts inclined to the separation direction and, for use in the formation of a joint according to the invention, the invention also provides a male or female joint of any said kind having at least one inclined wall portion which, upon the formation of the joint, forms a said cavity.

Thus, if one joint part only has the said inclined wall portion(s), the cavity or cavities formed between the two parts will taper in the direction opposite to that in which the part moves relative to the other part during joint separation. If both parts have the said inclined wall portion(s), the recesses formed by the inclined wall portions of the respective parts will deepen in opposite directions if it is desired to resist separation in one direction only. If separation in either direction is to be resisted, one or both parts may have wall portions inclined in both directions.

In one embodiment of the invention, the female part has a plurality of side-by-side annular cavities each having a frusto-conical annular wall which produces the desired taper of the cavity which is formed between the female part and a male part upon assembly of the joint. In another embodiment, one or both parts have recesses of alternating inclination, in order to resist separation in either direction.

The lengths and depths of the recesses need not be uniform on a particular joint part, nor, in cases where both parts have recesses, need the lengths and depths of the recesses on one part be the same as those on the other part. Indeed, the dimensions of the recesses may advantageously be selected according to dimensions of the two parts, for example their respective wall thicknesses when one is a pipe and the other a socket.

Two joint parts may be constituted by, for example, a pipe and a sleeve portion of a flange member to be attached to the pipe. In the other cases, an element such as a coupling sleeve or union may provide the female part of two joints each being in accordance with the invention.

Examples of such joints are a joint formed by a sleeve coupling two pipes or pegs together and any other joint formed by a union and one or more pipes, tubes or pegs.

The joint of the invention is particularly suitable for the attachment of a flange member to a ductile iron pipe. This operation has previously been carried out by welding or by the formation of a screw-threaded joint between the pipe and the flange member. The first operation gives rise to well-known metallurgical difficulties and the second is expensive and time-consuming and also wasteful of material. By use of a joint according to the present invention, these disadvantages can be mitigated or completely overcome.

The adhesive material used in a joint according to the invention may be any which is suitable having rgard to the nature of the materials of the joint parts and the conditions of intended service of the joint.

An epoxy resin is one material which will often be suitable.

Embodiments of the invention will now be described by way of example with reference to the drawings of this specification, in which: Figure 1 is a longitudinal sectional view of a part of a joint formed between a pipe and a flange member, and Figures 2 to 4 are views similar two Figure 1 of other joints embodying the invention.

The drawing shows an end portion of a pipe 10 which is received in a sleeve portion 12 of a flange member 14 which also has an annularflange portion which extends outwardly to form a flange 16 and inwardly to form a shoulder 18. The width of the shoulder 18 is similar to the wall thickness of the pipe 10.

The outer surface of the wall of the pipe 10 is cylindrical and joins an end face 20 of the pipe by way of an annular bevelled surface 22. The sleeve portion 12 of the flange member is formed internally with a set offourfrusto-conical recesses 24 which each taper inwardly towards the open end of the sleeve portion 12. At its open end, the interior of the sleeve portion flares outwardly to form an annular bevelled surface 26 which can co-operate with the bevelled surface 22 of the pipe 10 to facilitate insertion of the pipe into the sleeve portion and assist spreading the adhesive.

The peg and socket joint between the pipe 10 and the flange member 14 is formed by applying a suitable adhesive 28 such as an epoxy resin to the interior of the flange member 14 and/or the pipe surface 29 then inserting the pipe 10 into the socket formed by the sleeve portion 12 of the flange member. The resin 28 occupies the space between the pipe and flange member 12, including the recesses 24, shown in the drawing and is then allowed to set.

It will be seen from the drawing that relative movement of the pipe 10 and flange member 12 in the direction of withdrawal of the pipe subjects the set resin 28 to a compressive stress, as is in accordance with the present invention.

It has been found that ductile iron pipes with flanges attached by joints in accordance with the present invention can give performance test results at least as good as pipes to which flanges are attached by welding or screw threads.

The joint shown in Figure 2 of the drawings comprises first and second pipes 30,31 which are inserted into a sleeve 32 which is divided into two halves by an internal annular ridge 38, with the end faces of which the pipes 30,31 are in abutment. The sleeve 32 is formed internally with two sets of frusto-conical recesses 44, 45 occupying respective halves of the sleeve 32. The recesses 44 or 45 of each set become shallower in the direction towards the respective open end of the sleeve. Each set consists of three recesses.

The joint of Figure 2 is formed in a manner exactly analogous to that described above for the joint of Figure 1 and itwill be seen the withdrawal movement of each pipe 30,31 from the sleeve tends to place the set resin 48 in compression.

In one modification of the Figure 2 arrangement, the pipes are replaced by solid pegs. In another, the ridge 38 is omitted and the sleeve is replaced by a bore in any other component into which the pipes or pegs are to be secured.

In the joint of Figure 3, a female component 52 receives a male component 50 which extends through the aperture of the female component. The latter has six frusto conical recesses 54, 55 which are of alternating inclination. The joint is formed exactly as described above. After making of the joint, the resin occupying the recesses 54 is put into compression by application of a load on the male component 50 tending to move it to the right in Figure 3 (arrow A) and that occupying the recesses 55 is so-stressed by an oppositely-directed load (arrow B) on the male component.

Figure 4 of the drawings shows a modification of the embodiment of Figure 1. Corresponding parts of Figure 4 have been given the reference numerals of Figure 1 with prime marks added. The modification consists in the formation of a plurality of frusto conical recesses 64 in the outer surface of the end portion of the pipe 10'. These recesses 64 increase in depth in the direction of withdrawal of the pipe 10' from the flange member 14' and cause the adhesive 28' to be stressed compressively during such movement.

In a modification of this embodiment, the axial lengths of the recesses 24' of the sleeve portion 12' are different from those 64 of the pipe 10'. This arrangement may be particularly effective in joining components of different wall thicknesses.

In none of the embodiments described need the length of the recesses of the recessed components be uniform. Likewise, the recesses of any component may have non-uniform depths.

Claims

1. A joint comprising a male part received in a female part and an adhesive material bonding the parts together, the adhesive material occupying one or more cavities between the parts and the or each cavity being shaped such that force on the parts tending to produce relative separating movement thereof in at least one direction imposes a compressive stress on the adhesive material.

2. A joint according to claim 1, in which the cavity or cavities are formed by one or more wall portions of one or both of the joint parts, the wall portions being inclined to the separation direction.

3. A joint according to claim 2, in which the one part only has a said inclined wall portion.

4. A joint according to claim 3, in which the one part is the female part.

5. A joint according to any of claims 2 to 4, in which at least one joint part has a plurality of the said inclined portions arranged longitudinally of a direction of joint separation, alternate portions being inclined in opposite directions to the separation direction.

6. A joint according to any preceding claim, in which the male and female parts are each in the form of a continuous annulus in the region of the joint.

7. A joint according to claim 6, in which the cavity or cavities are annular.

8. A joint according to any preceding claim, in which the female joint part comprises a flange member having a sleeve portion receiving the male part.

9. A joint according to any of claims 1 to 7, in which the female joint part comprises a sleeve portion in opposite ends of which respective male parts are received, the joint cavities being shaped such that adhesive material of the joint is stressed upon application of force to the parts tending to produce separating movement of either male part from the female part.

10. A joint substantially as hereinbefore described with reference to any figure of the drawings.

11. Any novel feature or combination of features disclosed herein.