GB2070708A - Compression joints - Google Patents

Abstract

A compression joint includes male and female members (10 and 24), a resilient O-ring (28), and a radially deformable clip (30) one of the male and female members having a bore portion (16) which forms a groove for the reception of the O- ring. So that on assembly of the joint an effective mechanical joint can be obtained, the clip (30) is received in a tapered bore portion (18) of one said male and female members and is radially inwardly deformed as it is caused to move along said tapered bore portion. <IMAGE>

Description

SPECIFICATION Compression joints The invention relates to compression joints of the kind for producing a leak-proof seal on a tube or tubular connecting piece, for example a tubular connecting piece on a water tap or valve.

It has been found that mechanical joints which have attempted to perform the additional function of providing a leak-proof seal require a relatively high torque to ensure a seal, and this can be difficult to apply if the joint is inaccessibly situated, for example in a duct, in a corner, or between rafters. Moreover, a joint of this kind may be difficult to seal against leakage if the tube or tubular connecting piece concerned is a relatively weak walled tube, that is to say when it is a relatively thin walled metal tube, or a synthetic plastics tube, due to the high crushing pressure which it is generally necessary to apply. Consequently, it has been foun desireable to provide a compression joint of the kind in which the mechanical connection function is quite separate from the leak-proof seal function. Various compression joints of this kind are known.In one particular prior proposal, the leak-proof seal function is provided by a resilient O-ring and the mechanical function is provided by a steel toggle ring having inwardly projecting fingers which can be deflected by a tube or tubular connecting piece being entered into the joint, the arrangement being such that although the tube or tubular connecting piece concerned can be entered into the joint quite quickly and a strong mechanical connection is produced, the toggle ring cannot be removed from the tube or tubular connecting piece if it is subsequently desired to dismantle the joint, that is to say of course unless the toggle ring is destroyed or unless it is possible to slide the toggle ring along the full length of the tube or tubular connecting piece concerned. This is a serious disadvantage of this prior proposal.

The object of the invention is to provide a compression joint of simple construction which separates the mechanical connection and leak-proof seal functions, which can be assembled quickly and easily, and which can in addition be very quickly and easily dismantied for the components to be re-used.

According to one aspect of the invention, there is provided a combination of parts for making a compression joint, including male and female members, a resilient O-ring and a radially deformable locking clip, one of the members having a bore portion which forms a groove for the reception of the O-ring and one of said members having a further bore portion which is tapered and receives the locking clip through which a tube or tubular connecting piece is to extend and to engage the O-ring, the arrangement being such that when the joint has been assembled and a tube or tubular connecting piece has been entered into it, the male member can be caused to act against the locking clip to urge it axially so that, being in engagement with the tapered bore portion, said locking clip is radially inwardly deformed to grip the external surface of the tube or tubular connecting piece concerned.The male member will preferably have screwthreaded connection with the female member so that it can be caused to act against the locking clip. The locking clip will preferably have the form of a split ring and will preferably be relatively thin, that is to say having an axial thickness less than its radial thickness. An end portion of the male member may be externally knurled or serrated so that it can be tightened or slackened by hand or may alternatively have opposed flats or a square or hexagonal form so that it can be turned by means of a spanner or wrench.

According to another aspect of the invention, there is provided an assembled compression joint made by a combination of parts as described above.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, in which:~ Figure 1 is a longitudinal section through a compression joint embodying the invention, Figure 2 is a sectional view on the line 2-2 in Fig. 1, Figure 3 is an exploded view, Figure 4 is a view similar to Fig. 1 through a somewhat different compression joint embodying the invention, and Figure 5 is an exploded view of said joint.

Referring now to Figs. 1 to 3 of the drawings, the compression joint there illustrated includes a body part 10 with stepped bore portions 12 and 14, the bore portion 14 having a plain length 16, a tapered length 18 and a screw-threaded length 20 and constituting a female portion within which a male portion 22 of a so-called compression screw 24 is received. A length of said male portion of the compression screw is screwthreaded for engaging the screwthreaded length 20 of the female portion. An end portion of the compression screw is serrated at 26 so that it can be tightened or slackened by hand.

The compression joint also includes a resilient O-ring 28 and a radially deformable metal locking clip 30, the latter having the form of a split ring and being relatively thin, that is to say having an axial thickness less than its radial thickness. As shown in Fig. 2, the locking clip has a cylindrical external surface but has three equally spaced projections 31 at its internal surface. The O-ring is accommodatel in a groove formed by the plain length 16 of the bore portion 14. The deformable locking clip on the other hand is located in the tapered length 18 of the bore portion 14 and is acted upon by the end of the male member.The arrangement is such that when the joint has been assembled and a tube or tubular connecting piece (such as that shown in chain-dotted lines in Fig. 4)has been entered into it, the compression screw can be turned to cause the male portion to act against the locking clip to urge it axially.

Consequently, since the locking clip is in engagement with the tapered bore portion, it is radially inwardly deformed to grip the external surface of the tube or tubular connecting piece concerned. If the compression screw is turned in the opposite sense, the male portion is caused to back away from the locking clip so that the latter is able to expand radially outwards to release the tube or tubular connecting piece concerned.

Thus there is provided a compression joint of very simple construction which has been found to be very effective in use. A tube or tubular connecting piece can be entered into the loosely assembled joint without difficulty and the joint can be adequately tightened by hand which is a particularly useful feature where a joint is to be made in a somewhat inaccessible position, for example in corners or between rafters. The locking clip provides a very effective mechanical connection but it has been found that with normal usage the wall of the tube or tubular connecting piece has not been damaged even when it has been relatively weak walled. The locking clip is not subject to corrosion by contact with fluid passing through the joint. Consequently, the joint is suitable for use in a wide range of applications and can be expected to have a long useful life.

Various modifications may be made. For example, in Figs. 4 and 5 there is illustrated a compression joint which includes a body part 32 with stepped bore portions 34 and 36, but of which the bore portion 36 in this case is plain for the reception of the O-ring 28. In this case the external surface of the body part is screwthreaded for the reception of a compression nut 38, the latter being provided with a tapered portion 40 for the reception of the deformable metal locking clip 30. The arrangement is such that when the joint has been assembled and a tube or tubular connecting piece (such as that shown in chaindotted lines in Fig. 4) has been entered into it, the compression nut can be turned to cause the extreme end of the body part to act against the locking clip, the latter thereby being urged axially into engagement with the tapered portion of the nut.In this way, the locking clip is caused to grip the external surface of the tube or tubular connecting piece concerned. The deformable metal locking clip is in this case shown to have a plain cylindrical bore but it will be understood that if preferred it would be provided with three equally spaced projections 31 as in the first described embodiment.

Various other modifications could be made.

For example, in either case the male member could be differently connected to the female member so that it can be caused to act against the locking clip, that is to say connected otherwise than by a screwthread. It could be connected by what is usually referred to as a bayonet fixing. On the other hand the compression screw or compression nut as the case may be could be provided with opposite flats or with an end portion of square or hexagonal form so that it could be turned by means of a spanner or wrench.

Furthermore, the internal surface of the locking clip could be serrated instead of being provided with the three projections 31 or instead of being plain as the case may be. It will also be understood that in a compression joint intended exclusively for fitment on a plastics pipe or plastics connecting piece the locking clip could be made of plastics (ideally of a somewhat harder plastics material) and in this case may not necessarily require to#be made in the form of a split ring because plastics materials can be deformed more readily than metal. On the other hand, the angle of the tapered length of the bore porton 14 or of the compression nut as the case may be may require to be somewhat steeper than that shown in the drawings and of course it will be understood that an appropriate angle can be arrived at by trial and experiment.

The body part 10 of Fig. 1 may be a tubular spigot portion formed on some kind of fitting, for example on a water tap or valve.

On the other hand however it may be one end of a double ended joint for connecting two separate lengths of tube together end to end.

In the compression joints illustrated the body part in each case is shown to be provided with a somewhat smaller bore portion 13 so that when a tube or tubular connecting piece has been entered into the body part, the bore of the tube or tubular connecting piece, as the case may be, is continuous with the reduced diameter portion 13 as shown. However, this is not essential and the ends of two separate lengths of tube connected together by the joint could abut together within the body part.

Claims (7)

1. A combination of parts for making a compression joint, including male and female members, a resilient O-ring and a radially deformable locking clip, one of the members having a bore portion which forms a groove for the reception of the O-ring and one of said members having a further bore portion which is tapered and receives the locking clip through which a tube or tubular connecting piece is to extend and to engage the O-ring, the arrangement being such that when the joint has been assembled and a tube or tubular connecting piece has been entered into it, the male member can be caused to act against the locking clip to urge it axially so that, being in engagement with the tapered bore portion, said locking clip is radially inwardly deformed to grip the external surface of the tube or tubular connecting piece concerned.

2. A combination of parts according to claim 1 for making a compression joint, in which the male member has screwthreaded connection with the female member so that it can be caused to act against the locking clip.

3. A combination of parts according to either one of the preceding claims for making a compression joint, in which the locking clip has the form of a split ring and is relatively thin, that is to say having an axial thickness less than its radial thickness.

4. A combination of parts according to any one of the preceding claims for making a compression joint, in which an end portion of the male member is externally knurled or serrated so that it can be tightened or slackened by hand or has opposed flats or a square or hexagonal form so that it can be turned by means of a spanner or wrench.

5. An assembled compression joint made by a combination of parts according to any one of the preceding claims.

6. A combination of parts for making a compression joint substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.

7. An assembled compression joint substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.