GB2144508A

GB2144508A - Pipe joints

Info

Publication number: GB2144508A
Application number: GB08414040A
Authority: GB
Inventors: Keith Millward
Original assignee: Paragon Plastics Ltd
Current assignee: Paragon Plastics Ltd
Priority date: 1983-08-05
Filing date: 1984-06-01
Publication date: 1985-03-06
Also published as: GB8414040D0; GB2144508B; GB8321213D0

Abstract

A pipe joint comprises a female (a) socket end (10 Fig. 1) for receiving a male pipe part (14 Fig. 1) and also comprises a resilient sealing ring 18 and a locating collar 20 by means of which the sealing ring is retained in position at the mouth of the socket. So that the assembly force will not be excessive, a fluid sealing portion 24 of the sealing ring 18 has an annular rib 38 located within a bell-mouthed portion 40 of the socket, the sealing portion 24 of the sealing ring 18 and the adjoining rib 38 together forming substantially a V-shaped section so that on assembly the diminution of the angle of the V provides the initial fluid sealing pressure. <IMAGE>

Description

SPECIFICATION Pipe joints The invention relates to pipe joints of the kind used, for example, in rainwater and effluent drainage systems and in sanitary plumbing systems.

In our prior British patent No. 1 597 525 there is described and illustrated a pipe joint of this kind comprising a female pipe part having a socket end for receiving a male pipe part, and also comprising a resilient sealing ring and a locating collar at the mouth of the socket end of the female pipe part for retaining the sealing ring in position at said mouth of said socket end, the locating collar being provided at one end with a portion for embracing and engaging an outer end portion of the socket part and being at its other end of an inturned form, that is to say, being inturned so that the end extends in a reversed axial direction to that of the adjoining part, providing a portion having a radially inner and a radially outer wall defining an annular space receiving a part of a radially outer locating portion of the sealing ring, the latter including a fluid sealing portion connected integrally to said locating portion at one end and having a plurality of stepped lands axially spaced apart along its radially inner surface, the arrangement being such that when the male pipe part is entered into the female pipe part the fluid sealing portion of the resilient sealing ring is gradually deflected radially outwards as the end of the said male pipe part contacts the annular stepped lands in turn and such that as the resilient ring becomes fully deflected an endmost region of said ring, that is to say the endmost annular land becomes radially compressed between the periphery of the male pipe part and the radially inner surface of the socket end of the female pipe part. Such a pipe joint has usually been found to provide a good seal around the male pipe part.However, due to the fact that the seal is obtained by the endmost annular land becoming radially compressed between the periphery of the male pipe part and the radially inner surface of the socket end of the female pipe part, the force required to enter the male pipe part into the female pipe part has sometimes been somewhat excessive and it has been necessary to maintain very close dimensional tolerances in the manufacture of the various component parts so that on the one hand the required assembly force has not been too excessive whilst on the other hand a sufficient compression of the endmost annular land of the resilient sealing ring has been maintained to create an effective seal. The invention has for its object to provide a pipe joint in which these difficulties are at least alleviated.

According to the invention, there is provided a pipe joint comprising a female pipe part having a socket end for receiving a male pipe part, and also comprising a resilient sealing ring and a locating collar at the mouth of the socket end of the female pipe part for retaining the sealing ring in position at said mouth of said socket end, the locating collar being provided at one end with a portion for embracing and engaging an outer end portion of the socket part and being at its other end of an inturned form, that is to say, being inturned so that the end extends in a reversed axial direction to that of the adjoining part, providing a portion having a radially inner and a radially outer wall defining an annular space receiving a part of a radially outer locating portion of the sealing ring, the latter including a fluid sealing portion connected integrally to said locating portion, the sealing ring having an annular rib located within a bell mouthed portion of the socket, the arrangement being such that in cross section, the part of the fluid sealing portion of the ring remote from the radially outer locating portion, and the adjoining rib, together form substantially a V-shaped section on edge, the arrangement being such that when the male pipe part is entered into the female pipe part the fluid sealing portion of the resilient sealing ring is gradually deflected radially outwards and the V-shaped sectional part of said ring becomes deformed between the peripery of the male pipe part and the radially inner surface of the socket end of the female pipe part, whereby at least initially the fluid sealing pressure applied against the male pipe part by the fluid sealing portion of the resilient sealing ring is produced solely by the resilient deformation of said ring, that is to say by the diminution of the angle of the V of the V-shaped section part of said ring. Preferably, the arrangement will be such that the fluid sealing portion of the sealing ring does not contact the annular rib when fully deflected by the male pipe part, and such that the annular rib having been outwardly deformed to form a fluid tight seal within the bell mouthed portion of the socket, internal fluid pressure is able to act radially inwards against the fluid sealing portion of the sealing ring and radially outwards against the annular rib to enhance the fluid tight seal within the bell mouthed portion of the socket.

The annular rib formed on the fluid sealing portion of the resilient sealing ring may be of gradually tapering thickness. The radially outer locating portion of the sealing ring may be provided with a small annular protuberance the purpose of which is to create a ring of intense pressure against the end of the female pipe part. The sealing ring may be externally grooved to accommodate a certain amount of radially outwards movement of the resilient material of which the ring is made in the event of a slightly oversize or slightly deformed male pipe part being entered into the socket or of a lateral force tending to displace the male pipe part out of concentricity with the socket.

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, of which: Figure 1 is a side view, partly in section, of a pipe joint embodying the invention, Figure 2 is a sectional view, drawn to a much larger scale, which will presently be referred to, Figure 3 is a view similar to Figure 2 which will also be referred to presently, Figures 4 and 5 are views similar to Figures 2 and 3 and illustrate a possible modification which will be referred to, and Figure 6 illustrates a further possible modification.

Referring now to Figure 1 of the drawings, the pipe joint there illustrated includes a synthetic plastics socket part 10 with a cylindrical bore 12 receiving an end length of a synthetic plastics pipe 14 shown in chain-dotted lines.

(The socket part is provided with an annular abutment surface 16 which limits the maximum extent by which the male pipe part 14 can be entered into the female socket part although in practice the pipe 14 need not extend that far into the socket part to produce an effective joint). The pipe joint also includes a resilient sealing ring, generally indicated 18, for providing a fluid tight seal between the pipe 14 and the socket, and a locating collar 20 by means of which the sealing ring is retained in position at the mouth of the socket part 10.

Referring now in particular to Figure 2, it will be seen that the resilient scaling ring 18 has two main portions, namely a radially outer locating portion 22 of generally rectangular cross section and a radially inner fluid sealing portion 24 connected integrally to said locating portion. The outside diameter of the sealing ring is substantially the same as that of a circumferential ridge 26 which is formed around the socket part adjacent its mouth, but intermediate the axial length of the outside diameter of the ring there is provided an annular groove 25. A tapering annular rim portion 28 of the radially outer portion of the sealing ring abuts against an end surface of the circumferential ridge which is of complementary shape as shown.

The locating collar 20 has a radially inwardly turned circumferential lip 30 which when the pipe joint is assembled lies behind the ridge 26 of the socket part, as shown, the cross sectional shape of said lip being sidch that the locating collar has a tapering mouth portion which facilitates the snap fitment of the collar over the ridge 26 of the socket part.

At its end remote from the circumferential lip 30, the locating collar is of inturned form, as shown, providing a double walled portion de- fining an annular space 32 receiving a part of the radially outer portion of the sealing ring and providing an abutment surface 34 bearing against a stepped portion 36 of the sealing ring between the radially outer locating portion 22 and the fluid sealing portion 24.

The arrangement is such that when the locating collar has been engaged with the end portion of the socket part to locate the resilient sealing ring at the mouth of the socket part the locating portion 22 of the ring is contained loosely within the annular space in the locating collar but such that the portion of the ring between the locating portion and the fluid sealing portion is compressed between an end surface of the socket part and the abutment surface 34 of the locating collar, as shown in Figure 3.

The sealing ring is provided, on that side which contacts the mouth of the socket part, with an annular rib 38, this lying within a bell mouthed portion 40 of the socket. As shown, the annular rib is of generally tapering thickness. With the sealing ring in its unstressed condition and placed in contact with the mouth of the socket there is some very slight clearance surrounding the annular rib, and the angle of the radially outer tapered surface of the rib does not exactly match the angle ot taper of the bell mouthed portion 40 of the socket, as shown in Figure 2. The radially inner fluid sealing portion 24 of the ring, in the free unstressed condition of the ring as shown in Figure 2, is thin in relation to its radial extent. It can be seen in Figure 2 that its radial dimension is more than twice its thickness.

The arrangement is such that, as shown in Figure 3, when the male pipe part 14 is entered into the female pipe part the fluid sealing portion 24 of the resilient sealing ring is gradually deflected radially outwards so that the part of the ring radially inwards of the end surface of the socket part becomes deformed between the periphery of the male pipe part and the bell mouthed portion 40 of the socket. Thus it will be seen that the fluid sealing pressure applied against the male pipe part by the fluid sealing portion of the resilient sealing ring is produced, at least initially, solely by the resilient deformation of said ring, that is to say by the diminution of the angle of the V between the annular rib 38 and the fluid sealing portion 24 of said ring. In addition to the diminution of the angle of the V and the deflection of the inner limb of the V, the outer limb of the V, that is to say the annular rib 38, is caused to contact the bell mouthed portion of the socket. Consequently, fluid sealing contact between the sealing ring and the socket and between the sealing ring and the male pipe part is produced with an absolute minimum of compression of any part of the sealing ring. The fluid sealing portion 24 does not contact the bell mouthed portion of the socket when fully deflected. The result of this is that the force required to enter the male pipe part into the female pipe part is never excessive and also that it is not necessary to maintain very close dimensional tolerances in the manufacture of the various component parts of the joint.Furthermore, because the fluid sealing pressure applied against the male pipe part is produced without any compression of any part of the sealing ring between the male pipe part and the socket, any risk of the locating collar being inadvertently forced out of position by excessive compression of the ring is virtually eliminated. This is in fact made even less likely by the presence of the annular groove 25 surrounding the sealing ring, this being sufficient to accommodate a certain amount of radially outwards movement of the resilient material of which the sealing ring is made in the unlikely event of a slightly oversize or slightly deformed male pipe part being entered into the socket or of a lateral force tending to displace the male pipe part out of concentricity with the socket.

A further advantage is that with the annular rib 38 having been outwardly deformed to contact the bell mouthed portion of the socket part and forming a fluid seal thereat, it is possible for internal fluid pressure to act radially inwards against the fluid sealing portion 24 of the resilient sealing ring and outwardly against the annular rib 38 to enhance the sealing pressure. However, as shown in Figure 3, the fluid sealing portion 24 does not con: tact the annular rib 38 so that there is no danger of these parts sticking together in certain conditions of use.

Various modifications may be made. For example, although the part of the resilient sealing ring which contacts the periphery of the male pipe part is shown in the drawings to have a plain surface it will be understood that it could quite well be ribbed.

The cross section of the sealing ring may be varied in numerous ways whilst still including a fluid sealing portion and an adjoining rib which together form substantially a V-shaped section on edge. For example, in Figure 4 there is illustrated a cross sectional shape in which the fluid sealing portion has an annular recess 42 adjacent the adjoining rib 38. In Figure 5 it can be seen that the provision of the annular recess ensures that the two limbs of the V do not contact each other when the joint is in use.

The radially outer locating portion of the sealing ring shown in Figure 4 is provided with a small annular protuberance 44, this being a modification which could be included in the sealing ring of the first described embodiment. The purpose of the protuberance 44 is of course to create a ring of intense pressure against the end of the female pipe part when the joint has been made.

In Figure 6 there is illustrated a further possible modification of the sealing ring, this being the forming of the radially outer locating portion without the annular groove 25. (It will of course be understood that this is a modification which might be made whatever the precise form of the fluid sealing portion).

In this case the resilient material of which the ring is made may be sufficiently soft to allow, by spreading, some radially outwards movement of the material in the event of a slightly oversize or slightly deformed male pipe part being entered into the socket or of a lateral force tending to displace the male pipe part out of concentricity with the socket.

Claims

1. A pipe joint comprising a female pipe part having a socket end for receiving a male pipe part, and also ccmprising a resilient sealing ring and a locating collar at the mouth of the socket end of the female pipe part for retaining the sealing ring in position at said mouth of said socket end, the locating collar being provided at one end with a portion for embracing and engaging an outer end portion of the socket part and being at its other end of an inturned form, that is to say, being inturned so that the end extends in a reversed axial direction to that of the adjoining part, providing a portion having a radially inner and a radially outer wall defining an annular space receiving a part of a radially outer locating portion of the sealing ring, the latter including a fluid sealing portion connected integrally to said locating portion, the sealing ring having an annular rib located within a bell mouthed portion of the socket, the arrangement being such that, in cross section, the part of the fluid sealing portion of the ring remote from the radially outer locating portion, and the adjoining rib, together form substantially a Vshaped section on edge, the arrangement being such that when the male pipe part is entered into the female pipe part the fluid sealing portion of the resilient sealing ring is gradually deflected radially outwards and the V-shaped sectional part of said ring becomes deformed between the periphery of the male pipe part and the radially inner surface of the socket end of the female pipe part, whereby at least initially the fluid sealing pressure applied against the male pipe part by the fluid sealing portion of the resilient sealing ring is produced solely by the resilient deformation of said ring, that is to say by the diminution of the angle of the V of the V-shaped section part of said ring.

2. A pipe joint according to claim 1, in which the arrangement is such that the fluid sealing portion of the sealing ring does not contact the annular rib when fully deflected by the male pipe part, and such that-the annular rib having been outwardly deformed to form a fluid tight seal within the bell mouthed portion of the socket, internal fluid pressure is able to act radially inwards against the fluid sealing portion of the sealing ring and radially outwards against the annular rib to enhance the fluid tight seal within the bell mouthed portion of the socket.

3. A pipe joint according to any one of the preceding claims, in which the annular rib formed on the fluid sealing portion of the resilient sealing ring is of gradually tapering thickness.

4. A pipe joint according to any one of the preceding claims, in which the radially outer locating portion of the sealing ring is provided with a small annular protuberance the purpose of which is to create a ring of intense pressure against the end of the female pipe part.

5. A pipe joint according to any one of the preceding claims,in which the sealing ring is externally grooved to accommodate a certain amount of radially outwards movement of the resilient material of which the ring is made in the event of a slightly oversize or slightly deformed male pipe part being entered into the socket or of a lateral force tending to displace the male pipe part out of concentricity with the socket.

6. A pipe joint constructed and arranged substantially as hereinbefore described with reference to and as illustrated by Figures 1 to 3 of the accompanying drawings or with reference to those drawings when modified as shown in Figures 4 and 5 and/or Figure 6.