WO1996017200A1

WO1996017200A1 - Insertion indicator

Info

Publication number: WO1996017200A1
Application number: PCT/GB1995/002749
Authority: WO
Inventors: Alan Brook
Original assignee: Hepworth Building Products Limited
Priority date: 1994-11-25
Filing date: 1995-11-24
Publication date: 1996-06-06
Also published as: AU3931395A; GB9423852D0; GB2295429A

Abstract

A pipe joint comprises a spigot (40) and socket (20). The spigot (40) is provided with a formation (46) in an end region thereof and upon a radially outer surface or an end face thereof. The socket (20) is provided with a formation (27) located within the socket mouth (22), and arranged in such a position as to address and interfere mechanically with the formation (46) located upon the spigot end (40), when the spigot is fully inserted within the socket for indicating that the spigot is fully inserted within the socket.

Description

INSERTION INDICATOR

The present invention relates to an insertion indicator which can be used in conjunction with or form part of a pipe socket arrangement, to enable one to judge when the spigot is fully inserted within the socket. More particularly, but not exclusively, the invention relates to an insertion indicator for use in conjunction with a push-fit pipe coupling.

When a spigot end is inserted into a socket, it is not always possible to tell whether or not the spigot has been fully inserted, because the spigot end is not visible. Many attempts have been made to overcome this problem and these normally involve index marking a radially outer surface of the spigot, in such a way that its position relative to the socket can enable one to judge that the spigot is fully at home within the socket. One disadvantage of this approach is that it requires relatively good light to enable one to see the mark. It is quite common for piping to be fitted in conditions of poor light. The present invention, therefore, sets out to provide an insertion indicator which does not rely upon a visible index.

According to a first aspect of the invention there is provided a pipe spigot comprising a formation on an outer surface or an end surface thereof, the said formation being adapted to interfere mechanically with a formation located within the mouth of a socket during relative motion between the spigot and socket, so as to indicate full insertion of the spigot inside the socket, by enabling detection of the mechanical interference outside the socket.

Preferably, the mechanical interference can be felt or heard by a person inserting the spigot into the socket. The interference may occur upon relative rotary movement between spigot and socket or upon relative axial movement. Thus, embodiments of the invention enable one to judge that the spigot is fully inserted, because the respective formations on the spigot and socket mutually interfere mechanically at full insertion. This interference can be felt as a restriction or modification to relative movement in which slippage of the interface may or may not be felt, depending upon the precise configuration of the components. Because this interference can only be felt at full insertion, it represents a clear indication of proper assembly.

Preferably, the formation is in the form of a projection or a recess. In a particularly preferred embodiment, the formation is provided on an end surface of the spigot, so as to be suitable for co-operating with a formation provided on an axially outwardly facing shoulder within the socket mouth.

The formation may be integrally formed on the spigot. In one particularly preferred embodiment, the formation is located upon a frame which is fitted to the spigot end. Preferably, the frame arrangement comprises a cylindrical sleeve which can be located within the spigot mouth and which comprises a radially outwardly projecting annular flange for at least partially covering the spigot end face, with the projection located upon an axially facing surface of the flange, so that the projection projects in the axial direction when the sleeve is located within the spigot mouth. In an alternative arrangement, the sleeve fits over the spigot end and the annular flange extends radially inwardly.

Where the formation is a projection, it may have a rectangular or domed profile.

The spigot end may comprise a plurality of formations, which may be arranged at regular angular intervals in the circumferential direction of the spigot end. Preferably, the sleeve is provided with means for interference fitting to the spigot end. Where the sleeve is designed to fit within the spigot end, this can take the form of a radially outwardly projecting formation, interfering with a radially inner surface of the spigot for resisting rotation of the sleeve within the spigot end. Where the sleeve is configured to accept the spigot end coaxially within itself, a radially inwardly directed formation may be provided for interfering with an outer surface of the spigot end, so as to resist relative rotation.

According to the invention there is also provided a formation support frame for location upon a spigot end of a pipe, said frame comprising a projection for interfering with a projection provided within a socket mouth and means for supporting the projection in position in relation to the spigot end.

The frame may be in the form of a cylindrical sleeve with a radially inwardly or radially outwardly directed flange at one end thereof. In the preferred embodiment, the sleeve is configured for location within the mouth of a pipe spigot end and the flange is directed radially outwardly and configured for location in abutment against a spigot end face.

The cylinder may comprise a radially outwardly directed formation for interference with a radially inner wall of the spigot end. The flange may comprise more than one said projection for addressing an axially outwardly facing shoulder located within a mouth of a socket.

According to a further aspect of the invention there is provided a socket comprising a formation on an inner wall of the mouth thereof, said formation being adapted to interfere mech-anically with a formation provided upon a spigot during relative motion between the spigot and socket, so as to indicate the full insertion of the spigot within the socket, by enabling detection of the mechanical interference outside the socket.

Preferably, the mechanical interference can be felt or heard by a person inserting the spigot into the socket. The interference may occur upon relative rotary movement between spigot and socket or upon relative axial movement.

Preferably, the formation is located upon an axially outwardly facing annular shoulder located within the socket mouth. The shoulder may comprise several such formations. Or each formation may be an axially outwardly extending projection and may have a rectangular or domed profile. The formations may be integrally formed on the shoulder face, or located upon a ring which is, in turn, seated upon the shoulder.

According to a further aspect of the invention there is provided a pipe joint comprising a spigot and a socket, wherein the spigot is provided with a formation in an end region thereof and upon a radially outer surface or an end face thereof; and said socket is provided with a formation located within the socket mouth and arranged in such a position as to address and interfere mechanically with the formation located upon the spigot end, when the spigot end is fully inserted within the socket, for indicating the spigot is fully inserted within the socket.

Preferably, the formation provided on the spigot end is provided on an end face of the spigot end and the formation provided in the socket is provided on an axially outwardly facing annular shoulder. Preferably, both the spigot and the socket each comprises a plurality of axially projecting projections. These projections may be rectangular or domed in profile. In one particularly preferred embodiment, the formations provided on the spigot are located on a frame, which is fitted to the end of the spigot. This frame may comprise a cylindrical section, which fits within the spigot mouth and a radially outwardly directed flange, which abuts an end face of the spigot, the said formation or formations being located on the end face of the flange. The radially outer surface of the cylindrical section may be provided with a formation, such as a ridge, for interfering with a radially inner surface of the spigot end.

In a particularly preferred embodiment, the spigot end comprises four projections and the socket comprises four projections.

One further disadvantage of the above discussed known socket assembly, which requires visibly marking a spigot, is that it is ineffective if pipe lengths are to be cut from a continuous length of pipe by the user. It is possible to overcome this problem by providing index marks in pairs, one mark representing a point at which the pipe should be cut, so as to define a spigot end, and the other mark being provided to serve as the index mark. However, this means that a considerable amount of piping can be wasted, since the piping can only be cut at particular points. The present invention, therefore, also sets out to provide an insertion indicator which can be used in conjunction with piping which is supplied in continuous form and cut to appropriate lengths by the user.

The above described preferred embodiments in which the formations for the spigot end are provided upon a separate frame achieve this. This is because the piping may be cut to an appropriate length and the frame may be fitted to the end of the pipe, so that the pipe end comprises appropriately located projections. The spigot end can then be inserted into the socket and, when mechanical interference between the projections on the spigot and the socket can be felt through restrictions or modifications to the relative movement between the spigot and socket, then the assembler can be sure that the spigot is fully located within the socket.

Not only does this arrangement facilitate proper assembly of the joint in conditions of poor visibility, as with other embodiments of the invention, but it also enables lengths of pipe to be cut and properly inserted without the need for cutting the pipe at a particular marked point.

Preferred embodiments of the invention will now be described, by way of example, and with reference to the accompanying drawings in which: -

Figure 1 is a cut-away perspective view of a socket in accordance with an embodiment of the invention;

Figure 2 is a cut-away perspective view of a pipe spigot in accordance with an embodiment of the invention;

Figure 3 is a perspective view of a sleeve in accordance with an embodiment of the invention;

Figure 4 is a cross-section through one of the projections of the sleeve of Figure 3;

Figure 5 is a view corresponding to Figure 4 showing an alternative projection profile; and

Figure 6 is a cross-section through a cylindrical portion of the sleeve of Figure 3. Figure 1 shows a socket 20 which, moving from the axial end of the socket in the axially inward direction comprises: a first region of greatest diameter 22, a second region of lesser diameter 24, and a third region of smallest diameter 26.

Region 22 is for accommodating the spigot end and also for housing other jointing components such as a seal and grab ring (not shown). Section 24 has an internal diameter which corresponds generally to the external diameter of a spigot end. Section 26 has an internal diameter which corresponds generally to the internal diameter of a spigot end. Sections 24 and 26 are separated by an axially outwardly facing annular shoulder 25. The configuration is such that, when inserted, the outer surface of a spigot will fit comfortably against the radially inner surface of region 24, for purposes of support. The end face of the spigot will abut annular shoulder 25. The region 26 essentially defines a flow path and, therefore, has a diameter corresponding to that of the inner diameter of the spigot so as to provide little or no interruption to the passing fluid.

The socket 20 is provided with a plurality of block-shaped projections 27, which project from the surface of the annular shoulder 25 in the axial direction towards the open end of the socket. Four of these projections 27 are provided at 90° intervals in the circumferential direction.

The spigot 30 is defined by an end portion of a length of piping 32. A sleeve 40 is fitted to the end of the spigot 32. The sleeve 40 (shown fully in Figure 3) comprises a cylindrical section 42 with a radially outwardly extending annular flange 44 located at one end thereof. The flange 44 is provided with a plurality of block-shaped projections 46 on an axial end surface thereof 48 The four projections 46 .are arranged at 90° intervals in the circumferenti-al direction. The cylindrical section 42 also comprises a radially outwardly projecting, axially aligned elongated rib 43. The cylindrical section 42 of the sleeve 40 is inserted into the open mouth end of the spigot 32. The rib 43 ensures interference between the radially outer surface of the sleeve 42 and the radially inner surface of the spigot end 32. The outer diameter of the sleeve 42 and the extent of projection of the rib 43 are configured such that the cylinder 42 locates tightly within the spigot end, so as to resist relative rotation between the sleeve 40 and the spigot 32 in the circumferential direction. However, the degree of resistance to rotation is such that the sleeve can rotate, albeit stiffly, within the spigot mouth, if sufficient torque is applied to the sleeve or pipe.

In use, an appropriate length of pipe is cut and the sleeve 40 is inserted into the end of the pipe 32. It is pushed fully into the pipe so that the rear surface of the flange 44 abuts against the end surface of the pipe. The spigot end 32, complete with the sleeve 40, is then ready for insertion into the socket 20. During this process, the spigot is easily inserted into the socket in a standard fashion, because the radially outer diameter of the flange corresponds with the radially outer diameter of the spigot and, therefore, presents no additional resistance to insertion. However, when the spigot is fully inserted into the socket, the axially end-most surfaces of the projections 46 come into abutment with the annular shoulder 25 of the socket. Furthermore, the axially outer surfaces of the projections 27 of the socket come into abutment with the front face 48 of the flange 44. This is because the projections are of generally the same length. At this stage, relative circumferential rotation between the socket 20 and the pipe 30 will be limited by circumferential interaction of the projections 46 provided on the sleeve 40 and the projections 27 provided on the shoulder 25, which are interlocked. Thus, a person assembling the joint will realise that the spigot is fully inserted within the socket because rotation is limited, whereas before full insertion of the pipe is achieved, the rotation of the pipe within the socket is not restricted in any way. The degree of resistance to relative rotation of the sleeve 40 and the spigot 32 is controlled, as explained above, by the rib 43. This is designed such that, once the torque applied to the spigot 32 exceeds a particular level, the sleeve will rotate within the spigot, so as to accommodate any further rotational force. This avoids inflicting damage upon either of the components. Furthermore, the spigot 32 would normally be caused to maintain its axial position by means of a grab ring located within axial region 22 of the socket. This grab ring will accommodate a certain amount of relative axial movement between the spigot 32 and the socket 20, thus enabling the projections 46 on the flange 44 to slip over the projections 27 provided on the shoulder 25. This also serves to limit the amount of damage caused to the components, whilst providing a positive feel as the spigot, in a limited fashion, reciprocates axially with maintained torque and insertion force..

In addition to limiting the damage caused to components, the circumferential rotation permitted between the sleeve and the spigot and the axial movement permitted between the spigot and the socket can, if a sufficient number of projections are provided, enable the assembler to feel a 'ratchet-type' slipping, as the spigot is rotated relative to the socket, thus emphasizing the indication that the spigot is inserted fully within the socket.

It is not, of course, necessary for four projections to be provided on each of the flange and the shoulder. Any appropriate number of projections could be incorporated, for example an arrangement of three projections at 120° intervals or an arrangement of two projections at 180° intervals. Alternatively, each of the flange and the shoulder may be provided with radially aligned ribs.

Figure 4 shows a cross-section through the projections 46 of the sleeve 40. From this figure, it can be seen that the projections 46 each have a generally rectangular profile. Figure 5 shows an alternative profile for the projections 46, in which the projections have a somewhat domed profile. The arrangement shown in Figure 5 facilitates slippage between the projections provided on the flange 44 and the projections provided on the shoulder 25.

The sleeve 40 is made from stainless steel and can be punched and deep-drawn. The pipe spigot and socket are extruded and injection moulded from polybutylene respectively , although that is not to say that the invention cannot be used in conjunction with other materials or manufacturing techniques.

Although, in the above arrangement, the spigot-end projections are provided on a separate sleeve, this is not to say that they could not be integrally formed on the end of the spigot. Furthermore, the projections 27 provided on the socket shoulder 25 could, as an alternative, be formed on a ring which is simply inserted into the socκet prior to insertion of the spigot. If this is the case, the ring or socket, or both, should ideally include keying means for resisting relative rotation of the ring and the socket.

The above described sleeve 40 is particularly advantageous in that it fits easily within the spigot, but does not alter the outer surface configuration of the spigot. However, the sleeve could just as easily comprise a cylindrical section which fits over the spigot end with the flange being directed radially inwardly. Furthermore, the cylindrical section 42 of either type of sleeve could be replaced by a series of pins or some other formation which simply serves to locate the fhinge in position in relation to the spigot end. In fact, the flange could be replaced or even completely omitted. The only requirement is that some means are provided for locating the projections 46 in position in relation to the spigot. Whilst the projections 46 and 27 have been provided on the axially end surface of the spigot and a correspondingly orientated surface in the socket, this is not to say that suitable projections could not be provided on a radially outer or inner surface of the spigot end and on a corresponding surface of the socket. However, if the formations were to be provided on a radially inner surface of the spigot 32, then an inner sleeve of some description would need to be provided within the socket 20, for locating within the radially inner surface of the spigot.

Many further modifications and variations will suggest themselves to those versed in the art upon making reference to the foregoing illustrative embodiments, which are given by way of example only, and which are not intended to limit the scope of the invention.

Claims

1. A pipe spigot comprising a formation on an outer surface or an end surface thereof, the said formation being adapted to interfere mechanically with a formation located within the mouth of a socket during relative motion between the spigot and socket, so as to indicate full insertion of the spigot inside the socket, by enabling detection of the mechanical interference outside the socket.

2. A pipe spigot according to Claim 1, wherein the formation is such as to enable the mechanical interference to be felt or heard by a person inserting the spigot into a socket.

3. A pipe spigot according to Claim 1 or 2, wherein the interference occurs upon rotary movement of the spigot relative to a socket.

4. A pipe spigot according to any preceding claim, wherein the interference occurs when the spigot is moved axially relative to a socket.

5. A pipe spigot according to any preceding claim, wherein the formation is provided on an end surface of the spigot so as to be suitable for co-operating with a formation provided on an axially outwardly facing shoulder located within the mouth of a socket.

6. A pipe spigot according to any preceding claim, wherein the formation is a projection.

7. A pipe spigot according to any one of Claims 1 to 5, wherein the formation is a recess.

8. A pipe spigot according to Claim 6, wherein the projection has a rectangular or domed profile.

9. A pipe spigot according to any preceding claim and comprising a plurality of formations.

10. A pipe spigot according to Claim 9, wherein the plurality of formations are arranged at regular angular intervals in the circumferential direction of the spigot end.

11. A pipe spigot according to any preceding claim, wherein the formation is integrally formed on the spigot.

12. A pipe spigot according to any one of Claims 1 to 10, wherein the formation is located upon a frame, which is fitted to the spigot end.

13. A pipe spigot according to Claim 12, wherein the frame comprises a cylindrical sleeve which can be located within the spigot mouth and which comprises a radially outwardly projecting annular flange for at least partially covering the spigot end face, with the projection located upon an axially facing surface of the flange, so that the projection projects in the axial direction when the sleeve is located within the spigot mouth.

14. A pipe spigot according to Claim 12, wherein the frame comprises a cylindrical sleeve which can be located over the spigot end and which comprises a radially inwardly projecting annular flange for at least partially covering the spigot end face, with the projection located upon an axially facing surface of the flange, so that the projection projects in the axial direction when the sleeve is located over the spigot end.

15. A pipe spigot according to Claim 13 or 14, wherein the sleeve is provided with means for interference fitting to the spigot end.

16. A pipe spigot according to Claim 15 wherein dependent on Claim 13, wherein the said means for interference fitting comprises a radially outwardly projecting formation, interfering with a radially inner surface of the spigot for resisting rotation of the sleeve within the spigot end.

17. A pipe spigot according to Claim 15 wherein dependent on Claim 14, wherein the said means for interference fitting comprises a radially inwardly directed formation for interfering with .an outer surface of the spigot end, so as to resist relative rotation therebetween.

18. A formation support frame for location upon a spigot end of a pipe, said frame comprising a formation for interfering with a formation provided within a socket mouth and means for supporting the projection in position in relation to the spigot end.

19. A frame according to Claim 18, comprising a cylindrical sleeve with a radially inwardly or radially outwardly directed flange at one end thereof.

20. A frame according to Claim 19, wherein the sleeve is configured for location within the mouth of a pipe spigot end and the flange is directed radially outwardly and configured for location in abutment against a spigot end face.

21. A frame according to Claim 20, wherein the cylinder comprises a radially outwardly directed formation for interference with a radially inner wall of a spigot end.

22. A frame according to Claim 19, wherein the sleeve is configured to receive a pipe spigot end and the flange is directed radially inwardly and configured for location in abutment against a spigot end face.

23. A frame according to Claim 22, wherein the cylinder comprises a radially inwardly directed formation for interference with a radially outer wall of the spigot end.

24. A frame according to any one of Claims 19 to 23, wherein the flange comprises the said formation arranged for addressing an axially outwardly facing shoulder located within a mouth of a socket.

25. A frame according to Claim 24, wherein the formation provided on the flange is a projection.

26. A frame according to Claim 24 or 25 comprising a plurality of said formations on the flange.

27. A socket comprising a formation on an inner wail of the mouth thereof, said formation being adapted to interfere mechanically with a formation provided upon a spigot during relative motion between the spigot and socket, so as to indicate the full insertion of the spigot within the socket, by enabling detection of the mechanical interference outside the socket.

28. A socket according to Claim 27, wherein the formation is such as to enable the mechanical interference to be felt or heard by a person inserting a spigot into the socket.

29. A socket according to Claim 28, wherein the interference occurs upon rotary movement of the socket relative to a spigot.

30. A socket according to any one of Claims 27 to 29, wherein the formation is provided upon an axially outwardly facing shoulder located within the socket mouth.

31. A socket according to Claim 30 and comprising a plurality of said formations.

32. A socket according to any one of Claims 27 to 31, wherein the or each formation is an axially outwardly extending projection.

33. A socket according to Claim 32, wherein the or each projection has a rectangular or a domed profile.

34. A socket according to Claim 30 or any claim dependent thereon, wherein the or each formation is integrally formed on the shoulder face.

35. A socket according to any one of Claim 30 or any one of claims 31 to 33 when dependent thereon, wherein the or each formation is located upon a ring which is, in turn, seated upon the shoulder.

36. A pipe joint comprising a spigot and a socket, wherein the spigot is provided with a formation in an end region thereof and upon a radially outer surface or an end face thereof; and said socket is provided with a formation located within the socket mouth and arranged in such a position as to address and interfere mechanically with the formation located upon the spigot end, when the spigot end is fully inserted within the socket, for indicating the spigot is fully inserted within the socket.

37. A pipe joint according to Claim 36, wherein the formation provided on the spigot end is provided on an end face of the spigot end and the formation provided in the socket is provided on an axially outwardly facing annular shoulder.

38. A pipe joint according to Claim 36 or 37, wherein each formation forms one of a plurality of axially projecting projections.

39. A pipe joint according to Claim 38, wherein each projection has a rectangular or domed profile.

40. A pipe joint according to Claim 39, wherein the projections provided on the spigot are located on a frame, which is fitted to the end of the spigot.

41. A pipe joint according to claim 40, wherein the frame comprises a cylindrical section, which fits within the spigot mouth, and a radially outwardly directed flange, which abuts an end face of the spigot, the said formations being located on an axial end face of the flange.

42. A pipe joint according to Claim 41 , wherein the radially outer surface of the cylindrical section is provided with a formation, for interfering with a radially inner surface of the spigot end.

43. A pipe joint according to Claim 42, wherein the formation provided on the cylindrical section is a ridge.

44. A pipe joint according to any one of Claims 38 to 43, wherein the spigot end comprises four projections and the socket comprises four projections.

45. A pipe spigot substantially as hereinbefore described with reference to Figures 2 to 6 of the accompanying drawings.

46. A formation support frame for location upon a spigot end of a pipe substantially as hereinbefore described with reference to Figures 2 to 6 of the accompanying drawings.

47. A socket substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

48. A pipe joint substantially as hereinbefore described with reference to the accompanying drawings.