GB1571962A

GB1571962A - Spigot-and-socket joint for pipes

Info

Publication number: GB1571962A
Application number: GB1730277A
Authority: GB
Original assignee: Tiroler Rohren und Metallwerke AG
Current assignee: Tiroler Rohren und Metallwerke AG
Priority date: 1976-04-26
Filing date: 1977-04-26
Publication date: 1980-07-23
Also published as: DE2718208A1; AT350860B; SU645616A3; FR2349783A1; FR2349783B1; ATA304576A; CH622597A5

Abstract

The socket connection has a socket (4) with an outwardly protruding flange (6). An annular part (2) is pushed on to an end, designed as a spigot end (10) of the pipe, which has been introduced into the socket (4), whereupon a locking element (11), designed as a clamping ring which can be braced together, is fixed on the spigot end according to the desired depth of insertion of the spigot end into the socket. Like the socket (4), the annular part (2) has an outwardly directed flange (5) and, like the outwardly directed flange (6) of the socket (4), this flange (5) is embraced by a clip (7) which is essentially U-shaped in cross-section and can be braced together. After bracing of the clip (7), a socket joint is produced which withstands high tensile forces. <IMAGE>

Description

(54) "SPIGOT-AND-SOCKET JOINT FOR PIPES" (71) We, TIROLER RoHREN- UND METALLwERKEAKTIENGEsELLscHAFT, of Hall in Tirol, Austria, an Austrian Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: In spigot-and-socket joints for pipes, the spigot end of one pipe is introduced into the socket end of another pipe and a tight seal is provided by a sealing ring arranged within the socket. In most cases, this sealing ring is not sufficient for preventing the spigot-and-socket joint from becoming loose. It is known to arrange locking members at the socket and at the spigot to provide protection against the pipes being pulled apart.

Spigot-and-socket joints for pipes are -known in which the spigot end of one of the pipes to be mutually connected is introduced, with interposition of a sealing ring, into the socket end of the other pipe, an annular part being provided at the socket end and removably connected with this socket end, said annular part having a radially inwardly extending rim embracing an annular locking member and adapted to be secured to the spigot end of the pipe so as to extend at least over part of the circumference of the spigot end of the pipe.

In these known joints, said annular part provided at the socket end is an integral portion of the socket. Particularly with shaped pipes such as pipe elbows and curved pipes as well as connecting pieces, protection against the pipes being pulled apart is frequently not required so that such shaped pipes are provided with short sockets. To provide protection also in these cases, it was therefore necessary to provide sockets of various shapes for said known constructions. In view of the fact that pipe elbows of different radii of curvature and also pipe fittings of various shapes are required, storing of spare parts and also production of the different types of sockets becomes quite expensive. Furthermore, sockets of large axial extension often cannot be used in view of the limited space available in those frequently occurring applications which do not require protection against pulling apart of the pipes.

According to the invention, there is provided a spigot-and-socket joint between two pipes, wherein the end of one pipe has an annular socket in which an end of the other pipe (the spigot) is received, and a sealing ring is interposed between the pipes within the socket, the socket having an outwardly extending flange, and said spigot having an annular locking member fixed to the pipe and an annular part with inwardly and outwardly extending flanges surrounding the locking member and retained thereby, said outwardly extending flanges of the socket and of the spigot being connected by a multi-part clamping collar of U-shaped cross-section, the inwardly extending flange of the spigot having a recess around part of its circumference, with axially protruding parts of the locking member received in the recess.

Since the annular part in this construction is detachably mounted on the spigot, rather than fixed to the socket, the same sockets can be used both for pipe joints where it is not necessary to provide protection against separation of the pipes, and joints where it is necessary to provide protection against separation. This means that the necessary stock which has to be held can be reduced by half. A larger number of pipes of each different type can also be produced, which leads to further production economies.

The final connection between the outwardly extending flanges on the annular part connected to the spigot and the socket will resist substantial tension forces. In view of the inwardly extending flange being provided over part of its inner circumference with a recess accommodating axial protrusions of the locking member, the locking member embraced by the annular part can, when assembling the spigot-andsocket joint, be gripped from the outer side and be adjusted in its position relative to the annular part.

The annular locking member to be secured at the spigot end may be a split clamping ring which is provided at either side of the split with axially extending protrusions extending into the recess of the inwardly extending rim and which are adapted to be engaged by one or more clamping elements. This makes it possible to adjust the position of the locking member on the spigot end of the tube before tightening the clamping elements.

After completion of the joint, the clamping elements located within the recess of the annular part cannot affect the operational behaviour of the spigot-and-socket joint.

the spigot end of the pipe can be prevented from becoming excessively pulled apart from the joint if the outer surface of the locking member tapers away from the joint, and if the mating surface of the annular part also tapers in the same direction because in this case, when subjecting the spigot-and-socket joint to tension forces, the locking member is still further compressed by the annular part embracing the locking member and teeth on the locking member are pressed into the surface of the spigot. A clamping ring serving as the locking member may conveniently be provided with an annular insert of a harder material, said annular insert being provided at its radially inner surface with annular protrusions shaped like saw teeth. This provides the possibility to produce the clamping ring of a tough material, for example as a forging, and to exert on the annular insert the force required for pressing the teeth into the spigot by the annular part and the clamping ring, without risk of destroying the clamping ring.

The annular locking member to be secured on the spigot can be composed of two component parts, each of these component parts being provided on one of its ends with axially extending protrusions which can be mutually connected by means of a screw and which extend into the recess of the inwardly extending flange. The component parts of the locking member are supported on the spigot, abutted against a supporting ledge or weld bead. In this case it is also possible to use a bipartite annular locking member to be secured to the spigot and having one end each of the component parts provided with axially extending protrusions extending into the recess of the inwardly extending flange, a rod being arranged between said protrusions to secure in position the protrusions within the recess.

In known types of spigot-and-socket joints, in which the annular part provided at the end of the socket forms an integral part of the socket, the arrangement was such, that the spigot was provided at its outer surface with supporting ledges and that the inner diameter of the inwardly extending rim of the annular part of the socket was greater than the maximum diameter of the outer surfaces of the supporting ledge. After shifting the socket on one pipe over the spigot on the other pipe, the locking members were introduced for engaging the supporting ledge as well as the inwardly extending rim of the annular part provided at the socket end and for thus providing the desired pipe separation.

In this known embodiment, the supporting ledges had to be welded to the spigot or had the shape of a weld bead. The same type of construction of the spigot is now also possible with a spigot-and-socket joint according to the invention so that sockets of a joint according to the invention and sockets of known joints, in which the inwardly extending rim of the annular part forms an integral part of the socket, can, if desired, be used in the same pipe line.

The invention can provide still another advantage. When installing pipe lines, it becomes frequently necessary to use pipes of smaller length and to shorten existing pipes on site, thus removing the spigot with the supporting ridge. In this case, welding of new supporting ridges or applying a weld bead forming the supporting ridge is quite difficult. Even when a welding apparatus is available it is necessary to have at the site skilled welding personnel for doing the required work. Pipes which have been shortened at the site must therefore be brought into the workshop and provided there with a supporting ridge or weld bead, which is quite laboursome, time-consuming and expensive. By removably connecting the annular part provided at the end of the socket with the end of the socket, the locking member used can be a clamping ring adapted to be tightened, which, after the annular part has been correctly positioned, is tightened on the spigot end, whereupon the annular part is connected with the socket end. Clamping of the clamping ring on the spigot does not provide any difficulties whatsoever and can be effected by unskilled personnel and avoids the necessity of any welding operation at the site. The clamping ring is, at its ends to be mutually clamped, provided with axially extending protrusions to be acted upon by one or more clamping elements such as a screw protruding through holes provided in the protrusions and thus avoiding any undue enlargement of the outer circumference of the clamping ring at the clamping area. In known embodiments in which the annular part comprising the inwardly extending flange is integral with the socket and is provided with a recess, this recess can be used for inserting the bipartite locking member adapted for being supported against a supporting ridge or a weld bead provided on the spigot. However, when the recess is provided on the inwardly extending flange of a separate annular part, which is connected with the socket only after clamping the clamping ring, the axially extending protrusions of the clamping ring can be mutually clamped first and the clamping ring can also be clamped to the spigot first, whereupon the annular part is positioned relative to the socket so that the axially extending protrusion will be accommodated within the recess. Thus, the invention provides the possibility of using a clamping ring together with a smooth spigot or of using a bipartite locking member together with a spigot provided with a supporting ridge behind which the bipartite locking member can be inserted.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an axial section through a first embodiment of the joint according to the invention; Figure 2 is a perspective, partly cut-away and partly exploded view of the joint of Figure 1; Figures 3 and 4 show alternative forms of a part of the joint, in axial section; Figure 5 is a perspective view of an alternative form of locking member; Figure 6 is an axial section through a second embodiment of joint according to the invention; Figure 7 is a perspective exploded and partially cut-away view of a third embodiment of joint according to the invention; and Figure 8 is an axial section through the assembled joint of Figure 7.

As shown in Figures 1 and 2, an annular part 2 with an inwardly extending flange 1 is detachably connected to an end 3 of a socket 4. The annular part 2 has on its outer circumference an outwardly extending flange 5. The end 3 of the socket 4 has also an outwardly extending flange 6.

These two flanges 5 and 6 are embraced by a bipartite clamping collar 7 of U-shaped cross-section. Both parts of the clamping collar 7 are provided at their ends with outwardly extending lugs 8 being provided with holes 9 for accommodating clamping screws. By clamping together both parts of the clamping collar 7, the annular part 2 is firmly clamped to the end 3 of the socket 4. A clamping ring 11 with a slot 12 is clamped to the spigot end 10 of a pipe.

This clamping ring 11 has at its radially inner surface annular protrusions 13 of saw tooth shape. Said annular protrusions serve the purpose of improving the seat of theclamping ring on the spigot. At the area of the slot 12, axially extending protrusions 14 are provided at the ends of the clamping ring, said protrusions being provided with holes 15 into which a clamping screw is to be inserted. A sealing ring 16 is accommodated within the socket 4 when assembling the spigot-and-socket joint, the annular part 2 being put into position first on the spigot, whereupon the clamping ring 11 is clamped in position and subsequently the annular part 2 is clamped to the flange 3 of the socket 4 by means of the bipartite clamping collar 7.

The inwardly extending flange 1 of the annular part 2 has a recess 17 providing the space required for accommodating the axially extending protrusions 14 of the clamping ring 11.

In the embodiment shown in Figures 1 and 2, the locking member is formed by the clamping ring 11. Figure 3 shows an embodiment in which a locking member 18 is abutted against a supporting ledge 19 welded to the spigot 10. Figure 4 shows an embodiment in which a weld bead 20 applied to the outer surface of the spigot 10 of the pipe forms the abutment for the locking member 18.

Such a locking member 18 is shown in Figure 5. This locking member consists of two segments 18a and 18b. Both segments are provided with axially extending protrusions 21. A rod 22 is welded to the protrusion 21 of the segment 18a. The supporting ledge 19 and the weld bead 20, respectively, have an outer diameter smaller than the inner diameter of the flange 1 of the annular part 2. This annular part 2 can thus be shifted over the supporting ledge 19 or the weld bead 20, even if this annular part is already connected to the socket 4 by means of the bipartite clamping collar 7. After having shifted the annular part over the supporting ledge 19 or the weld bead 20, the segment 18b of the locking member 18 is inserted into the recess 17 and shifted in a clockwise direction around the spigot 10 behind the flange 1. Subsequently, the segment 1 8a is inserted into the recess 17, with the rod 22 assuming an outwardly bent position. This segment 1 8a is then shifted in a counterclockwise direction around the spigot 10 behind the flange 1 until the protrusion 21 contacts the left hand side of the recess 17. In this position, the rod 22 is bent into the plane of the locking member 18, so that the end of the rod 22 contacts the protrusion 21 of the segment 18b. Both segments 18a and 18b are thus in the relative position as illustrated in Figure 5.

A further possible embodiment of a bipartite locking member is illustrated in Figure 7. Both parts 18a and 18b of the bipartite clamping ring are secured to the spigot by means of a screw introduced into the holes 15 provided in the axial extending protrusions 14. A further slot 12b is provided in the ring 18 opposite to the slot 12a located between the axial extending protrusions 14. The two parts of the clamping ring can be held together by means of the clamping screw so that they are supported against the weld bead 20 on the spigot 10. The assembled spigot-andsocket joint is shown in an axial section in Figure 8 which has incorporated the reference numerals used before.

Figure 6 illustrates an embodiment of a spigot-and-socket joint in which an insert 21 consisting of a material which is harder than the material of the clamping ring is provided at the inner side of the clamping ring. Teeth 21a are provided at the inner side of this insert 21, so that when subjecting the spigot-and-socket joint to tension forces, these teeth 21a are pressed into the spigot 10. The reference numerals contained in Figure 6 are the same as in Figure 1.

WHAT WE CLAIM IS: 1. A spigot-and-socket joint between two pipes, wherein the end of one pipe has an annular socket in which an end of the other pipe (the spigot) is received, and a sealing ring is interposed between the pipes within the socket, the socket having an outwardly extending flange, and said spigot having an annular locking member fixed to the pipe and an annular part with inwardly and outwardly extending flanges surrounding the locking member and retained thereby, said outwardly extending flanges of the socket and of the spigot being connected by a multi-part clamping collar of U-shaped cross-section, the inwardly extending flange of the spigot having a recess around part of its circumference, with axially protruding parts of the locking member received in the recess.

2. A joint as claimed in claim 1, wherein the annular locking member is a split ring having axially protruding parts on either side of the split which are adapted to be drawn together by a clamping element.

3. A joint as claimed in claim 2, wherein the inner circumference of the locking member, which contacts the pipe, is provided with teeth.

4. A joint as claimed in claim 2, wherein the locking member has an annular insert of harder material for contacting the spigot, the surface of the insert in contact with the spigot being provided with annular projections having a saw-tooth profile.

5. A joint as claimed in claim 1, wherein a supporting ridge is formed directly on the spigot, and the annular locking member has two members, each member having an axially protruding part, the axially protruding parts being received in the recess in the inwardly extending flange of the annular part, both parts of the annular locking member engaging the retaining ridge to prevent the spigot being withdrawn from the socket.

6. A joint as claimed in claim 5, wherein the axially protruding parts are connected by a clamping member.

7. A joint as claimed in claim 5, wherein a circumferentially extending rod is provided on one of the axially protruding parts and an abutment for an end of the rod on the other of the parts.

8. A spigot-and-socket joint substantially as herein described, with reference to any one embodiment shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. shifted in a counterclockwise direction around the spigot 10 behind the flange 1 until the protrusion 21 contacts the left hand side of the recess 17. In this position, the rod 22 is bent into the plane of the locking member 18, so that the end of the rod 22 contacts the protrusion 21 of the segment 18b. Both segments 18a and 18b are thus in the relative position as illustrated in Figure 5. A further possible embodiment of a bipartite locking member is illustrated in Figure 7. Both parts 18a and 18b of the bipartite clamping ring are secured to the spigot by means of a screw introduced into the holes 15 provided in the axial extending protrusions 14. A further slot 12b is provided in the ring 18 opposite to the slot 12a located between the axial extending protrusions 14. The two parts of the clamping ring can be held together by means of the clamping screw so that they are supported against the weld bead 20 on the spigot 10. The assembled spigot-andsocket joint is shown in an axial section in Figure 8 which has incorporated the reference numerals used before. Figure 6 illustrates an embodiment of a spigot-and-socket joint in which an insert 21 consisting of a material which is harder than the material of the clamping ring is provided at the inner side of the clamping ring. Teeth 21a are provided at the inner side of this insert 21, so that when subjecting the spigot-and-socket joint to tension forces, these teeth 21a are pressed into the spigot 10. The reference numerals contained in Figure 6 are the same as in Figure 1. WHAT WE CLAIM IS:

1. A spigot-and-socket joint between two pipes, wherein the end of one pipe has an annular socket in which an end of the other pipe (the spigot) is received, and a sealing ring is interposed between the pipes within the socket, the socket having an outwardly extending flange, and said spigot having an annular locking member fixed to the pipe and an annular part with inwardly and outwardly extending flanges surrounding the locking member and retained thereby, said outwardly extending flanges of the socket and of the spigot being connected by a multi-part clamping collar of U-shaped cross-section, the inwardly extending flange of the spigot having a recess around part of its circumference, with axially protruding parts of the locking member received in the recess.