IE44418B1

IE44418B1 - Improvements in or relating to pipe sockets

Info

Publication number: IE44418B1
Application number: IE17977A
Authority: IE
Original assignee: Wavin Bv
Priority date: 1976-01-29
Filing date: 1977-01-28
Publication date: 1981-11-18
Also published as: AT354198B; DK149993C; IE44418L; GB1547082A; DE2703300A1; SE7700932L; FR2339801B1; ATA55877A; JPS5833436B2; FR2339801A1; DK36577A; JPS575995B2; DE2703300B2; BE850832A; IT1076350B; JPS5718887A; DK149993B; NL170048B; JPS52115425A; ES455466A1

Abstract

Plastic tube plug tube and method of forming said tube, whose plug tube has a slot for receiving an annular portion of a sealing body, said slot limited by a radially extending head portion, and in the slot comprises an additional cavity that extends into a thickened wall portion, disposed at the end of the plug, this portion of the thickened wall extending between the inner side of the plug and the outer side thereof, and a part of the plug extending from the groove inwardly has an inner diameter greater than the remaining part of the plug.

Description

This invention relates to pipe sockets.

It is an object of the invention to provide a pipe socket with a radially inwardly opening groove adapted to retain an annular portion of a sealing member.

The invention includes a thermoplastics pipe socket having an annular radially inwardly opening groove adapted to retain an annular portion of a sealing member, said groove comprising an axially outwardly opening recess in a wall portion of the socket and defined between said wall portion and an integral extension thereto radially outwardly of the recess, the end portion of which extension extends radially inwardly opposite said recess.s The invention also includes a method of making a thermoplastics pipe socket, comprising providing a thermoplastics tube with a wall portion having an axially outwardly opening recess therein and an axially extending integral extension thereto radially outwardly of the recess, heating the extension to plasticize it, and deforming the extension such that an end portion of the extension extends radially inwardly opposite said recess to define with the wall portion an annular radially inwardly opening groove adapted to retain an annular portion of a sealing member. - 3 In order that the invention may be well understood, some embodiments thereof, which are given by way of example only, will now be described, reference being made to the accompanying drawings, in which: Figure 1 is a fragmentary axial section of a tube for forming a coupling comprising two pipe sockets; Figure 2 is an enlarged view of part of one of the sockets of Figure 1; Figure 3 is a view similar to Figure 2 but showing a radially inwardly opening groove formed in the socket; and Figure 4 is a similar view to Figure 3 of part of a pipe socket formed at the end of a pipe length.

Referring to the drawings, Figure 1 shows an injection moulded tube 1 of polyvinylchloride or other thermoplastics material for forming a coupling comprising a socket 2a at each end for receiving spigots (not shown) to be coupled. An internal abutment flange 16 is provided for limiting axial inward movement of the spigots.

The following description concerns only the right-hand socket (as viewed in the drawings) but it is to be understood that the same applies to the left-hand socket.

The tube is provided with an annular wall portion 7 which 44^·® . 4 . is shown as being radially thicker than the remainder of the wall 17 of the socket axially inwardly thereof. The wall portion 7 has an annular axially outwardly opening recess 6 and an axially outwardly extending integral extension 10 thereto radially outwardly of the recess with a common outer surface 9.

In order to form an annular radially inwardly opening groove 3 adapted to retain an annular portion 4 of a sealing member 18, the extension 10 is plasticized and deformed such that its end portion 19 extends radially inwardly opposite the recess 6 as shown in Figure 3. Advantageously, tne deformation is such that the free end 15 of the extension 10 extends substantially axially inwardly towards the part 11 of the wall portion to reduce the axial extent of the mouth 13 of the groove and thus the possibility of the portion 4 of the sealing member being drawn out of the groove 3, in use, by tensile forces. The provision of the recess 5 in the wall portion 7 also assists retention of the sealing member and is provided with rounded corners. In order to provide good strength properties when deforming extension 10, care is also taken to make the connection of the portion of the extension between the wall portion 7 and the end portion 19 of the extension rounded, at least externally as shown as 12 and preferably also internally as shown as 14. - 5 The socket end 2 adjacent to, and axially inwardly of, the groove 3 has a greater inner diameter than the remainder of the socket to provide a surface 8 which forms with a spigot (not shown) inserted in the socket an annular recess in which a sealing sleeve 5 integral with the portion 4 of the sealing member is located to make sealing contact between the surface 8 and the external surface of the spigot, the spigot having an external diameter substantially equal to the internal diameter of the remainder of the socket.

To manufacture the above described coupling, the tube 1 is first injection moulded. As will be appreciated the fact that the recess 3 opens axially outwardly and the extension 10 extends axially outwardly at this stage makes the configuration of the tube readily mouldable. Then, at least the extension 10 of each socket is plasticized ready for deformation by heating with hot air, by means of oil, or by means of ultra-sonic vibrations to a temperature of between 120 and 200°C.in the case ofapolyvinylchloride tube.

It is advisable to carry out this heating very quickly in order to have a fast production rate and a tool in the form of a beaded mould used for deforming the extension 10 also is preferably heated, for instance to over 50°C in order to prevent the end portion 19 of the extension becoming brittle. Care should be taken to ensure that the desired plasticizing temperature is achieved throughout the end portion 19 to maintain the highest possible strength properties for this part in the finished socket.

In a modified method, the annular portion 4 of the sealing member 18 is located in position in the recess 6 prior to deformation of tho extension 10 as shown in the bottom right-hand corner of Figure 1, and the extension is deformed around the annular portion 4 to form the groove 3 with the portion 4 securely retained therein.

Figure 4 shows another socket 2a which is provided at the. end of a length of pipe 20, an internal radial shoulder between the pipe 20 and the socket 2a forming an abutment limiting axially inward movement of a spigot 21 (shown in chain-dotted lines) into the socket. This socket is similar to the socket described above and the same reference numerals have been used in the figures to indicate like parts.

However, it should be noted that the end portion 19 of the extension has been deformed such that its free end extends substantially radially and not axially towards part 11 of the wall portion in which the groove 6 is provided. Thus, in this arrangement it is primarily the groove 5 which is relied upon to retain the annular 44411 portion of the sealing member within the groove 3.

Of course, the free end of the end portion 19 could be deformed radially inwardly (as in Figure 5) in the socket in Figure 4 and the free end portion 15 of the end portion in the first-described socket could be retained in its substantially radially extending position (as in the socket in Fig.4) and not be deformed axially inwardly.

Claims

1. A thermoplastics pipe socket having an annular radially inwardly opening groove adapted to retain an annular portion of a sealing member, said groove

2. A socket as claimed in claim 1, wherein the extension has been plasticized and deformed such that the end portion thereof extends radially inwardly.

3. A socket as claimed in claim 1 or 2, wherein 15 . the recess has rounded corners. 4. 4 4 i 8 - 10 accompanying drawings. 11. A method of making a thermoplastics pipe socket, comprising providing a thermoplastics tube with a wall portion having an axially outwardly opening

4. A socket as claimed in any one of the preceding claims, wherein the portion of said extension between the wall portion and the end portion of the extension is rounded at its connection to said end portion, 20 5. A socket as claimed in arty one of the preceding claims, wherein the free endof said end portion of the extension extends substantially radially. A socket as claimed in any one of claims 1 to 4,

5. Recess therein and an axially extending integral extension thereto radially outwardly of the recess, heating the extension to plasticize it, and deforming the extension such that an end portion of the extension extends radially inwardly opposite said recess to define 10 with the wall portion an annular radially inwardly opening groove adapted to retain an annular portion of a sealing member. 12. A method as claim'ed inclaim 11, wherein the extension is deformed such that the portion of the 15 extension between the wall portion and the end portion of tne extension is rounded at its connection to the end portion. 13. A method as claimed in claim 11 or 12,wherein the extension is deformed such that the free end 20 thereof extends substantially radially. 14. A method as claimed in claim 11 or 12, wherein the extension is deformed such that the free end thereof extends substantially axially inwardly towards the wall portion. 15. A method as claimed in any one of claims 11 to 14, wherein the annular portion of a sealing member is located in said recess prior to the deformation of the extension, and the extension is deformed around 5 said annular portion to form said groove. 16. A method as claimed in any one of claims 11 to 15, wherein said tube is injection moulded. 17. A method of making a thermoplastics pipe socket substantially as herein described with reference to 5 comprising arr axially outwardly opening recess in a wall portiop of the socket and defined between said wall portion and an integral extension theretoradially outwardly of the recess, the end portion of which extension extends radially inwardly opposite said 10 - recess.

6. wherein the free end of said end portion of the extension extends substantially axially inwardly towards said wall portion.

7. A socket as claimed in any one of the preceding claims and provided with said sealing member, said annular portion thereof being retained by said groove,

8. A socket as claimed in claim 7,wherein said annular portion of the sealing member has a sealing sleeve portion integral therewith which in use is located in an annular recess formed adjacent to and axially inwardly of the groove between an end portion of the socket having a greater inner diameter than the remainder of the socket and a spigot inserted into the socket.

9. A socket as claimed in any one of the preceding claims, wherein said wall portion is radially thicker than the remainder of the wall of the socket axially inwardly thereof. 10. A pipe socket substantially as herein described with reference to Figures 1 to 3, or Figure 4 of the

10. Figures 1 to 3, or Figure 4 of the accompanying drawings.