IE84826B1 - A pipe connector for coupling at least two pipes together - Google Patents

Abstract

ABSTRACT A pipe connector for coupling two corrugated pipes (2,3) comprises first and second socket connectors (8,9) for engaging the pipes (2,3). The first and second socket connectors (8,9) are coupled by a main connecting member (15) which is coupled to the first and socket members (8,9) by coupling flanges (22). The coupling flanges (22) co—operate with the main connecting member (15) for facilitating angular movement of the coupling flanges (22) which in turn permits deflection of the first and second socket connectors (8,9) relative to a main central axis (17) of the pipe connector (1) during engagement of the pipe connector (1) with the pipes (2,3) for avoiding fracturing of the pipe connector (1) as it is being engaged with the pipes (2,3). The pipe connector (1) is formed in one piece of plastics material by rotational moulding.

Description

A pipe connector for coupling at least two pipes together The present invention relates to a pipe connector for coupling at least two pipes together, and in particular, though not limited to a pipe connector for coupling relatively large diameter pipes together. The invention also relates to a method for forming a pipe connector, and to a mould for forming the pipe connector.

Pipe connectors for coupling pipes together are well known. Such pipe connectors may be a straight connector, which is used for connecting two pipes of a continuous run of pipes together, a reducer for coupling two pipes of different diameter together, an elbow for connecting two pipes at right angles to each other, a bend for coupling two pipes also at right angles to each other, or indeed, at an angle greater than a right angle, a T-connector for connecting three pipes together, where one of the pipes is to be teed off at right angles from a continuous pipe run, a Y-connector for coupling three pipes together, where one or two of the pipes are to extend at respective angles to another one of the pipes. Indeed, there are many other types of pipe connectors which are variations on the above types of pipe connectors.

Large bore pipes of the type typically used for foul sewage and surface water may be of concrete, metal or plastics material. Large bore pipes of plastics material and of plain construction suffer from a lack of inherent hoop strength, which typically can lead to fracturing of the pipes, particularly during back filling of a trench in which the pipes are located, unless back filling is carried out with particular care. In order to enhance the hoop strength of such pipes of plastics material, it is known to provide the pipes with spaced apart circumferentially extending hoops, which provide the pipes with a corrugated type external shape. Such pipes are disclosed in Australian Patent Application No. 58874/90, and are commonly referred to as corrugated or twin wall pipes. Connectors of plastics material are provided for connecting such corrugated pipes. The connectors are formed by injection moulding. The connectors, depending on the number of pipes to be connected, are provided with the appropriate number of sockets for engaging the pipes to be connected. An 0- ring seal is located in an annular groove defined between a pair of adjacent hoops adjacent the end of each pipe to be connected. The O-ring seals sealably engage the corresponding sockets of the pipe connector, and thereby form a watertight and airtight seal between the sockets and the corresponding pipes.

Straight connectors for such corrugated pipes comprise a pair of socket connectors facing in opposite directions for engaging the ends of the respective pipes. End stops are required at the proximal ends of the respective socket connectors for abutting the corresponding pipes, when the pipes are fully engaged in the corresponding socket connectors. Each end stop is provided by an end stop ring extending circumferentially into the pipe connector adjacent the proximal end of the corresponding socket connector. Where the pipe connector is short a single end stop ring forms the end stop of both socket connectors. Due to the presence of one or more end stop rings extending into such pipe connectors, it is not possible without particularly expensive injection moulding equipment to mould such straight connectors in one piece. Accordingly, such straight connectors are moulded in two pieces, each piece comprising a socket connector and an end stop ring. The two sockets are joined with their respective end stop rings abutting each other and are circumferentially welded around the end stop rings. This method for producing such straight connectors of injection moulded plastics material is relatively expensive, and is not particularly satisfactory. Furthermore, such straight connectors, in general, are unsuitable for joining relatively large bore corrugated plastics pipes together due to the unyielding nature of the straight connector. When such corrugated pipes are being joined together by a straight connector, significant bending stresses are induced in the straight connector between the two pipes, which commonly lead to fracturing of the straight connector. Similar problems arise with other pipe connectors, for example, with bend connectors, reducers, elbow connectors, T- and Y-connectors, and other such pipe connectors.

There is therefore a need for a pipe connector which is suitable for connecting at least two pipes together which overcomes this problem, and in particular, which is suitable forjoining large bore corrugated pipes of plastics material together. There is also a need for a method and a mould for producing such a pipe connector.

The present invention is directed towards providing such a pipe connector, as well as a method and a mould for producing the pipe connector.

According to the invention there is provided a pipe connector for coupling at least two pipes together, the pipe connector comprising at least two socket connectors, each socket connector comprising a circumferentially extending socket wall defining a corresponding socket bore for engaging an end of a corresponding one of the pipes, and terminating in a distal socket mouth for accommodating the corresponding one of the pipes therethrough to the socket bore, and a connecting means coupling the socket connectors together and defining a communicating means for communicating the socket bores of the respective socket connectors with each other, a coupling flange extending circumferentially around and radially inwardly from the socket wall of each socket connector at a proximal end thereof to the connecting means, each coupling flange forming an end stop for abutting a corresponding one of the pipes extending into the socket bore of the corresponding socket connector, and each coupling flange co-operating with the connecting means and the corresponding socket connector for permitting limited relative movement between the corresponding socket connector and the at least one other socket connector.

In another embodiment of the invention the connecting means comprises a main tubular connecting member coupling two socket connectors together, and defining a main communicating bore extending between the socket bores of the socket connectors for forming the communicating means.

In a further embodiment of the invention the main communicating bore of the main connecting member is of constant transverse cross-sectional area. Alternatively, the main communicating bore of the main connecting member tapers from one end to the other.

Preferably, the main communicating bore of the main connecting member is of circular transverse cross-section.

In one embodiment of the invention the connecting means comprises at least one secondary tubular connecting member branched from the main connecting member, and extending to a corresponding one of the other socket connectors, each secondary connecting member defining a secondary communicating bore of the communicating means for communicating the socket bore of the corresponding socket connector with the main communicating bore of the main connecting member.

In a further embodiment of the invention the secondary communicating bore of each secondary connecting member is of constant transverse cross-sectional area, and preferably, the secondary communicating bore of each secondary connecting member is of circular transverse cross-section.

In one embodiment of the invention the transverse cross-sectional area of the secondary communicating bore of each secondary connecting member is similar to the transverse cross-sectional area of the main communicating bore of the main connecting member.

In another embodiment of the invention the socket bore of each socket connector defines a central socket axis.

In a further embodiment of the invention the central socket axes of two socket connectors are aligned with each other. Alternatively, the central socket axis of one of the socket connectors is offset from the central socket axis of at least one of the other socket connectors.

In one embodiment of the invention the socket bore of each socket connector is of circular transverse oross—section.

Preferably, the pipe connectgrfiis. of plastics material, and advantageously, the pipe connector is formed in one piece by rotational moulding.

In one embodiment of the invention the pipe connector is a reducer comprising two socket connectors for coupling two pipes of different transverse cross-section together. in another embodiment of the invention the pipe connector is a straight connector comprising two socket connectors for coupling two pipes together. in a further embodiment of the invention the pipe connector is a bend connector comprising two socket connectors for coupling two pipes together at an angle relative to each other, and the connecting means is of arcuate shape.

In a still further embodiment of the invention the pipe connector is an elbow connector comprising two socket connectors for coupling two pipes together at substantially 90° to each other.

In a still further embodiment of the invention the pipe connector is a T-connector comprising three socket connectors for connecting three pipes together with one of the pipes extending at an angle relative to the other two pipes. in a further embodiment of the invention the pipe connector is a Y-connector comprising three socket connectors for coupling three pipes together with at least one of the pipes extending at an angle to at least one of the other two pipes.

The invention also provides a method for forming a pipe connector for coupling at least two pipes together, the pipe connector comprising at least two socket connectors, each socket connector comprising a circumferentially extending socket wall defining a corresponding socket bore for engaging an end of a corresponding one of the pipes, and terminating in a distal socket mouth for accommodating the corresponding one of the pipes therethrough to the socket bore, and a connecting means coupling the socket connectors together and defining a communicating means for communicating the socket bores of the respective socket connectors with each other, a coupling flangerextending circumferentially around and radially inwardly from the socket wall of each socket connector at a proximal end thereof to the connecting means to form an end stop for abutting a corresponding one of the pipes extending into the socket bore of the corresponding socket connector, the method comprising forming the pipe connector of plastics material by rotational moulding, and adapting each coupling flange to co—operate with the connecting means and the corresponding socket connector for permitting limited relative movement between the socket connector and the at least one other socket connector.

In one embodiment of the invention the pipe connector is formed in a mould having a mould cavity formed therein defining the outer surface of the pipe connector.

In another embodiment of the invention the mould is a two-part mould, the respective parts being releasably coupled together, and being moveable relative to each other for facilitating removal of the formed pipe connector from the mould.

In a further embodiment of the invention the two parts of the mould are coupled together in a plane containing respective central socket axes defined by the socket bores of at least two of the socket connectors.

In another embodiment of the invention the plane in which the two parts of the mould are coupled contains the central socket axes of each of the socket connectors.

In one embodiment of the invention each part of the mould defines a semi-cylindrical portion of the pipe connector.

Preferably, the mould is rotated about two rotational axes extending at an angle relative to each other, and preferably, the mould is rotated about the two rotational axes extending at 90° relative to each other.

The invention also provides" a mould for moulding a pipe connector for coupling at least two pipes together, the pipe connector comprising at least two socket connectors, each socket connector comprising a circumferentially extending socket wall defininga corresponding socket bore for engaging an end of a corresponding one of the pipes, and terminating in a distal socket mouth for accommodating the corresponding one of the pipes therethrough to the socket bore, and a connecting means coupling the socket connectors together and defining a communicating means for communicating the socket bores of the respective socket connectors with each other, a coupling flange extending circumferentially around and radially inwardly from the socket wall of each socket connector at a proximal end thereof to the connecting means, each coupling flange forming an end stop for abutting a corresponding one of the pipes extending into the socket bore of the corresponding socket connector, and each coupling flange co-operating with the connecting means and the corresponding socket connector for permitting limited relative movement between the socket connector and the at least one other socket connector, the mould having a mould cavity which defines the outer surface of the pipe connector for forming the pipe connector by rotational moulding.

Preferably, the mould is formed in two parts releasably coupled together.

Advantageously, the two parts of the mould are moveable relative to each other for removing the formed pipe connector therefrom. in one embodiment of the invention the two parts of the mould are coupled together in a plane containing respective central socket axes defined by the socket bores of at least two socket connectors. in another embodiment of the invention the plane in which the two parts of the mould are coupled contains the central socket axes of each of the socket connectors.

Preferably, the mould is adapted for use in a rotational moulding process.

[Q ‘Jr outer diameter in the range of 100mm to 1000mm. A particularly important advantage of the invention results from the fact that the connecting means is coupled to the socket connectors for permitting limited relative movement of the respective socket connectors relative to each other. By permitting relative movement, and in particular, relative deflection of the socket connectors, the danger of the pipe connector being fractured during connection to the pipes is avoided. It has been found that it is virtually impossible to connect relatively large diameter pipes, and in particular, relatively large diameter corrugated pipes to a pipe connector without causing one of the socket connectors to deflect relative to the other socket connector or socket connectors, or without causing the socket connector which is being engaged by the pipe to deflect relative to the pipe connector or to the other socket connector or socket connectors. Such deflection of a socket connector relative to a pipe connector or to the other socket connector or socket connectors in many cases can lead to fracturing of the pipe connector, and thus, rendering the pipe connector unusable. By permitting limited deflection of each socket connector relative to the pipe connector, and indeed, relative to the other socket connector or socket connectors, the socket connector which is being engaged by a pipe can deflect relative to the pipe connector and to the other socket connector or socket connectors without the danger of the pipe connector fracturing.

By forming the pipe connector of plastics material in a rotational moulding process, a particularly advantageous form of the pipe connector is provided. Rotational moulding is a particularly simple and relatively inexpensive form of moulding, which requires minimal capital expenditure, particularly on moulds, and thus, the pipe connector according to the invention can be produced relatively efficiently and at relatively low cost using a rotational moulding process.

Additionally, by forming the pipe connector of plastics material by a rotational moulding process, the coupling flanges which couple the socket connectors to the connecting means can be formed so that they co-operate with the connecting means for permitting the limited relative movement between each socket connector and the other socket connector or socket connectors.

The invention will be more clearly understood from the following description of some preferred embodiments thereof, which are given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a pipe connector according to the invention, Fig. 2 is an end elevational view of the pipe connector of Fig. 1, Fig. 3 is a transverse cross-sectional side elevational view of the pipe connector of Fig. 1 on the line Ill-Ill of Fig. 2, Fig. 4 is a transverse cross-sectional side elevational view of the pipe connector of Fig. 1 illustrated in use, Fig. 5 is a cutaway perspective view of the pipe connector of Fig. 1 illustrated in use, Fig. 6 is a cutaway exploded perspective view of the pipe connector of Fig. 1 also illustrated in use, Fig. 7 is a perspective view of a pipe connector according to another embodiment of the invention, Fig. 8 is a side elevational view of the pipe connector of Fig. 7, Fig. 9 is an end view of the pipe connector of Fig. 7, Fig. 10 is a transverse cross-sectional side elevational view of the pipe connector of Fig. 7 on the line X-X of Fig. 9, Fig. 11 is a side elevational view of a pipe connector according to another embodiment of the invention, Fig. 12 is an end view of the pipe connector of Fig. 11, Fig. 13 is a transverse cross-sectional side elevational view of the pipe connector of Fig. 11 on the line Xlll-Xlll of Fig. 12, Fig. 14 is a side elevational view of a further pipe connector according to the invention, Fig. 15 is a plan view of the pipe connector of Fig. 14, Fig. 16 is a transverse cross-sectional side elevational view of the pipe connector of Fig. 14 on the line XVI-XVI of Fig. 15, Fig. 17 is a side elevational view of a pipe connector according to a still further embodiment of the invention, Fig. 18 is an end elevational view of the pipe connector of Fig. 17, Fig. 19 is another end elevational view of the pipe connector of Fig. 17, Fig. 20 is a transverse cross-sectional side elevational view of the pipe connector of Fig. 17 on the line XX-XX of Fig. 19, Figs. 21(a) and (b) are perspective views of respective parts of a mould according to the invention for rotationally moulding the pipe connector of Fig.

Fig. 22 is a top plan view of one of the parts of the mould of Fig. 21, and Fig. 23 is a transverse cross-sectional side elevational view of the mould of Fig. 21 on the line XXIII — XXIII of Fig. 21.

Referring to the drawings and initially to Figs. 1 to 6, there is illustrated a pipe connector according to the invention, indicated generally by the reference numeral 1, for joining two pipes, namely, a first pipe 2 and a second pipe 3 together, see Figs. 4 to 6. in this embodiment of the invention the pipe connector 1 is a straight connector and is particularly suitable forjoining pipes of the type of the first and second pipes 2 and 3 which are of large bore of plastics material having a plurality of spaced apart strengthening hoops 4 extending circumferentially around the pipes. As discussed above, such pipes are commonly referred to as corrugated or twin wall plastics pipes. Typically, such pipes comprise an inner sleeve 5 of plastics material onto which an outer sleeve 6 also of plastics material is shrunk. The outer sleeve 6 is formed with the hoops 4, which define a plurality of grooves 7 therebetween, prior to being shrunk onto the inner sleeve 5.

The pipe connector 1 is of plastics material, namely, medium density polyethylene, and is formed in one piece by rotational moulding according to the invention, as will be described below, although the pipe connector 1 may also be moulded from high or low density polyethylene. The pipe connector 1 comprises a first socket connector 8 and a second socket connector 9 which define respective first and second socket bores 10 and 11 for engaging the first and second pipes 2 and 3, respectively, adjacent ends 12 thereof. A connecting means comprising a main tubular connecting member 15 couples the first and second socket connectors 8 and 9 together. The main connecting member 15 defines a communicating means, in this case a main communicating bore 16 of circular transverse cross-section of constant diameter, which communicates the first and second socket bores 10 and 11, for in turn accommodating fluid flow between the first and second pipes 2 and 3.

The first and second bores 10 and 11 are of constant circular transverse cross- section of similar diameter, and define respective central socket axes which are aligned with each other and coincide with a main central axis 17 defined by the main communicating bore 16.

Each first and second socket connector 8 and 9 is formed by a circumferentially extending socket wall 20 which defines the corresponding first or second socket bore or 11, and terminates in a distal socket mouth 21 for accommodating the corresponding first or second pipe 2 or 3 into the corresponding first or second socket bore 10 or 11. A coupling flange 22 which extends circumferentially around the socket wall 20 of each first and second socket connector 8 and 9 extends radially inwardly from the socket wall 20 at a proximal end 23 of the corresponding one of the first and second socket bores 10 and 11 to the main connecting member 15 for coupling the corresponding one of the first and second socket connector 8 or 9 to the main connecting member 15. The respective coupling flanges 22 form end stops which define the proximal ends of the corresponding first and second socket bores and 11, and abut the ends 12 of the corresponding first and second pipes 2 and 3 in the corresponding first and second socket bores 10 and 11, when the first and second pipes 2 and 3 are fully home in the respective first and second socket connectors 8 and 9.

The coupling flanges 22 are slightly angularly moveable relative to the main connecting member 15 for permitting limited movement of the respective first and second socket connectors 8 and 9 relative to each other. In other words, the slight angular movement of the coupling flanges 22 relative to the main connecting member 15 permits deflection of the first and second connectors 8 and 9 relative to each other from the main central axis 17 as the first and second pipes 2 and 3 are being engaged in the respective first and second socket connectors 8 and 9. The slight angular movement of the coupling flanges 22 relative to the main connecting member 15 is obtained by appropriately matching the wall thickness of the coupling flanges 22 and the strength of the plastics material to provide the appropriate degree of relative angular movement, for in turn providing the desired degree of deflection of the first and second socket connectors 8 and 9 relative to the main central axis 17.

The socket wall 20 of each tirst and second socket connector 8 and 9 is slightly flared outwardly adjacent the distal socket mouth 21 for facilitating entry of the first and second pipes-2 and 13 into the corresponding first and second socket connectors and 9.

In use, prior to entering the first and second pipes 2 and 3 into the flrst and second socket connectors 8 and 9 of the pipe connector 1, O-ring seals 25 are engaged in respective ones of the annular grooves 7 of the first and second pipes 2 and 3 adjacent the ends 12 thereof, see Figs. 4 to 6. One of the first and second socket connectors 8 and 9 is engaged with the end 12 of the corresponding one of the first and second pipes 2 and 3, and the one of the first and second socket connectors 8 and 9 is urged onto the end 12 of the corresponding one of the first and second pipes 2 and 3 over the O-ring seal 25 until the end 12 of the corresponding one of the first and second pipe 2 or 3 engages the coupling flange 22 of the corresponding one of the first or second socket bore 10 or 11. Once the one of the first and second socket connectors 8 and 9 is fully engaged on the corresponding one of the first and second pipes 2 and 3, the other one of the first and second pipes 2 and 3 is similarly engaged in the other one of the first and second socket connectors 8 and 9. During engagement of each of the first and second socket connectors 8 and 9 with the corresponding ones of the first and second pipes 2 and 3, the first and second pipes 2 and 3 may go out of alignment with the main central axis 17, thus causing the first and second socket connectors 8 and 9 also to go out of alignment with each other and to deflect relative to the main central axis 17. The fact that the coupling flanges 22 are provided to be moveable relative to the main connecting member with relative angular movement accommodates the deflection of the first and second socket connectors 8 and 9 relative to the main central axis 17, thereby avoiding any danger of fracturing of the pipe connector 1. Additionally, the flaring of the free ends 26 of the socket connectors 8 and 9 facilitates entry of the O-ring seals 25 into the socket connectors 8 and 9.

Referring now to Figs. 7 to 10, there is illustrated a pipe connector according to another embodiment of the invention, which in this case is a reducer indicated generally by the reference numeral 30. The reducer 30 is substantially similar to the pipe connector 1, and similar components are identified by the same reference numerals. The main difference between the reducer 30 and the pipe connector 1 is that the second socket bore 11 defined by the second socket connector 9 is of smaller diameter than that of the first socket bore 10 of the first socket connector 8, and accordingly, the reducer 30 is suitable for coupling first and second pipes (not shown) of different diameters. In this embodiment of the invention the main communicating bore 16 defined by the main connecting member 15 is of circular transverse cross-section. but tapers from the coupling flange 22 which couples the main connecting member 15 to the first socket connector 8 to the coupling flange 22 which couples the main connecting member 15 to the second socket connector 9.

Additionally, in this embodiment of the invention the first and second socket connectors 8 and 9 define central socket axes 31 and 32, respectively, which are parallel to each other, but offset relative to each other. The coupling flanges 22 co- operate with the main connecting member 15 for facilitating limited angular movement of the coupling flanges 22 relative to the main connecting member 15, for permitting relative angular deflection of the first and second socket connectors 8 and 9 relative to each other. The reducer 30 is rotatably moulded in one piece of plastics material.

Otherwise, the reducer 30 and its use in coupling two pipes together is similar to that of the pipe connector 1.

Referring now to Figs. 11 to 13, there is illustrated a pipe connector according to another embodiment of the invention, which in this case is a bend connector, indicated generally by the reference numeral 40. The bend connector 40 is substantially similar to the pipe connector 1, and similar components are identified by the same reference numerals. The main difference between the bend connector 40 and the pipe connector 1 is that the main connecting member 15 is of arcuate shape for coupling the first and second socket connectors 8 and 9 so that their respective central socket axes 41 and 42 extend at right angles to each other. The diameter of the first and second socket bores 10 and 11 of the first and second sockets 8 and 9 are of similar diameter to each other, and the main communicating bore 16 of the main connecting member 15 is of constant circular transverse cross- sectional area. The coupling flanges 22 co-operate with the main connecting member 15 for facilitating limited angular movement of the coupling flanges 22 relative to the main connecting member 15 so that the first and second socket connectors 8 and 9 can deflect slightly relative to each other. In other words, the first and second socket connectors 8 and 9 can deflect relative to each other, so that the angle defined by the central socket axes 41 and 42 may be slightly greater or less than 90° for accommodating engagement of the bend connector 40 with respective first and second pipes (not shown).

The bend connector 40 is rotatably moulded in one piece of plastics material, and its use in coupling two pipes together is substantially similar to that described with reference to the pipe connector 1.

Referring now to Figs. 14 to 16, there is illustrated a pipe connector according to a 1 further embodiment of the invention, which in this case is a Y or branch connector, indicated generally by the reference numeral 50, for coupling three pipes (not shown), which are each similar to the first and second pipes 2 and 3 described with reference to the pipe connector 1. The branch connector 50 is substantially similar to the pipe connector 1 and similar components are identified by the same reference numerals. The main difference between the branch connector 50 and the pipe connector 1 is that a secondary connecting member 51 extends from the main connecting member 15 for coupling a third socket connector 52 to the main connecting member 15. and in turn to the first and second socket connectors 8 and 9. The third socket connector 52 is similar to the first and second socket connectors 8 and 9, and is provided for engaging a third one of the pipes to be connected. The secondary connecting member 51 defines a secondary communicating bore 54 which communicates a third socket bore 55 defined by the third socket connector 52 with the main communicating bore 16 of the main connecting member 15 for communicating the third socket connector 52 with the first and second socket ’ connectors 8 and 9. The third socket bore 55 defines a central socket axis which coincides with a secondary central axis 56 defined by the secondary communicating bore 54, which extends from the main central axis 17 at an angle or, which in this embodiment of the invention is 45°. However, it will be readily apparent to those skilled in the art that the secondary connecting member 51 may extend from the main connecting member 15 at any desired angle oi, and in the case of a T- connector, the secondary connecting member 51 would extend from the main connecting member 15 so that the secondary central axis 56 would extend from the main central axis 15 at an angle a of 90°.

The coupling flange 22 which couples the third socket connector 52 to the secondary connecting member 51 co-operates with the secondary connecting member 51 for facilitating limited angular movement of the coupling flange 22 relative to the secondary connecting member 51, for in turn facilitating deflection of the third socket connector 52 relative to the secondary central axis 56 for facilitating engagement of the branch connector 50 with the three pipes to be coupled thereto.

The branch connector 50 is rotatably moulded of plastics material in one piece, and its use in coupling three pipes together is substantially similar to that described with reference to the pipe connector 1.

Referring now to Figs. 17 to 20, there is illustrated a pipe connector according to a still further embodiment of the invention, which in this case is a bend connector, indicated generally by the reference numeral 60. The bend connector 60 is substantially similar to the pipe connector 1 and similar components are identified by the same reference numerals. Indeed, the bend connector 60 is virtually identical to the bend connector 40, with the exception that strengthening hoops 61 are formed around the main connecting member 15 for increasing the hoop strength of the main connecting member 15, and in turn the bend connector 60. The strengthening hoops 61 are integrally formed with the bend connector 60 during formation of the bend connector 60, and the bend connector 60 is formed by rotational moulding of plastics material in one piece. Otherwise, apart from the strengthening hoops 61, the bend connector 60 is identical to the bend connector 40, and its use in coupling two pipes together is also similar.

Referring now to Figs. 21 to 23, there is illustrated a mould according to the invention, indicated generally by the reference numeral 70 for moulding the pipe connector 1 by rotational moulding from plastics material. The mould 70 is formed in two identical parts, namely, a first part 71 and a second part 72. The two parts 71 and 72 each comprise a semi-cylindrical portion 74 which defines a semi-cylindrical moulding surface 75 which when the two parts 71 and 72 are joined together define a mould cavity 76, which in turn defines the outer surface of the pipe connector 1, and within which the pipe connector 1 is rotationally moulded. The respective semi- cylindrical portions 74 of the first and second parts 71 and 72 terminate in sidewardly extending flanges 77 which extend around the periphery of the respective first and second parts 71 and 72 forjoining the two parts 71 and 72 together. Abutting faces 78 of the flanges 77 define a split plane along which the first and second parts 71 and 72 are joined. The split plane contains the central axis 17 of the pipe connector 1 as well as the central socket axes of the first and second sockets 8 and 9 which coincide with the main central axis 17. Half rings 79 extend from the moulding surface 75 into the mould cavity 76 for forming the coupling flanges 22 and the main connecting member 15. Portions 80 on respective opposite sides of the half rings 79 of each first and second part 71 and 72 form portions of the mould cavity 76, which form the first and second socket connectors 8 and 9. Angled recesses 81 at respective opposite ends of the mould cavity 76 form the flared ends at the socket mouths 21 of the first and second socket connectors 8 and 9 of the pipe connector 1.

End walls 82 close the mould cavity 76, and an opening 83 in one of the end walls 82 of each part 71 and 72 is provided for venting the mould cavity 76 during moulding. Bores 85 in the respective side flanges 77 of the first and second parts 71 and 72 are provided for accommodating screws 86 forjoining the first and second parts 71 and 72 together.

In use, with the two parts 71 and 72 of the mould 70 separated, the appropriate amount of plastics material in granular or powder form is placed in one of the mould parts 71 and 72. The mould parts 71 and 72 are then secured together with the side flanges 77 abutting each other and secured by the screws 86 through the bores 85.

The mould 70 is then placed in a rotational moulding apparatus and subjected to rotation about two axes perpendicular to each other in a heating station of the moulding apparatus for moulding the pipe connector 1. This aspect of rotational moulding will be well known to those skilled in the art. On completion of moulding of the pipe connector 1, the mould 70 is transferred to a cooling station of the moulding apparatus, where rotation of the mould about the two axes continues, while the mould is cooling for solidifying the pipe connector 1 therein. After cooling to a handling temperature, the parts 71 and 72 of the mould 70 are separated and the moulded pipe connector 1 is removed. End flashes which form on the end walls 82 of the mould 70 are removed by appropriate machining, and the pipe connector is ready for use.

While particular types of pipe connectors have been described, it will be readily apparent that other pipe connectors according to the invention may be provided. For example, the pipe connector may be provided as an elbow pipe connector, a T—plpe connector, and indeed, in certain cases, it is envisaged that the pipe connector when provided as a branch pipe connector, may comprise more than one socket connector branched from the main connecting member. For example, the pipe connector may be a cross-pipe connector, or indeed, may include more than two branches which may branch at any desired angle or angles from the main connecting member, and may be branched from the main connecting member at different angles to each other.

While the mould according to the invention has been described for rotationally moulding the pipe connector described with reference to Figs. 1 to 6, it will be appreciated that suitable moulds according to the invention will be provided for moulding the other pipe connectors described with reference to Figs. 7 to 20, and indeed, it will be appreciated that moulds suitable for rotationally moulding other pipe connectors according to the invention but not illustrated or described will similarly be provided.

While the plastics material from which the pipe connector described with reference to Figs. 1 to 6 has been described as being high, medium or low density polyethylene, the pipe connectors according to the invention may be produced using any other suitable plastics material.

Indeed, in certain cases, it is envisaged that the pipe connectors according to the invention may be formed by an injection moulding process.

It is also envisaged that the pipe connectors of Figs. 1 to 16 may if desired be provided with strengthening hoops, similar to the strengthening hoops of the pipe connector of Figs. 17 to 20. It is envisaged that the strengthening hoops may be required on the larger diameter pipe connectors.

Claims (22)

Claims

1. A pipe connector for coupling at least two pipes together, the pipe connector comprising at least two socket connectors, each socket connector comprising a circumferentially extending socket wall defining a corresponding socket bore for engaging an end of a corresponding one of the pipes, and terminating in a distal socket mouth for accommodating the corresponding one of the pipes therethrough to the socket bore, and a connecting means coupling the socket connectors together and defining a communicating means for communicating the socket bores of the respective socket connectors with each other, a coupling flange extending circumferentially around and radially inwardly from the socket wall of each socket connector at a proximal end thereof to the connecting means, each coupling flange forming an end stop for abutting a corresponding one of the pipes extending into the socket bore of the corresponding socket connector, and each coupling flange co- operating with the connecting means and the corresponding socket connector for permitting limited relative movement between the corresponding socket connector and the at least one other socket connector.

2. A pipe connector as claimed in Claim 1 in which the connecting means comprises a main tubular connecting member coupling two socket connectors together, and defining a main communicating bore extending between the socket bores of the socket connectors for forming the communicating means.

3. A pipe connector as claimed in Claim 2 in which the main communicating bore of the main connecting member is of constant transverse cross-sectional area.

4. A pipe connector as claimed in Claim 3 in which the main communicating bore of the main connecting member tapers from one end to the other.

5. A pipe connector as claimed in any of Claims 2 to 4 in which the main communicating bore of the main connecting member is of circular transverse cross- section,

6. A pipe connector as claimed in any of Claims 2 to 5 in which the connecting means comprises at least one secondary tubular connecting member branched from the main connecting member, and extending to a corresponding one of the other socket connectors, each secondary connecting member defining a secondary communicating bore of the communicating means for communicating the socket bore of the corresponding socket connector with the main communicating bore of the main connecting member.

7. A pipe connector as claimed in Claim 6 in which the secondary communicating bore of each secondary connecting member is of constant transverse cross-sectional area.

8. A pipe connector as claimed in Claim 6 or 7 in which the secondary communicating bore of each secondary connecting member is of circular transverse cross-section.

9. A pipe connector as claimed in any of Claims 6 to 8 in which the transverse cross-sectional area of the secondary communicating bore of each secondary connecting member is similar to the transverse cross-sectional area of the main communicating bore of the main connecting member.

10. A pipe connector as claimed in any preceding claim in which the socket bore of each socket connector defines a central socket axis.

11. A pipe connector as claimed in Claim 10 in which the central socket axes of two socket connectors are aligned with each other.

12. A pipe connector as claimed in Claim 10 or 11 in which the central socket axis of one of the socket connectors is offset from the central socket axis of at least oneother of the socket connectors.

13. A pipe connector as claimed in any preceding claim in which the socket bore 22 of each socket connector is of circular transverse cross-section.

14. A pipe connector as claimed in any preceding claim in which the pipe connector is of plastics material.

15. A pipe connector as claimed in any preceding claim in which the pipe connector is formed in one piece by rotational moulding.

16. A pipe connector as claimed in any preceding claim in which the pipe connector is a reducer comprising two socket connectors for coupling two pipes of different transverse cross-section together.

17. A pipe connector as claimed in any preceding claim in which the pipe connector is a straight connector comprising two socket connectors for coupling two pipes together.

18. A pipe connector as claimed in any of Claims 1 to 16 in which the pipe connector is a bend connector comprising two socket connectors for coupling two pipes together at an angle relative to each other, and the connecting means is of arcuate shape.

19. A pipe connector as claimed in any of Claims 1 to 16 in which the pipe connector is an elbow connector comprising two socket connectors for coupling two pipes together at substantially 90° to each other.

20. A pipe connector as claimed in any of Claims 1 to 16 in which the pipe connector is a T-connector comprising three socket connectors for connecting three pipes together with one of the pipes extending at an angle relative to the other two pipes.

21. A A pipe connector as claimed in any of Claims 1 to 16 in which the pipe connector is a Y-connector comprising three socket connectors for coupling three pipes together with at least one of the pipes extending at an angle to at least one of the other two pipes.

22. A pipe connector substantially as described herein with reference to and as illustrated in