This invention relates to mould cores, and more particularly to a mould core for an angled joint coupler.

In the art of electrofusion couplers manufacture, most of the couplers which have been proposed hitherto have been straight in-line couplers. The electrofusion coils are first helically wound upon a core, the ends of the coils are connectorised, and the core is placed in a mould. Plastics material is then injected into the mould, forming the shape of the coupler and surrounding the electrofusion coils, which become embedded in the plastics material, Finally the core is removed and the coupler is ready for use.

It will be apparent that the winding of the electrofusion coils onto the core is quite straightforward in the case of an in-line joint, because the core can easily be rotated to form the helical turns of wire. It is also a simple matter to connect the coils together by passing the wire along the core. This is, however, not so with an angled joint, for example an elbow joint, where the core cannot be rotated to wind the turns of wire thereupon.

It has been proposed to form an elbow joint by using a core which is in two halves, each half having an angled

CONFIRMATION COW

end face. The coils are separately wound on the core halves which are then connected by their angled end faces to form the elbow. Finally the two coils are connected together in a separate operation. This method involves several extra handling steps, which add greatly to the cost of manufacture.

In GB 2268436 there is described a method for manufacturing an elbow socket connector which utilises a core comprising two parts which are releasably directly connectable together in a substantially straight configuration to facilitate winding of an electrically conductive wire over the core parts for incorporation in the connector and in an elbow configuration for positioning in a mould for moulding the connector. The present invention provides a new mould core for an angled joint, and a method for winding electrofusion coils thereon which, in preferred embodiments, can enable the coils to be wound in-line, and a connection to be made by passing the wire along the core, in the same way as described hitherto for in-line joint core winding. According to the invention this is achieved by providing a mould core in two or more parts which can be assembled either in an in-line or in an angled configuration.

In a first aspect, therefore, the invention provides a mould core assembly for an angled joint coupler which comprises first and second elongate mould parts which can be assembled, together with a spacer means, in a first

in-line configuration, wherein the longitudinal axes of the elongate mould parts lie parallel or on a common axis of rotation, and in a second, angled configuration.

In a second aspect of the invention there is provided a mould core assembly for an angled joint coupler which comprises:

a first elongate core part having an end face which is at an oblique angle with respect to the longitudinal axis of the first core part;

a second elongate core part having an end face mateable with the angled end face of the first core part; and

a spacer means mateable with the angled end face of the first core part and the end face of the second core part and so shaped as to connect the core parts about a common longitudinal axis of rotation and to be de¬ mountable or rotatable with respect thereto.

Preferably the mould core assembly comprises:

a first elongate core part having an end face which is at an oblique angle with respect to the longitudinal axis of the first core part; and

a second elongate core part having an end face which is at an oblique angle with respect to the longitudinal axis of the second core part and which is mateable with the angled end face of the first core part. In a further aspect the invention provides a method for winding electrofusion coils onto a mould core assembly, the assembly comprising two or more elongate parts which can be assembled in a first in-line configuration, together with a spacer means, wherein the longitudinal axes of the elongate parts lie parallel or on a common axis of rotation, and in a second, angled configuration, in which the electrofusion coils are wound upon the mould core assembly whilst it is in the said in¬ line configuration, and the assembly is then converted to an angled configuration.

In a preferred embodiment, the assembly comprises a spacer means which, in the first configuration, is so shaped as to distance the first and second core parts such that when electrofusion coils are wound thereupon, the distance between adjacent ends of the coils corresponds to the length of the outer surface of the bend angle. With this arrangement, when the cores are mated together, a bridge wire connecting a coil on the first core part to a coil on the second core part can lie flush with the outer surface of the bend around the angled joint when the spacer means is removed.

Preferably the spacer means is so shaped that the assembly of the cores and the spacer means is stable under end load, in order to permit simultaneous rotation of the cores without disconnection, but the spacer means is de-mountable when the end load is removed.

After the coils have been wound on the first and second core parts, the spacer means is preferably de¬ mountable without severing the bridge wire between the coils.

An embodiment of the invention will now be described with reference to and as illustrated in the accompanying Drawings in which:

Figure 1 shows an exploded view of a mould core assembly according to the invention in its first configuration in side elevation;

Figure 2 shows the assembled mould core assembly of Figure 1 in side elevation, after coil winding has commenced;

Figure 3 shows the mould core assembly with the completed electrofusion coils wound thereupon, also in side elevation;

Figure 4 is a side elevational exploded view of the assembly of Figure 3, showing the removal of the spacer; and

Figure 5 shows the mould core assembly in its angled configuration with the electrofusion coils wound thereupon and ready for moulding.

Referring now to Figure 1, the mould core assembly illustrated generally at 1 comprises a female core part 2 and a male core part 3, separated by a spacer 4. The female core part 2 has an obliquely angled end surface 5 with a recessed slot 6 therein. The external surface 7 of the core part 2 is curved to provide a smooth outer surface for the angled bend. The core part 3 is of similar shape and has a similarly obliquely angled end surface 8, which has a location lug 9 extending therefrom.

The spacer 4 is of generally triangular shape and has obliquely angled surfaces 10, 11 which are provided respectively with a location lug 12 and a recessed slot 13. The lug 12 is profiled to cooperate with the slot 6 and the lug 9 is similarly profiled to cooperate with the slot 13. It can readily be seen that the angled surfaces 5, 10, 8 and 11 are such that when the spacer is mated with the first and second core parts the entire

assembly has a longitudinal axis which includes the longitudinal axes of the first and second core parts.

The assembly of core parts and spacer is shown in Figure 2. An end load applied to the core part ends 14 and 15, which are the ends remote from the spacer, is sufficient to maintain stability of the assembly and to permit axial rotation thereof. In Figure 2, winding of the coil 16 on core part 2 has commenced. A first end of the electrofusion wire is connected to a first terminal 17, mounted on the core part 2, and the assembly is then rotated to wind the helical coil 16 onto the core part 2.

Figure 3 shows the assembly with the winding completed. After the first coil 16 has been wound, its second end is anchored by a weld or crimp to an anchor point 18. Without breaking the wire, it can then be extended to the second core part and anchored by a weld or crimp to a second anchor point 19. This results in the formation of a bridge wire 20 extending between the coils 16 and 21. When the coil 21 has been fully wound, its end is again anchored to a second terminal 22. Preferably the terminals 17, and 22, and the anchor points 18 and 19, comprise shearable terminals as described in our European Patent No. 0260014, the entire disclosure of which is incorporated herein by reference.

Figure 4 shows the release of the spacer 4 whilst maintaining the bridge wire 20 intact. This can be readily achieved by removing the end load and angularly displacing the core parts 2 and 3 to allow the spacer 4 to drop away.

The wound core assembly, ready for moulding, is shown in Figure 5. The end faces 5 and 8 are mated together with the location lug 9 located in the recessed slot 6 (not shown in Figure 5). The bridge wire 20 is of the correct length to fit around the angled bend 23 formed by the core parts 2 and 3.

Although the invention has been described with reference to a 90° angled joint coupler mould core, it will be apparent that any other angle, for example 30°, 45° or 60° may be similarly produced using core parts with appropriately angled faces.

In certain embodiments of the core assembly of the invention it may not be necessary to remove the spacer 4 which, in such embodiments, may be connected to each of the core parts, for example, by joints or connecting means permitting relative axial rotation. In such cases it would be possible to rotate each of the core parts 2 and 3 axially with respect to the spacer 4, about the rotatable connecting means, so that the completed

assembly forms a bend with the spacer situated at the apex of the bend.

The reader's attention is directed to all papers and documents which are filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps or any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features

disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.