GB2321870A

GB2321870A - Heated moulding apparatus

Info

Publication number: GB2321870A
Application number: GB9702283A
Authority: GB
Inventors: David Nicholson; Mark Butler; Peter Dennis
Original assignee: PDM NEPTEC Ltd
Current assignee: PDM NEPTEC Ltd
Priority date: 1997-02-05
Filing date: 1997-02-05
Publication date: 1998-08-12
Anticipated expiration: 2017-02-05
Also published as: GB9702283D0; GB2321870B

Abstract

A heated mould apparatus includes a block (3) of thermally conductive material provided with one or more slots (7) for receiving a mould assembly (9). A heater (11) is provided for heating the block (3) of thermally conductive material to a predetermined temperature. A mould assembly (9) is provided for receiving a material to be moulded, the mould assembly incorporating an inlet (25) for the material to be moulded and a vent (27) and further incorporating first and second separable mould components (13, 15). The mould assembly (9) is adapted to be received in the one or more slots (7) provided in the block (3) of thermally conductive material. The heated mould apparatus can be used, for example, in the repair of cables.

Description

HEATED MOULD APPARATUS The present invention relates to a heated mould apparatus which may be used, for example, in the repair of cables.

The repair of underwater and other large cables is a complex and time-consuming task which generally involves retrieving the cables and removing them to a suitable location for repair, which involves securing the ends of the broken cable (such as by soldering) and coating the joined ends, for example with a plastics material, for protection and insulation. It would be a significant improvement if such cables could be repaired in situ.

Moreover, the repair, particularly the coating of the joined ends of the cable, takes a substantial time and it would be desirable to reduce the length of time required to repair such cables.

It is therefore an object of the present invention to provide a heated mould apparatus which is capable of applying a plastics coating to the joined ends of a cable without the need to remove the cable to a remote location and in a reduced time.

According to the present invention there is provided a heated mould apparatus comprising a block of thermally conductive material provided with one or more slots for receiving a mould assembly; means for heating the block of thermally conductive material to a predetermined temperature; and a mould assembly for receiving a material to be moulded, the mould assembly incorporating an inlet for the material to be moulded and a vent and comprising first and second separable mould components, the mould assembly being adapted to be received in the one or more slots provided in the block of thermally conductive material.

The slots provided in the block may be tapered such that the width of each slot is narrower at the base than at the mouth thereof. The walls of the one or more slots may be tapered at an included angle of up to about 10 degrees, and preferably at about 4 degrees. The outer walls of the mould assembly may be tapered to conform to the taper of the one or more slots.

The heating means may comprise a flat plate heater or a cartridge heater which may be secured to a face of the block, for example the underside thereof. Alternatively, the heating means may comprise means for heating the block with steam. A temperature sensor may be provided for controlling the temperature of the heater such that the block is maintained at the predetermined temperature. The predetermined temperature may be constant or may be variable, for example under user control.

The mould assembly may include a bore extending therethrough for receiving an article to have the material moulded thereto. The bore may have a greater crosssectional area in a central region than in outer regions thereof. The inlet and vent may communicate with the central region of the bore.

The mould assembly components may be provided with means for securing the components together. The securing means may comprise co-operating bores provided in the mould assembly components and dowel means removably secured into the bores.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 is an exploded perspective view of a portable heated mould apparatus for repairing cables in situ; Figure 2 is a side elevational view of a modified mould retaining block forming part of the apparatus shown in Figure 1; Figure 3 is a side elevational view of one component of a mould assembly forming part of the apparatus shown in Figure 1; Figure 4 is a top plan view of the mould assembly component shown in Figure 3; Figure 5 is an end elevational view of two mould assembly components forming a mould assembly; Figure 6 is a cross-sectional view of the mould assembly shown in Figure 5; and Figure 7 is a circuit diagram illustrating a heater mat for the mould apparatus and control means therefor.

The mould apparatus shown in the figures is portable and can therefore be used at any convenient location for repairing cables on site. The apparatus comprises a base box 1 having mounted thereon a heated block 3. The block 3 is secured to, but spaced a small distance above, the base box.

The base box is conveniently made of a coated metal and is provided with a handle 5 at each end to facilitate carrying of the apparatus and contains circuitry for controlling heating of the block 3 as will be explained in more detail hereinafter.

The heated block 3 is shown in Figures 1 and 2 and is made of a suitable thermally conductive material, such as aluminium or an aluminium alloy, and is formed with a number of slots 7, five as illustrated in Figure 1 and four as illustrated in Figure 2, for receiving a mould assembly 9 as will be explained in more detail hereinafter. The slots 7 are tapered such that the width of each slot is narrower at the base and wider at the top. The effect of this is that the mould assemblies 9 are effectively retained within the slots, urging the components of the mould assemblies together and improving thermal conduction from the heated block 3 to the mould assemblies 9, while at the same time facilitating removal of the mould assemblies from the block 3 when required. The walls of the slots 7 may be inclined at any suitable included angle, for example in the range up to 10 degrees relative to each other, with an angle of about 4 degrees being preferred. A flat plate heater 11 (shown in Figure 7) is clamped to the underside of the heated block 3 by any suitable means, such as clamping bars (not shown). Alternatively, the heating means may comprise a cartridge heater or means for heating the block with steam.

The mould components are shown in Figures 1 and 3 to 6, the mould assembly 9 being made from two separable mould components 13 and 15. The mould components may be made of a thermally conductive material, for example of aluminium or an aluminium alloy. The mould assembly is formed with an elongate, generally cylindrical, bore 17 for receiving a cable 19 (shown in dashed lines) which is being repaired, the cable comprising a metallic conductor encased in a plastics insulating sheath. The ends of the metallic conductor have previously been secured together, as by soldering, but the exposed cable requires insulation. The central region 21 of the bore 17 is of greater cross sectional area, that is of greater diameter, than the outer regions 23 such that the outer regions engage closely against the insulating sheathing of the cable with the sheathing extending into the central region 21 to ensure an effective seal between the existing sheathing and the new sheathing that is to be applied to the joined ends of the cable. The central section 21 of the bore 17 communicates at each end thereof with an upright bore 25, 27. One upright bore 25 serves as an inlet bore for new sheathing material, while the other upright bore 27 serves as a vent.

The lower region of each mould component 13, 15 is provided with two holes 29 and 31, the holes of one component aligning with the holes of the other component. A dowel 33 is secured into the holes to position the two mould components together during the repair process. The outer walls of the mould assembly 9 are tapered such that the width of the mould assembly is narrower at the base and wider at the top, the taper being such as to conform to the taper of the slots 7 in the heated block 3. The reasons for the taper have been explained hereinbefore.

The block 3 is heated by way of the flat plate heater 11, the heater and the controls therefor being illustrated in Figures 1 and 7. A power input socket 34 is arranged at a suitable location on the box 1, for example in the region of the middle of one side, and a control knob 35 is provided at one end of the box. A temperature sensor 37 is located in thermal contact with the heater 11, for example a thermistor may be embedded in the heater, and serves to regulate the temperature of the heated block 3 to a predetermined value by way of a controller 39. The predetermined value may be fixed, for example at about 70 "C or may be selected by the user by way of the control knob 35.

The mould apparatus is used by first joining the ends of the cable as explained above, for example by soldering, and securing the cable between the two mould components 13 and 15 such that the insulation material remaining on the cable extends into the central region 21 of bore 17. A curable plastics material, such as a two-part cold cure polyurethane material, is poured into the central region 21 through inlet bore 25, while air is vented through the vent bore 27. Although a cold cure polyurethane material will cure at room temperature, the curing time can be accelerated by heat. The mould assembly 9 (comprising the mould components 13 and 15 secured together) is therefore placed in a slot 7 in the heated block 3, the taper provided on the mould assembly and in the slots facilitating insertion, thermal contact and, in due course, removal. The block 3 is then heated to the predetermined temperature by the user manipulating the control knob 35 to energise the heater 11.

Once the plastics material has set, the heater can be deenergised and the mould assembly 9 removed from the slot 7 and dismantled. It has been found that this method of repairing the sheathing of a cable gives rise to very good adhesion between the new sheathing material and the original sheathing material and can be effected very much more quickly than previously, for example in as little as four minutes as compared with up to about two hours previously. Moreover, the repair can be effected on site and the cable does not require to be removed to another location.

As can be seen from the drawings, it is possible to repair up to four cables simultaneously with the illustrated apparatus, but the number of slots can be varied as required.

Additionally, it is possible to employ in conjunction with the apparatus described in relation to Figures 1 to 7 a plastics material which cures at a raised temperature.

This has the advantage that it is not necessary to mix and use the plastics material within a fixed time.

Claims

1. A heated mould apparatus comprising: a block of thermally conductive material provided with one or more slots for receiving a mould assembly; means for heating the block of thermally conductive material to a predetermined temperature; and a mould assembly for receiving a material to be moulded, the mould assembly incorporating an inlet for the material to be moulded and a vent and comprising first and second separable mould components, the mould assembly being adapted to be received in the one or more slots provided in the block of thermally conductive material.

2. A heated mould apparatus as claimed in claim 1, wherein the slots provided in the block are tapered such that the width of each slot is narrower at the base than at the mouth thereof.

3. A heated mould apparatus as claimed in claim 2, wherein the walls of the one or more slots are tapered at an included angle of up to about 10 degrees.

4. A heated mould apparatus as claimed in claim 3, wherein the walls of the one or more slots are tapered at an included angle of about 4 degrees.

5. A heated mould apparatus as claimed in claim 3 or 4, wherein the outer walls of the mould assembly are tapered to conform to the taper of the one or more slots.

6. A heated mould apparatus as claimed in any preceding claim, wherein the heating means comprises a flat plate heater.

7. A heated mould apparatus as claimed in any one of claims 1 to 5, wherein the heating means comprises a cartridge heater.

8. A heated mould apparatus as claimed in claim 6 or 7, wherein the heating means is secured to a face of the block.

9. A heated mould apparatus as claimed in claim 8, wherein the heating means is secured to the underside of the block.

10. A heated mould apparatus as claimed in any one of claims 1 to 5, wherein the heating means comprises means for heating the block with steam.

11. A heated mould apparatus as claimed in any preceding claim, wherein a temperature sensor is provided for controlling the temperature of the heater such that the block is maintained at the predetermined temperature.

12. A heated mould apparatus as claimed in claim 11, wherein the predetermined temperature is constant.

13. A heated mould apparatus as claimed in claim 11, wherein the predetermined temperature is variable.

14. A heated mould apparatus as claimed in claim 13, wherein the predetermined temperature is variable under user control.

15. A heated mould apparatus as claimed in any preceding claim, wherein the mould assembly includes a bore extending therethrough for receiving an article to have the material moulded thereto.

16. A heated mould apparatus as claimed in claim 15, wherein the bore has a greater cross-sectional area in a central region than in outer regions thereof.

17. A heated mould apparatus as claimed in claim 15 or 16, wherein the inlet and vent communicate with the central region of the bore.

18. A heated mould apparatus as claimed in any preceding claim, wherein the mould assembly components are provided with means for securing the components together.

19. A heated mould apparatus as claimed in claim 18, wherein the securing means comprises co-operating bores provided in the mould assembly components and dowel means removably secured into the bores.

20. A heated mould apparatus substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.