Technical Field The present invention relates to the field of joining (splicing) or repair of rubber or rubber- containing layers, and in particular to the splicing or repair of conveyor belts, rubber-coated rollers or conveyor systems.

Background

Conveyor belts, particularly those for heavy industrial use, may need to be installed or repaired in situ at the site of use. At the installation stage, the two ends of the belt material are spliced together to form the continuous belt. If a belt is made up from multiple sections of belt material, each section will need to be spliced to the previous section. If the conveyor belt is damaged, a new section may need to be spliced in or the existing damaged section repaired.

After preparation of the belt, the repair or splicing operation involves the application of a rubber- based repair medium or repair patch to the conveyor, followed by the application of heat and pressure which vulcanises the repair medium or patch to effect the splice or repair. This is known as a "hot vulcanising" process.

The systems currently used for installation and repair are heavy and cumbersome due to the use of metal frameworks to contain the conveyor belt. Current systems are sold by Shaw Almex, Wagner Schwelm, Nilos, Beltwin and MLT, among others. A current system to hot vulcanise a 900mm wide belt can weigh in excess of 400kg. The process of getting the equipment to site is, therefore, lengthy and expensive requiring the use of heavy lifting equipment. Current systems are also not flexible in terms of the repair width; machines can be added to increase the length of the repair along the belt direction, but the width is governed by the maximum width of the support beams, which is usually 1 metre. Current systems also work at high pressure, in the range of 75-200 psi, and it would be advantageous to be able to work at lower pressures to lower the cost and size/weight of the equipment. Summary of the Invention

In accordance with a first aspect, the invention relates to an airbag cover for use in the joining or repair of a rubber or rubber-containing layer by a hot vulcanising process, the cover being made from a flexible material and comprising at least one pocket for containing an airbag and comprising means for locating one or more attachment straps for securing the cover to or around the rubber or rubber-containing layer. Preferably, the means for locating one or more attachment straps comprises one or more loops in the top surface of the cover. The loops form passages or channels into which the attachment straps can be inserted.

The airbag cover may comprise two pockets, one pocket for containing an airbag and the other pocket for containing a reinforcing plate or a heat pad. Alternatively, the airbag cover may comprise a single pocket for an airbag.

In accordance with a second aspect, the invention provides an airbag assembly for use in the joining or repair of a rubber or rubber-containing layer by a hot vulcanising process, the assembly comprising the airbag cover described above and an airbag located in the pocket of the airbag cover.

In accordance with a third aspect, the invention relates to apparatus for applying heat and pressure to a rubber or rubber-containing layer during joining or repair of the layer a by a hot vulcanising process, the apparatus comprising the airbag cover described above, an airbag for locating in the pocket of the airbag cover, a reinforcing plate, a heat pad, and one or more attachment straps for securing the cover to or around the rubber or rubber-containing layer.

In a preferred embodiment, the apparatus includes a plurality of airbag covers, each airbag cover further comprising means for attaching one cover to an adjacent cover to form a composite airbag structure from a plurality of modular individual airbag covers. In accordance with a fourth aspect, the invention provides two sets of apparatus as described above, the sets being located on either side of the rubber or rubber-containing layer during the hot vulcanising process. In a preferred embodiment, the apparatus includes a control system for controlling the airbags and/or heat pad.

The one or more attachment straps may comprise belts, cables or the like, but preferably The one or more attachment straps comprise a ratchet strap.

Preferably, the reinforcing plate comprises a planar plate and two right-angled reinforcing bars along opposite sides of the plate. Means for attaching one reinforcing plate to an adjacent reinforcing plate may be provided, to form a composite reinforcing structure from a plurality of individual reinforcing plates.

The invention also relates to a method of joining or repairing a rubber or rubber-containing layer by a hot vulcanising process employing the apparatus described above, comprising the steps of applying a rubber-based repair medium or repair patch to the layer, attaching or securing the apparatus to or adjacent to the repair area, and activating the airbag and heat pad to apply heat and pressure to the layer to vulcanise the repair medium or patch to effect the join or repair.

In any aspect of the invention, the airbag cover is preferably substantially planar when not in use (i.e. when the airbag is not inserted in the cover or is not inflated). In plan view, the cover may be of any suitable shape, but preferably it is rectangular or square. In the modular system, the airbag covers may all be of uniform size and shape. Alternatively, the covers may be of different sizes or shapes, which provides increased flexibility so that the most appropriate overall shape may be selected.

The heat pad is preferably electrical. Preferably the heat pad is flexible, and more preferably comprises a heavy duty electrical heating element encased in rubber such as chlorobutyl.

The technology described may be employed in the joining or repair of conveyor belts of all types, including heavy duty conveyor belts used in mining, quarrying and off-the-road mining, as well as covered support rollers such as those employed in conveyor systems. In at least preferred embodiments of the invention, the system is lightweight and portable. In fact, everything needed for the operation can be carried in a small van. The invention avoids the need for a heavy, rigid support frame through the use of a flexible airbag cover and a reinforcing plate, together with a heat pad and an attachment system which preferably employs lightweight straps.

Although preferably planar, the shape or profile of the reinforcing plate could be adapted to suit the shape/contours of the layer bring joined or repaired, and the airbag within the flexible cover can also adapt to the shape and contours of the reinforcing plate.

The modular nature of preferred embodiments provides a very flexible system which can be readily adapted to suit the desired join/repair area. A single hot vulcanising unit can be added to as required by the operator to facilitate larger joins or repairs. As conveyor belts come in a large amount of sizes and thicknesses, the versatility of this system makes it particularly efficient and easy to handle. Additional components can be purchased as required without the necessity to purchase a whole new system.

The system is straightforward to assemble and operate. In testing, the system has been proven to provide high-quality joins and repairs, with a strength comparable to or even improved on that given by the very heavy prior art systems that have been used for many years.

Brief Description of the Drawings Fig. 1 shows a schematic, cross-sectional view of a conveyor belt repair system in accordance with a first embodiment of the invention, with attachment straps removed;

Fig. 2 shows a schematic, cross-sectional view of the conveyor belt repair system of Fig. 1 with attachment straps present;

Fig. 3 shows a side elevation view of the embodiment of Fig. 1 with attachment straps removed; Fig. 4 shows a plan view of the embodiment of Fig. 1 with attachment straps present;

Fig. 5 shows a perspective view of a reinforcing plate for use in the invention;

Fig. 6 shows a perspective view of a configuration of two reinforcing plates for use in the invention; Fig. 7 shows a perspective view of an alternative configuration of two reinforcing plates for use in the invention;

Fig. 8 shows a perspective schematic view of an airbag assembly for use in the invention;

Fig. 9 shows a photograph of a complete repair system in accordance with the first embodiment; Fig. 10 shows a perspective view of a conveyor repair containment pack in accordance with a second embodiment;

Fig. 11 shows a perspective view of a conveyor repair containment pack system in accordance with a third embodiment;

Fig. 12 shows a perspective view of a primary containment pack in accordance with the third embodiment;

Fig. 13 shows a perspective view of a secondary containment pack in accordance with the third embodiment;

Fig. 14 shows a perspective view of an outer containment pack in accordance with the third embodiment;

Fig. 15 shows a plan view of a first combination of primary, secondary and outer containment packs;

Fig. 16 shows a plan view of a second combination of primary and outer containment packs; Fig. 17 shows a plan view of a third combination of primary and secondary containment packs; Fig. 18 shows a plan view of a fourth combination of primary and secondary containment packs; Fig. 19 shows a plan view of a primary containment pack;

Fig. 20 shows a perspective view of an air bag cover for containing an airbag suitable for use in the system of the present invention;

Fig. 21 shows a perspective view of a heat pad cover for containing a heat pad suitable for use in the system of the present invention;

Fig. 22 shows a side view of a conveyor repair containment pack system in accordance with the third embodiment;

Fig. 23 shows plan and side views of the conveyor repair containment pack system of Fig. 22 in use on a first conveyor belt, in which heat and pressure are required on both sides of the belt; Fig. 24 shows plan and side views of the conveyor repair containment pack system of Fig. 22 in use on a second conveyor belt with a support bed, in which heat and pressure are required on only one side of the belt;

Fig. 25 shows a roller repair containment pack in accordance with a fourth embodiment;

Fig. 26 shows a perspective view of multiple roller repair containment packs of Fig. 25; Fig. 27 shows side and end views of a rigid-framed containment pack system in accordance with a fifth embodiment;

Fig. 28 shows the use of the rigid-framed containment pack of Fig. 27 in a multiple-repair configuration, with single and combined packs;

Fig. 29 shows the use of the rigid-framed containment pack of Fig. 27 in a multiple-repair configuration;

Fig. 30 shows a basic control unit for use with the containment packs of the invention;

Fig. 31 shows a standard control unit for use with the containment packs of the invention;

Fig. 32 shows combined basic and standard control units for use with the containment packs of the invention;

Fig. 33 shows a large control unit for use with the containment packs of the invention;

Fig. 34 shows a standard control panel operating multiple heat pads; and

Fig. 35 shows a standard control panel operating multiple airbags. Detailed Description of Preferred Embodiments

First Embodiment

Fig. 1 shows a front elevation view of a conveyor belt repair system in accordance with a first embodiment. The conveyor belt 10 undergoing repair or splicing is shown at the centre. On each side of the belt, moving outwards, is shown a heat pad 120, reinforcing plate 130 and airbag assembly 140. The various components are shown separated for clarity. In practice, each component will be in contact with the adjacent one. The entire assembly will be strongly secured together by attachment straps 150 shown in Fig. 2. Fig. 3 shows a side elevation view and Fig. 4 shows a plan view of the arrangement.

Heat pads 120 are placed between the reinforcing plates 130 and conveyor belt 10. Heat pad 120 is preferably an electrical heat pad, to be connected to an external electrical power source via an electrical connector (not shown). The pad is strong but flexible, and is designed to withstand the extreme conditions. A preferred construction is a rubber-encapsulated electric heating element with the required durability to operate reliably under the pressure and temperature of the hot vulcanising process. Depending on the thickness of the repair, only one heat pad on one side of the conveyor belt 10 may be required. For full-thickness repairs or splicing, a heat pad will be required both above and below the conveyor belt 10. Each heat pad may be provided with a handle 121 (Figs. 3 and 4). A preferred heat pad comprises a heavy duty heating element encased in chlorobutyl. The temperature is controlled to 150°C by a thermocouple.

Reinforcing plates 130 comprise a planar or flat plate 131 and two right-angled reinforcing bars 132 along opposite sides of the plate. Each reinforcing plate therefore has a broad, U-shaped cross-section when viewed from the front (Figs. 1 and 2). In a preferred embodiment, the flat plate 131 is made from a 12mm thick sheet of aluminium. Each leading end of the plate is cut with a 180° radius to prevent damage to attachment straps 150 or any other component. The purpose of the reinforcing plates is to provide rigidity to the system in use, so that the heat pads 120 remain flat against the conveyor and the pressure from the airbags is applied evenly across the working area. The plates may provide a limited amount of flexibility so that the heat pads can conform to the surface of the conveyor belt 10.

In a preferred embodiment, one or both reinforcing plates may be provided with an additional reinforced radiator sheet which has internal channels for water or air so that the system can be more rapidly cooled after the hot vulcanisation process.

Fig. 5 shows a perspective view of reinforcing plate 130. A series of holes 133 are provided at desired positions on each reinforcing bar 132 which allow adjacent reinforcing plates to be bolted together in a side-by-side configuration (Fig. 6 - for wider belts) or in an end-to-end configuration (Fig. 7 - for longer repairs or splices along the belt direction), the latter configuration being achieved with the addition of connecting plates (not shown). These configurations increase the overall size of the system and therefore allow larger repairs to be carried out in a single operation. With reference to Figs. 1-4 and 8, airbag assembly 140 comprises an internal chlorobutyl rubber airbag bladder (not shown) and several heavy duty fabric covers (made from e.g. nylon) which provide abrasion resistance and prevent the bladder from over inflating. The outermost cover 141 is shown in more detail in Figs. 4 and 8. Cover 141 provides a pocket into which the airbag (including any internal covers) is inserted. Cover 141 is provided with loops 142 which form passages or channels for attachment straps 150 (shown as hatched areas in Fig. 4). The loops 142 hold the straps in the correct location during inflation of the airbag and help to simplify the set-up operation. Buckles or preferably ratchets (not shown) may also be required to secure the attachment straps 150. Apertures 143 are provided in the outer cover 141 and the inner covers, to allow the airline fitting 144 to extend through the covers from the internal airbag. In use, the airbag assembly 140 sits in between the reinforcing bars 132 of the reinforcing plate 130, so the reinforcing bars help to locate and restrain the airbag assembly 140 as well as providing rigidity to the reinforcing plate 130.

As mentioned in the Background section above, the hot vulcanising repair and/or splicing operation involves the application of a rubber-based repair medium or repair patch to the conveyor, before the application of heat and pressure which vulcanises the repair medium or patch to effect the repair. The repair medium or patch may comprise or include rubber cement and a thin layer of uncured rubber. The repair medium or patch is applied to the belt 10 before the stack of components described above is placed onto/around the conveyor. Ratchet straps 150 are placed around the outside of the components and secure the repair system around the belt. The resulting assembly is shown in Fig. 9.

With the heat pads 120 connected to the electrical supply and the airbags 140 connected to the air supply, the air bags are inflated and, with the heat pads 120 at temperature (typically 150°C), the required heat and pressure is applied to the repair for the appropriate duration.

The invention allows a lower inflation pressure than the prior art systems. Typically, a pressure of around 30psi has been shown to work well.

The construction and arrangement of further embodiments of the invention will now be discussed in more detail. The invention can provide a modular containment pack system in which a number of units can be connected to form larger or more complex arrangements, which can be configured for the specific shape of repair or splice required.

Second Embodiment - Single-design Modular Containment Pack

In a basic form, as shown in Fig. 10, the invention provides a uniform, single-design conveyor containment pack 200. In this system, all modular sections are the same size and configuration. The containment pack 200 is made from a heavy duty fabric and comprises a pocket for an airbag and optionally a pocket for a reinforcing layer or a heat pad. The containment pack 200 can be used as a single unit or combined with further packs for larger repairs. A combination of D-rings 201 and corresponding straps (not shown) allow multiple units to be interconnected. The top cover is provided with loops 202 which form passages or channels for conveyor attachment straps 203. Buckles or ratchets (not shown) may also be required to secure the attachment straps 203. All materials should be designed to withstand the extreme conditions encountered in the field.

Third Embodiment - Modular Containment Pack System

A more versatile modular system in accordance with the invention is shown in Figs. 11 to 19. This system allows for a greater range of sizes to be built up around a primary containment pack, employing further containment packs which may have different sizes and configurations. The system shown in Fig. 11 is built up around a primary containment pack 300, two secondary containment packs 310 and six outer containment packs 320, as described further below. Loops 301 and conveyor attachment straps 302 are shown. Buckles or ratchets (not shown) may also be required to secure the attachment straps 302.

A primary conveyor containment pack 300 is shown in more detail in Fig. 12. The primary pack is provided with a lip 303 all the way round (e.g. 2" or 5cm wide). The lip 303 is used as an initial attachment point using a hook-and-loop (e.g. Velcro) or similar attachment system to facilitate the initial assembly of multiple units, with corresponding attachment components provided on the other units, before the conveyor straps 302 are made fast. This primary unit 300 can be used on its own if desired.

A secondary conveyor containment pack 310 is shown in Fig. 13. The secondary packs 310 attach to each side of the primary containment pack 300, and in this preferred embodiment, the secondary also has a 2" (5cm) lip 311 with hook-and-loop (e.g. Velcro) or similar attachment system on two sides, to attach to other packs in the system.

An outer conveyor containment pack 320 is shown in Fig. 14. The outer packs 320 fit each side of the primary and secondary packs as seen in Fig 11.

The inter-containment pack attachment system is described in more detail below, with reference to Fig. 22.

Primary, secondary and outer containment packs may be made in any convenient size or range of sizes. With reference to Figs. 15 to 19, through any combination of primary, secondary and outer containment packs in any size, the required curing area can be achieved. Examples which are shown as follows:

FIG 15: 1 large primary, 1 large secondary, 2 large outer, 2 medium outer, 1 small outer,

1 medium outer narrow, 1 secondary narrow.

FIG 16: 1 large primary, 2 large outer

FIG 17: 1 small primary, 2 medium secondary

FIG 18: 1 medium primary, 2 secondary

FIG 19: 1 primary

Fig. 20 shows an air bag cover 331 for containing an airbag suitable for use in the system of this embodiment of the present invention. A range of airbags in various shapes and sizes may be provided. Each airbag assembly may be placed inside a specially-designed cover set as shown in Fig 22. A hook-and-loop (e.g. Velcro) or similar attachment system may be used to initially assemble the system, and this facilitates the use of more than one airbag. Multiple airbags may be needed for more complex repair topography, to achieve the correct shape of repair.

Fig. 21 shows a heat pad cover 351 for containing a heat pad suitable for use in the system of this embodiment of the present invention. Preferably, the pad is strong but flexible, and is designed to withstand the extreme conditions. Heat pads may be provided in multiple sizes, with or without covers.

Details of the system for attaching containment packs to one another and for securing the containment packs around the conveyor are shown in Figs. 22 to 24.

Fig. 22 shows a primary containment pack 300 attached to an outer containment pack 320. Both packs have strap guides or loops 301 for conveyor attachment straps 302 to pass though. They are also provided with containment pockets 321 and 322 for airbags and reinforcing layers respectively. The containment packs are preferably made of heavy duty fabric such as nylon.

The inset shows the attachment of the primary 300 to the outer 320, employing a hook-and-loop (e.g. Velcro) or similar attachment system, as mentioned above. The hook-and-loop system is used to aid the initial build of the containment pack system prior to final securement with the straps. One component of the hook-and-loop attachment system is provided on the underside of lip 303 of the primary containment pack 300 and the other component is provided on the upper outer edge 321 of the outer containment pack 320.

The combined primary and outer containment pack system of Fig. 22 is shown in-use in Figs. 23 and 24. As mentioned above, before the application of heat and pressure by the repair system of the invention, a rubber-based repair medium or repair patch will be applied to the conveyor. The heat and pressure subsequently applied vulcanises the repair medium or patch to effect the repair. The appropriate repair method will depend on the size and type of repair and the technical features of the conveyor belt system.

Fig. 23 shows a repair requiring heat and pressure on both sides of the same belt 10, with heat pads 350 located either side of the belt 10. The securement straps 302 are wrapped around the belt as shown in the end on view Fig. 23B, with combined containment packs above and below. Buckles or ratchets 304 are shown schematically as black circles and are used to tighten the straps 302 to secure the system around the conveyor belt.

Fig. 24 shows a repair requiring heat and pressure on only one side of the belt, with the belt being supported by support bed 360. Fig. 24B shows the combined containment pack on one side only with the straps 302 passed around the whole conveyor unit.

Fourth Embodiment - Roller Repair Containment Pack

In addition to the repair of conveyor belts, the repair system of the invention can be used as a roller vulcanising system to repair or re-cover support rollers under the belt. An example of a suitably-configured roller repair containment pack 400 is shown in Fig. 25A and is made up of a cover 401 with two main pockets 402 and 403 which respectively contain an airbag and a heat pad. As with the conveyor belt containment packs, loops 404 and attachment straps 405 are provided on the exterior surface. Additional pockets may be provided to allow the fitting of reinforcing sections.

In use, as shown in Fig. 25B, the heat pad is positioned closest to the roller under repair, after application of the repair medium or patch, and the containment pack is then wrapped around the roller and the ends of the heat pad are butted together. The underside of Flap A is provided with one component of a hook-and-loop system and the other component is provided on the upper side of edge B, which facilitates initial attachment and positioning. Straps 405 and buckles 406 are then tightened, and the hot vulcanising process can begin.

As shown in Fig. 26, multiple roller repair containment packs 400 can be connected together using the hook-and-loop system provided on edges A and B to form a larger curing area. These units can be made to a standard size, but as with the conveyor belt system, they can also be made in different sizes.

Fifth Embodiment - Rigid framed system

To further enhance the system, a range of rigid-framed (e.g. metal) containment pack systems for carrying out repairs to the thicker side walls and scoops of conveyor systems has been designed. As shown in Fig 27, the repair unit 500 comprises a U-shaped rigid frame 501 with built-in heat pads 502 and airbags 503. The heat pad 502 is pressed into the shape of the sidewall or scoop as the airbags 503 inflate.

The rigid frame systems can be linked together in the same way as the conveyor belt repair system to allow for repair of longer sections of side wall, as shown at the top of Fig. 28. The rigid system may also be linked together electronically to allow the repair of multiple areas or on multiple scoops at the same time, as shown in Figs. 28 and 29.

Control panels

Once in position, the heat pads and airbags of the various containment packs of the invention are controlled within predetermined parameters depending on the size and extent of the repair underway. A set of control panels has been developed for use with containment packs of the invention, which can be added to as required by the operator, starting with a single channel unit for basic repairs which can be built on to allow larger more complex repairs to be carried out employing multiple containment packs.

Fig. 30 shows a basic unit 601 with the ability to operate up to 6 heat pads and airbags. Fig. 31 shows a standard unit 602 with the ability to operate up to 18 heat pads and airbags. Fig. 32 shows a standard unit 602 and basic unit 601 combined, having the ability to operate up to 24 heat pads and airbags. Fig. 33 shows a large unit 603 with the ability to operate up to 36 heat pads and airbags.

At least in preferred embodiments, the invention provides the ability to control a single heat pad or multiple heat pads by the use of a bespoke wiring loom. Fig. 34 shows a standard control panel 602 operating multiple heat pads 650 via wiring loom 604.

At least in preferred embodiments, the invention provides the ability to control multiple airbags through a gallery system. Fig. 35 shows a standard control panel 602 operating multiple airbags 630 via gallery 605.

A control panel for use with the invention may include one or more of the following features:

• Mains power indication

• Temperature indication and control

· Timer indication and control

• Curing indication

• Alarm system to indicate loss of mains power

• Alarm system to indicate failed Heat-Pad

• Alarm system to indicate loss of air pressure

Other features may also be provided in the control panel as required.

The control panel may include a data logging system to record data regarding the repair, such as for example date, time, curing identification number, pressure and temperature of the cure. The ability to download the information logged to an external device, by means of a memory device, hard wired connection, Bluetooth or Wi-Fi connection for example, may also be provided.