This application claims priority from Australian provisional patent application No 2009902302 entitled "Wear Plate for Cable handler" filed on 20 May 2010 the entire contents of which are incorporated herein by reference.

Field of the Invention

This invention relates to a wear plate for a dynamic cable handler. Cable handlers are used for protecting electric cables, water hoses and the like (hereinafter referred to as lines or service lines), particularly, but not exclusively, in underground mine workings.

Background of the Invention

During mining operations, it is necessary to protect a variety of electrical cables, water hoses and other service lines from damage. Articulated cable handlers are used to perform this function. One particular area where cable handlers are required, is in the area of coal mining, particularly in long wall coal mining, in which a coal cutter traverses back and forth across a coal face, depositing coal cut from the coal face into a conveyor disposed behind the coal cutter. In order to function, the coal cutter requires a supply of water and electricity, which are provided by the service lines. The service lines are located in a trough which is typically disposed on the opposite side of the conveyor from the coal cutter. The lines travel up and down the trough as the coal cutter moves along the coal face.

In order to protect such service lines it is known to enclose, or least partially enclose them in a protective articulated cable handler formed from a plurality of interconnected links. International Patent application WO2006/039750, the entire contents of which are incorporated herein by reference, discloses one such cable handler formed from a plurality of interconnected links.

In WO2006/039750, each link of the cable handle has a body portion having a first wall and two opposed side arms integral with and extending generally perpendicular to the first wall and defining a channel for receiving one or more service lines. The side arms are flexible and define free ends and may be deflected inwards, and outwards for receiving service lines. Each free end defines engaging formations. A closure means includes an end wall from which extend two relatively shorter side arms which define complementary engaging formations. The side arms deflect towards each other to engage and disengage the closure means from the body portion. WO2006/039750 discloses that such cable handlers may be side pulls, twin pulls or tri pulls.

It has been found that, in use, certain links in a cable handler tend to wear more that others particularly with twin and tri pull totally enclosed cable handlers. This creates problems as the high wear links have to be replaced more often than the lower wear links and means that the cable handlers are out of action for repair and replacement of links more often than is desirable, affecting mine productivity.

The present invention aims to alleviate the above mentioned cable handler wear problems. Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Summary of the Invention

In a first broad aspect the present invention provides a wear plate for a cable handler which is adapted to quickly clip onto the cable handler and attach to the same without the need for glue, adhesive or the like. Typically the wear plate will be made of a moulded plastics material of similar hardness to the cable handler, such as, nylon.

In a preferred embodiment, the wear plate in generally planar and defines clips which in use locate either side of the centre wall of a link of a cable handler. The links may define a lip or overhang for retaining the wear plate on the cable handler. The top portion of each clip may be rounded.

The thickness of the wear plate is not critical, but may be in the range of 8 to 12mm, or more, and is typically about 10mm.

In a particularly preferred embodiment a groove extends along the central longitudinal axis of the wear plate parallel to side edges of the plate. The groove is preferably rounded, and typically about 4 to 8mm deep, typically about 6mm deep.

The plate may also define side walls extending along its side edges for stability. In use the wear plates are attached to the top and/or bottom of the cable handlers

In practice the wear plates need and typically will only be used where extreme wear occurs in cable handlers which is typically at the "mid point" of the cable handler/spill plate. These wear plates are placed on the top and bottom of the cable handler links to cater for movement in opposite directions.

The wear plates are made to be an interference fit and the cable handlers typically will require some force, such as a mallet or hammer, in order to attach the wear plate. After use the wear plate can be removed using a tool inserted between the cable handler and the wear plate to lever the wear plate off. Each wear plate can incorporate a wear indicator.

In one preferred aspect there is provided a wear plate for a cable handler comprising a generally planar body portion, defining two opposed side walls extending along two opposed edges of the planar body portion, and a pair of spaced apart clips located on each side wall, each clip defining a lip which projects towards the opposed clip, and wherein the head of each clip is rounded to assist in deflecting the clips away from the centre of the plate during attachment of the wear plate to a chain link.

The invention also provides a combination of a wear plate and a chain link of a cable handler attached to the chain link, the chain link comprising a central wall having a width W at its base, and two pairs of side arms extending away from opposed sides of the central wall and defining opposed channels for receiving service lines, the wear plate comprising a generally planar body portion, defining two opposed side edges of the planar body portion, and a pair of spaced apart clips located on each side edge, separated by a distance approximately equal to W, each clip defining a lip which projects towards the opposed clip, and wherein the head of each clip is rounded to assist in deflecting the clips away from the centre of the plate during attachment of the wear plate to a chain link and wherein the wear plate is an interference fit on the chain link and attaches to the same without glue, pins, bolts or the like.

Brief Description of the Drawings A specific embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure l is a plan view of a wear plate embodying the present invention;

Figure 2 is a side view of the wear plate of Figure 1;

Figure 3 is an end view of the wear plate of Figure 1; Figure 4 is perspective view of the wear plate of Figure 1; and

Figure 5 shows a variant of the wear plate attached to a cable handler. Detailed Description of Preferred Embodiments

Referring to the drawings, Figures 1 to 4 show a wear plate 10 embodying the present invention. The wear plate is for attachment to a link of a cable handler. Figure 5 shows a similar wear plate 10a attached to a link of the cable handler lOOsuch as is shown and described in WO2006/039750.

The wear plate is made from nylon having a hardness similar to that of the cable handler itself. The wear plate may be moulded or machined.

By way of background, Figure 5 shows a triple or tri pull chain link 100. The link has a central wall 101 having a greatest width W at its base, and two pairs of parallel side arms 102, 104 extending away from either side of the central wall 101 and defining opposed channels for receiving service lines. A steel insert, not shown, is embedded in the central wall 101 which define holes for joining the link to a similar link. The link is made of moulded nylon. The free ends 102a and 104a of the side arms define engaging formations in the form of a channel and rebate (not visible). End walls 106 are provided for closing the channels. The end walls 106 define short side arms which have complementary engaging formations which engage with those of the free ends 102a and 104a of the side arms. Each of the end walls 106 includes an embedded steel insert (not shown) defining holes for joining the link to a similar link. As described in WO2006/039750 variants of the link are possible in which the linkage is in the central wall only for a centre pull link or in the end walls only for a twin pull link. The reader should refer to WO2006/039750 for a more detailed description of the cable handler link and variants.

Figures 1 to 4 show an embodiment of a wear plate 10 for use with the chain link 100. The wear plate is generally rectangular in plan view but has bevelled ends 12. As best seen in Figures 3 and 4, in cross section the wear plate is generally U shaped defining a generally rectangular planar body portion 14 and relatively short side walls 16 which extend upwards from opposed side edges of the planar portion 14. The side walls 16 extend along the length of the plate 10. Whilst the dimensions and thickness of the wear plate are not critical, and can be varied, in the described embodiment, the thickness of the planar portion 14 is about 10mm. This thickness will diminish during use as the plate wears.

The plate defines a generally planar inner surface 18 defined by one surface of the planar portion 14 for engagement with the top or bottom of the cable handler 100. However, in the centre of that generally planar surface there is a channel 21 which extends along the central longitudinal axis L of the wear plate. In the specific embodiment the channel is about 6mm deep and 8mm wide however, the dimensions may be varied. The plate may flex about the groove due to the reduced thickness of the groove and the flexibility of the nylon material from which the plate is made. The outer or external surface of the wear plate which is best shown in Figures 3 and 4 defines radiused/rounded corners 17 which tend to reduce the affects of wear and abrasion on the wear plate with fragments of coal, rock or the like.

Two pairs of clips 22 (four in total) extend up from the side walls 16 either side of the central axis C of the wear plate. The head or top part 24 of each clip defines a lip or overhang 26 which projects in from the side wall 16 of the wear plate, best seen in Figure 3. The head of each clip is curved/rounded. Each pair of clips is spaced apart by a distance W equivalent to the width/thickness of the base of the centre wall 101 of the cable handler.

There are four upstanding protrusions 28 located adjacent each corner of the wear plate. In use, with reference to Figure 5, in order to attach the wear plate 10 to the cable handler 100, it is simply placed in position over the cable handler optionally with a lubricant such as soapy water disposed on the cable handler The wear plate 10 is simply pushed or more typically struck with a mallet or the like to force the wear plate onto the cable handle by deflecting the four clips 22 outwards prior to their snap fitting over the outer surface of the cable handler. This occurs as a result of flexing of the clips themselves and also flexing of the planar portion 14 about the channel 21. The rounded upper surfaces 24 of the clips assist in this process and help deflect the clips outwards as the plate is forced onto the handler, in a snap fitting type process. The provision of one clip 22 on each side of the central wall 101 helps locate and retain the wear plate securely on the cable handler. The protrusions 28 (not shown in the variant shown in Figure 5) located adjacent each corner of the wear plate help prevent the ends of the wear plate wobbling or moving.

The wear plates may only be used where high wear occurs in cable handlers and as few as half a dozen or so links in any one cable handler may be protected with wear plates. However, it is possible to use them on a much greater percentage of the links in a chain particularly where it is desirable to reduce wear and tear on the cable links generally, noting that, in general, it is cheaper and easier for a mine operator to replace a wear plate than a chain link.

Worn wear plates may be removed by inserting a suitably configured tool between the wear plate and the cable handler and levering the plate off. . The wear plate needs to be made such that it fits the cable handler with minimal tolerances. This avoids the need for glue or pins or the like for comfortable retention of the wear plate to the cable handler.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the scope of the invention as broadly described.

The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.