AU2007101043B4 - Improved utility cross-arm - Google Patents

Description

Cc,

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION Innovation Patent Applicant(s): Preformed Line Products (Australia) Pty Ltd Invention Title: IMPROVED UTILITY CROSS-ARM The following statement is a full description of this invention, including the best method for performing it known to me/us: -2- IMPROVED UTILITY CROSS-ARM o Field of the Invention y The present invention relates to a cross-arm and a process for manufacturing the cross-arm and, particularly, but not exclusively, to a cross-arm for supporting power cables and a process for manufacturing the cross-arm.

Background of the Invention It is well-known to utilise supporting members, generally known in the art as "cross-arms", for supporting utility cables, such as power cables, suspended above the ground. These cross-arms are usually mounted to poles ("utility poles"). Cross-arms have to withstand weight bearing, transverse and longitudinal loads as well as having electrically insulating properties, in view of the weight of power cables and also the high voltages that are often carried.

The most common type of cross-arm is of wood (usually a hard wood). While this is a suitable load bearing and insulating material, in order to enable cables to be carried many components have to be separately mounted to the cross-arm. These components include, for example, porcelain insulators arranged to mount the cables, components arranged to retain the cables to the crossarms, components arranged to affix the cross-arm to the utility pole, components arranged to enable drop wires to be taken off the cables, and other components.

The requirement to separately mount different components to the cross-arm leads to complexity in assembly and installation. It also leads to expense. The addition of the components and the requirement to provide mountings in the hardwood drilling holes) can also lead to long term degradation of the entire structure.

Composite cross-arms, manufactured from materials o other than wood, have been proposed. These include, for example, pultruded glass fibre composite cross-arms.

These types of cross-arms are usually nothing more than a rectangular cross-section cross-arm similar to the shape of the known wooden cross-arms and still require components such as insulators, gain blocks etc to be affixed to them, retaining the complexity of the prior art wooden cross-arm in assembly and installation. Further, pultruded sections are hollow, which can lead to a difficulty in effectively mounting components as well as risking the ingress of water over a period of time.

A composite cross-arm is disclosed in Korean patent application no KR3037221A. The cross-arm is formed from an insulating material and includes sheds, extending in a vertical (in use) direction. A cross-arm with similar features is disclosed in Canadian patent application no.

2051515. In both these cross-arms, the insulating sheds are provided to reduce the potential for conductive tracking across the cross-arm. The conductors are mounted on flat parts of the cross-arms, however, so tracking can occur to some extent across the cross-arm from the conductors. This can still result in a dangerous situation.

The cross-arms disclosed in both these prior art documents include gain blocks which have a concave profile. This has the disadvantage that the cross-arm would not be able to easily fit to utility poles of different sizes.

The profiles of the prior art composite cross-arms are generally rectangular in cross-section. There are therefore a number of flat surfaces along which conductive MAY.26.2008 12:41 +61299255911 GRIFFITH HACK #7304 P.005 /019 00 0 0 ^sD cO

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0 0 0 ci 1-( 1^ tracking can occur, underneath surfaces evaporate. This is which faces upwards 5 retaining water.

particularly on the top and where water can settle and then particularly so for the flat surface in use and can provide a surface for Summary of the Invention In accordance with a first aspect, the present invention provides a cross-arm for supporting an 10 electrical cable, the cross-arm comprising an inverted "v" shape top section to promote run-off of water from the cross-arm, a shed arrangement, having one or more sheds which in use, extend substantially vertically, and wherein the cross-arm is an integrated cross 7 arm.

In an embodiment, the shed arrangement include a plurality of sheds. In an embodiment, the shed arrangement also includes a cable mounting means for mounting an electrical cable. In one embodiment, the cable mounting means is a recess arranged between adjacent sheds. The recess may have a profile which reduces wear on a received cable. The profile may be substantially saddle-like. A supporting mechanism, such as a supporting pad, may be mounted in the recess to provide further support to the cable. The pad may be a silicon pad, for example.

In an embodiment two or more cable mounting means ma be provided in the shed arrangement so that cables (usually of the same potential) may be mounted adjacent each other.

In an embodiment, there are two or more shed arrangements on the cross-arm. In one embodiment, the cross-arm includes four shed arrangements.

The cross-arm top section is profiled to promote the

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COMS ID No: ARCS-191842 Received by IP Australia: Time 12:47 Date 2008-05-26 D4AY.26.2006 12:41 +61299255911 GIFT AK#34206/1 GRIFFITH HACK #7304 P.006 /019 0 ormn-off of water. The profile is an inverted 'IV" shape forming a peak running, in use, along the top of the cross-arm. Such a profile has a further advantage in deterring birds from settling or nesting on the cross-arm, In an embodiment, the cross-arm has a concave base section, the concave base section being arranged to reduce the likelihood of conductive tracking along the concave 2 base section.

In an embodiment, the cross-arm includes an integrated gain block. In one embodiment, the gain block o includes a profile which enables mounting of the crossz-arm 0 to poles having a plurality of different girths. In one embodiment, the profile provides a wedge shaped crosssection.

In an embodiment, the cross-arm includes integrated hooks, which facilitate lifting the cross-arm to position on the utility pole and which also provide mountings for attaching drop cables. In an embodiment one hook is provided proximate each end of the cross-arm.

In an embodiment, the cross-arm includes integrated threaded inserts to enable cross-arms to be linked together. In an embodiment, a threaded insert is provided in each end of the cross-arm.

In an embodiment, the crqss arm includes an integrated mounting feature on the opposite side from the integrated gain block, the integrated mounting feature COMS ID No: ARCS-191842 Received by IP Australia: Time 12:47 Date 2008-05-26 -6being usable with an assembly for mounting the cross-arm to a utility pole that cannot be drilled.

o In an embodiment, the cross-arm is manufactured by ND casting in a closed mould using a casting material. In an embodiment, formers are included in the closed cast to form integrated components of the cross-arm.

In an embodiment, the cross-arm is formed by pultrusion. In an embodiment the cross-arm is formed by moulding component features over a pre-existing pultruded cross-arm.

In an embodiment the cross arm is formed by casting material in an open cast and by creating features above the surface of the casting by inserting formers into the cast. In an embodiment, the formers are provided with projections enabling them to be secured within the liquid resin being moulded in the casting. In an embodiment, the formers are premoulded plastics parts.

In an embodiment, the cross-arm is formed from a plurality of individual components which are assembled together into an integrated form. One component may comprise a basic frame of simple shape, in one embodiment being an elongate cylinder forming a carrying arm for other components. In other embodiment, an elongate rectangular block forms the carrying arm. The other components may include one or more shed arrangements, arranged to be secured to the frame. In one embodiment, a shed arrangement includes a body mounting one or more sheds, the body having a bore therethrough which is arranged to receive a portion of the frame so as to mount the shed arrangement on the frame.

This embodiment has the advantage that the components, being generally of simpler shape, may be manufactured relatively inexpensively.

MAY.26.2008 12:41 +61299255911 GRIFFITH HACK #7304 P.07 /019 00 -7- 0 o In an embodiment, the material used is a composite material.

In one embodiment, the present invention has the advantage of an integrated cross-arm for supporting one or INO 5 more cables which includes a plurality of integrated components. Unlike the prior art wooden cross-arm very Men few or no components need to be added to the integrated o cross-arm during installation.- Further, the ability to Sprovide a single integrated cross-arm without a multiplicity of components reduces expense and, advantageously, reduces wear and increases life time.

In at least an embodiment, the cross-arm has the particular advantage of being designed to reduce and minimise conductive tracking from a conductor being carried by the cross-arm. In one embodiment, all the three shape components described above are utilised in the cross-arm, advantageously minimising tracking.

The term "integrated" used in this specification is intended to mean that the cross-arm includes one or more components (in this aspect of the invention being the shape components) formed as one piece with the cross-arm, so that the components do not have to be added after the cross-arm has been produced.

COMS ID No: ARCS-191842 Received by IP Australia: Time 12:47 Date 2008-05-26 THIS PAGE HAS BEEN LEFT AS A BLANK PAGE, INTENTIONALLY THIS PAGE HAS BEEN LEFT AS A BLANK PAGE, INTENTIONALLY THIS PAGE HAS BEEN LEFT AS A BLANK PAGE, INTENTIONALLY MAY.26.2008 12:42 +61299255911 GIFT AK#34208/1 GRIFFITH HACK #7304 P.008 /019 0 Brief Description of the Drawings Features and advantages of the present invention will become apparent from the following description of embodiments thereof by way of example only, with en reference to the accompanying drawings, in which: o Figure 1 is a view from the top of a cross-arm in o accordance with an efidbodiment of the present invention; Figure 2 is a -view from the bottom of the cross-arm of Figure :I; Ci Figure 3 is a view from the back of the cross-arm of Figure 1; Figure 4 is a section on line A-A of Figure 3; Figure 5 is a section on line B-B of Figure 3; Figure 6 is a perspective view from underneath and the front of the cross-arm of Figure 1; Figure 7 is a view from the top of a cross-arm in accordance with a further embodiment of the present invention; Figure 8 is a view from the bottom of the cross-arm of Figure 7; Figure 9 is a view from the back of the cross-anm of Figure 7; Figure 10 is a section on line A-A of Figure 9; Figure 11 is a section on line B-B of Figure 9; Figure 12 is a perspective view from underneath and the back of the cross-arm of Figure 7; Figure 13 is a view from the bottom of a cross-arm in accordance with a further embodiment of the present invention, together with components enabling the cross-arm to be mounted to a pole which cannot be drilled; Figure 14 is a view from the front of the embodiment COMS ID No: ARcS-191 842 Received by IP Australia: Time 12:47 Date 2008-05-26 -12of Figure 13 showing it mounted to a utility pole; Figure 15 is a further view from the underneath of o the embodiment of Figure 13, showing the cross-arm mounted N to a utility pole; Figure 16 is a perspective view from behind and one side showing the cross-arm of Figure 13 mounted to a utility pole; Figure 17 is a perspective view from above and one side of a former for use in a method of manufacture in accordance with an embodiment of the present invention; Figure 18 is a computer generated view of a profile of a cable receiving groove in a cross-arm in accordance with an embodiment of the present invention; Figure 19 is a computer generated view of the profile of the groove of Figure 18, incorporating a pad for reducing friction with a received cable; Figure 20 is a view from the side of a cross-arm in accordance with yet a further embodiment of the present invention; Figure 21 is a detailed cross-section of a shed arrangement of the cross-arm of Figure Figure 22 is a perspective view of the cross-arm of Figure 20; and Figure 23 is a perspective view from above and one side of unassembled components of a cross-arm in accordance with yet a further embodiment of the present invention.

Detailed description of embodiments A first embodiment of the present invention will now be described, with reference to Figures 1 to 6.

This embodiment is an integrated cross-arm, generally designated by reference numeral 1 which comprises, in this -13example, three shape features 2, 3, and 4, which are arranged to reduce conductive tracking from conductors o (not shown) carried by the cross-arm 1.

N In this embodiment, cable receiving means 5 are provided in the form of (in this example) a cable receiving groove 5 in the shape feature 2. In this embodiment, two cable receiving grooves 5 are provided side by side, so that two cables may be laid adjacent to each other. This can enable, for example, a cable dead end and further cable extending in a desired direction, to be supported by a single cross-arm. In use, cables are supported within the cable receiving grooves 5 (a single cable will usually be supported by one of the shape features 2 the cross-arm may carry one, two, three or four cables in this embodiment). The cables may be secured by helically preformed rods, such as those provided by PLP® Pty Ltd.

The cross-sectional profile of the cable receiving groove 5 is arranged to be substantially curved, falling away at either end of the groove with the curvature of the cross-arm. This profile minimises any long term wear on the cable (there are no sharp corners or edges). This creates a virtual saddle shape in which the cable can deviate from the horizontal or vertical line or both whilst still being correctly supported by the cable receiving groove. The profile may be circular in part.

The shape component 2 is in this example in the form of a shed arrangement, wherein sheds 6 are arranged to run vertically (in use). Each shed arrangement in this embodiment has seven sheds of varying diameter, but it will be appreciated that any number of sheds that may be necessary may be included. In this embodiment, the sheds 6 extend all the way around the periphery of the -14cross-arm 1. In this embodiment, the conductors are carried by the receiving grooves 5 formed between the o sheds 6, facilitating reduction in the potential for ND tracking.

Shape component 3 is in the form of an inverted "V" shape profile of the top of the cross-arm, extending between the shed arrangements 2 and forming a "peak". The profile is best seen in Figure 1 and Figure 5. This profile is in contrast to prior art cross-arms, which usually have a relatively flat top surface. The inverted profile encourages shedding of water and contaminants.

Again, this facilitates a reduction in the potential for tracking.

Shape component 4 is in the form of a concave section running along the base 7 of the cross-arm. The concave shape 4 forms a "meniscus" type profile running along the base between the shed arrangements 2. The profile can best be seen in Figures 2, 4 and 5. The concave section 4 reduces tracking along the base of the cross-arm 1.

The cross-arm 1 also includes an integrated gain block 8. The gain block 8 enables the cross-arm 1 to be mounted to a utility pole and includes a mounting means 9 having a cross sectional profile (best viewed in Figures 1 and 2) which facilitates mounting to utility poles of different girths or cross sectional profiles. The mounting means 9 includes a pair of projecting portions and 11 which project outwardly of the gain block 8 and which have a curved cross sectional profile. These projecting portions 10 and 11 abut the utility pole providing a secure mounting surface which contacts the utility pole, providing connection with the utility pole along the length of the projecting portion 10 and 11.

Holes 12 are provided through the gain block area to l receive screws or bolts for mounting to the utility pole.

oAlternative mounting means in the form of pads 13 and N 14 are provided on the opposite side of the gain block 8 from the mounting means 9. The alternative mounting means 13, 14 are provided to facilitate mounting to a utility pole using an assembly of components which will be described later on in this document, in particular where it is not possible or inconvenient to drill holes in the utility pole.

The cross-arm 1 also includes an integrated threaded hole 15 in each end of the cross-arm (only one hole 15 is shown in Figures 6, but a similar hole 15 is included in the opposite end of the cross-arm The threaded inserts 15 may be used to secure a pair of cross-arms together on opposite sides of a utility pole, as may sometimes be required for various cable support configurations.

A further embodiment of the invention will now be described with reference to Figures 7 to 12. This embodiment has many of the same features as the embodiment of Figures 1 to 6, and the same reference numerals have been used to designate these features. No further description will be given of these features unless there is any variation from the features of the embodiment of Figures 1 to 6.

It can be seen that the embodiment of Figures 7 to 12 has a substantially flat base 7, and does not include the shape feature 4 (concave base) of the Figure 1 to 6 embodiment. In addition, each of the shed arrangements 2 includes sheds 6 which only extend approximately three quarters away around the circumference of the cross-arm 1.

At the base 7 the sheds 6 do not continue and instead -16merge into a flat base 7. Otherwise the shed arrangements 2 are the same as the embodiments of Figures o1 to 6 and include receiving grooves 5 for mounting ND cables.

The embodiment of Figures 7 to 12 includes a different gain block 16 arrangement. As can best be seen in Figures 7 and 8, gain block 16 includes a mounting means 17 which has a wedge shaped profile. It does not have the "tear drop" shaped projections 10 and 11 of the embodiment of Figures 1 to 6. The wedge shaped mounting means 17 still, however, enables the cross-arm to be mounted on utility poles having varying breadths, at any point on the utility pole. The wedge shape allows contact with two line features, rather than point contact, facilitating stability of the cross-arm 1 when mounted.

Note that Figures 9, 10 and 11 include dimensions.

These dimensions are given in millimetres. While the dimensions are suitable for this embodiment, the cross-arm may be of any convenient dimension and is not limited to these dimensions.

Figures 13 to 16 illustrate yet a further embodiment of the present invention. The illustrations also include an assembly for attaching the cross-arm 1 to a utility pole which cannot mount a bolt or screw arrangement.

The cross-arm 1 of the embodiment of Figures 13 to 16 is illustrated using the same reference numerals for features equivalent to the features of the earlier described embodiments, and no further description will be given of these features. The cross-arm of this embodiment does include a concave base section 4, similar to the first embodiment. The sheds 6 of the shed arrangements 2 do not extend all the way around the circumference of the cross-arm 1, similar to the embodiment of Figures 7 to 12.

-17- This embodiment is provided with mounting means 20 at the ends of the cross-arm 1, in this embodiment being in o the form of hooks embedded during manufacturing in the ND ends of the cross-arm 1. The hooks 20 have a dual purpose. Firstly, they can be used to provide a purchase for ropes or wires which may be used (together with a pulley arrangement) to raise the cross-arm to position on the utility pole.

Secondly, the rings 20 can be used to provide mounting points for drop cables.

Note that this embodiment also has threaded inserts 15 provided in the ends of the cross-arm 1.

The hooks 20 may be provided in any of the earlier described embodiments.

The guide block 8 is the same guide block as the cross-arm 1 of the embodiment of Figures 1 to 6. It can be seen, from Figures 14, 15 and 16, particularly, that the mounting means 9 is not utilised in this embodiment to mount the cross-arm 1 to the utility pole (reference numeral 21 in Figures 14, 15 and 16). Instead, the other side of the guide block 8, having alternative mounting means 13 and 14 faces the utility pole 21 in use.

Utility pole 21 may be a concrete utility pole or other type of pole where drilling holes in the pole to provide a mounting to the guide block 8 is not feasible (concrete poles are hollow) or is difficult. In such a case, the mounting assembly generally designated by reference numeral 25 is utilised.

Mounting assembly 25 includes stainless steel bands 26 which are arranged to go around the mounting block 21, and a fastener 27 for fastening the steel bands 26 around the pole 21 (note that stainless steel is one preferred material only for the band and other -18materials may be used) The mounting means 25 also includes a separate guide o block piece 28 which is arranged to be mounted over IN pads 13 and 14 and secured to the cross-arm 1 by a nut 29 and bolt 30 passing through the holes 12 in the cross-arm.

The separate guide block piece 28 is arranged to receive the steel bands 21 via a slot through the guide block 28, as most clearly shown in Figure 16. Note that the stainless steel band 26 may be a single band or two (several) parts as illustrated in Figure 16.

In operation, the separate guide block piece 28 is mounted to the pads 13 and 14 using the nut 29 and bolt 30. Steel band (or bands) 26 are passed through the slot in separate guide block piece 28 and passed around the pole 21, where they are secured and tightened by attachments 27.

Manufacture of the embodiments described above is by way of moulding a polymeric material (any suitable polymeric or plastics material having the requisite strength and lifetime for operation as a cross-arm may be used). The mould in this case is an open type mould with base and sides to form the integrated shape features.

Formers are used where extra features need to be added.

For example, in the embodiment of Figures 1 to 6, in order to ensure that the sheds 6 extend around the entire circumference of the cross-arm 1, shed portion formers are used at the top of the mould to bind to the sheds formed by the sides and base of the mould. Threaded inserts are placed in the mould as are hooks 20. Any other desired feature may be incorporated utilising an appropriate former or mould shape. Note that the concave underside of the cross-arm may be formed in any number of ways. For example, a top bar laid across an open cast -19mould can be used to cause the resin to sit proud of the mould at the sides. Alternatively, a very grainy layer 0 may be placed around the top of the mould to increase ND surface tension and form a concave meniscus.

Figure 17 illustrates one type of former which may be used in the manufacture of the cross-arm in accordance with an embodiment of the present invention. The former in this illustration is generally designated by reference numeral 50, and includes a shed portion arrangement 51 which includes a plurality of shed portions 6A. Planar projections 52 project outwardly of a surface 53 of the shed portion arrangement 51. Holes 54 are included in these projecting portions 52.

In manufacture, where the integrated cross-arm is being manufactured e.g. from a liquid resin material poured into an open mould, the projections 52 are inserted where appropriate in the liquid resin material before it sets. On setting, the holes 54 and projections 52 retain the projections within the resin material and the shed portions 6A are formed in position with respect to further shed portions formed in the mould, to give a cross-arm having shed portions where sheds extend about the circumference of the cross-arm.

Note that formers such as this could be used in a closed mould and they are not limited to operation in an open mould.

Formers such as this, including projections (which do not need to be planar or have holes) may be used for integrating any other component into the cross-arm during manufacture.

Figure 18 is a computer generated view showing the profile of the cable receiving groove 5 from the previously described cross-bar embodiments. The groove has a substantially circular profile which "falls away" at either end 5A, 5B that the sides SC, 5D presenting smooth o surfaces to the cable received by the cable receiving groove 5 and allowing the cable to move whilst minimising "wear and tear" on the cable. The profile is a "saddle" type profile, in which the cable can deviate from the horizontal or vertical line or both while still being correctly supported by the cable receiving groove Figure 19 is another view of the cable receiving groove 5 profile, showing the positioning of a silicone pad 60 within the cable receiving groove 5. The cable rests on the silicone pad 60 and this acts to prolong electrical and mechanical life by reducing electrical and mechanical aging of the conductor. This is particularly useful for insulated or jacketed cable, but can also be used with uninsulated or unjacketed cable.

Above embodiments of the cross-arm show variations where a shed which surrounds the entire circumference of the cross-arm is provided (and other variations where a shed which only partly surrounds the circumference of the cross-arm is provided). A shed arrangement where the sheds entirely surround the circumference of the cross-arm is useful in that it enables fitting of industry standard helical fittings.

A further embodiment of the present invention will now be described with reference to Figures 20 to 22.

Forming complex shapes, by casting or other processes, can be difficult and relatively expensive. In this embodiment, the cross-arm is formed by adding components to a relatively simply shaped base frame. This has the advantage that the cross-arm may be relatively inexpensive to form. The cross-arm 100 in this embodiment is not cast as a single shape but is instead formed from -21separate components which are assembled to form the integrated cross-arm 100.

O

O The components of this cross-arm 100 include a IND substantially cylindrical cross-arm frame 101 and, in this example, four shed arrangements mounted on the cross-arm frame 101.

In this embodiment, the shed arrangements 102 are initially separate from the cylindrical frame 101. A separated shed arrangement 102 is shown in cross-section in more detail in Figure 21. The shed arrangement 102 includes a body having a bore therethrough, which in this central passageway 103 which tapers outwardly in either direction from a centre 104. The circumference of the passageway 103 is therefore slightly greater at the ends 105, 106 of the shed arrangement 102 than at the centre 104. Note that otherwise, the features of the shed arrangement are the same as the features of the shed arrangements of previous embodiments and similar reference numerals have been used for these features. The shed arrangement 102 may be adhesively secured to the cylindrical frame 101. In some cases, where composite materials are utilised, composite resins may be used as an adhesive and will make an exceptionally good bond to the cylindrical frame 101. Adhesives may bond poorly to HDPE, and other materials. The "wedge" shape of the central passageway 103 and the shed arrangement 102 will act as a "glued on wedge" which will hold the shed arrangement by adhesion and also by acting as a mechanical wedge.

To assemble the cross-arm 100, each shed arrangement 102 is slid into position on the cross-arm frame 101 and affixed in position. The shed arrangement 102 in this embodiment are affixed into position by using an appropriate adhesive (which will -22generally depend upon material that the cross-arm frame 101 and sheds 102 are made from).

o In one embodiment, the cross-arm frame 101 is made N from filament wound composites. The filament wound composites may be formed around any type of mandrel. It may be covered with a layer of urethane for UV resistance.

The sheds 102 may be separately cast.

The integrated cross-arm 100 of this embodiment is therefore relatively simple and cheap to manufacture. The fact that in this embodiment it is cylindrical also promotes runoff of water and reduces tracking. Other manufacturing methods could be used to make the cylindrical frame e.g. casting, casting and filament winding, pultrusion and filament winding or casting over pultrusion (and other methods of manufacture).

The sheds 102 may be cast plastics, moulded plastic, cast or moulded composites or any other UV resistant insulating material (and may be made in other ways).

Other components, such as the gain block, may be separately adhered to the cross-arm frame 101 to produce the integrated cross-arm 101. Other components are not shown in the Figures 20 to 22, but it will be appreciated that they may be utilised as for the previously described embodiments.

A further embodiment of the cross-arm will now be described with reference to Figure 23.

The cross-arm 200 of Figure 23 is assembled into integrated form from a number of component parts. As with the embodiment of Figures 20 to 22, this enables the cross-arm 200 to be formed from components having simple fundamental shapes. These components may be manufactured relatively inexpensively, e.g. by casting of the simple shapes from polymers.

-23- The cross-arm 200 includes an elongate rectangular cross-section base frame 201 having extending along its 0 underside shape features 202 in the form of elongate ND grooves for reduction of tracking across the underside of the frame 201.

A plurality of shed arrangements 203 (only one is shown in Figure 23 but in this embodiment there could be four shed arrangements, and in other embodiments varying number of shed arrangements) are arranged to be slid onto the base frame 201 and affixed into position, in a similar manner to the shed arrangements 102 of the embodiment of Figures 20 to 22. In the embodiment of Figure 23, the shed arrangement 203 includes a body having a rectangular cross-section bore 204, which corresponds with the outer cross-sectional shape of the frame 201.

In an embodiment, the cross-arm 200 is mounted so that a corner of the rectangle is direct to promote runoff of water i.e. the rectangle cross-section is mounted, tilted or diagonal form.

The above embodiments incorporate a number of novel and inventive features in a single cross-arm. Note that in accordance with aspects of the present invention, all these features need not be used in a single cross-arm, but instead one or more features may be used in cross-arms.

For example, an embodiment of the cross-arm may include the integrated shed arrangements, but not the other shape components (inverted shape top surface and concave underside). Similarly, the sheds could be dispensed with in another type of cross-arm, but the inverted shaped top retained. Further, other types of cross-arms may have only the concave underside in order to improve tracking performance.

Various embodiments for cross-arms may be made with MAY.26.2008 12:42 +61299255911 GRIFFITH HACK #7304 P.009 /019 00 -24- 0 o one or all of the features disclosed in the abovedescribed embodiments.

In the above embodiments, the sheds 6 are shown as oriented vertical in use. They need not be exactly NO 5 vertical, but could deviate either side at an angle, as long as they still sufficiently provide insulation, and reduction of tracking.

SIn yet a further embodiment, horizontal sheds (the insulators standing up from the cross-arm, or either side) may be provided, and in this case the cables may be Sreceived on top of the shed arrangement not between 0- the sheds, but on top of the entire shed arrangement).

As well as being manufactured by casting in an open or closed cast, the cross-arm could alternatively be manufactured by using a pultruded cross-arm as a base and moulding components on the pultruded cross-arm to provide the requisite shape (and other) components.

Other methods of manufacture may be utilised that can implement the shape components and other components discussed above- It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made COMS ID No: ARCS-191842 Received by IP Australia: Time 12:47 Date 2008-05-26 o to the invention as shown in the specific embodiments without departing from the spirit or scope of the

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o invention as broadly described. The present embodiments \O are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims (4)

1. A cross-arm for supporting an electrical cable, the cross-arm comprising an inverted shape top section to IC 5 promote run-off of water from the cross-arm, a shed arrangement, having one or more sheds which in use, ecn extend substantially vertically, and wherein the cross-arm Sis an integrated cross-arm.

2. A cross-arm in accordance with Claim 1, the shed arrangement further comprising cable mounting means for mounting a cable. Ci

3. A cross-arm in accordance with Claim 1 or Claim 2, wherein a profile of a bottom section of the cross-arm is different from the profile of the top section of the cross-arm.

4. A cross-arm in accordance with Claim 1, 2 or 3, the cross-arm including an integrated gain block. A cross-arm in accordance with Claim the cable mounting means comprising a recess arranged adjacent a shed. COMS ID No: ARCS-191842 Received by IP Australia: Time 12:47 Date 2008-05-26