AU2009201393A1 - An Insulation Arrangement for an Electric Fence - Google Patents

Description

1 An Insulation Arrangement For An Electric Fence Field of the invention [001] This invention relates to an insulation arrangement for an electric fence. The invention is particularly suited for providing an electric fence which can be quickly assembled. Background of the invention [002] Electric fences have been constructed using an upright formed by a star picket to which an outrigger was attached, the outrigger including a means for holding the live wire and means for insulating the upright from the live wire. Prior electric fence insulator arrangements used a metal arm having a "pig-tail" coil at its distal end adapted to receive a wire. The arm is adapted to be connected to a metal post. The pig-tail is insulated to isolate the wire from the metal arm. The insulation is subject to wear as the wire is of a harder material than the insulation. This can lead to defective operation of the electric fence. [003] Australian patent no 200069619 discloses an insulation arrangement for an electric fence in which a stub arm is connected to a metal post by a bolt-on attachment. The stub arm is in two separate parts. The distal end of the stub arm includes a pig-tail coil adapted to receive a wire, and the other end is adapted to be connected to a post. The distal end is isolated from the attachment end by an insulator which serves to hold the two parts of the arm together. [004] The prior art arrangements required that the arm be attached to a post, eg, by the use of a bracket and bolt attachment arrangement. [005] It is desirable to provide an electric fence post arrangement which facilitates assembly of an electric fence. [006] Any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled in the art to which the invention relates, at the priority date of this application. Summary of the invention [007] According to a first embodiment of the invention there is provided a post for an electric fence including an elongated upright and a footing, wherein the footing includes a foot engaging portion and a ground engagement member. [008] The ground engagement portion can include a pair of parallel ground spikes.

2 [009] The foot engaging portion can include a projection transverse to the upright. [010] According to an embodiment of the invention, there is provided a post for an electric fence having a wire support arm affixed thereto, the support arm being affixed to the post by an insulator arrangement, the support arm being insulated from the post by the insulator arrangement. [011] The insulator arrangement can include an insulator moulded to the post and the support arm so that the post and support arm are electrically isolated. [012] The post can include a ground engagement base having a ground piercing member and a foot element. [013] The base can be in the form of an inverted "J". [014] The insulator arrangement can include a lifting grip. [015] The support arm can be inclined relative to the post. [016] The support arm can include wire retaining means. [017] The wire retaining means can be a pig tail coil. [018] According to a further aspect of the invention a clip-on wire retaining member can include a post engagement portion and a wire retaining portion. [019] The post engaging portion can include at least two oppositely facing clip elements spaced apart by a distance sufficient to receive the width of the post, and adapted to snap-fit on the post. [020] The wire retaining portion can include an upwardly open recess and an inverted recess arranged so that the wire is supported in the upwardly facing recess and inhibited from exiting the upwardly facing recess by the inverted recess. Brief description of the drawings [021] An embodiment or embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [022] Figure 1 is a schematic perspective view of a post; [023] Figure 2 is a schematic perspective view of a secondary live wire attachment adapted for use with a post of Figure 1; [024] Figure 3 illustrates an insulated pig tail; 3 [025] Figure 4 illustrates a schematic perspective view of another post; [026] Figure 5 illustrates a schematic perspective view of a further post; [027] Figure 6 is a partial section view through an insulator arrangement used with the posts of Figures 1 or 4; [028] Figure 7 illustrates a schematic perspective view of post and or support arm termination having a flattened form for encapsulation by an insulator; [029] Figure 7A illustrates a schematic cross section similar to Figure 6 of two terminations of Figure 7 encapsulated within an insulator; [030] Figure 8 illustrates a schematic perspective view of post and or support arm termination having a dog-leg or bent form for encapsulation by an insulator; [031] Figure 8A illustrates a schematic cross section similar to Figure 6 of two terminations of Figure 8 encapsulated within an insulator; [032] Figure 9 illustrates a schematic perspective view of post and or support arm termination having opposed ground or milled scallops for encapsulation by an insulator; [033] Figure 9A illustrates a schematic cross section similar to Figure 6 of two terminations of Figure 9 encapsulated within an insulator; [034] Figure 10 illustrates a schematic perspective view of post and or support arm termination having a bulbous form for encapsulation by an insulator; [035] Figure IOA illustrates a schematic cross section similar to Figure 6 of two terminations of Figure 10 encapsulated within an insulator; [036] Figure 11 illustrates a schematic perspective view of post and or support arm termination having opposed pinched or flattened portions for encapsulation by an insulator; [037] Figure 1 IA illustrates a schematic cross section similar to Figure 6 of two terminations of Figure 11 encapsulated within an insulator; and [038] Figure 12 illustrates the lower end of a post having an alternative construction to that of figures 1, 4 and 5. [039] The numbering convention used in the drawings is that the digits in front of the full stop indicate the drawing number, and the digits after the full stop are the element reference 4 numbers. Where possible, the same element reference number is used in different drawings to indicate corresponding elements. Detailed description of the embodiment or embodiments [040] Figure 1 shows an electric fence post 1.000 having a main upright portion 1.006 of a length suitable for restricting the movement of livestock. The upright is shown as broken to indicate a greater relative length than that shown in the drawing. The foot of the upright 1.006 is welded to a support base in the form of an inverted "J", having a long leg 1.002, and a short leg 1.004 adapted to be pressed into the ground to provide a stable support for the post. The weld 1.008 is located between the horizontally turned portion 1.005 of the upright 1.006, and the interconnection 1.003 of the legs of the inverted J support base. The horizontal portion 1.005 thus provides a user's foot engageable portion so that the base of the post 1.000 can be pushed into the ground using the foot without applying a tensile load to the weld. This can be of use where the post material or the weld is brittle, for example, where the material used for the post is spring steel rod. [041] The top of the post 1.006 terminates in an insulator 1.014. [042] The support arm 1.010 has a wire support in the form of a coil or pig tail 1.012 at its distal end. The other end of the wire support arm terminates in the insulator 1.014. [043] Measurements for the device are set out below by way of example only. [044] The post, base, and support arm can be constructed from 8 mm spring steel wire and can be powder coated. [045] The coil or pigtail 1.012 can have a diameter of the order of 38 mm and a gap G being the distance between adjacent winds of the coil, of the order of 4 mm to 5mm to permit insertion of a wire. The angle 0 (Figure 3) between the end of the coil and the support arm can be of the order of 75'. [046] The length of the post from coil to the top of the base can be of the order of 1000 mm. The length of the base can be of the order 170 mm and the width 90 mm. The short base leg can be about half that of the long leg. [047] As shown in Figure 6, the end 1.007 of the post 1.006 and the end 1.011 of the support arm 1.010 are separated by insulator material sufficient to withstand the voltage applied to the electric fence.

5 [048] The insulator can be of the order of 65 mm long, 20 mm wide, and 15 mm deep, with an insulating separation between the ends of the post and arm of the order of 6 mm. The lifting grip can be about 33 mm wide. [049] The insulator 1.014 can be moulded about the ends of the post 1.006 and the support arm 1.010. The end 1.007 of the post 1.006, and the end 1.011 of the support arm can be formed, e.g., flattened, to provide resistance to axial load. If desired a notch or protrusion can be formed at 6.007 or 6.011, such a notch or protrusion being encapsulated by the moulded insulator when it is formed, and once the polymer has set, the insulator will cooperate with the notch or protrusion thereby preventing relative rotation between the insulator 6.014 and the respective ends 6.007 and 6.011. [050] The insulator enables a user to grip the post 1.006 below the insulator even when a live wire is inserted in the pig-tail. The insulator can be a straight sided cylinder. In Figure 1, the insulator 1.014 is provided with a gripping contour 1.016. In addition, a lifting grip 1.018 can be formed on the insulator. [051] Where an intermediate wire between the top wire through the pig tail and the ground is required, an auxiliary support insulator 1.020 can also be provided. Auxiliary support insulator is shown in more detail at 2.020 in Figure 2. The auxiliary support insulator has a post gripping arrangement and a wire support arrangement. The post gripping arrangement includes an insulating panel 2.026 having a face adapted to conform to the curvature of the post, and a pair of gripping tangs 2.022, 2.024 adapted to grip the post. The gripping tangs are of sufficient length so that together they encompass more than half the post diameter. Preferably, the gripping tangs overlap circumferentially. The gripping tangs are vertically spaced so the post diameter can fit between the gripping tangs when the auxiliary support insulator is rotated through 900, and gripping tangs snap onto the post when the auxiliary support insulator is rotated back to the vertical orientation. [052] The auxiliary support insulator also has a wire support arrangement in the form of inverted "U" or "J" shaped projections 2.028, 2.030 so that a second wire can be readily inserted. [053] The auxiliary support insulator can be moulded as a single piece. [054] Figure 3 shows a variation of the pig tail in which the pig tail 3.012 is covered with ajacket 3.032 of softer material than the wire. This can be plastic or other insulating material, but the jacket is not required to be electrically insulating because the pig tail is already 6 insulated from ground by the insulator 1.014. This jacket 3.032 thus reduces the wear of the wire against the material of the pig tail. [055] Figure 4 shows a modified post arrangement where the support arm 4.010 is inclined at an angle to the post 4.006. This is achieved by providing an intermediate insulator 4.014 which is bent at the required angle so that the upper portion 4.034 which carries the support arm 4.010 is inclined at the required angle to the lower portion 4.036 to which the post is attached. The angle can be chosen to be between the vertical and several degrees below the horizontal. Preferably, the angle chosen is horizontal, i.e., a 900 bend. [056] Figure 5 illustrates a further post in which a pivot arrangement is provided between the post and the support arm, so that the support arm can be placed at any angle within the permitted range of movement of the pivot. The post terminates in a first pivot member 5.036 which carries a pivot hole at its end, and support arm 5.034 terminates in a second pivot member having the pivot axle 5.042. A wing nut can be provided in association with the pivot axis 5.042 to fix the angle of the insulator parts. Stop limiters such as 5.038, 5.040 can also be provided. Only one of the members 5.034 or 5.036 needs to provide insulation, so the other member can be formed of any suitable material. [057] The arrangement of Figure 5 has an electrically insulated moulding formed on the end of each of the post and the support arm which are then joined by a pivoted connection, which maintain the electrical isolation of the post from the support arm. If desired the connection need not be pivoting, but some other joining or connection method used which will maintain the integrity of the electrical isolation and the insulated mouldings of the ends of the post and the support arm with respect to each other. [058] The terminations 6.007 and 6.011 of the post 6.006 and support arm 6.010 are in figure 6 illustrated as generally conical formations. Illustrated in Figures 7 and 7A is a similar arrangement where the terminations are flattened, in Figures 8 and 8A the terminations are formed by forming a dog-leg portion at the end by a bending process; Figures 9 and 9A illustrate a termination which is formed by a scalloping which can be made by a pressing, grinding or milling process; Figures 10 and I OA show a termination formed by means of a bulbous formation, which may be produced by forging, or integrally moulded in the formation of the post or support arm or by any appropriate means ; and Figures 1 and 11 A show a termination formed from opposed pinched or flattened sides of the bar from which the post or support arm is formed.

7 [059] The terminations of post and support arm as described above, are illustrated as being the same. However, this need not be so and a combination of terminations of the post and support arm can be used within a single insulator. That is, in the one insulator, the post can have a termination different to the termination of the support arm. [060] Illustrated in Figure 12 is a post lower end which is constructed by a different method to that illustrated in Figures 1, 4 and 5. In this arrangement the upright 12.006 of the post terminates in a sharpened end, formed by an angled cut-off A short offset leg 12.004 is formed by a Z-shaped, or with two 90 degree bends in the rod, also having an angled cut-off ground engaging spike, with the short leg 12.004 being welded to the upright 12.006 of the post by welds 12.008. [061] In this specification the terms indicating direction, such as "vertical", "horizontal", "up, "down", "left", right", etc., are used in a relative sense, and generally refer to the directions relative to the drawings unless the context requires otherwise. [062] Where ever it is used, the word "comprising" is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of'. A corresponding meaning is to be attributed to the corresponding words "comprise", "comprised" and "comprises" where they appear. [063] It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text. All of these different combinations constitute various alternative aspects of the invention. [064] While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, and all modifications which would be obvious to those skilled in the art are therefore intended to be embraced therein.

Claims (12)

1. A post for an electric fence having a wire support arm affixed thereto, the support arm being affixed to the post by an attachment arrangement, the support arm being electrically insulated from the post.

2. A post as claimed in claim 1, wherein the attachment arrangement includes an insulator moulded to the post and the support arm so that the post and support arm are electrically isolated.

3. A post as claimed in claim I or claim 2, including a ground engagement base having a ground piercing member and a foot element.

4. A post as claimed in claim 3, wherein the base is in the form of an inverted "J".

5. A post as claimed in any one of the preceding claims, wherein the insulator includes a lifting grip.

6. A post as claimed in any one of the preceding claims, wherein the support arm is inclined relative to the post.

7. A post as claimed in any one of the preceding claims, wherein the support arm includes wire retaining means.

8. A post as claimed in claim 7, wherein the wire retaining means is a pig tail coil.

9. A post for an electric fence including an elongated upright and a footing, wherein the footing includes a foot engaging portion and a ground engagement member.

10. A post as claimed in claim 9, wherein the ground engagement portion includes a pair of parallel ground spikes.

11. A post as claimed in claim 9 or claim 10, wherein the foot engaging portion includes a projection transverse to the upright.

12. A post substantially as herein described with reference to the accompanying drawings. Dated this 8th day of April 2009 Australian Rural Industries Pty Ltd, by their patent attorneys HALFORD & CO