WO2006015484A1

WO2006015484A1 - Insulator for electric fencing

Info

Publication number: WO2006015484A1
Application number: PCT/CA2005/001231
Authority: WO
Inventors: Eric White
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-08-09
Filing date: 2005-08-09
Publication date: 2006-02-16
Anticipated expiration: 2007-02-09
Also published as: CA2476853A1

Abstract

The present invention relates to an insulator (1) for electric fencing, and in particular to an injection moulded plastic insulator for such fencing that may be mounted directly onto a support surface, especially a fence post, and which is capable of use with electrically conductive rope, polymer tape or wire, and high tensile wire. The insulator will accommodate electric fencing material up to a 3/8 inch in diameter with ease of application and dismantling in the field.

Description

INSULATOR FOR ELECTRIC FENCING TECHNICAL FIELD

This invention relates generally to insulators for electric fences. More particularly, this invention relates to an injection moulded plastic insulator for such fencing that may be mounted directly onto a support surface, especially a fence post.

BACKGROUND ART

Since the advent of agrarian society, fences have been a necessary tool to keep animals in or out of enclosures. However, they are expensive to build and troublesome to maintain. Animals, particularly horses, can kick or chew through wood fences. When the fence is penetrated the animals escape, causing injury or loss to themselves and others.

Puncture wounds and cuts from wood splinters, nails and loose wire ends tangled around their legs are common. The early stone and wood fences were followed by barbed wire, high tensile wire, as well as vinyl board and wire mesh. None of these materials have effectively discouraged the tenacious beasts from their destructive behaviour.

Electric fence technology has introduced a more effective psychological deterrent. Electric fences may be used either as separate fencing or as a supplement along an existing wood, wire or plastic fence line. Electric fencing may also be used to section off an area within a field, a roadside, or other designated area.

Several attempts have been made to devise a strong and durable electric fence suitable for permanent use. One factor that must be considered is the selection of electric fencing materials. A wide range of such materials have been deployed. Although electrified high tensile wire has been widely used, this material is heavy and cumbersome to manipulate during installation and repair operations. It also expands and contracts with changes in temperature. Twisted rope has also been used wherein twisting wire conductors with strands of fibreglass or polymer fibres are formed. The use of tapes of woven textile or fibreglass threads with electrically conductive filaments has been disclosed by Olsson in US Patent Number 4,449,733. Electrically conductive rope was disclosed by White in Canadian Patent

Number 2,267,771.

A second factor for consideration in the design of permanent electric fencing is the selection of support posts for the electric fencing materials. A variety of support posts can be selected from a range of construction materials and shaped configurations. The posts can be constructed of wood, metal, plastic or other materials. The shape of these posts can be round, square, T-bar, flat, or irregular in the case where the surface of a tree trunk or other naturally formed surface is used.

A third factor that must be considered is the selection of the appropriate insulator necessary to isolate the electric fencing materials from the support post structure.

Different types of insulators are designed for use with specific support structures. Examples include groove line insulators, corner insulators, strain insulators, wooden post insulators, rod insulators, steel post insulators, gate anchors, tape insulators, and reel insulators.

Finally, a fourth factor for consideration is the manner in which the insulator is secured to the support post. Some insulators are attached with wire or screw systems, while others fit directly onto a particular style of post, such as a T-bar post.

In the past, attempts to design a permanent electric fence have not adequately addressed these factors. When environmental activities such as vibration, wind, or snow loading create a constant motion in the fence lines, the resulting friction between the lines and the insulators causes wear and failure in both the fencing materials and the insulators. This friction is the principal problem for most fence operators.

One problem with existing insulators is their inability to receive fencing materials in a range of diameter sizes. Most electric fence insulators were designed for use in temporary and portable fencing where smaller 2 to 3 mm diameter fence materials were used. In contrast, the braided or twisted construction typically used for permanent fencing systems is sized in a range up to 3/8 inches (9.4 mm) in diameter. Existing insulators are incapable of accommodating these larger diameter sizes. When the larger size fencing materials are forced into existing insulators, the freedom of movement within the insulator is restricted. The fencing material cannot react to the constant motion created by the environmental forces described above. The resulting friction, chafing and rubbing leads to the failure of the fence system over a period of time.

Another problem with most of the existing designs is the generally protruding shape typical in most conceptions. Many insulators include a claw or finger which protrudes vertically outward toward the fence line in order to secure it in a horizontal position. These protruding claws or fingers are typically formed with sharp edges that pose a threat to nearby animals. The claw or finger snaps away from the insulator base on contact or after the line is weighed down with snow, ice, or fallen trees. The brittleness of the insulator material is a related problem which increases the likelihood of breakage in cold climates. This unwelcome characteristic is a property of the prior art thermoplastic resin used in the moulding process. As a result of these problems, the fence lines require frequent maintenance and repairs. The farmer must disengage the fence line from the insulator and fence support post in order to replace worn or broken components. Unfortunately, the poor insulator design creates problems here as well. Since the installed fence line is under tension in a closed system, it is very difficult to detach the fence line without first removing the insulator from the fence post support. The strenuous effort required to pry the insulator from the fence post support is time consuming and will often damage the insulator as well. In an emergency situation, the rapid removal of the fence line from the posts is almost impossible.

It would be helpful to obtain a durable insulator for electric fencing that can be used with a variety of fence materials, on a variety of posts, in a variety of attachment methods, in a substantially universal and flexible manner.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide an insulator that will permit fence line in a closed system to be disengaged from fence post supports in an easy and quick manner that does not damage the insulator.

It is another object of the present invention to provide an insulator with a passage and a holding chamber, both of which will accommodate various diameters of electric fencing materials. It is a further object of the present invention to provide an insulator that attaches to any type of fence post support, such as steel, concrete, plastic, and trees, using a variety of attachment methods such as nails, screws, strapping and tape.

It is a further object of the present invention to provide an insulator with the ability to flex upon contact to reduce breakage and injury to animals. It is a further object of the present invention to provide an insulator with a one-piece solid design with smooth edges that reduces injury to animals upon contact.

Accordingly, one aspect of the present invention provides an insulator for electric fencing cables, the insulator having a base portion for mounting the insulator to a surface, and a cable support portion for attachment to the base portion. The base portion has a first end and a second end. The cable support portion has defined therein a passage extending from a passage opening to a cable holding chamber. The passage is adapted to facilitate insertion of cables and retention of cables within the cable holding chamber. The passage passes through a first point positioned in a vicinity of the base portion second end and a second point intermediate to the base portion first end and the cable holding chamber. The second point is on a plane passing through the centre of the cable holding chamber and the plane is parallel to the base portion.

The base portion may have an integrally moulded cable support portion extending therefrom. The cable support portion may be smoothly contoured with the base portion, and having means, such as at least one orifice to facilitate the attachment of the base portion directly to a support surface with attachment means.

In an embodiment of the present invention, each of said base and cable support portion are injection moulded from a non-conductive thermoplastic composition.

In a further embodiment, the cable support portion is joined to the base by a flared integral junction on each side of the support.

In another embodiment, the attachment means on the base comprises a plurality of ridge projections extending from said base to facilitate attachment of the base to a support surface by the use of cable, wire or strapping.

In yet another embodiment, the ridge projections have a non-rounded apex. In further embodiments, the projections may be in the form of ridges with a planar upper edge, in a parallel alignment and with the ridges having a W cross-section.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be further described with reference to the accompanying drawings, in which:

Fig. 1 is a schematic representation of a perspective view of an insulator with an engaged cable;

Fig. 2 is a schematic representation of a side view of an alternative embodiment of an insulator; Fig. 3 is a schematic representation of a side view of a second alternative embodiment of an insulator;

Fig. 4 is a schematic representation of a side view of a third alternative embodiment of an insulator; and

Fig. 5 is a schematic representation of a side view of a fourth alternative embodiment of an insulator.

DETAILED DESCRIPTION OF THE INVENTION

A purpose of the invention is to enable the user to install and disengage a fence line which is under tension from initial tightening or loading from snow or other objects. The unique design of the insulator will enable the user to readily disengage the fence line in a crisis such as fire, flooding, animal entrapment in the line, or stampede. The innovative design allows the user to quickly and easily replace broken insulators. Freedom of choice is provided, wherein the user may attach or detach the fence lines at the particular insulators best suited to the need.

The present invention utilizes an innovative open channel design which permits installation of the fence materials in a closed system without restricting the movement of the installed fence line. The passage and the holding chamber are designed to accommodate all sizes of electric fencing material typically up to 3/8 inches in diameter. Fig. 1 illustrates a perspective view of an insulator, generally indicated by 1.

Insulator 1 has base 2 from which extends a support 3.

Base 2 has first end 4 and second end 5, with support 3 being spaced therebetween. First end 4 is shown as having base orifice 6 therein, for use in attachment of insulator 1 to a surface. Second end 5 is shown as having base orifice 7 therein, for use in attachment of insulator 1 to a surface.

Support 3 is shown as being integrally contoured with base 2, at integral contour 8 in a one-piece design. Integral contour 8 occurs on both ends of support 3, and at the juncture with base 2. Integral contours 8 provide strength and support for support 3 to resist strains and stress during use of the insulator. It is preferred that the integral contour be radiused and flared in order to eliminate any sharp juncture between the base and support, thereby maximizing the strength of the juncture of the base and support.

Support 3 is shown as having holding chamber 9, which is used for retention of the fencing material 10 during use and is typically sized in a diameter in the range of 1/8 inch to 1/2 inch. The holding chamber 9 is typically circular to allow the fencing materiaHO to float freely with multi-directional movement virtually free of friction caused by rubbing or chafing. The edges 11 of the holding chamber 9 are chamfered to minimize the frictional forces exerted between the edges and the surface of the fencing material 10.

Support 3 is further shown as having passage 12, which is typically sized in a diameter in the range of 1/16 to 3/8 inch. The passage 12 is used for the insertion of the fencing material 10 into the holding chamber 9 and the removal therefrom. The fencing material 10 enters the passage 12 at an open end of the passage and is routed through an acute angle 13 at the end of the passage 12 and into the holding chamber 9. The acute angle 13 is described as shown in Fig. 4. The inner and outer edges of the passage 14, 15, respectively, are also chamfered to minimize friction between these edges and the surface of the fencing material 10. This design accommodates temporary, portable, protective and permanent fencing.

While the embodiment in Fig.1 illustrates that fencing material 10 may be threaded horizontally through the holding chamber 9 and engaged in an 180 degree orientation, it is understood that fencing material 10 may also be engaged through the chamber in a variety of other configurations. For example, the fencing material 10 can be threaded in the horizontal plane at an angle other than the 180 degrees. In other embodiments, the fencing material 10 can be threaded diagonally from above the chamber to a lower elevation in an 180 degree orientation, or otherwise at an angle other than 180 degrees. Still further embodiments include configurations wherein the both ends of the fencing material 10 threaded through the chamber are at either a higher or a lower elevation.

The insulator of the present invention can be installed either before or after tension is applied to the fence lines. The insulator is readily attachable to a support structure at the base orifices 6, 7 using various means such as nails, screws, strapping and tapes. In many instances, the insulator can be installed using one nail, then adjusted and secured in position with a second nail. This facilitates easy adjustment of the insulator when the electric fencing material 10 is threaded from an irregular position.

Where it is inconvenient or difficult to attach the insulator with nails or screws, the use of strapping, wire or tape is another option available to the user. For example, where the electric fencing material 10 does not pass through the insulator in a horizontal manner, tape can be applied by hand or from a dispenser in order to attach the insulator to the post.

The alternate embodiments shown in Figs. 3, 4 and 5 illustrate this manner of attachment, wherein the tape or strapping is secured to prevent movement by the insulator.

The ridges 16 on the face of the base 2 accommodate a range of different types of strapping material in a fixed position. The ridges 16 permit the insulator to move freely in a horizontal direction along the tape, facilitating the proper orientation with respect to the direction of tension on the electric fencing material 10. As the tension is applied, the strapping is secured into the ridge to prevent slippage, tipping or flipping in a vertical direction. This feature allows the insulator to be attached to different types of posting such as steel, concrete, plastic and trees. Various numbers of ridges may be included on the insulator.

In an embodiment, the support 3 is injection moulded as a single unit with a base 2. The solid design has no protrusions that would introduce a structural weakness at the joints or at the connection to the base. All outer edges are chamfered to reduce the risk of injury when an animal makes contact. The dimensions of the passage 12 and holding chamber 9 are typically 3/8 inch and 1/2 inch respectively.

The injection moulding process uses a thermoplastic polymer combination of a non-conductive thermoplastic polymer resin and a non-conductive rubber powder. The unique combination of resin and rubber powder creates a less brittle insulator with the ability to flex upon contact, thereby reducing breakage from environmental forces and animals. The combination of resin and powder can vary depending on the required insulator strength. The range of resin may vary from 50 to 80 percent by weight. The range of powder may vary from 20 to 50 percent by weight. A stronger insulator will require a higher concentration of resin, such as a ratio of 70 percent resin mixed with 30 percent powder. For the domestic market, a ratio of 60 percent resin mixed with 40 percent powder can be used.

Various combinations of resins and powder can be used. For example, the resin can be polyethylene or another polymer such as polyesters and polyamides. One or more constituent resins may be combined to create the resin which is mixed with the powder. The powder may be carbon black or another compound. One example of a combination of resin and powder is polyethylene mixed with carbon black. It is understood that several other combinations can also be used.

In an embodiment, the compositions may contain ultraviolet (UV) and other stabilizers in order to provide the insulator with protection against sunlight and other environmental conditions. The composition may also have self-lubricating properties. The insulator may be used in a wide range of applications, including line fencing, corners, directional post changes, end posts, top board, rail, or angled fencing. It is not necessary to have insulators of different constructions for different locations. In extreme cases, two or more insulators located in close proximity can be used to attach the electric fence to a support post at the corner. Although the design in an embodiment shown in Figure 1 is configured in the shape of a horse's head and neck, it is understood that the design could otherwise be in the shape of any animal, bird, fish or human head and neck, or an inanimate configuration. Two such alternative embodiments are shown in Figures 4 and 5. The foregoing are exemplary embodiments of the present invention and a person skilled in the art would appreciate that modifications to these embodiments may be made without departing from the scope of the invention as described herein. INDUSTRIAL APPLICABILITY

Advantages of the present invention include a durable insulator for electric fencing that can be used in a variety of fence materials, on a variety of posts, in a variety of attachment methods, and in a substantially universal and flexible manner.

Claims

CLAIMS:

1. An insulator (1 ) for electric fencing cables (10), said insulator (1 ) comprising a base portion (2) for mounting the insulator to a surface, and a cable support portion (3) for attachment to said base portion (2), said base portion (2) having a first end (4) and a second end (5), and said cable support portion (3) defining therein a passage (12) extending from a passage opening to a cable holding chamber (9), said passage being adapted to facilitate insertion of said cables (10) and retention of said cables (10) within said cable holding chamber (9); characterized in that said passage (12) passes through a first point positioned in a vicinity of said base portion second end (5) and a second point intermediate to said base portion first end (4) and said cable holding chamber (9), said second point being on a plane passing through the centre of said cable holding chamber (9) and said plane being parallel to said base portion (2).

2. An insulator (1) according to claim 1 , characterized in that said cable support portion (3) is integrally formed with said base portion (2) and extends therefrom.

3. An insulator (1) according to claim 2, characterized in that said cable support portion (3) is joined to said base portion (2) by a flared integral junction on each side of said cable support portion (3).

4. An insulator (1) according to any one of claims 1 to 3, characterized in that a contour of said cable support portion (3) is adapted such that a juncture of said cable support portion (3) and said base portion (2) has a continuous even surface.

5. An insulator (1) according to any one of claims 1 to 4, characterized in that each of said base portion (2) and cable support portion (3) are injection moulded from a non-conductive thermoplastic composition.

6. An insulator (1) according to claim 5, characterized in that said non-conductive thermoplastic composition is a combination of a non-conductive thermoplastic resin and a non-conductive rubber powder.

7. An insulator (1) according to claim 6, characterized in that said non-conductive thermoplastic composition comprises said non-conductive thermoplastic resin in a range of 50% to 80% by weight.

8. An insulator (1) according to claim 6 or 7, characterized in that said non-conductive thermoplastic composition comprises said non-conductive rubber powder in a range of 20% to 50% by weight.

9. An insulator (1) according to claim 6, characterized in that said non-conductive thermoplastic composition comprises said non-conductive thermoplastic resin and said non- conductive rubber powder in a ratio of 60% to 40%, respectively, by weight.

10. An insulator (1) according to any one of claims 6 to 9, characterized in that said non- conductive thermoplastic resin is selected from the group consisting of: polyethylene, polyesters, polyamides, and combinations thereof.

11. An insulator (1) according to any one of claims 6 to 10, characterized in that said non- conductive rubber powder is carbon black.

12. An insulator (1) according to any one claims 5 to 11 , characterized in that said non- conductive thermoplastic composition further comprises a photo-stabilizer.

13. An insulator (1) according to any one claims 5 to 12, characterized in that said non- conductive thermoplastic composition is self-lubricating.

14. An insulator (1) according to any one claims 5 to 13, characterized in that said non- conductive thermoplastic composition is flexible.

15. An insulator (1) according to any one of claims 1 to 14, characterized in that said base portion (2) comprises attachment means (6,7,16) for attachment of said insulator to said surface.

16. An insulator (1) according to claim 15, characterized in that said attachment means comprises at least one orifice (6,7).

17. An insulator (1) according to claim 15, characterized in that said attachment means comprises a plurality of ridge projections (16) extending from said base portion (2).

18. An insulator (1) according to claim 17, wherein said ridge projections (16) have a non- rounded apex.

19. An insulator (1) according to claim 16 or 17, characterized in that said ridge projections (16) are in the form of ridges with a planar upper edge.

20. An insulator (1) according to claim 19, wherein said planar upper edges of said ridge projections (16) are in parallel alignment.

21. An insulator (1) according to claim 17, characterized in that said ridge projections (16) have a W-shaped cross-section.

22. An insulator (1) according to any one of claims 1 to 21 , characterized in that said cable holding chamber (9) is dimensioned in a size range of 0.125 inch to 0.5 inch for retention of said electric fencing cables (10).

23. An insulator (1) according to any one of claims 1 to 22, characterized in that said cable holding chamber (9) is adapted to allow said electric fencing cables (10) to float freely in a multi-directional movement.

24. An insulator (1 ) according to any one of claims 1 to 23, characterized in that edges (11) of said cable holding chamber (9) are chamfered.

25. An insulator (1 ) according to any one of claims 1 to 24, characterized in that said passage (12) has a passage width ranging from 0.0625 inch to 0.375 inch for insertion and removal of said electric fencing cables (10) from said cable holding chamber (9).

26. An insulator (1) according to any one of claims 1 to 25, characterized in that an inner edge (14) and an outer edge (15) of said passage (12) are chamfered.

27. An insulator (1) according to any one of the claims 1 to 26, characterized in that said insulator is provided in a geometric shape.

28. An insulator (1) according to any one of the claims 1 to 26, characterized in that said insulator is provided in a shape of a head of an animal.

29. An insulator (1) according to claim 28, characterized in that said animal is a horse.

30. An insulator (1) according to any one of the claims 1 to 28, characterized in that said housing chamber (9) is circular in shape.