Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE:
INSULATOR FOR ELECTRIC FENCING
The present invention relates to an insulator for electric fencing,
and in particular to an injection molded plastic insulator for such fencing
that
may be mounted directly onto a surface, especially a fence post, at straight
(line) or angled sections of electric fencing and which is capable of being
used with electrically conductive rope, electrically conductive polymer tape
or
wire and with high tensile wire. In embodiments, projections or ridges are
provided to maintain the insulator in position.
Traditional fences are barrier type fences which attempt to keep
animals in or out of the enclosure by creating an immovable barrier. Stone
walls and wood were the early materials of choice. Barbed wire and high
tensile wire have been widely used for many years. Vinyl board fence and
wire mesh fence are more recent developments. Recycled rubber, rigid pipe,
polymer coated wire and extruded polymer (non-metallic) wire are all used
today as fence materials.
Fences have always presented problems. They are expensive
to build and troublesome to maintain. When a weak link is found, or created,
by an animal, or by a falling tree, the fence is penetrated. When a fence is
penetrated, animals escape from the enclosure with the risk of serious injury
to animals or people, and potential loss of the animals.
Animals, particularly horses, can both damage and be damaged
by traditional fence materials. Horses can kick through wood fences, chew
wood until it is severed, get puncture wounds from wood splinters, nails and
loose wire ends, get cut by wire, and get serious injuries from loose ends of
wire which tangle around their legs.
The most frustrating problems to farmers are the time, trouble
and cost to erect traditional fences, and the constant need to repair them.
Electric fence technology introduced a psychological deterrent
to fences. Electric fences may be used as separate fencing or to supplement
and protect traditional fences made of wood or wire or plastic.
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Several attempts have been made to devise a strong and
durable electric fence, suitable for use as a permanent fence. Electrified
high
tensile wire on posts has been widely used as permanent electric fencing, but
it is heavy and cumbersome to install and repair, and it undergoes expansion
and contraction with changes in temperatures. Another type of electric fence
is made by twisting wire conductors with strands of fibreglass or polymer
fibres to form a twisted rope. A further type of electric fence line comprises
tapes woven from a plurality of textile or fibreglass threads with
electrically
conductive filaments of wire woven-in longitudinally, as disclosed by Olsson
in
US 4,449,733.
Electrically conductive rope is disclosed by Eric White in
published PCT application No. WO 98/20505 published on May 14, 1998.
In use, the electric fencing may be strung along a fence line, so
as to prevent an animal from pushing through the fence. The electric fencing
may also be used to section off an area of a field and restrict movement of an
animal or animals within the field. Electric fencing may be strung along
roadsides or in other areas to prevent or restrict access of animals to a
designated area. The electric fencing may be supported on posts, which may
be wooden, metal, plastic or other materials. Moreover, the posts may be
round, square, T-bar or flat, the uneven surfaces of tree trunks or any other
suitable support surfaces. All of these methods require use of insulators to
isolate the electric fencing from the support structure.
A wide variety of methods are used for attachment of the
insulator to a substrate. Insulators may be sold commercially as for instance
groove line insulators, corner insulators, strain insulators, wooden post
insulators, rod insulators, steel post insulators, gate anchors, tape
insulator,
reel insulators, with different types of insulators being intended for use
with
different support structures. Some such insulators are intended to be
attached to the support using wire or screw systems, whereas other systems
are adapted to be fitted directly onto a particular style of posts e.g. T-bar
posts.
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An insulator for electric fencing that is capable of being used on
a wide variety of substrates, and for use on line fencing, corners or other
angles in a substantially universal manner would be useful. Such an insulator
has now been found.
Accordingly, one aspect of the present invention provides an
insulator for electric fencing, said insulator being directly attachable to a
substrate, comprising:
(a) a base having a pair of opposed integrally moulded
supports extending therefrom, said supports being smoothly contoured with
said base, each support having an orifice therethrough, said base having at
least one orifice for attachment of the base directly to a substrate;
(b) an elongated roller with a smoothly tapered waist and an
axial orifice, said roller being located between said supports with the axial
orifice cooperatively aligned with the orifices of each support;
(c) an axle extending through said orifices and adapted for
retention of the roller between said supports, said roller being rotatable.
In a preferred embodiment of the present invention, each of said
base and said roller are injection moulded from a non-conductive
thermoplastic composition.
In a further embodiment, the supports are joined to the base by
a radiused and flared integral junction on each side of each support.
In another embodiment, the base has a plurality of ridge
projections extending from said base befinreen the opposed integrally
moulded supports.
In yet another embodiment, the ridge projections have a non-
rounded apex.
In further embodiments, the projections are in the form of ridges
with a planar upper edge, especially in a parallel alignment and in particular
with the ridges having a W cross-section.
The present invention is illustrated by the embodiments shown
in the drawings, in which:
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Fig. 1 is a schematic representation of a perspective view of an
insulator;
Fig. 2 is a schematic representation of an end view of the
insulator of Fig. 1;
Fig. 3 is a schematic representation of a longitudinal cross-
section, along A-A of the insulator of Fig. 1;
Fig. 4 is a schematic representation of a perspective view of an
alternate insulator; and
Fig. 5 is a schematic representation of the insulator of Fig. 4,
through B-B.
Fig. 1 shows a perspective view of an insulator, generally
indicated by 1. Insulator 1 has base 2 from which extend first support 3 and
second support 4. First support 3 and second support 4 are in a spaced
apart relationship, but are aligned with roller 5 therebetween.
Base 2 has first end 6 and second end 7, with first support 3
and second support 4 being spaced therefrom, respectively. First end 6 is
shown as having base orifice 8 therein, for use in attachment of insulator 1
to
a support substrate. Base 2 would normally have a second base orifice
located on second end 7, not shown in Fig. 1.
First support 3 is shown as having support orifice 10, which is
used in attachment and retention of roller 5 in position. It is understood
that
second support 4 would also have an orifice and such orifices would be
aligned.
First support 3 is shown as being integrally contoured with base
2, at integral contour 9. Integral contour 9 occurs on both sides of first
support 3, and similarly is on both sides of second support 4 at the juncture
of
first support 3 and second support 4 with base 2. Integral contours 9 are
important to provide strength and support for first support 3 and second
support 4, to resist strains and stress during use of the insulator. It is
preferred that the integral contour be radiused and flared, so that there is
not
a sharp juncture between the base and support, to maximise the strength of
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the juncture of the base and support. It is intended that first support 3 and
second support 4 would be injection moulded as a single unit with base 2.
Roller 5 has roller waist 11 located between first roller end 12
and second roller end 13. Roller waist 11 is for retention of the electric
fencing i.e. rope or wire, during use and could have a depth of 25-75% of the
radium of the roller. Roller 5 is located between first support 3 and second
support 4, and is freely rotatable therein. Roller 5 is retained in position
using
an axle or other attachment means located in support orifice 10, extending
through an orifice (not shown) that is axially located within roller 5 and
into a
support orifice located in second support 4.
Fig. 2 shows an end view of the insulator of Fig. 1. First support
3 extends upwards from base 2, and is shown as being in a truncated tri-
angular shape. This is a preferred shape. First support 3 is integrally
connected to base 2 at an integral contour 9. Roller 5 is located behind first
support 3, as viewed, and has first roller end 12 and roller waist 11. Roller
5
is supported at support orifice 10, using an axle therein.
Fig. 3 shows a cross-section of the insulator of Fig. 1, through
A-A. Base 2 has two base orifices, shown as 8A and 8B. Base orifice 8A is
shown in first end 6 and base orifice 8B is shown in second end 7. First
support 3 and second support 4 extend from base 2, being connected thereto
at integral contours 9. First support 3 has support orifice 10A and second
support 4 has support orifice 10B. Roller 5 has roller orifice 14 extending
therethough in an axial position. Roller orifice 14 is cooperatively aligned
with
support orifices 10A and 10B. Support orifice 10A would have an axle or
other attachment means extending therethrough and through roller orifice 14
for retention of roller 5 in position between first support 3 and second
support
4 so as to permit rotation of roller 5 between the supports. The gaps 16A and
16B between roller 5 and first support 3 or second support 4, should be small,
of sufficient width to permit roller 5 to freely rotate between first support
3 and
second support 4 but to do so without significant wobble or axial movement.
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Electrically conductive rope 15 is shown as located in waist 11
of roller 5, in a location between roller 5 and the section of base 2 located
between first support 3 and second support 4.
In an embodiment of the invention, the region of the base 2
between first support 3 and second support 4 has a plurality of ridge
projections, which preferably have non-rounded apices. It is to be understood
that the ridges could have a non-planar upper edge e.g. the ridge could have
peaks and valleys, also known as peaks and saddles. However, as illustrated
in Figs 4 and 5 discussed below, the projections are preferably in the form of
ridges with a planar upper edge. The ridges should be aligned in parallel and
extend for at least a substantial part of the width of base 2. The ridges
preferably have a cross-section that is in the form of a "W". For instance,
each ridge could be of a V cross-section and the intervening valley in the
shape of an inverted V. An example of such an alternate and preferred
embodiment is illustrated in Figs 4 and 5.
In Fig. 4, base 2 has a plurality of ridges 22 extending
transversely across the base in the region of base 2 located between first
support 3 and second support 4. Ridges 22 have a V shape, and the
intervening valleys have an inverted V shape. In Fig. 4, ridges 22 are aligned
in parallel and extend across the full width of base 2. Ridges 22 should
extend across a major part of such width. In addition, ridges 22 are shown as
extending from first support 3 to second support 4, which is a preferred
embodiment of the invention.
The embodiment of Fig. 4 shows axle 20 located in support
orifices 10A, as discussed herein.
Fig. 5 shows a cross-section of Fig. 4, through B-B. Axle 20,
with axle head 24, is located in support orifices 10A and 10B. Axle 20 retains
roller 5 in position. Roller 5 is rotatable, but axle 20 is preferably in a
force-fit
in support orifices 10A and 10B. While being removable, e.g. by prying out,
axle 20 is intended to remain in position during normal use.
Reference has been made to use of an axle to retain the roller
in position, and permit rotation. A wide variety of axles may be used. For
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instance, one end could resemble the head of a bolt and the other end have a
nut, split pin, cotter pin or other means to retain the axle in position. The
axle
could be a tapered spindle that would be retained in position by a friction
fit or
the tapered spindle with the walls of the orifice of the support or of the
roller.
The axle could be intended to rotate with the roller, or be independent
thereof. In preferred embodiments, the axle is readily capable of insertion
and removal, while remaining in position during use.
The insulator of the present invention is readily attachable to a
substrate. If the substrate is a wooden post, the insulator may be nailed on.
If the post is other than a wooden post, then the insulator may be wired,
taped or strapped onto the post, or attached using ratchet-type systems or by
a variety of other methods.
In many instances, it is inconvenient, time-consuming or not
feasible to attach the insulator using nails or screws, especially when the
post
will not readily accept nails or screws. In such cases, use of wire, tape or
straps may be preferred. This is usually done before roller 5 is placed in
position. The tape, or other attachment, would normally be applied by hand,
or using a convenient dispenser, in a tight manner. Nonetheless, in use, and
especially in use at angles or corners in the fence, tension may be applied to
the insulator due to contours of land, presence of an animal contacting the
fence or for other reasons. For example, the electric fencing passing through
the insulator may not do so in a horizontal manner, but may angle upwards or
downwards from the insulator. In such situations, there is a tendency for tape
used to attach the insulator to the post to move position within the insulator
so
that it becomes adjacent to either the first support 3 or second support 4,
depending on the direction of the tension. The consequence is that the
insulator has a tendency to tip or flip out of position. In the latter
situation, the
insulator could be useless and not perform its expected function as an
insulator.
The alternate embodiment, illustrated in Figs 4 and 5, alleviates
tendencies for the tape or other attachment to move out of position. The
raised ridges permit the insulator to move freely in a horizontal direction
along
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the tape, thereby allowing the insulator to orient with respect to the
direction
of tension on the electric fence rope or wire. As the tension is applied, the
tape bites into the ridges, which stops slippage of the tape in a vertical
direction, upward or downward, and this tends to prevent tipping or flipping.
The insulator may be used on line fencing, and at corners or
angles of 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 rope or
wire
to a substrate (post) at the corner.
The base and roller may each be formed in injection moulding
processes from thermoplastic polymer compositions. The compositions
should contain UV and other stabilizers for protection against sunlight and
other environmental conditions of use. For example, the compositions could
be polyethylene filled with carbon black. Other polymers may be used e.g.
polyesters and polyamides.
The composition should be electrically non-conductive and
preferably have self-lubricating properties.
An insulator may be used with a single electrically conductive
rope, or with two or even more e.g. at a junction of electric fences.
In many instances, the insulator can be installed using one nail,
with a second nail added later. This will permit adjustment of the position of
the insulator when the electric fencing is entering the insulator from a non-
horizontal position.
