Note: Descriptions are shown in the official language in which they were submitted.
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LIG~IT FENCING MATERIAL
The present invention relates to a light fencing
material made from woven polyolefin fabric, of particular
use in minimizing the effects of drifting snow, sand or
soil~
It is known to use fencing as a means to minimize
the effects of drifting from blown snow, sand or soil. A
typical fence used heretofore eomprises a plurality of
spaced-apart vertical wooden slats, eaeh slat being
adjoined to ad~acent slats by two or more strands o twisted
wire. Typically such fencing is held in an upright position
by attaching the feneing to Eenee posts, usually of the
steel T-bar type, a-t intervals of about 4O5 meters. Another
type of feneing is made from integrally~extruded plastic net
similar to that disclosed in U.SO Patent 4 242 295 which
issued 1980 December 30 to T. Urquhart. A disadvantage of
using this type of plastie feneing is that the supporting
posts need to be placed about 3 metres apart.
Canadian Patent 991 925 which issued 1976 June 29
to Fash et al., discloses a fencing product, made from
fibrous strands of synthetic plastie material, woven in a
pattern having areas of relatively tight weave and other
areas that are relatively open, in whieh the fabric is
coated with an elastomeric weather-resistant composi-tion.
The elastomeric material is said to bond the fibres to each
other, as well as providing abrasion resistanee and low
temperature stability, among other things.
A fencing product, which is light weight ancl which
does not require an elastomeric coating, has now been found.
Accordingly, the present invention provides a
fencing material comprising a woven fabric of oriented poly-
ethylene or polypropylene tapes, said fabric having a band
of warp tapes at least about 2.5 centimetres wide at each
selvedge of the fabric, and at least one band oE warp tapes
at least 2 cen-timetres wide between the selvedge bands such
that the distance between adjacen-t bands of warp tapes is
between about 5 centimetres and 60 centimetres, said war
tapes being held in position by a plurality of bands oE wef-t
tapes woven in leno weave form, each band of weft tapes
being at least l cm wide and spaced apart from other bands
of weft -tapes such that the ratio of the area oE the fabric
covered by the bands of warp and wef-t tapes to the total
area of the fabric is between about 0.20 and 0.50.
In one embodiment oE the invention, the warp tapes
have a width of between about l.O and about 1.5 millimetres
and have a linear density between about 400 and about 600
dtex.
In another embodiment, the weft tapes are in bands
comprising a plurality of weft tapes, said bands being
between about 5 and 15 centimetres in width and adjacent
bands of weft tapes being spaced apart from between about
5 and 15 centimetres.
In yet another embodiment, the weft tapes have a
width of between about 2.5 and about 3.5 millimetres and
have a linear density between about 900 and about llOO dtex.
In a preferred embodimen-t the ratio of the area oE
the fabric covered by the bands of warp and wef-t tapes -to
the total area of the fabric is between about 0.25 and 0.40.
In yet another embodiment the bands of warp -tapes
are spaced apart about 8 to 12 centimetres.
The invention may be further understood by
reference to the drawing which shows one embodiment of the
present invention.
The fencing material of the present invention may
comprise two selvedge bands, l and 2, of oriented poly-
ethylene or polypropylene warp tapes, having spaced -there-
between at least one band, 3, of oriented polyethylene or
polypropylene warp tapes. Typically these in-termedia-te
bands are spaced apart about 30-45 centimetres. The warp
a.9~ 3
-- 3 --
bands are held in position by a plurality of we~t bands e.g.
4a, 4b, 4c, of oriented polyethylene or polypropylene we~-t
tapes. ~t the crossings between -the warp and weft bands,
the warp tapes are held securely to the wef-t tapes by means
o~ a leno weave. Leno weavinq is accomplished by methods
known in -the art.
The fencing material is preferably made from
oriented polyethylene tapes. The polyethylene may be a
homopolymer of ethylene or a copolymer oE ethylene with a
C4 to Clo ~-olefin. A polyethylene having a density in the
range of 0.940 to 0.970 g/cm3 is preEerred. The densi-ty of
the polyethylene is measured, prior to being extruded into
tapes, by ASTM procedure D1505. The material preferably
contains an inhibitor against ultraviolet light degradation.
The tapes are oriented to provide the necessary strength to
the fabric. The oriented tapes may be made by known
methods. For example the polyethylene or polypropylene may
be extruded into flat Eilm form, slit into tapes and then
oriented. The tapes may also be made, for example, from
co-oriented laminated film wherein two similar films are
brought together and co-oriented laminated in a narrow gap
orientation process. Slitting of the film may be accom-
plished by known methods e.g. using a method and apparatus
disclosed by M.J. Wolstencro~t in U.S. Patent 4 137 614,
which issued 1979 February 6.
The ~abric may be woven using, for example, a
projectile weaving machine wi-th dobby and leno weave
attachmen-ts.
Fabrics of -the present invention are particularly
suitable Eor Eencing material, espec:ially for placement to
minimize driEting oE dry snow, sand or soil. In use such
fabric is attached to vertical support posts e.g. steel
T-bar pos-ts, placed at in-tervals. Preferably the posts are
spaced a-t intervals of about 4.5 metres. Although
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securement of the fabric to the posts may be made through
use of wire ties a preferred method of securement is to use
a clip comprising a piece of plastic tube having a longitu-
dinal slit therein. The slit is preferably splayed at one
end to aid in sliding the clip over the support post. The
clip may be slid over the support post in such a manner to
trap the fabric between the support post and the inside of
the tubular clip. The sliding action tends to keep the
feneing material taut in the weft direction.
The following example serves to illustrate -the
present invention:
EXAMPLE I
A fabric was prepared, having two warp selvedge
bands about 50 millimetres wide and -two intermediate bands,
each about 25 millimetres wide and situated about 34 centi-
metres -from the edge bands. Warp bands, each 50 millimetres
wide and spaced 50 millimetres apart, were woven to the warp
bands. The warp bands comprised polyethylene tapes having a
linear density oE 1050 dtex. There were 49 ends per 10
centimetres of warp tapes in each band. 'Fhe weft tapes had
a linear density of 1500 dtex. There were 47 ends per 10
centimetre of weft tapes in each band. The selvedges were
50.8 mm wide, each warp band was 25.4 r~m wide and each weft
band was 50.8 mm wide r Weft band spacings were 50.8 m,n and
warp band spacings were 35.6 cm.
The fabric was woven together using a leno weave.
Several metres of this fabric were taken and secured to
steel T-bar posts placed at ~.5 metre intervals. The
fencing material was attached to the T-bar posts by means of
a "continuous clip" comprising a piece of plastic tubing
with a longitudinal slit therein. The sli-t is preEerably
splayed a-t one end to aid in sliding the clip over -the T-bar
post and to trap the Eabric. The fencing material, erected
in Kingston, Ontario, Canada survived 12 weeks during the
months February -to May, experiencing temperatures in the
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range of -20 to +15C and a variety of weather conditions
e.g. snow, freezing rain, and gusting high winds. After
this test, the material, was removed and observed to be
substantially in its original form i.e. -there were no rips
in the material and the leno weave had not become
unravelled.
Advantages oE the present fencing material over
conventional types are that it is light e.g. about 1.1 kg
for 30 metres, is no-t bullcy and is easily stored.
