Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02442529 2003-09-29
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Belt comprising a woven fabric having exactly two woven
fabric layers
This invention relates to a belt comprising a woven fabric as
a traction layer.
The term "belt" is used herein as a collective term for drive
belts, conveyer belts and process belts.
The traction layer of a belt, and especially of a drive belt,
frequently consists of one or more layers of a thermoplastic
synthetic material or of one or more layers of a textile
article, in particular of a woven fabric. This traction layer
is rubber coated.
A traction layer made from thermoplastic synthetic material
is made, for example, from an extruded polyamide sheet. Such
a traction layer is characterised by high flexural strength
and low compressive strength.
The threads of the textile articles and especially of the
woven fabrics, can be made from synthetic raw materials, for
example from polyamids, aramids, polyesters, polyolefins,
etc. However, they can also be made from natural raw
materials, for example from cotton, from stalk fibers such as
flax or hemp, from wool, from silk etc. Moreover, mineral raw
materials such as, for example, glass or carbon are a
possibility for use as a raw material for the threads.
Lastly, mixtures of all these raw materials come into
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consideration as well. The woven fabric can be produced from
all known types of yarn, such as for example multifilaments,
monofilaments, staple fiber yarns or folded or cabled yarns.
The traction layer of the belts, especially of the drive
belts, is exposed to enormous stresses in operation. Traction
layers composed of thermoplastic synthetic material are not
very flexible (see above) and therefore require large rollers
or pulleys to guide or deflect them, which entails a
comparatively large consumption of drive energy (the mass of
the rollers or pulleys has to be driven). In the case of,
traction layers composed of textile articles, in contrast,
flexibility is high but at times the transmission of force is
not sufficient, which is why plural such textile traction
layers are frequently adhered together. This is
disadvantageous in that this requires a further operation in
manufacture, namely the adhering together of the textile
traction layers. Furthermore, the material requirements
increase as a result, since two or more textile traction
layers. are needed. However, above all, an impairment of the
flexibility of the traction layer as a whole results.
This is where this invention seeks to provide a remedy. It is
accordingly an object of this invention to propose a belt, in
particular a drive belt, which not only permits a large
transmission of force, but also remains flexible at the same
time and if possible provides a suitable surface structure
for the mechanical grip of the rubber coating.
CA 02442529 2010-03-31
20152-1285
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To achieve good transmission of force and
flexibility at the same time, the traction layer has a woven
fabric, which comprises (a construction of) two layers,
which are interlaced together. At least one of the woven
fabric layers has a plain weave, a derived plain weave, a
mixed plain weave or a stain weave. In this way it does not
need a further production step to adhere together the
layers. Finally, by this change in the technique to join
together both of the fabric layers a ribbed-form surface
structure arises, which improves the mechanical bond between
the rubber coat and the woven fabric. Depending on which
type of weave is applied, the rib can appear on one side or
both sides of the woven fabric.
In accordance with an aspect of the present
invention, there is provided drive belt having as a traction
layer a woven fabric (G), which comprises exactly two layers
of woven fabric (1,2), which are interlaced together,
characterized in that at least one of the woven fabric
layers (1,2) has a plain weave, a derived plain weave, a
mixed plain weave or a satin weave.
In accordance with another aspect of the
invention, there is provided a drive belt having as a
traction layer a woven fabric, which comprises exactly two
layers of woven fabric, which are interlaced together,
wherein the woven fabric contains weft threads and warp
threads which are multifilaments, wherein at least one of
the woven fabric layers has a plain weave, a derived plain
weave, a mixed plain weave or a satin weave, and wherein the
CA 02442529 2009-10-08
20152-1285
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traction layer is provided with a coating selected from the
group consisting of rubber and a rubber-like thermoplastic
material.
In accordance with another aspect of the
invention, there is provided a method of using a drive belt
for driving a machine, the method comprising: providing a
drive belt having as a traction layer a woven fabric, which
comprises exactly two layers of woven fabric, which are
interlaced together, wherein the woven fabric contains weft
threads and warp threads which are multifilaments, wherein
at least one of the woven fabric layers has a plain weave, a
derived plain weave, a mixed plain weave or a satin weave,
and wherein the traction layer is provided with a coating
selected from the group consisting of rubber and a rubber-
like thermoplastic material; bringing the drive belt in
force-transmitting engagement with a machine to be driven;
and, driving the drive belt.
Further advantages are revealed in the subsequent
description of embodiments aided by reference to the
drawings, where
Figs. 1-5 each show a weave repeat, with which the
formation of a first embodiment of the woven fabric (Fig. 5)
of a traction layer of a drive belt of this invention is
apparent;
Figs. 6-8 of the embodiment of the weave repeat
according to Fig. 5 together with a less idealized depiction
of the corresponding woven fabric unit and a larger section
from the corresponding woven fabric;
Figs. 9-10 each show a weave repeat of further
embodiments of the woven fabric of a traction layer of a
drive belt of this invention; and
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Figs. 11-14 the embodiment of the weave repeat according to
Fig. 5, together with further depictions of the same weave
repeats (therefore of the same woven fabric).
Figures 1-5, which each show a weave repeat, should
illustrate the formation of a first embodiment of a woven
fabric of a traction layer of a belt of this invention, here
in the form of a drive belt, as described below. A weave
repeat is the smallest weave unit whose repetition forms the
fabric. A weave diagram is a schematic depiction of the
interlacing of horizontal weft threads and vertical warp
threads. The crossing points are symbolized by small boxes
(squares in the present case). A filled box or square
indicates that the warp thread in question passes above the
particular weft thread and a blank box or square indicates
that the warp thread in question passes under the particular
weft thread. A weave diagram can be used to depict either
only one repeat, a plurality of whole repeats or one repeat
and a plurality of parts of the repeat to indicate how the
repeats join up. The figures more particularly described
herein below each depict one weave repeat, which, however,
may also be referred to as a weave diagram.
In Fig. 1 one can see the two woven fabric layers 1 and 2,
which are depicted in the same weave diagram. The weaves of
both layers are depicted in one plane. Therefore for layer 1
only the first and third column and the first and third row
are relevant and for layer 2 only the second and fourth
column and the second and fourth row are relevant. The
numbering of the warp and weft threads begins in the bottom
left corner of the weave repeat, or weave diagram.
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The depiction in Fig. 1 denotes that in the first layer 1 the
warp thread K1 passes under the weft thread S2, but over the
weft thread S4. The situation is exactly the opposite for
warp thread K3, it passes over the weft thread S2, but under
the weft thread S4. In the second layer 2 the warp thread K2
passes over the weft thread S1, but under the weft thread S3,
with warp thread K4 the situation is reversed, it passes
under the weft thread S1 but over the weft thread S3. If both
layers are viewed separately, it can be seen that each
individual layer has a simple plain weave. In this case there
are two weave repeats for each individual layer, multiples of
this are also possible. There are four weave repeats for the
whole weave diagram in this case, multiples of this are also
possible.
In Fig. 2, layer 2 is defined as the upper of the two layers
through further passes of the warp threads K2 and K4 over the
weft threads S2 and S4 (with broken line-filled squares).
This is also included in the weave diagram in Fig. 3. In this
construction stage both layers are not yet interlinked.
In Fig. 4, to mark the position at which both layers 1 and 2
should be interlinked, a cross V1, V2 is placed in the
appropriate square. The interlink is carried out in such a
way, that at one position, e.g. in the square, corresponding
to the first column and the third row of the weave diagram
(cross V1), the warp thread K1 of the "bottom" layer is over
the weft thread S3 of the "upper" layer; whereas in the
square, corresponding to the fourth column and the second row
(cross V2), the warp thread K4 of the "upper" layer runs
under the weft thread S2 of the "bottom" layer (first layer).
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In this manner both layers are interlinked and result in a
woven fabric, the weave repeat or weave diagram Pl (diagram
with a single repeat) of which is depicted as a whole in Fig.
5. The different depiction of both layers in Figures 1-5 aids
simply in the explanation of the construction of the woven
fabric.
The depiction in Fig. 5 denotes therefore that the warp
thread K1 passes under the weft threads S1 and S2, but over
the weft threads S3 and S4. The warp thread K2 passes over
weft threads Si and S2, under the weft thread S3 and again
over the weft thread S4. The warp thread K3 passes under the
weft thread S1, over the weft thread S2 and under the weft
threads S3 and S4. The warp thread K4 finally runs under the
weft threads Si and S2 and over the weft threads S3 and S4.
The linking of both woven fabric layers is therefore chosen
so that the alternating threads between the woven fabric
layers bind both layers together as strong as possible and at
the same time form a transverse rib.
The weave diagram P1 in Fig. 5, whose construction is
explained by Figures 1-5, is once again repeated in Fig. 6 to
facilitate the comparison of the "technical" weave diagram
with a less idealised depiction of the thread crossovers in
Fig. 7 and Fig. 8. For the sake of simplicity the threads of
the two layers are again differently depicted.
As is able to be seen from Fig. 7, the warp thread K1 is
under the weft threads S1 and S2, but over the weft threads
S3 and S4, exactly as presented in weave diagram P1 (Fig.6)
with the aid of the filled out and empty squares. All other
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threads cross over each other according to the schematic
depiction in the weave diagram Pl.
In Fig. 8 a larger section from the corresponding woven
fabric G is presented, in which the weave repeat P1 repeats
itself within the woven fabric G. So that the pattern of the
weave diagram P1 can be found again, the warp threads K1, K2,
K3, K4 and the weft threads Sl, S2, S3, S4 are
correspondingly named.
Further embodiments of woven fabrics are presented in Fig. 9
and Fig. 10, in the form of the respective weave repeat or
weave diagram P2 and P3, which are able to be utilized in the
belt of this invention, in particular for a drive belt. The
embodiments according to the weave diagrams P4-P6 (Figures 12
to 14) are only different depictions of the already described
weave diagram P1, which for the sake of clarity is once again
presented in Fig. 11.
Therefore for example the depicted form of the weave repeat
or the weave diagram P4 according to Fig. 12 is the
"negative" of the weave diagram P1 from Fig. 11. As far as
the woven fabric itself is concerned, it means that one looks
at the woven fabric from the other side (one looks therefore
at the "reverse" side of the woven fabric). The woven fabric
itself however remains the same.
From the depiction of the weave repeat or the weave diagram
P4 from Fig. 12 one comes to the depiction of the weave
repeat or the weave diagram P5 from Fig. 13, by virtually
turning over the weave diagram P4 around its lower edge. The
depiction of the weave repeat or the weave diagram P6
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according to Fig. 14 corresponds to the "negative" of the
weave repeat or the weave diagram from Fig. 13.
In principle therefore, at least one woven fabric layer has a
plain weave, a derived plain weave (for example Panama, Reps
etc), a mixed plain weave, and a mixed derived plain weave,
or a satin weave. The second woven fabric layer can either be
formed in the same manner as the first woven fabric layer or
it can be formed differently to the first woven fabric layer,
so that can result in the fact that both woven fabric layer
sides have the same or different surface structures.
Furthermore, the woven fabric may contain conductive threads,
which is particularly advantageous since drive belts - in
order to ensure driving - and other belts always generate
friction on the surface of a drive element (e.g. a metal
pulley). An electrostatic charge can build up in this manner.
At the separation point of the rubbing bodies - for example
where the drive belt loses contact with the pulley - a spark
discharge can then occur. Electrically conductive fibers can
then prevent the occurrence of this sparking by, for example,
carrying the charge to a spot where the drive belt is in
contact with an electrically earthed structural component or
surface (e.g. on the metal pulley), so that the charge is
lead away without the formation of a spark.
The warp threads and the weft threads used may be yarns that
may be constructed as continuous filament yarns
(monofilaments, multifilaments) or which may also be staple
fiber yarns or folded or cabled yarns (folded yarns are two
yarns twisted together, cabled yarns are several folded yarns
twisted together).
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Yarn linear density may vary as a function of the number of
threads per centimeter in the range from about 3 tex to about
300 tex not only for the warp threads but also for the weft
threads.
The thread count can vary as a function of yarn linear
density in the range from about 4 threads/cm to about 4000
threads/cm not only in the warp direction but also in the
weft direction. The woven fabric may have the same or else
different thread counts in the warp and weft directions.
Possible fiber base materials include not only natural base
materials such as, for example, cotton, stalk fibers (e.g.,
flax, hemp), wool, silk and also ramie etc., but also
synthetic base materials such as for example, polyesters,
polyamids, polyolefins, aramids, etc., as well as mineral
base materials such as, for example glass and carbon etc.,
and also mixtures thereof.
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