Note: Descriptions are shown in the official language in which they were submitted.
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INTERWOVEN BELT FABRIC
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to belts for use on conveyors, treadmills, and the
like, and
more particularly to an interwoven belt fabric for use in such belts.
Background Art
Endless belts are typically formed by joining opposite ends of a section of
belt
material and used in a number of different applications. One commonly known
application for such endless belts is in physical exercise equipment such as
treadmills, as
well as in various material handling applications such as check-out counters
in stores, and
the like.
. In a treadmill used for physical exercise, a motor driven belt extends over
a flat
running deck. The typical treadmill belt consists of woven material provided
with a top
layer of polyvinyl chloride or the like. Since the woven belt 'material
forming the bottom
surface of the woven belt is forced into contact with the top surface of the
running deck
by the weight of the person using the exercise equipment, the belt preferably
has specific
characteristics such that the belt has a low coefficient of friction with the
deck, has a
consistent stability when under load, produces a minimum noise and provides
enhanced
performance with the addition of lubricants between the surface of the deck
and the belt.
The type of fabric used, to a very large extent, determines certain
characteristics
of the belt, such as the coefficient of friction, ability to dissipate heat,
ability to absorb
lubricants, stability, and noise generation. Typically, in prior art belts,
the quieter belts
have a higher coefficient of friction and belts made with a mufti-filament
warp yarns (i.e.,
yarns with long staple lengths) tend to have a lower coefficient of friction
than spun warp
yarns (i.e., yarns with short staple lengths). Furthermore, treadmill belts
made with a
typical plain weave fabric using mufti-filament warp yarns and monofilament
fibers in the
weft generally have a relatively low coefficient of friction, but generate a
relatively high
level of noise.
In a typical prior art plain weave fabric, mufti-filament warp yarn is
alternately
woven over and under a series of adjacently disposed monofilament weft fibers.
In one
prior art belt fabric, referred to as a one-by-three whisper weave-broken
twill fabric, a
mufti-filament warp extends over one monofilament weft and under three
monofilament
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2
controller is manually operable from a location remote from the latches such
that the latches
are manually and remotely controlled
In another embodiment, the present invention is a fingerboard having at least
one
fingerboard row for storing a plurality of threaded tubulars. A plurality of
latches are
connected to the at least one fingerboard row, wherein each of the plurality
of 'latches is
biased into a locked position and movable between the locked position and an
unlocked
position. A piston having an elongated rod is slidingly engaged with a casing,
wherein the
casing has a plurality of exhaust ports in fluid connection therewith, and
wherein each of the
plurality of exhaust ports is connected to a corresponding one of the
plurality of latches. An
air source is in fluid connection with the casing, wherein the elongated rod
is movable
between a fully retracted position and a plurality of extended positions
corresponding to each
of the plurality of exhaust ports, wherein in the fully retracted position
each of the exhaust
ports are covered by the elongated rod, such that air from the air source
cannot flow
therethrough allowing each of the corresponding latches to be biased iri the
locked position,
and wherein in each successive one of the plurality of extended positions a
successive one of
the plurality of exhaust ports is uncovered such that air flows therethrough
to force a
successive one of the corresponding latches to move from the locked position
to the unlocked
position.
In yet another embodiment, the present invention is a fingerboard having at
least one
2 0 fingerboard row for storing a plurality of threaded tubulars. A plurality
of latches are
connected to the at least one fingerboard row, wherein each of the plurality
of latches is
biased into a locked position and movable between the locked position and an
unlocked
position. A piston having an elongated rod is slidingly engaged with a casing,
wherein the
casing has a plurality of exhaust ports in fluid connection therewith. Each of
a plurality of
2 5 conduits fluidly connects one of the plurality of exhaust ports to a
corresponding one of the
plurality of latches. An air source is in fhlid connection with the casing,
wherein the
elongated rod is movable between a fully retracted position and a plurality of
extended
positions corresponding to each of the plurality of exhaust ports, wherein in
the fully
retracted position each of the exhaust ports are covered by the elongated rod,
such that air
3 0 from the air source cannot flow therethrough allowing each of the
corresponding latches to be
biased in the locked position, and wherein in each successive one of the
plurality of extended
positions a successive one of the plurality of exhaust ports is uncovered such
that air flows
therethrough to force a successive one of the corresponding latches to move
from the locked
position to the unlocked position. A piston guide is connected to the piston
and has a
3 5 plurality of stop positions, wherein each of the plurality of stop
positions corresponds to one
of the plurality of extended positions of the elongated rod.
In still yet another embodiment, the present invention is a method of storing
a
plurality of threaded tubulars in a fingerboard including providing a
fingerboard row for
storing the plurality of threaded tubulars; providing a casing having a
plurality of exhaust
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wefts. Another prior art belt fabric, referred to as an interwoven fabric, has
a layer of
upper monofilament weft yarns and a layer of lower monofilament weft yarns.
The two
layers are separated by a light denier yarn and each of a plurality of multi-
filament warp
binder yarns extend under one of the lower monofilament weft yarns and over an
adjacent
upper monofilament weft yarn.
A problem with the prior art one-ply plain weave and whisper weave belts, when
used in a treadmill belt or the like, is that they lack the desired stiffness
required under
vaxious loads and at various speeds. When such materials are used, a two ply
belt is
typically required to obtain the desired stiffness. However, two ply belts are
considerably
more expensive to produce than single ply belts. For example, the manufacture
of a two-
layer belt may require as many as five passes through a belt making machine,
one for the
inner layer, one for the cover and three for the glue layers.
Prior art interwoven fabrics axe generally considered to be undesirable for
use in
belts, because belts made of such fabrics are relatively noisy and the fabric
typically has
to be saturated with a plastic material to prevent the weft yarns from
migrating out of the
side of the belt.
Treadmill belts typically are operated at a higher speed than standard
conveyer
belts used for material handling and are typically subjected to greater
concentrated loads
as a result of the running action of a person on the belt. Hence, treadmill
belts must be
relatively stiff, particularly in the lateral direction. Such stiffness is
generally obtained in
prior art belts by making a thicker one-ply belt or by using two-ply belts.
Prior art one-ply and two-ply belts axe comprised of a single layer of fabric
or a
double layer of a fabric, respectively, and a top cover layer of rubber or
vinyl, or the like.
The majority of such belts use monofilament yarns in their weft since material
of that
construction typically provides a relatively stable belt that lays flat, does
not bunch up,
and tracks straight. Generally, thicker belts are more stable than thinner
belts and two-ply
belts are more stable than one-ply belts.
However, thicker belts are typically relatively heavy and stiff in the
longitudinal
direction, thereby presenting a relatively higher load to the electric motor
used to drive
the belt. The higher load to the motor requires that a larger, more expensive
motor be
used which typically draws more current, all of which adds to the cost of the
equipment
and its operation. Therefore, a light weight, highly flexible, low friction
belt is clearly
desirable for applications such as treadmills. Furthermore, treadmill belts
are subjected to
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much greater speed variations than standard conveyer belts. Hence, a belt for
use in a
treadmill application must be stable at high speeds as well as at low speeds.
To reduce power consumption and the generation of heat, it is desirable to
reduce
friction between the belt and the running deck. Hence, belts with a low
coefficient of
friction are preferred. Additionally, lubricants are often applied between the
belt and the
running deck to further reduce friction.. A lubricant such as paraffin wax,
Teflon~, or
solventless silicone is commonly used to reduce friction between the belt and
the deck. In
order for a lubricant to be used effectively, however, the belt must be able
to absorb a
certain amount of the lubricant. Certain prior art plain weave and interwoven
belts
having monofilament yarns in their weft, have the desirable properties that
they tend to
lay flat, do not bunch up, and track straight. However, such belts do not
absorb or hold
lubricants well.
An interwoven fabric disclosed in U.S. Patent No. 6,328,077 is two-ply fabric
made of two layers of weft yarns in couplets, with warp yarns extending over
and under
adjacent couplets in a pattern where warp yarns extend under more couplets in
the lower
layer than extend over couplets in the upper layer. A central warp yarn of
standard light
denier extends between the upper and lower layers. This fabric works well as a
solution
to the aforementioned problems, but an improvement has been discovered that
more
effectively performs.
SUMMARY OF THE INVENTION
According to the invention, a belting fabric comprises a plurality of
adjacently
disposed couplets of weft yarns, a plurality of binder warp yarns, and a
plurality of
middle warp yarns. The couplets form an upper layer of weft yarns and a lower
layer of
weft yarns. The binder warp yarns each extend over at least one of the
couplets of weft
yarns in the upper layer and under at least two of said adj acently disposed
couplets of
weft yarns in the lower layer. The middle warp yarns extend between the upper
layer and
the lower layers and axe sufficiently straight and inelastic to bear loads
under tension
without twisting or stretching.
Preferably, the middle warp yarns are formed of PET and have a denier of at
least
550. Also, preferably, the middle warp yarns are heat set under tension.
In another aspect of the invention a method of making a belting fabric
includes the
steps of arranging a plurality of couplets of weft yarns adjacent one another
into an upper
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layer of weft yarns and a lower layer of weft yarns and weaving a plurality of
middle
warp yarns between the upper and lower layers. Also, a first waxp yarn is
woven over a
first of said couplets of weft yarns and under a second and a third of the
couplets of weft
yarns, disposed adjacent the first of the couplets, a second warp yarn over a
second of the
couplets of weft yarns and under a third and fourth of the couplets of weft
yams, disposed
adjacent the second of the couplets; and a third warp yarn over a third of the
couplets of
weft yarns and under fourth and fifth of the couplets of weft yarns, disposed
adjacent the
third of the couplets. Finally, the middle warp yarns axe heat set.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is side elevational view of a section of conveyer belting material
incorporating the principles of the invention;
Fig. 2 is an enlarged side elevational view of the belting fabric of Fig. 1,
having a
weave pattern in accordance with principles of the invention;
Fig. 3 illustrates the pattern of a single warp binder yarn in the weave
pattern of
Fig. 2; >
Fig. ~ is an enlarged side elevational view of a section of conveyer belting
fabric
of Fig. 1 having an alternate weave pattern in accordance with principles of
the invention;
and
Fig. 5 illustrates the pattern of a single warp binder yarn in the weave
pattern: of
Fig. 4.
DETAILED DESCRIPTION
Shown in Fig. 1 is a section of conveyor belting material 100 comprising a
fabric
layer 101 and a cover layer 102. The cover layer 102 may be a standard rubber
or
plasticized polyvinyl material or the like. One embodiment of a belting fabric
100 in
accordance with the invention is illustrated in Fig. 2 in an enlarged side
elevational view
of a portion of the belt 100. The belting fabric of Fig. 2 includes an upper
layer of
monofilament weft yarns 105 and a lower layer of monofilament weft yarns 106.
The
individual weft yarns of layer 105 are disposed in substantial alignment with
individual
weft yarns of layer 106, forming a plurality of couplets, 110 through 119. The
monofilament weft yarns preferably have a diameter of approximately 0.3 mm.
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The two layers of weft yarns 105, 106 are separated by inelastic middle warp
yarns 107 in accordance with the invention. The middle warp yarns are
sufficiently
straight and inelastic to bear loads under tension without twisting or
stretching. Each
middle warp yarn 107 is preferably formed of PET having a denier of 550,
although any
polymer, rendered effectively inelastic, will suffice. The middle warp yarns
107 are heat
set under tension to make them straight and inelastic.
A plurality of binder warp yams 120,121,122 axe woven on the weft yarns to
form
a belt fabric. The fabric layer 101 is woven in a repeating weaving pattern
wherein three
binder warp yarns 120, 121, and 122 are woven through a plurality of
adjacently disposed
couplets formed from aligned pairs of weft yarns of layers 105 and 106, in a
specified
pattern. In this pattern the first binder warp yarn 120 extends over a first
aligned couplet
of weft yarns 110 and under second and third couplets 111, 112, respectively;
the second
binder warp yarn 121 extends over the second couplet 111 and under third and
fourth
couplets 112,113, respectively; and the third binder warp yam 122 extends over
the third
couplet 122 and under fourth and fifth couplets 113,114, respectively.
The specific pattern of the warp yarns shown in Fig. 2 is further illustrated
in Fig.
3 in which the pattern of a single binder warp yarn 120 is shown sepaxate from
the other
binder warp yarns.
Fig. 4 depicts an alternate embodiment of a belt 200 in accordance with the
invention wherein the fabric 201 comprises four binder warp yarns 220, 221,
222, and
223 woven into two layers of weft yams 206,207. The layers of weft yarns
206,207 are
separated by inelastic middle warp yarns 208 in accord with the invention. As
before,
each middle warp yarn 107 is preferably formed of PET having a denier of 550,
although
any polymer, rendered effectively inelastic, will suffice. The middle warp
yarns 107 are
heat set under tension to make them straight and inelastic.
The binder warp yarns 220, 221, 222, 223 are preferably 1,000 denier yarns and
the weft yarns 206,207 are preferably approximately 0.3 mm monofilament yarns.
The
fabric 201 is woven in a repeating weaving pattern wherein four binder warp
yarns 220,
221, 222 and 223 are woven in a specified pattern through a plurality of
couplets formed
from pairs of aligned weft yarns of layers 206, 207. In this pattern the first
binder waxp
yarn 220 extends over a first aligned couplet of weft yams 210 and under the
second,
third and fourth couplets 211, 212 and 213, respectively; the second warp yarn
221
extends over the second couplet of weft yarns 211 and under the third, fourth
and fifth
couplets 212, 213 and 214, respectively; the 'third warp yarn 222 extends over
the third
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couplet of weft yarns 212 and under the fourth, fifth and sixth couplets 213,
214 and 215,
respectively; and the fourth warp yarn 223 extends over the fourth couplet of
weft yarns
213 and under the fifth, sixth and seventh couplets 214, 215 and 216,
respectively.
The specific pattern of the binder yarns of Fig. 4 is further illustrated in
Fig. 5 in
which the pattern of a single binder warp yarn, yarn 221, is shown separate
from the other
binder warp yarns.
Belt material in accordance with the present invention is preferably
manufactured
by feeding the woven belt fabric, e.g., 100, 200, from a roll of the fabric
into a well-
known belt coating apparatus. Such apparatus typically includes a feeding
mechanism
extending the belt between a roller and a coating knife. Liquid PVC, such as a
well-
known product referred to in the trade as "Plastisol," is applied in a
standard fashion. The
belt material with the newly applied coating is then fed into an oven and
heated by
infrared lamps or the like to dissolve the applied PVC. After passing through
the oven,
the belt material with the applied PVC is fed between a roller and a cooling
drum while
cooling the belt. This causes the PVC to be forced into cavities in the woven
material.
One advantage of the belting fabric is that it has cavities of substantial
size that
provide for proper adhesion of the PVC layer to the fabric. As a result, glue
lining
required for belts made of prior art belt fabrics is not required. The
application of such a
glue lining requires that the belt material be fed through a glue application
mechanism,
similar to the PVC application mechanism. Accordingly, a belt made in
accordance with
the present invention is substantially less expensive to manufacture. More
importantly,
however, the stronger middle warp yarns axe believed to be the ones primarily
under
tension during operation of the belt. Since they are the load-carrying yarns,
the upper and
lower layers on either side of the middle warp yarns are under no load, an
thus do not
wear as quickly as belts of the prior art. The result is a more durable belt.
