Note: Descriptions are shown in the official language in which they were submitted.
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IMPROVED FABRIC WITH REINFORCED INTERLACES
Field of the Invention
The embodiments described herein are directed to a fabric having reinforced
interlaces and at
least two different average pore sizes created by at least two different
stitch or weave
patterns. An interface is created where the spacing of the nodal points
change. The
reinforced interlaces help to strengthen the larger pores at the interface and
reduce the
potential for fray or unravel.
Background of the Invention
Medical textiles are used in a multitude of applications both for external
application as well
as internal and implantable applications. Today, due to the advancement in
technology and
the rising cost of health care, more medical and surgical procedures are done
using minimally
invasive techniques. This includes the use of endoscopes, and the like, to
view, explore and
perform surgical procedures on a patient within the parameters of an endoscope
or other
minimally invasive instrument.
In such an application, minimally invasive procedures require the instruments
and other
components of the process to be capable of significant compression. This is to
enable the
components to travel through a catheter to the site of the procedure. Further
the components
must be designed to unroll or otherwise decompress so as to function as
designed once they
arrive at the predeteimined location.
In this regard, many components of minimally invasive procedures are specially
adapted to
meet the needs of the particular procedure or instrument used for a
predetermined purpose.
For example, in certain exploratory procedures, a capturing device may be used
to enclose a
tissue sample which will be analyzed by the surgeon once it is retrieved from
the body. In
all cases, the materials must be extremely light weight and relatively thin or
capable of being
compacted into a thin profile for travel via a catheter. Furthermore, the
components must be
strong enough to function as designed so that their slightness in weight does
not detract from
their structural integrity. These two characteristics are difficult to design
as each
compromises the other. A fabric that is designed to be strong is typically
heavier in weight
and bulk. Conversely, a fabric that is light weight and capable of assuming a
slight profile
for travel via a catheter is typically not strong and does not hold up well
under tension.
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In materials and textile components used in minimally invasive applications,
another issue is
that of unravel or fray of the structure. This is especially true with very
open mesh or net
structures. It is undesirable to have a loose yarn or have a fabric
unraveling. The loose yarn
may cause a blockage of a passageway, for example in applications relating to
arterial or
venal repair. In addition, any unravel of a textile component may compromise
the structural
integrity and ultimately the function of the component or device.
One patent addresses the issue of fray or unravel in US Patent No. 5,456,711
entitled
"Warped Knitted Carotid Patch Having Finished Selvage Edges." The patent
solves the need
for cutting by providing knit mesh patches of predetermined width with
finished edges, and
thus eliminates the problem of unravel or fray.
It is desirable to provide a light weight fabric capable of assuming a slight
profile for travel
via a catheter while maintaining a level of strength needed to perform as
designed and to
prevent any fray or unravel of any yarn. It should be noted that the term fray
as described
herein refers to the ability of the fabric in the areas of more concentrated
interlacings or nodal
points to absorb strain from the areas of less concentrated interlacings and
nodal points and
reduce the potential for the stitches to loosen or come undone.
Further, it is desirable to provide a fabric capable of use in a minimally
invasive procedure
that may be cut for manufacturing purposes and reduce the potential for any
fray or unravel.
Summary of the Invention
The embodiments described herein relate to a fabric having a first fabric
section having first
fabric pores created by the first interlacings of yarn in a first pattern, and
having a first
average pore size. The fabric further includes a second fabric section having
second fabric
pores created by the second interlacings of yarn in a second pattern, and a
second average
pore size. The number of first interlacings of yarn exceeds the number of
second interlacings
of yarn. The first interlacings enhance the integrity of the second fabric
section and reduce
the potential for fray.
The fabric of the embodiments described herein has a configuration where the
first fabric
section may surround the second fabric section.
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The fabric of the embodiments described herein may have a difference in
average pore size
between the first average pore size and the second average pore size, where
the difference is
at least 100%.
The fabric of the embodiments described herein may have a difference in weight
between the
first and second fabric sections, where the difference is at least 50%.
The fabric of the embodiments described herein may have a difference in
thickness between
the first and second fabrics, where the difference may be at least 10%.
The fabric of the embodiments described herein may have a difference in the
burst strength
between the first and second fabric sections, where the difference is at least
50%.
The fabric of the embodiments described herein may have a difference in the
number of
interfacings, where the number first interlacings is at least 50% more than
the number of
second interlacings.
The fabric of the embodiments described herein may have a difference in the
percentage of
open area, where the open area of the first fabric section may be about at
least 7% less than
the percentage of open area of the second section.
The fabric of the embodiments described herein may be knit or woven. The
embodiments
further provide for a method of creating a reinforced mesh fabric, by creating
a first fabric
section having first fabric pores created by the first interlacings of yarn in
a first pattern, and
having a first average pore size, and creating a second fabric section having
second fabric
pores created by the second interlacings of yarn in a second pattern, and a
second average
pore size, wherein the number of first interfacings of yarn is greater than
the number of
second interlacings of yarn.
Other objects, features and advantages of the embodiments described herein
will become
more apparent upon reading the following detailed description, when taken in
conjunction
with the drawings and appended claims.
Brief Description of the Drawings
Fig. lA is front view of a first embodiment fabric.
Fig. 1B is a contracted view of the embodiment of Fig. 1A.
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Fig. 1C is an enlarged view of the embodiment of Fig. 1A.
Fig. 1D is a diagrammatic representation of Fig. 1C.
Fig. lE is an enlargement of Fig. lA at the interface of the first and second
pores along the
crosswise direction.
Fig. 1F is a diagrammatic representation of Fig. 1E.
Fig. 1G is an enlarged view of Fig. lA at the interface of the first and
second pores along the
machine direction.
Fig. 1H is a diagrammatic representation of Fig. 1G.
Fig.2A is an enlarged view of a representative second pore.
Fig. 2B is an enlarged view of a representative first pore.
Fig. 3 is a front view of the second embodiment.
Fig. 4 is a diagrammatic representation of the threading layout for the
embodiment of Fig. 3.
Fig. 5 is a diagrammatic representation of the guide bar movement for the
embodiment of
Fig. 3.
Fig. 6 is an enlarged view of Fig. 3.
Fig. 7 is a front view of a third embodiment.
Fig. 8 is a front view of a fourth embodiment.
Detailed Description
Referring now to the drawings in which like numerals indicate like parts
throughout the
several views, Fig. lA shows a first embodiment 10 of the fabric having first
12 and second
14 sections. The first embodiment 10 is a knit mesh made of a monofilament PET
yarn. The
first section 12 is made using a first stitch pattern and forming first pores
16. The second
section 14 is formed by using a second stitch pattern and forms second pores
18.
The particular stitch pattern used for the first embodiment 10 is set forth
below.
Guide bar 1= (2-1/1-2/2-1/1-0/1 -2/2-1/1-2/2-3)x 17 (2-1/1-0/1 -2/2-3)x12
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Guide bar2= (1-2/2-1/1-2/2-3/2-1/1-2/2-1/1-0)x17 (1-2/2-3/2-1/1-0)x12
Guide bar 3= (2-1/1-0/1-2/2-3)x46
Guide bar 4= (1-2/2-3/2-1/1-0)x46
It should be noted that any number of stitch patterns may be used to create a
fabric as
described herein and that the stitch pattern described above is not intended
to limit the scope
of the embodiment in any way. As will be appreciated by one skilled in the
art, the stitch
pattern may be modified to design a fabric where dimensions may need to be
altered but the
function of the fabric remains essentially the same. Fig. 1B is a retracted
view of the first
embodiment 10 and shows the first 12 and second 14 sections. Fig. 1C is a
further enlarged
view of the first embodiment 10 and particularly shows a corner where the
first 12 and
second 14 sections interface. Fig. 1D is a computer generated representation
of Fig. 1C. Fig.
1E is an enlarged view of the first embodiment 10 at the interface of the
first 12 and second
14 sections along a cross direction. Fig. 1F is a computer generated
representation of Fig. 1E.
Fig. 1G is an enlarged view of the first embodiment 10 at the interface of the
first 12 and
second 14 sections along the machine direction. Fig. 111 is a computer
generated
representation of Fig. 1G.
Generally, pores are defined as the opening created between the knitted
pillars of the mesh.
Each pillar consists of the loops formed in a single needle. The spacing
between the yarns
within each knitted pillar is not considered a pore in the formed mesh
described herein. Fig.
2A shows a representative first pore 16 formed by the interlacing of knit
first pillars 20 of the
first embodiment 10. Fig. 2B shows a representative second pore 18 formed by
the
interlacing of knit second pillars 22. As shown in Fig. 1A, the first section
12 surrounds the
second section 14, as shown by interface line 15. The first section 12
encapsulates the second
section 14 by using reinforcing interlaces which work in opposition to one
another to support
the second section 14 by providing additional points within the section where
the yarns
interlace. The first section 12 of additional interlaces provides enhanced
structural support to
the second pores 18 when stressed. In addition, the additional interlaces of
the first section
12 mitigate or prevent fray or unravel by absorbing any cut yarn or end from
further unravel
by absorbing the tension into a point of interlacing or node, and discouraging
further travel
of the end of frayed yarn.
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The first section 12 has a greater density than the second section 14 because
the first pores 16
are smaller arid the number of interlacings is greater over a fixed area. In
the first
embodiment 10, the number of interfacings in the first section 12 is
approximately 26 per
inch, while the number of interlacings in the second section is approximately
14 per inch. As
such, the first section 12 also has a greater weight than the second section
14.
Several tests conducted on the fabric of the first embodiment 10. The results
are set forth in
Table A below.
TABLE A
Parameter # of Test Method Second Sectionl First Section %
Samples Difference
Filament N=5 1-N/A¨ Monofi lam ent Mon ofi lament n/a
Configuration
____________________________ _J _____
Denier N=5 ASTM 20 20 nJa
D1577-07
Material n/a N/A PET PET n/a
Minimum N=20 Microscopy 5.74 1.12 -135%
pore size
(nun2)
Maximum N=20 Microscopy 7.25 1.95 -115%
pore size
(Thrn2)
% Open Area N=5 Microscopy 93% 87% -7%
Weight (g/m2) -N=5 N/A 5.96 10.83 58%
Thickness N=5 ASTM 0.137 0.157 14%
(mm) D1777-96
Option 1
Burst Strength N-5 ASTM 6.5 13.1 67%
(PSI) D3786-06
% Elongation N-5 ISO 7198 54.1 75.8 33%
@ break
Interlacings per N=5 Count Pick 14 26 60%
inch in width
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more effectively installing the mesh piece onto a frame or other object which
will result in a
higher quality product.
The use of a greater number of nodal points as a visual and/or tactile aid may
be incorporated
into all facets of manufacturing where fabric having fewer nodal points or
fewer interlaces is
manipulated onto a frame or other device. The reinforcement area where the
nodal points are
greater helps to provide visual guidance to the person threading the fabric
onto the wire or
tube. The higher interlacing area provides visual guidance to the worker so as
to ensure that
the pores are threaded properly and thus the product quality is greater.
Variation on the number of interlaces in a given fabric at a particular
location may also help
.. to provide a visual or tactile aid to ensure that the less dense area is
oriented properly. The
surgeon may be able to look at the fabric or feel the fabric and determine by
the pattern
whether the mesh is oriented properly. When the mesh is oriented properly, the
success rate
of the procedure increases and thus patient quality of life is enhanced.
It should also be noted that the fabrics described herein may apply to both
woven and knitted
fabrics. With respect to knit fabrics, different stitch patterns may be used
as applications
require. The stitch pattern and density impact the knit mesh qualities of
strength, pore size,
stability and elongation. Where such properties need to be altered, the stitch
pattern and/or
density are altered
Figures 7 and 8 show third and fourth embodiments in a woven construct. Figure
7 discloses
a third embodiment 30 having a first section 32 having a tighter weave and
more interlacings
and nodal points. The second section 34 of the third embodiment 30 has a more
open weave
with fewer interlaces and nodal points. The first section 32 of the third
embodiment 30 has a
1,1 weave, and the second section 34 has a 2,2 weave. Fig. 7 also shows the
weave pattern of
both first 32 and second 34 sections.
.. Figure 8 is another example of a woven embodiment 36 and provides a view of
the fourth
embodiment having a first section 38 having a tighter weave surrounding a
second section 40
of a more open weave. As can be seen from Figure 8, the interfaces between the
first 38 and
second 40 sections is circular but may be designed as needed or desired to
support need and
function of the fabric. The weave pattern of both the first 38 and second 40
sections is also
provided. The first section 38 of the fourth embodiment 36 has a 1,1 weave and
the second
section 40 has a 4,4 weave.
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A further application of the present embodiments is for the creation of fabric
scaffolding for
cell in-growth. It is anticipated that by configuring fabrics of varied pore
size, cell in-growth
can be encouraged. As a result, a fabric scaffold may be designed to encourage
growth of
particular cells by size and thus location on or in the fabric scaffold.
It should also be appreciated that the knit patterns shown herein are linear
in shape, having a
straight length and width. However, applicant anticipates that the embodiments
described
above could also be created by knitting to the desired size or width of the
particular
application. For example, if a resulting piece was desired to have a diamond
shape, that
shape may be achieved either by cutting that shape into a sheet of fabric, or
by knitting the
piece to the desired shape. If the piece were being knitted, the knit pattern
would need to
include tapered sections to create the diamond shape. It will be appreciated
that any number
of linear and curved shapes may be achieved and that the diamond is an example
and in no
way intended to limit the scope of the embodiments described herein.
Applicant further notes that there is at least one alternative method for
creating the
embodiments disclosed herein. Instead of varying the stitch pattern to create
a fabric having
varied number of interlacings, an alternative method is to apply tension to an
area of fewer
nodal points and subsequently heat treat the fabric. The area under tension
will maintain its
density while the remaining fabric will shrink or retract, thus creating a
higher number of
nodal points or interlacings. This method can be applied to the variety of
embodiments
described above.
As used herein, the singular forms "a," "an," and "the" include plural
referents unless the
context clearly dictates otherwise. Thus, for example, the term "a yarn" or "a
pore" is
intended to mean a single yarn or a single pore, or more than one yarn or
pore. Furthermore,
uses within the specification of terms such as "upper," "lower," "vertical,"
"horizontal," and
the like are words of convenience used to describe the structure and function
of the parts of
the embodiments herein relative to each other and are not meant in any way to
be construed
as limiting terms.
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