Note: Descriptions are shown in the official language in which they were submitted.
CA 02279408 1999-07-14
WO 98/39507 PCT/SE97/00355
NETWORK-LIKE WOVEN 3D FABRIC MATERIAL
TECHNICAL FIELD
This invention relates to a woven 3D fabric and its method of production. In
particular. the woven 3D
fabric comprises select multilayer warp yams occurring substantially linearly.
the remainder multilayer
warp yams occurring in a helical configuration and two orthogonal sets of weft
and such a network-like
fabric construction made possible through a dual-directional shedding
operation of the weaving
process. Such a fabric. which may additionally incorporate non-interlacing
multi-directionally
orientated yams across the fabric cross-section for improving its mechanical
performance. is considered
useful in technical applications like the manufacture of composite materials,
filters. insulating
materials. separator-cum-holder for certain materials, electrical/electronic
parts, protection material,
etc.
BACKGROUND
In the conventional weaving process the foremost operation of shedding is
limited in its design to form
a shed in only the fabric-width direction. The employed warp, which is either
in a single or a multiple
layer. is separated into two parts in a 'crossed' manner, in the direction of
the fabric-thiclrness through
the employment of the heald wires which are reciprocated through their frames
by means such as cams
or dobb~~ or jacquard to form a shed in the fabric-width direction. Each of
these heald wires are
reciprocated either singly or jointly or in suitable groups in only the fabric-
thiclrness direction to form a
shed in the fabric-width direction. A weft inserted into this formed shed
enables interconnection
between the separated two layers of the warp. The so interconnected warp and
weft results in an
interlaced structure which is called the woven fabric. A fabric when produced
using a single layer warp
results in a sheet-like «roven material and is referred to as a woven 2D
fabric as its constituent yams are
supposed to be disposed in one plane. Similarly, when a fabric is produced
using a multiple layer warp.
the obtained fabric which is characteristically different in construction from
the woven 2D fabric. is
referred to as a woven 3D fabric because its constituting yams are supposed to
be disposed in a three
mutually perpendicular plane relationship. However, in the production of both
these types of woven 2D
and 3D fabrics the conventional weaving process, due to its inherent working
design, can only bring
about interlacement of two orthogonal sets of yam: the warp and the weft. It
cannot brine about
interlacement of three orthogonal sets of yams: a multiple layer warp and t«~o
orthogonal sets of weft.
ThlS 15 an inherent limitation of the existing weaving process. The present
invention provides a dual=
directional shedding method to form sheds in the columnwise and the row-wise
directions of a
multilayer warp to enable interlacement of the multilaver warp and two
orthogonal sets of weft in such
a way that select yams of the multilayer warp occur substantially linearly and
the remainder yarns.
which interlace with the t<vo orthogonal sets of weft, occur in a helical
eonfirmuation and the obtained
fabric has a network-like structure.
Certain technical fabric applications require complex or unusual shapes
besides 'other specific
characteristics for performance such as a high degree of fabric integration
and proper orientation of the
constituent yarns. For example. at present it is not possible to obtain a
suitable fabric block from which
1
CA 02279408 2006-05-O1
preforms (reinforcement fabric for composite material application) of any
desired shape may be
cut obtained. This is because the present fabric manufacturing processes of
weaving, knitting,
braiding and certain nonwoven methods which are employed to produce preforms
cannot deliver
a suitable highly integrated fabric block from which preforms of any desired
shape may be cut
obtained. With a view to obtain certain regular cross-sectional shaped
preforms, suitable fabric
manufacturing methods working on the principles of weaving, knitting, braiding
and certain
nonwoven techniques have been developed. Such an approach of producing
preforms having
certain cross-sectional shapes is referred to as near-net shaping. However,
through these various
techniques preforms of only certain cross-sectional profiles can be produced
and preforms of any
desired shape cannot be manufactured. The obtaining of preforms of any desired
shape can be
made practically possible if only a highly integrated fabric block can be made
available so that
the required shape can be cut from it without the risk of its splitting up.
Also, fabrics for other
applications like filters of unusual shapes can be similarly cut obtained from
a suitable fabric
block. For analogy, this strategy of obtaining any desired shape of three-
dimensional fabric item
may be seen as the cutting of different shapes of fabric items from a suitable
sheet of 2D fabric,
for example, during the manufacture of a garment. Therefore, as can be
inferred now, to cut
obtain three-dimensional fabric items of any desired shape it is essential to
first produce a highly
integrated fabric in the form of a block. The present invention provides a
novel woven 3D fabric
and the method to produce such a fabric block which can be cut without the
risk of splitting up
and which may additionally incorporate non-interlacing yarns in a multi-
directional orientation to
impart mechanical performance to the fabric, so as to be useful in technical
applications.
SUMMARY
In accordance with a broad aspect, the invention provides a block of network-
like integrated 3D
fabric which additionally incorporates yarns suitably orientated to impart
proper mechanical
strength to the fabric so that suitable fabric items of any desired shape can
be cut without the risk
of its splitting up. Because certain fabric items of any desired shape may be
obtained easily this
way, such an approach can be advantageous in technical applications such as
the manufacture of
preforms, i.e. reinforcement fabric for composites application, filters, etc.
In accordance with another broad aspect, the invention provides a dual-
directional shedding
method to enable interlacement of three orthogonal sets of yarn: a set of
multilayer warp and two
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orthogonal sets of weft. Such an interlacement of the three orthogonal sets of
yarn is necessary to
provided a high degree of integrity to the fabric to render the fabric
resistant to splitting up in the
fabric-width as well as in the fabric-thickness directions. This way the
objective of producing a
network-like interlaced 3D fabric, which may additionally incorporate non-
interlacing multi-
directionally orientated yarns, is made possible.
The integrity of the fabric is made possible through the formation of multiple
row-wise
columnwise sheds in the employed multiple layer warp. Two orthogonal sets of
weft when
inserted in the formed row-wise and columnwise sheds produce a network-like
interlaced 3D
fabric. Because the foremost operation of the weaving process happens to be
the shedding
operation, all other subsequent complementing operations of the weaving
process, for example
picking, beating-up etc., will follow suit accordingly. As the dual-
directional shedding method
enables interlacement of two orthogonal sets of weft and a multilayer warp by
way of forming
sheds in the columnwise and row-wise directions of the multilayer warp to
produce a highly
integrated network-like fabric structure having a high mechanical performance,
it will be
described in detail. The subsequent complementing weaving operations like
picking, beating-up,
taking-up, letting off etc. will not be described as these are not the
objectives of this invention.
With a view to keep the description simple and to the point, the simplest mode
of carrying out the
dual-directional shedding operation will be exemplified and will only pertain
to the production of
the woven plain weave 3D fabric according to this invention. The method of
producing
numerous other weave patterns through this invention will be apparent to those
skilled in the art
and therefore it will be only briefly mentioned as these various weave
patterns can be produced
on similar lines without deviating from the spirit of this invention.
In accordance with another broad aspect, the invention provides a device for
producing woven
fabric material with a weaving method incorporating the operation of shedding
in two mutually
perpendicular directions to form row-wise and column-wise sheds in a
multilayer warp disposed
according to a cross-sectional profile of the fabric to be produced. The
device comprises
shedding means which include one or more shafts capable of being reciprocated
linearly along its
longitudinal axis and also angularly about its longitudinal axis. Each of the
shafts bear a set of
means along the shaft's length direction such that the length direction of
each of these means is
orientated perpendicular to the length direction of the shaft. The set of
means are intended to
support warp strings threaded through its entry port and exit port in
accordance with the cross-
sectional profile of the fabric to be produced.
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BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in reference to the following illustrations.
Fig. 1 shows the general arrangement of the shedding shafts for carrying out
dual-directional
shedding .
Fig. 2 shows the disposal arrangement of the active and the passive warp yarns
comprising the
multilayer warp.
Fig. 3 shows the location of the shedding shafts in relation to the passive
yarns of the multilayer
warp indicated in Fig. 2.
Fig. 4a shows the top view of the level position of the shedding shafts and
the multilayer warp
prior to columnwise shed formation.
Fig. 4b shows the top view of the shedding shafts displacing the active warp
yarns drawn through
its eyes towards the right side of the passive warp yarns and the formation of
the multiple right
side columnwise sheds with the passive warp yarns.
Fig. 4c shows the top view of the shedding shafts displacing the active warp
yarns drawn through
its eyes towards the left side of the passive warp yarns and the formation of
the multiple left side
columnwise sheds with the passive warps yarns.
Fig. Sa shows the side view of the level position of the shedding shafts and
the multilayer warp
prior to row-wise shed formation.
Fig. Sb shows the side view of the shedding shafts displacing the active warp
yarns drawn
through its eyes in the upward direction to form the multiple upper row-wise
sheds with the
passive warp yarns.
Fig. Sc shows the side view of the shedding shafts displacing the active warp
yarns drawn
through its eyes in the downward direction to form the multiple lower row-wise
sheds with the
passive warp yarns.
Fig. 6a is a three-dimensional representation of the typical yarn paths of the
active warp yarns at
the edges and the surfaces of the plain weave construction of the woven 3D
fabric.
Fig. 6b is a three-dimensional representation of the typical yarn paths of the
active warp yarns in
the interiors of the plain weave construction of the woven 3D fabric.
3a
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Fig. 7 is a two-dimensional representation of the front view of the fabric
construction shown in
Fig. 6.
Fig. 8a is a two-dimensional representation of the top view of the fabric
construction shown in
Fig. 6a.
Fig. 8b is a two-dimensional representation of the side view of the fabric
construction shown in
Fig. 6a.
Fig. 9a is a two-dimensional representation of the top view of the fabric
construction shown in
Fig. 6b.
Fig. 9b is a two-dimensional representation of the side view of the fabric
construction shown in
Fig. 6b.
3b
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PCT/SE97/00355
Fig. IOa is a two-dimensional representation of the axial view of a modified
fabric construction
showing the path of the active wasp yarns obtainable according to a specific
shedding order.
Fig. lOb is a two-dimensional representation of the axial view of a modified
fabric construction
showing the path of the active warp yarns obtainable according to a specific
shedding order.
Fig. lOc is a two-dimensional representation of the axial view of a modified
fabric construction
showing the path of the active warp yams obtainable according to combined
specific shedding orders
indicated in Figs. l0a and I Ob.
Fig. 11 is the firont view of the fabric construction incorporating additional
non-interlacing yams in the
fabric-width, -thiclmess and the two diagonal directions.
Fig. 12a is a two dimensional representation of the finnt view of a useful
fabric construction producible
in which the exterior part is only interlaced to fimrxion as a woven covering
for the non-interlacing
yarns which occur internally withoutinterlacement.
Fig. 12b is a two dimensional representation of the front view of a useful
fabric construction producible
in which specifically disposed yams of the multilayer warp are interlaced to
form a sandwich or a core
type of fabric construction.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The method of producing the woven 3D fabric using two orthogonal sets of weft
and a muttilaver warp
will now be described in reference to the above stated drawings. The working
principle of the dual-
directional shedding method will be described first and then the particular
way of constructing usefirl
fabrics according to this invention will be described.
The method to be described now follows a completely new plan for erecting
shedding compared with
the conventional shedding methods. In Fig. 1 is shown the essential features
of the novel dual-
directional shedding arrangement ( 1 ) for effecting shed fomration in the
fabric-width and -thickness
directions. Each of the cylindrical heald shafts (2) carry a set of fixed flat
healds {3) as indicated. Each
heald has two openings: the front one is the heald-eye (4) and the n"ar one is
a heald-guide (5). Such an
assembly comprising the cylindrical heald shaft (2) and the flat healds (3) is
suitably supported in
supports (s), as indicated in Fig. 1, in a manner that each of these
assemblies can be reciprocated in two
directions: (i) along and (ii) about the shaft axis: that is linearly and
angularty respectively.
The disposal arrangement of the employed multilaver~ed warp (6) is indicated
in Fig. 2. Such a disposal
is required to achieve a uniform integration at the fabric's surfaces
(excluding end surfaces) and for the
balanced distribution of the yarns in the fabric. The peculiarity of this
arrangement is that it comprises
active (7) and passive (8) warp yarns such that each passive warp end (8) is
'surrounded' by active
warp ends (7) for achieving uniform fabric integration. Such a multilayer wrp
disposal arrangement
(6) may be described as comprising alternate rows or columns of active (7) and
passive (8) warp ends.
Thus. the alive-warp yarn rows will be designated by 'a', 'c', 'e'. etc. and
the passive-warp yarn rows
by 'b', 'd', 'f etc. as indicated in Fig. 2. The occurring aitemate columns of
the active (7) and passive
(8) warp yams will be designated by 'A', 'C', 'E' etc. and 'B', 'D'. 'F' etc.
respectively as indicated in
Fig 2. Each of the active warp ends (7) of a given row (or column) is drawn
through the corresponding
flat heald's (3) guide (~) and the eye (4). The passive warp yams (8) of a
given row (or column) are
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drawn through the open space occurring between corresponding two adjacent
heald shafts (2). Thus.
the multilayer warp yarns (6) and the heald shafts (2) will occur as indicated
in Fig. 3.
The above described disposal arrangement of the multilaver warp (6) and the
shedding shafts (2) shown
in Fig. 3 defines the level position of the system. From this level position,
each of the active warp ends
(7) passing through a corresponding heald eye (4) can be displaced in the
fabric-width and -thiclmess
directions by moving the heald shaft (2) along its axis and turning it about
its axis respectively. In
relation to the passive wasp ends (8), which do not pass through the heald
eyes (4), and hence are
stationary, the displaceable active warp ends (7) readily form multiple
columnwise (10) and row-wise
( 11 ) sheds upon their displacement in the required direction from the level
position as shown in Figs. 4
and 5. The Linear and the angular displacements of the heald shafts (2) from
its level position to form
the row-wise ( 11 ) and the columnwise ( 10) sheds can correspond to the
distance between two adjacent
active (7) (or passive (8)) warp yams in the given direction of movement and
may be referred to as the
shedding displacement pitch. In the formation of these multiple sheds ( 10)
and ( I 1 ), the displacement
of the active warp ends (7) of a given row or column may thus be referred to
as a unit shedding
displacement pitch. However in real practice this displacement can be
increased up to a maximum of
1.5 times the shedding displacement pitch to form a correspondingly greater
shed for practical
advantage in weft insertion.
In its simplest mode, all the shafts (2} are moved simultaneously, either
linearly or. arrgularly, and in the
same direction to form corresponding directional movement's multiple sheds as
shown in Figs. 4 and 5
respectively. Hy picking a weft ( 12) in each of these fob sheds ( 10) and (
11 ), interlacement within
the individual columns and the rows of the multilayer warp (6) with the
corresponding v~~efts (12c and
12r) is achieved. Such an alternate row-wise and columnwise shedding and
corresponding picking thus
leads to the production of the plain weave woven 3D fabric of this method. The
typical yarn paths at the
edges and the surfaces of the fabric (9), and in the interiors of fabric (9)
are respectively indicated in
Figs. 6a and 6b. The simplest working of this dual-directional shedding system
( 1 ) is outlined below in
reference to Figs. 4 and 5.
1n Fig. 4 is illustrated the formation of the columnwise sh~s ( 10). Fig. 4(a)
indicates the level position
of the system. In Figs. 4 (b) and (c) are shown the directions of the linear
movement of a heald shaft (2)
along its axis. The former and the latter figures respectively show the
displacement of the active warp
ends (7), from their level positions, in the fabric-width direction to form
the right side and the leR side
coltunnwise sheds (10) with the stationary passive warp yams (8). Fig. 5 shows
the formation of the
row-wise sheds (11). Fig. 5(a) indicates the level position of the system. In
Figs. 5 (b) and (c) are
illustrated the directions of the angular movement of a heald shaft (2) about
its axis. The former and the
latter figures respectively show the displacement of the active warp ends (7),
from their level positions.
in the fabric-thiclrness direction to form the upper and lower row-wise sheds
(I l) with the stationary
passive warp yarns (8).
As can be inferred from the Figs. 4 (b) and (c) and 5 (b) and (c), the optimum
displacement of the
shafts can be up to 1.~ times the shedding displacement pitch in practice to
obtain relatively larger
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WO 98!39507 PCTISE97/00355
sheds for convenience in weft insertion. The shafts may be displaced up to the
extent that an active
warp yarn (?) does not cross two passive warp yarns (8).
It is to be noted that in reference to the stationary passive warp yarns (8),
the right and the left side
colummvse sheds, and the upper and the lower row-wise sheds are not formed
simultaneously but in a
specific order. The shedding shafts (2) revert to their level position every
time subsequent to a
particular shed formation and picking operation. For example, in the
construction of the plain weave
woven 3D fabric (9) obtainable tluough this method, and indicated in Fig. 6,
the order of shedding and
picking indicated below is followed, starting from the level position of the
system. The movements of
the shedding shafts described below are viewed from the rear of the shedding
means in the direction of
the fabric-fell.
1 ) Upward angular movement of the shedding shafts (2); fom~ation of the row-
wise upper sheds ( 11);
followed by pick insertion in the formed sheds (i.e. in the fabric-width
direction)
2) Reverting shedding shafts (2) to the !eve! position of the system
3) Righttvard linear movement of the shafts (2); formation of the columnwise
right side sheds { 10);
followed by pick insertion in the formed sheds (i.e. in the fabric-thickness
direction)
4) Reverting shafts (2) to the level position of the system
5) Dowward angular movement of the shafts {2); formation of the row-wise lower
sheds (11);
followed by pick insertion in the formed sheds {i.e. in the fabric-width
direction)
6) Reverting shafts (2) to the level position of the system
7) Leftward linear movement of the shafts (2); formation of the columnwise
left side sheds(10);
followed by pick insertion in~the formed sheds (i.e. in the fabric-thickness
direction)
8) Reverting shafts (2) to the level position of the system '
The above indicated shedding order, together with the necessary complementing
operations of the
weaving process like picking, beating-up, taking-up etc. at appropriate
moments constitute one
complete «rorking cycle of the process. Fig. 7 shows the front view of the
plain weave woven 3D fabric
construction (9) obtainable through the above stated shedding order. It is to
be noted that the two sets
of weft ( 12c and 12r), which may be inserted in their respective sheds by
employing means like
shuttles. rapiers etc. and may be picked in as either a single yarn or hairpin-
like folded yam, uniquely
interlace with the active warp yams (?) and get connected to the passive warp
yarns (8). Because of
their interlacement with the active warp yarns (?) the two sets of weft ( 12c
and 12r) will occur in an
undulating manner and not straight as indicated in Figs. 6 and ?. These two
sets of weft (12c and 12r)
are shown straight for only easy representation. However, the incidence of its
crimp can be reduced, for
example, by feeding the active warp yarns (?) under suitable tension and at a
suitable rate.1n Figs. 8a
and 8b are shown the top and the side views respectively of the fabric (9) to
indicate the typical paths of
the active warp yarns (?) at the fabric's edges and surfaces. The series of
letters A-B-C-D, P-Q-R-S
etc. respectively indicate the individual active warp yam (?) paths at the
edges and surfaces of the
fabric construction shown in Figs. 6a and 7. 1n Figs. 9a and 9b are shown the
top and the side views
respectively of the fabric (9) to indicate the typical path of the active warp
yam (?) in the interior of the
fabric construction shown in Fig. 6b. The series of numbers 111-112-113-114
indicates the individual
active warp yarn (?) path in the interior of the fabric construction shown in
Figs. 6b and 7.
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An important feature of the fabric construction (9) to be noted in Figs. 6, 7,
8 and 9 is the occurrence of
the active warp yams in a 'helical' configuration. Though not following a
circular path, the active warp
yarns occur in a 'triangular helix' at the fabric's edges and surfaces
(indicated by different series of
letters, A-B-C-D, P-Q-R S etc. in Fig. 7) and in a 'square helix' in the
interiors (indicated by differcnt
series of numbers, 101-102-103-104, 131-132-133-134 etc. in Fig. 7). Further,
both these helices are
not fom~ed about any of the passive warp yams. Also, the fabric has a network-
like construction.
There may be introduced minor alterations in the above fiarrrework of
operations. For example, the
above indicated order of shedding operations may be altered to produce a
modified network-like fabric
construction (9m) shown in Fig. 10. In reference to the shedding order
indicated above. if the order
given below is carried out, then modified network-like fabric constructions
(9m) may be obtained and
will correspond with those indicated in Fig. 10 in which the general path of
the active warp yam in the
interior of the fabric is only shown and corresponds as follows:
a) Shedding order: 1, 2, 5, 6, 3, 4, 7, 8 and repeat
b) Shedding order: 1, 2, 5, 6, 7, 8, 3, 4 and repeat
c) Shedding order: 1, 2, 5, 6, 3, 4, 7, 8, 1, 2, 5, 6. 7, 8, 3, 4 and repeat.
These obtained modified network-like fabric constructions (9m) shown in Fig.
10 will differ from the
one indicated in Figs. 6, 7, 8 and 9 in which the typical paths of the active
warp yarns (7) in accordance
with the initially mentioned shedding order are indicatcd. The difference in
the fabric construction (9m)
due to the change of the shedding order will be that the wefts of a given set
will occur successively and
not aitemately as shown in the figures, and also the active warp yarns (7)
will additionally occur in the
fabric-width and -thiclrness directions in addition to the diagonal directions
as represented in Fig. 10.
This is because the wefts ( 12c and 12r) will be picked successively in the
'forward and backward'
directions of the respective side (row-wise or columnwise direction).
Nevertheless, the active warp
yams (7) in all these constructions (9) and (9m) may be considered to occur in
a helical configuration
for the purpose of easy understanding.
Fmm the foregoing description of the dual-directional shedding method, the
following points will be
apparent to those skilled in the art.
a) All the columnwise (or the row-wise) sheds can be formed simultaneously for
increased production
efficiency and not successively one columnwise (or row-wise) warp layer after
the other.
b) Multiple wefts of a set may be picked simultaneously employing means like
shuttles, rapiers etc. and
each of the wefts may be inserted as either a single yarn or a hairpin-like
folded yarn.
c) The active warp yarns (7) may be made to occur in the fabric-length
direction either in ahelical
configuration or additnnally in the fabric-width and - thickness directions by
corrtrollinghe
shedding order.
d) The helical progression of all the active warp yams (7) provides unique
network-like fabric
integration throughout the fabric by interlacing with the two sets of weft and
interconnecting these
t<vo sets of weft to the passive warp yams.
e) The helical progression of the active warp yams (7) provides unique
discrete placement of the active
warp yams (7) in either the 'diagonal' directions or additionally in the
fabric-width and -thiclmess
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directions.
f) The optimum shedding displacement pitch of the shedding shaft (2) in the
fabric-thicirness and the -
width dituctions is 1.~ since a greater displacement will cause interference
with the pick insertion and
unnecessary concentration of the active warp yams (7) at the fabric's surfaces
and thus lead to
uneven fabric surface and unbalanced fabric construction.
g) Dii~erent v~ave patterns can be created by displacing independently and
selectively in the fabric
width and thicaaiess directions the required shafts {2) which bear the healds
(3) which are suitably
h) It is possible to carry out shedding involving only the active warp ends
(7) by displacing
independently pairs of the shafts (2) in opposite directions, and the healds
(3) of which are suitably
threaded.
i) Tubular fabrics of either square or rectangle cxoss-section and solid
profiled fabrics like L, T, C etc.
can be directly produced by disposing the multilayer warp in accordance with
the cross-sectional
profile to be produced and suitably effecting the shedding and the picking
operations in a suitable
discrete manner. for example by employing more than one set of picking means
in each of the two
directions.
It will now be apparent to those skilled in the art that the mechanical
performance of the fabric can be
improved. if required, by the inclusion of non-interlacing 'stuffer' yams in
the fabric-width. -thickness
and the two diagonal directions across the fabric cross-section. An example of
one such construction is
outlined below.
In reference to the shedding and picking order mentioned earlier, the
insertion of non-interlacing yarns
(nl-n8) may be included in the fabric according to the steps indicated below
and illustrated in Fig. l l .
1 ) Upward angular movement of the shedding shafts: formation of the row-wise
upper sheds: followed
by pick insertion (12r) in the formed sheds
2) Reverting shedding shafts to the level position of the system
3) Insertion of the set of non-interlacing yarn (nl) between given two rows of
the passive wasp yarns
(8)
4) Insertion of the set of diagonal non-interlacing yarn (n2) between given
two diagonally occurring
layers of the passive warp yarns (8)
5) Right<vard linear movement of the shafts; formation of the right side
columnwise sheds: followed by
pick insertion ( 12c) in the formed sheds
6) Reverting shafts to the level position of the system
7) Insertion of the set of non-interlacing yam (n3) between given two columns
of the passive warp
yarns (8)
8) Insertion of the set of diagonal non-interlacing yam (n4) between given two
diagonally occxuxing
layers of the passive warp yarns (8)
9) Downward angular movement of the shafts: fom~ation of the lower row-wise
sheds: follov~ed by pick
insertion ( 12r) in the formed sheds
10) Reverting shafts to the level position of the system
8
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11 ) Inserrion of the set of non-interfacing yarn (n5) between given two rows
of the passive warp
yarns(8)
12) Insertion of the set of diagonal non-interlacing yam (n6) between given
two diagonally occurring
layers of the passive warp yarns (8)
13) Leftward linear movement of the shafts: formation of the left
sidecolumnwise sheds: followed by
pick insertion ( 12c) in the formed sheds
14) Reverting shafts to the level position of the system
15) Insertion of the set of non-interlacing yam (n7) between given two columns
of the passive warp
yarns (8)
16) Insertion of the set of diagonal non-interlacing yarn (n8) between given
two diagonally occurring
layers of the passive warp yarns (8)
Further, this method is not limited to the producxion of a block of either
fabric construction (9) or (9m)
or (9n) having either a square or a rectangle cross-section. By disposing the
multilayer warp in
accordance with the desired shape of cross-section. including tubular types
with square or rectangle
cross-section, and following suitable discrete sequence of operations
described above, network-like
fabric constructions either (9) or (9m) or (9n) of the cotTesponding cross-
sectional profile can also be
produced. It may be mentioned here that depending on the complexity of the
cross-sectional profile
being produced, more than one set of weft inserting means for each of the two
directions can be
employed. Such different sets of the weft insetting means of a given direction
(i.e. row-wise or
colummvise) tray be operated either simultaneously or discretely to achieve
the required weft insertion
for the profile under production. This method of fabric production is
therefore not limited to the
production of a fabric of a particular cross-sectional profile. Further,
because of the unique network-
like interlacement, there is no need to carry out any separate binding
operation at the exterior surfaces
of the fabric to achieve the fabric integrity. This elimination of the binding
process is apparently
advantageous in simplifying and quickening the fabric production. Further.
this method of producing
network-like interlaced 3D fabric blocks and other cross-sectional profiles
eliminates to the need to
develop methods for producing certain cross-sectional shapes as from the
produced block of the
network-like fabric obtainablc through this method, any desired shape of
preform, filter etc. material
can be easily cut obtained without the risk of its splitting up.
Further, it is possible to produce another useful fabric material by carrying
out shedding involving only
the warp yams occurring at the exteriors of the disposed multilayer warp (6)
by suitably displacing the
shafts (2), the healds (3) of which have been correspondingly threaded as
described earlier. In reference
to Fig. 12a, the top and the bottom woven surfaces can be produced by moving
angularly the top and
the bottom shafts (2), and hence displacing the healds (3), to displace the
active warp yarns (7) to form .
row wise sheds with the passive warp yarns (8) and inserting the wefts ( 12r)
into these exterior top and
bottom row-wise sheds. Similarly, the left and the right side woven surfaces
can be produced by moving
linearly the shafts {2), and hence displacing the heaids (3), to displace the
active warp yams (7) to form
columnwise sheds with the passive warp yarns (8) and inserting wefts (12c)
into these exterior left and
right columnwise sheds. Thus such operations will produce an interlaced
exterior surface which will
function as a woven covering for the interrtally occurring non-interlacing
multilayer yams (6n) of the
9
CA 02279408 1999-07-14
WO 98/39507 PCT/SE97/00355
fabric material (9e) as shown in Fig. 12a.
Further, it is also possible to produce a core or a sandwich type of fabric
material (9s) shown in Fig:
12b by interlacing the suitably disposed multiiayer warp yarns. Here again. by
displacing independently
the heald shafts (2), the healds (3) of which have been correspondingly
threaded, the row-wise and the
columm~~ise sheds can be respectively formed by moving these shafts (2)
angularly and linearly as
described earlier. Inserting wefts ( 12r) and ( 12c) into the formed row-wise
and columnwise sheds
respectively, the interlaced fabric structure (9s), generally referred to as
sandwich or core type fabric
structure, shown in Fig. 12b is obtained.
Further, it is also possible to produce multiple woven 2D fabric sheets
employing the described
shedding means. Such multiple sheets can be produced by disposing the
multilayer warp as described
before and moving the shafts (2) either angularly or linearly to form
correspondingly either the row-
wise or the columnwise sheds and inserting correspondingly either wefts (12r)
or (12c) into the formed
sheds of the given direction. Thus, by forming row-wise sheds and effecting
corresponding picking, the
multiple sheets of woven 2D fabric will be produced in the horizontal form.
Similarly; by forming
columnwise sheds and~effecting corresponding picking, the multiple sheets of
woven 2D fabric will be
produced in the vertical form in reference to the arrangement shown in Fig. 3.
Needless to mention, in all the above described methods of fabric production.
the other complementing
operations of the weaving process like the beating-up, taking-up etc. will be
canied out at the
appropriate moments of the weaving cycle to produce a satisfactory fabric of
the required specification.
It will be now apparent to those skilled in the art that it is possible to
alter or modify the various details
of this invention without departing from the spirit of the invention.
Therefore. the foregoing description
is for the purpose of illustrating the basic idea of this invention and it
does not limit the claims which
are fisted below.
SUBSTITUTE SHEET (RULE 26)
