BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a method for knitting a slit yarn made of a sheet-like
raw material such as a film or a non-woven fabric and having a width of several millimeters,
using a knitting machine while covering a core yarn with the slit yarn, an apparatus
used therefor and a knit fabric obtained thereby.
2. Description of Related Art
[0002] Conventionally, knitting has been performed using a knitting yarn obtained through
spinning of staples or false-twisting of filaments of natural fiber or chemical fiber
for a knitting machine. In recent years, a flat raw material called a slit yarn has
been developed that is obtained by cutting, into a width of several millimeters, a
sheet-like raw material of, for example, a film made of polypropylene, polyethylene
or the like, or a non-woven fabric having a structure in which fibers are aligned
and laminated in parallel or undirectionally.
[0003] Note that manufacturers of synthetic fiber call a filament yarn that has not been
subjected to crimping processing as a flat yarn. Although the name flat yarn conjures
up an image of a flattened yarn, a flat yarn refers to raw yarn that has not been
subjected to crimping processing and is not necessarily a flattened yarn. A sheet-like
material having a yarn width of 1 to 7 mm is herein called a slit yarn to distinguish
it from the flat yarn, regardless of whether or not the sheet-like raw material having
a yarn width of 1 to 7 mm is obtained through slitting processing.
[0004] JP-A-2005-023445 discloses a circular knitted fabric that is knitted using a yarn obtained by twisting
flattened yarns made from Japan paper that has been slit into elongated pieces and
then reeled by being wound around a core yarn.
[0005] JP-A-2005-248407 discloses a fabric-like material obtained by knitting a biodegradable flat yarn that
is a flat, ribbon-shaped long material composed of multiple layers. The knit structures
are those obtained by known knitting methods, including, for example, a warp knitted
structure, a weft knitted structure, a Raschel knitted structure and a tricot knitted
structure.
[0006] JP-A-2010-144288 discloses a polyester knit fabric obtained by knitting a flat yarn (raw yarn) and
a false-twisted yarn that are put together in parallel. This knit fabric is a mesh
reversible knitted fabric having a known knit structure obtained using a double circular
knitting machine (model: LIL-4AL, manufactured by Precision Fukuhara Works, Ltd.).
SUMMARY OF THE INVENTION
[0007] As described above,
JP-A-2005-023445,
JP-A-2005-248407 and
JP-A-2010-144288 are patent applications relating to yarns related to a flattened yarn and a flat
yarn and a knit fabric using such yarns, as well as methods and apparatuses for knitting
such yarns with a knitting machine, and the patent documents do not disclose a technique
for knitting a slit yarn using a knitting machine while covering a core yarn with
the slit yarn. If such slit yarn knitting is to be performed, there is a problem that
twist is applied to the slit yarn when the slit yarn is unwound from a cheese-wound
bobbin, and the slit yarn is knitted while being twisted. Further, there is also a
problem in that the slit yarn creases before it is knitted and the front and back
thereof are inverted.
[0008] The present invention solves the problem with regard to how to guide the slit yarn
to the covering means located in the final stage while keeping it in a flattened state,
and it is an object of the invention to provide a knitting method for a knit fabric
with high additional value that fully exhibits the characteristics of a flattened
slit yarn that has been developed by being added high functionality and an apparatus
therefor, as well as a knit fabric obtained thereby.
[0009] Furthermore in view of the recent economic situations, it is also an object of the
invention to reduce the number of manufacturing steps, thus achieving a reduction
in manufacturing costs.
[0010] A slit yarn knitting apparatus according to the present invention is a circular knitting
machine including legs, a bed supported by the legs, a knitting portion disposed above
the bed, a yarn feeding device for feeding a knitting yarn to the knitting portion,
and a rolling portion for rolling a knit fabric knitted in the knitting portion, wherein
the yarn feeding device is composed of a core yarn feeding device for feeding a core
yarn and a slit yarn feeding device for feeding a slit yarn, a covering means for
wrapping the core yarn in the slit yarn is provided between the slit yarn feeding
device and the knitting portion, and a guide means for guiding the slit yarn from
the slit yarn feeding device to the covering means such that the slit yarn will not
be twisted and will not crease, and the front and a back thereof will not be inverted.
[0011] Preferably, the slit yarn feeding device is composed of at least two types of yarn
feeding devices including a first yarn feeding device located closer to the knitting
portion and a second yarn feeding device located farther therefrom, and the covering
means is provided between the first yarn feeding device and the knitting portion.
[0012] Preferably, the covering means includes a yarn inlet having a cylindrical shape,
a central portion having a diameter that is substantially half the diameter of the
yarn inlet, and a yarn outlet having a rectangular shape, and a portion extending
from the central portion to the yarn outlet is gradually changed from a cylindrical
shape to a rectangular shape.
[0013] Also preferably, a circumference of the central portion and a perimeter of the rectangular
shape of the yarn outlet are smoothly connected so as to be equal.
[0014] A shorter side (T) of the rectangular shape of the yarn outlet is preferably 0.3
to 0.7 mm, and a longer side (L) of the rectangular shape of the yarn outlet is preferably
L = 1/2 × W + α (mm), where W is the width of the slit yarn, and α is 0 to 0.6 mm.
[0015] Further preferably, an internal corner of the yarn outlet is rounded.
[0016] Preferably, the guide means is composed of at least three guide means including a
first guide means provided in a region of the first yarn feeding device, a third guide
means provided immediately upstream of the covering means, and a second guide means
provided between the first guide means and the third guide means.
[0017] Further preferably, the guide means is a cylindrical pin.
[0018] A slit yarn knitting method according to the present invention is a slit yarn knitting
method using a circular knitting machine including legs, a bed supported by the legs,
a knitting portion disposed above the bed, a core yarn feeding device for feeding
a core yarn to the knitting portion, at least one slit yarn feeding device for supplying
a slit yarn, and a rolling portion for rolling a knit fabric knitted in the knitting
portion, the method including the steps of: wrapping the core yarn in the slit yarn
between the slit yarn feeding device and the knitting portion, using a covering means;
and guiding the slit yarn from the slit yarn feeding device to the covering means
such that the slit yarn will not be twisted and will not crease, and a front and a
back thereof will not be inverted.
[0019] Preferably, the slit yarn is mountain-folded, i.e., folded into an inverted-V shape
by the covering means, and brought into a state in which the core yarn is wrapped
therein.
[0020] A knit fabric according to the present invention is a knit fabric knitted by the
above-described apparatus or method, including a line of thread in which the core
yarn is covered with the slit yarn.
[0021] With the method and apparatus according to the present invention, a flat slit yarn
developed by being added with high functionality is knitted in a state in which a
core yarn is covered and wrapped in the slit yarn, and therefore, it is possible to
obtain a knit fabric that has been knitted with a line of threads exhibiting the respective
characteristics of the slit yarn and the core yarn. Also, such a line of threads can
be obtained on the knitting machine without the need of a reeling process, and therefore
it is possible to achieve a reduction in manufacturing costs. Furthermore, although
the slit yarn tends to be detached from the core yarn in a state in which the core
yarn is wrapped in the slit yarn due to a lack of stability when the line of threads
is wound around the bobbin in the reeling process, such a problem will not arise in
the manufacturing method of the present invention since the slit yarn is knitted immediately
after the core yarn is wrapped therein.
[0022] Hereinafter, an embodiment of the present invention will be described with reference
to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023]
FIG. 1 is a front view showing an entire circular knitting machine.
FIG. 2 is a front view showing a feeding path of a knitting yarn according to the
present invention.
FIG. 3 is an enlarged view of a yarn carrier composed of a carrier plate to which
a covering means according to the present invention is attached.
FIG. 4 is a schematic diagram showing a feeding path of a knitting yarn in a knitting
portion according to the present invention.
FIG. 5a is a perspective view of a covering means according to the present invention.
FIG. 5b is a rear view of a covering means according to the present invention.
FIG. 6 is a diagram of a knit structure obtained by a knitting method according to
present invention.
DETAILED DESCRIPTION OF THE INVENTION
1. Overview of Circular Knitting Machine
[0024] FIG. 1 is an overall view of a knitting machine, showing two types of feeding devices,
namely, first and second yarn feeding devices 10 and 20, first and second drive pulleys
11 and 21 for driving these yarn feeding devices, a plurality of legs 30, a bed 40
supported by the legs 30, and a knitting portion 50 disposed above the bed. The first
and second yarn feeding devices 10 and 20 are driven by the first and second drive
pulleys 11 and 21 via a drive belt, but the drive belt is not shown for the sake of
convenience.
[0025] Although not shown, in the knitting portion 50, a plurality of cylinder knitting
needles are accommodated in needle grooves of a vertically slidable cylinder. Opposing
the cylinder, a cam holder provided with a control cam for the cylinder knitting needles
is supported by a cam ring. As will be described in detail below, knitting yarns that
are fed from the first and second yarn feeding devices 10 and 20 through a plurality
of guide means 12, 61 and 63 and guide holes 13 and 62 are fed from a yarn carrier
60 provided with a covering means 80 to the cylinder knitting needles.
[0026] In the double-knit circular knitting machine, a needle dial hub 51 that synchronously
rotates with the cylinder is provided above the cylinder. A needle dial having needle
grooves on which a plurality of dial knitting needles are horizontally slidable is
attached to the needle dial hub 51. A gear ring 41 for driving the cylinder is disposed
inside the bed 40, a top gear 42 for driving the needle dial hub 51 is rotatably supported
on a dial yoke 43 located above the bed, and the gear ring 41 and the top gear 42
are connected by a driving shaft 44 so as to synchronously rotate with each other.
The top gear 42 is covered with a top gear cover 45, a plurality of posts 46 are set
up on the top gear cover 45, and the upper portions of the posts 46 are fixed to a
horizontal member 48 with a connecting member 47. A rolling portion 70 for rolling
a knit fabric that has been knitted is installed below the bed 40.
2. Yarn Feeding Device
[0027] Although a single yarn feeding device is usually used for slit yarn since the yarn
has no elongation, two types of yarn feeding devices (the first and second yarn feeding
devices 10 and 20) are used in this embodiment as shown in FIG. 1. The first yarn
feeding device 10 is driven by the first drive pulley 11. The drive pulley 11 is driven
by a gear box 49 driving the knitting machine as the driving source, and drives the
first yarn feeding device 10 (for example, an MPF manufactured by Memminger-IRO GmbH
in Germany) via a drive belt (not shown). The second yarn feeding device 20 is driven
by the second drive pulley 21. The second drive pulley 21 is driven by the above-described
top gear 42 as the driving source, and drives the second yarn feeding device 20 (for
example, an MER manufactured by Memminger-IRO GmbH in Germany) via a drive belt (not
shown). The two types of yarn feeding devices 10 and 20 are fixed to attachment rings
15 and 24 via connecting rods 14 and 23 hanging down from the horizontal member 48
in the same manner.
[0028] Note that the first and second yarn feeding devices 10 and 20 that are used are not
limited to the devices described above, and can be appropriately modified according
to the raw material of the knitting yarn.
[0029] Although not shown, a core yarn CY that is covered with a slit yarn SY is fed to
the first yarn feeding device 10 via a yarn bobbin such as a creel stand separately
disposed around the knitting machine.
3. Embodiment of Yarn Feeding Device and Method
[0030] A knitting yarn feeding method according to one embodiment of the present invention
will now be described.
[0031] First, the slit yarn SY is "rotationally fed" by the second yarn feeding device 20
from a bobbin 25 around which the slit yarn SY is cheese-wound (FIG. 2).
[0032] Next, the slit yarn SY fed out from the second yarn feeding device 20 is wound around
a spool feed wheel 16 of the first yarn feeding device 10 so as not to be twisted,
to such an extent that turns of the slit yarns SY do not overlap, and is fed out into
a first guide hole 13 provided in the attachment ring 15 (FIG. 2).
[0033] The first guide means 12 is attached at the front of the first guide hole 13. The
slit yarn SY that has been fed out from the first yarn feeding device 10 is passed
through the first guide hole 13 via the first guide means 12, and its direction is
changed downward where the knitting portion 50 of the knitting machine is located
(FIG. 2).
[0034] Further, the slit yarn SY is passed through a second guide hole 62 via the second
guide means 61, and its direction is changed downward where the yarn carrier 60 is
located. Further, the slit yarn SY is guided to the third guide means 63, and its
direction is changed toward the center of a yarn inlet 81 of the covering means 80
(FIG. 4).
[0035] The slit yarn SY is passed through the yarn inlet 81 of the covering means 80 via
the third guide means 63 (FIG. 4).
[0036] Also, the core yarn CY that has been fed out from another first yarn feeding device
(not shown) is passed, by way of another yarn guide hole, through the yarn inlet 81
of the covering means 80 below the slit yarn, along the central portion in the width
direction of the slit yarn SY (FIG. 4).
[0037] The slit yarn SY that has come out from a yarn outlet 82 of the covering means 80
is mountain-folded (folded into an inverted V-shape) by the covering means 80 and
is fed to the needle, with the core yarn CY being wrapped therein (FIG. 4).
[0038] Preferably, each of the guide means 12, 61 and 63 is a cylindrical pin having a diameter
of about 2.5 mm. The cylindrical pin may be a linear pin 63 as shown in FIG. 4, but
may alternatively be gradually curved throughout its length. In the case of curving
the pin, taking the pin 63 of FIG. 4 as an example, both ends of the pin are bent
toward the covering means 80 side so as to allow the slit yarn SY to pass the back
portion of the curved central portion. Doing so provides the effect of stretching
any creases in the slit yarn as a result of the slit yarn SY riding on the back portion
of the curved central portion. The installation position and the number of the guide
means may be appropriately modified according to the type of the knitting machine.
[0039] FIG. 3 shows the yarn carrier 60 including the covering means 80 in which the core
yarn CY is covered with the slit yarn SY according to the present embodiment. The
covering means 80 including a yarn inlet 81 and a yarn outlet 82 is provided integrally
with a lower portion of the carrier plate 64. The covering means 80 and the carrier
plate 64 may be a unitary member, or may be separately manufactured and fixed integrally.
Any method, including, for example, bonding or welding may be used as the fixation
method. The covering means 80 and the carrier plate 64 may be installed separately
as long as they achieve their respective objectives.
[0040] A right-hand portion 89 of the yarn outlet 82 is at the position where the latch
of the knitting needle starts closing.
[0041] Preferably, a left inclined portion 65 of the carrier plate 64 is expanded to the
limit so as to cover the latch opened at a bulging portion 66, such that the open
latch of the knitting needle will not be closed before the knitting yarn is fed.
[0042] As shown in FIG. 3, the core yarn CY and the slit yarn SY that have entered the yarn
inlet 81 pass through the inside of the covering means 80, exit from the yarn outlet
82, and reach the knitting point where the latch is closed, with the core yarn CY
being wrapped in the slit yarn SY.
[0043] FIGS. 5a and 5b show the covering means 80 for covering the core yarn CY with the
slit yarn SY according to the present embodiment. The covering means 80 has the yarn
inlet 81 on one end and the yarn outlet 82 on the other end. An inclined portion 84
extending from the cylindrical yarn inlet 81 to a central portion 83 having a diameter
that is substantially half the diameter of the yarn inlet 81 is changed in a tapered
manner. The portion extending from the central portion 83 to the yarn outlet 82 is
gradually changed in its shape from the cylindrical shape of the central portion 83
into the rectangular shape of the yarn outlet 82. Preferably, the circumference 85
of the central portion 83 and the perimeter 86 of the rectangular shape of the yarn
outlet 82 are smoothly connected so as to be equal.
[0044] The yarn outlet 82 is a vertically oriented rectangular hole. Preferably, internal
corners 87 of the yarn outlet are rounded.
[0045] The width (T) of the yarn outlet 82 is preferably 0.3 to 0.7 mm, more preferably
0.5 mm. It is sufficient that the slit yarn SY in which the core yarn CY is wrapped
can smoothly pass through the outlet having this width.
[0046] Preferably, the length (L) of the yarn outlet 82 is changed according to the width
of the slit yarn SY used. For example, the length (L) of the yarn outlet 82 relative
to the width (W) of the slit yarn is such that L = 1/2 × W + α, and α is preferably
in the range from 0 to 0.6 mm. Accordingly, in the case of using 5 mm as the width
(W) of the slit yarn, the length (L) of the yarn outlet 82 is preferably 2.5 to 3.1
mm, particularly preferably 2.6 mm.
[0047] In order for the circumference 85 of the central portion 83 and the perimeter 86
of the rectangular shape of the yarn outlet 82 to be equal, the diameter of the central
portion 83 is preferably 2.0 mm, and the diameter of the yarn inlet 81 is preferably
4.0 mm, which is substantially two times the diameter of the central portion 83.
[0048] With this dimensional restriction, the slit yarn that is folded substantially in
half is caught in the knitting needle, in a state in which it is folded in half without
being displaced. Note that the width of the slit yarn SY used is preferably 3 to 7
mm.
4. Example of Manufacture of Knit Fabric
[0049] Knitting was performed using an apparatus according to the present invention under
the following conditions.
<Model used> V-LEC6F, 19-inch, 6 gauge-cylinder/24 gauge-dial, manufactured by Precision
Fukuhara Works, Ltd.
<Knit structure> Quarter gauge reversible knitted structure
<Yarn used> Plain knitting portion of cylinder : 5-mm-width slit yarn
Product name: MILIFE, Type: TY-grade (cross-laminated fabric), manufactured by JX
Nippon ANCI Corporation
Core yarn, polyester, 56-dtex 36 filament
Plain knitting portion of dial: cotton yarn, No. 30 count
Tuck portion: nylon textured yarn, 33-dtex 10 filament
[0050] A method for knitting the above-described knit structure will be described with reference
to FIG. 6. Knitting is performed using cylinder needles 52 and dial needles 53 that
are aligned as shown in FIG. 6. The slit yarn SY in which the core yarn CY is wrapped
is fed at a first yarn feed port [1], and is knitted by the cylinder needles 52. The
cotton yarn MY is fed at a second yarn feed port [2] and a third yarn feed port [3],
and is knitted by the dial needles 53. The nylon textured yarn NY is fed at a fourth
yarn feed port [4], and is tucked by all the cylinder needles 52 and every three other
dial needles 53.
[0051] Note that the knit structure that can be knitted by the slit yarn SY in which the
core yarn CY is wrapped is not limited to a quarter gauge reversible knitted structure.
[0052] Further, the feeding of the slit yarn SY in which the core yarn CY is wrapped is
not limited to that to cylinder needles, and the slit yarn can be fed to both cylinder
needles and dial needles in the case of using dial needles and a raw material having
an elongation as the slit yarn.
[0053] Possible knit structures include a plain knitted structure, a piqué knitted structure,
an inlay knitted structure and the like in the case of a single knitting machine,
and an interlock knitted structure in the case of a double-knitting machine. Furthermore,
for example, the use of a metal yarn such as copper wire as the core yarn makes it
possible to obtain a knit fabric intended for electromagnetic shielding.
[0054] The invention may be embodied in other forms without departing from the spirit or
essential characteristics thereof. The embodiments disclosed in this application are
to be considered in all respects as illustrative and not limiting. The scope of the
invention is indicated by the appended claims rather than by the foregoing description,
and all changes which come within the meaning and range of equivalency of the claims
are intended to be embraced therein.
1. A slit yarn knitting apparatus for feeding a core yarn (CY) and a slit yarn (SY) to
a knitting machine,
wherein a covering means (80) for wrapping the core yarn (CY) in the slit yarn (SY)
is provided immediately upstream of a knitting portion (50).
2. The apparatus according to claim 1,
wherein the covering means (80) includes a yarn inlet (81) having a cylindrical shape,
a central portion (83) having a diameter that is substantially half the diameter of
the yarn inlet (81), and a yarn outlet (82) having a rectangular shape, and a portion
extending from the central portion (83) to the yarn outlet (82) is gradually changed
from a cylindrical shape to a rectangular shape.
3. The apparatus according to claim 2, wherein a circumference (85) of the central portion
(83) and a perimeter (86) of the rectangular shape of the yarn outlet (82) are smoothly
connected so as to be equal.
4. The apparatus according to claim 2 or 3, wherein a shorter side (T) of the rectangular
shape of the yarn outlet (82) is 0.3 to 0.7 mm.
5. The apparatus according to any one of claims 2 to 4, wherein a longer side (L) of
the rectangular shape of the yarn outlet (82) is L = 1/2 × W + α (mm), where W is
the width of the slit yarn, and α is 0 to 0.6 mm.
6. The apparatus according to any one of claims 2 to 5, wherein an internal corner (87)
of the yarn outlet (82) is rounded.
7. A slit yarn knitting apparatus that is a circular knitting machine comprising legs
(30), a bed (40) supported by the legs (30), a knitting portion (50) disposed above
the bed (40), a yarn feeding device for feeding a knitting yarn to the knitting portion
(50), and a rolling portion (70) for rolling a knit fabric knitted in the knitting
portion (50),
wherein the yarn feeding device is composed of a core yarn feeding device for feeding
a core yarn (CY) and a slit yarn feeding device (10, 20) for feeding a slit yarn (SY),
a covering means (80) for wrapping the core yarn (CY) in the slit yarn (SY) is provided
between the slit yarn feeding device (20) and the knitting portion (50), and
a guide means (12, 61, 63) for guiding the slit yarn (SY) from the slit yarn feeding
device (20) to the covering means (80) such that the slit yarn (SY) will not be twisted
and will not crease, and a front and a back thereof will not be inverted.
8. The apparatus according to claim 7,
wherein the slit yarn feeding device is composed of at least two types of yarn feeding
devices comprising a first yarn feeding device (10) located closer to the knitting
portion (50) and a second yarn feeding device (20) located farther therefrom, and
the covering means (80) is provided between the first yarn feeding device (10) and
the knitting portion (50).
9. The apparatus according to claim 7 or 8,
wherein the guide means is composed of at least three guide means comprising a first
guide means (12) provided in a region of the first yarn feeding device (10), a third
guide means (63) provided immediately upstream of the covering means (80), and a second
guide means (61) provided between the first guide means (12) and the third guide means
(63).
10. The apparatus according to any one of claims 7 to 9, wherein the guide means is a
cylindrical pin.
11. A slit yarn knitting method using a circular knitting machine comprising legs (30),
a bed (40) supported by the legs (30), a knitting portion (50) disposed above the
bed (40), a core yarn feeding device for feeding a core yarn to the knitting portion,
at least one slit yarn feeding device (10, 20) for supplying a slit yarn (SY), and
a rolling portion (70) for rolling a knit fabric knitted in the knitting portion (50),
the method comprising the steps of:
wrapping the core yarn (CY) in the slit yarn (SY) between the slit yarn feeding device
(20) and the knitting portion (50), using a covering means (80); and
guiding the slit yarn (SY) from the slit yarn feeding device (20) to the covering
means (80) such that the slit yarn (SY) will not be twisted and will not crease, and
the front and a back thereof will not be inverted.
12. The method according to claim 11, wherein the slit yarn (SY) is mountain-folded, i.e.,
folded into an inverted-V shape by the covering means (80), and brought into a state
in which the core yarn (CY) is wrapped therein.
13. A knit fabric knitted by the method according to claim 11 or 12, comprising a line
of thread in which the core yarn (CY) is covered with the slit yarn (SY).