EP2246465A1

EP2246465A1 - Yarn guide in circular knitting machine and knitting method using the yarn guide

Info

Publication number: EP2246465A1
Application number: EP09715203A
Authority: EP
Inventors: Yasushi Onishi; Tsuyoshi Yamada
Original assignee: Precision Fukuhara Works Ltd
Current assignee: Precision Fukuhara Works Ltd
Priority date: 2008-02-26
Filing date: 2009-02-17
Publication date: 2010-11-03
Also published as: TW200940769A; CN101910490A; WO2009107338A1; JP2009203566A

Abstract

OBJECT: To prevent dropped stitches when knitting a quilt knitting fabric

MEANS: A dropped stitch preventive tool (thread keeper) (5) used in a double knit circular knitting machine for quilt knitting, having a first guide surface (53) for preventing a knitting yarn from deflecting in the radial direction of the circular knitting machine and coming off the guide surface, and a second guide surface (54) for preventing the knitting yarn from deflecting in the vertical direction and coming off the guide surface. The first guide surface (53) is located between a yarn carrier (4) and a cylinder needle (1) for capturing a yarn fed from the yarn carrier (4), so that the yarn fed from the feeder maintains the substantially same feed angle. The lower side of the second guide surface (54) extends substantially parallel to a needle dial (D) and prevents the yarn from being routed to the back of the cylinder needle (1).

Description

TECHNICAL FIELD

The present invention relates to a yarn guide in a circular knitting machine and a knitting method using said yarn guide. The invention relates in particular to a preventive tool (thread keeper) that prevents dropped stitches when welt needle selection continues for long at a feeder for jacquard knitting in knit-welt needle selections and a knitting method using said preventive tool.

BACKGROUND ART

A quilted knit fabric is generally knitted using a double knit circular knitting machine set up for rib gating in a knitting process as shown in FIG. 1. B1 in FIG. 1 is an example of a movement line of a cylinder needle (code 1 in FIG. 2), and A1 is an example of a movement line of a dial needle (code 2 in FIG. 2).
In this knitting process, first yarn Y1 is supplied to cylinder needles 1 in knit-welt positions at first feeder F1; second yarn Y2, which will be filler, is fed from between first feeder F1 and second feeder F2 to between cylinder verge S1 and dial verge D1; third yarn Y3 is supplied to cylinder needles 1 in knit-welt positions and to dial needles 2 in knit positions at second feeder F2; fourth yarn Y4 is supplied to cylinder needles 1 in knit-welt positions at third feeder F3; and fifth yarn Y5 is supplied to cylinder needles 1 in knit-welt positions and to dial needles 2 in knit positions at fourth feeder F4.
A fabric obtained in the knitting process as described above has three layers: front fabric N1, which is knitted by cylinder needles 1 (see FIG. 6), back fabric N2, which is knitted by dial needles 2 (see FIG. 6), and filler Y2, which is inserted between them. If all cylinder needles 1 are in knit positions from the first feeder F1 to the fourth feeder F4 shown in FIG. 1, a solid front fabric is obtained. In order to obtain an intricate design, however, these feeders may also be used to perform jacquard knitting. Specifically, to obtain a desired jacquard pattern, cylinder needles 1 from the first feeder F1 to the fourth feeder F4 are in knit-welt positions. In order to prevent the knitting yarn from coming off the needles (i.e., to avoid dropped stitches) at the first feeder F1 and the third feeder F3, where only cylinder needles 1 are used to knit, a preventive tool (code 3 in FIG. 1 and FIG. 2) is installed at the stitch parts of these feeders.

DISCLOSURE OF INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

A problem with the prior art as described above is that when knit-welt needle selections are performed at high speed to knit a jacquard pattern, in which there are few knit needle selections and a long sequence of welt needle selections, if a yarn of a hard and non-elastic material is used, such as a rayon spun yarn or a polypropylene yarn, yarn breaking tends to occur while forming a loop at a yarn tension of 7 grams or more because of the lack of elasticity of the yarn. For this reason, the yarn feeding tension has to be set at 4-6 grams. At this time, as shown in FIGs. 10 (a)-(c), yarn Y4 between the yarn carrier 4 and the cylinder needle 1, which captures the yarn supplied from the yarn carrier 4, is not required as much to form a loop as the amount of yarn actually supplied, so the excess yarn deflects substantially for approximately 3 mm as shown by dotted lines and comes off the guide surface of the preventive tool. As a result, yarn may not be supplied to the cylinder needle 1, which should be selected to be in the knit position, and this causes dropped stitches. If the yarn comes off the guide surface of the preventive tool and welt selection continues for long, the welt yarn may run horizontally and be knitted at the stitch part of the next feeder, resulting in an erroneous pattern.
The object of the present invention is to provide a dropped stitch preventive tool (thread keeper) that prevents the knitting yarn from coming off the guide surface of the preventive tool that guides the knitting yarn.

MEANS FOR SOLVING THE PROBLEMS

The dropped stitch preventive tool of the present invention is a tool for preventing dropped stitches in a double knit circular knitting machine that performs knit and welt knitting with only cylinder needles, which is one process of knitting various fabrics, and comprises a first guide surface for preventing knitting yarn from deflecting in the radial direction of the circular knitting machine and coming off the guide surface and a second guide surface for preventing the same from deflecting in the vertical direction and coming off the guide surface.
The knitting method of the present invention is a method for knitting a quilted knit fabric using a double knit circular knitting machine set up for rib gating, comprising: a step for supplying first yarn to cylinder needles in knit-welt positions at the first feeder, a step for feeding second yarn, which will be filler, from between the first feeder and the second feeder to between the cylinder verge and the dial verge, a step for supplying third yarn to cylinder needles in knit-welt positions and to dial needles in knit positions at the second feeder, a step for supplying fourth yarn to cylinder needles in knit-welt positions at the third feeder, and a step for supplying fifth yarn to cylinder needles in knit-welt positions and to dial needles in knit positions at the fourth feeder, characterized in that the dropped stitch preventive tool is installed between the third feeder and the fourth feeder.

EFFECTS OF THE INVENTION

Using the present invention, a yarn supplied from the feeder is guided by the first guide surface of the dropped stitch preventive tool installed between the yarn carrier and the cylinder needle, so it can maintain the same yarn-feed angle regardless of the yarn selection that varies according to the desired jacquard pattern. Moreover, even if the yarn makes a large swing, the second guide surface that is positioned substantially parallel to the needle dial prevents the yarn from being routed to the back of the cylinder needle and causing dropped stitches. As a result, when knitting a quilt, for example, this can effectively prevent the knitting yarn from coming off the needle and prevent production of a defective knit fabric.
In the prior art, the rotating speed of the knitting machine is slowed down to prevent dropped stitches, but in the present invention, the installation of the dropped stitch preventive tool makes it possible to knit at high speed and this can dramatically improve the productivity of knit fabric production. In an experiment using the V-LEC6BSB, 38-inch, 20-gauge machine made by Precision Fukuhara Works, Ltd., knitting was carried out at a low speed of 10 rpm before installing the dropped stitch preventive tool of the present invention, but after the installation of the tool, high-speed operation at 15 rpm became possible.

BEST MODE FOR CARRYING OUT THE INVENTION

Knitting and welting using only cylinder needles is a process commonly performed in the production of various knit fabrics. The dropped stitch preventive tool of the present invention can be used, for example, in quilt knitting.
The dropped stitch preventive tool of the present invention is shaped like a plate and is installed from the top toward the bottom of a cylinder stitch part of a feeder, where only cylinder needles are selected in knit and welt positions. At this stitch part, a first guide surface of the dropped stitch preventive tool located just above the hook of the cylinder needle slants upward by 10-30 degrees (preferably approximately 20 degrees) toward the center of the circular knitting machine, and bends at an angle of approximately 90 degrees toward the yarn carrier, to which the guide surface supplies yarn in the back of the cylinder needle, forming a second guide surface. The lower side of the second guide surface is positioned substantially parallel to the needle dial. After that, the second guide surface extends horizontally at about the same height as the stitch bottom of the needle dial.
The dropped stitch preventive tool is preferably adjustable vertically, horizontally and depthwise according to the approach angle of the knitting yarn. This structure makes it possible to fine tune the position of the dropped stitch preventive tool.
The dropped stitch preventive tool is made of carbon tool steel and has a thickness of 0.1-0.3 mm (preferably 0.2 mm). By using this material and thickness, when the circular knitting machine is in operation, the dropped stitch preventive tool is fastened at the aforementioned position, but when an abnormal event occurs and a foreign body hits the dropped stitch preventive tool, a spring action kicks in and the dropped stitch preventive tool escapes to a different position so as to prevent damage from spreading.
As another embodiment of the dropped stitch preventive tool, the lower side of the second guide surface of the dropped stitch preventive tool may be formed of a linear part such as wire. The lower side of the first guide surface can also be formed of a linear part such as wire.
For a knitting machine that rotates in the reverse direction, the components can be installed horizontally inverted to obtain the same effect as the present invention.
The dropped stitch preventive tool of the present invention and the knitting method using it will now be described by reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a quilt knitting process according to a prior art.
FIG. 2 is a left side view of a preventive tool of a prior art.
FIG. 3 shows an elevation view of a dropped stitch preventive tool of the present invention.
FIG. 4 is a front view of the knitting process of quilt knitting of the present invention.
FIG. 5 is a left side view of the dropped stitch preventive tool of the present invention.
FIG. 6 shows structures of knit fabrics that are quilt knitted by the present invention.
FIG. 7 shows a front view of a dropped stitch preventive tool also provided with a pipe yarn carrier in a second embodiment of the present invention.
FIG. 8 shows an elevation view of a dropped stitch preventive tool in a third embodiment of the present invention.
FIG. 9 shows (a) a side view and (b) a front view of a dropped stitch preventive tool and its holder attached to a knitting machine in a fifth embodiment.
FIG. 10 shows the problems of the prior art shown in FIG. 1.

EMBODIMENT 1

FIG. 3 shows an elevation view of a dropped stitch preventive tool 5 in a first embodiment. FIG. 5 shows a left side view of the dropped stitch preventive tool 5. FIG. 4 is a front view showing the knitting process of quilt knitting of the present invention, which also shows front views of the dropped stitch preventive tool 5.
As shown in FIG. 3, dropped stitch preventive tool 5 is supported by rod 58. The rod 58 has a cylindrical upper part and a flat lower part 581. The dropped stitch preventive tool 5 is attached to the flat lower part 581 of the rod 58 via mounting screws 59.
Dropped stitch preventive tool 5 and rod 58 are established adjacent to a yarn carrier 4. As shown in FIG. 7, rod 58 of the dropped stitch preventive tool 5 is mounted to dropped stitch preventive tool holder 55 via screw 60 in such a way that it can move vertically and rotate. The dropped stitch preventive tool holder 55 is fastened adjustably in the left and right direction of the dropped stitch preventive tool 5 via screw 62 so as to grab yarn carrier ring 6. Screw 63 of the dropped stitch preventive tool holder 55 is mounted adjustably in the direction of the depth of the dropped stitch preventive tool 5.
As shown in FIGs. 3 and 5, the dropped stitch preventive tool 5 is a plate made of carbon tool steel and has a thickness of approximately 0.2 mm. The dropped stitch preventive tool 5 is located at a feeder where only cylinder needles 1 are in knit-welt positions, and comprises an extension 51 that extends from the top toward the bottom of the cylinder stitch part as well as a formation part 52 that forms first and second guide surfaces 53, 54, which are established at the lower end of this extension. The end of the first guide surface 53 is a protrusion 57 that extends downwards. The protrusion 57, which prevents yarn from loosening and coming off the first guide surface 53, has a height of approximately 1.6 mm.
The first guide surface 53, the purpose of which is to maintain the yarn supplied from the feeder at substantially the same yarn feed angle at point X, is installed between yarn carrier 4 and cylinder needle 1 that captures the yarn supplied from the yarn carrier 4. The first guide surface 53 of the dropped stitch preventive tool 5 is located just above the hook of cylinder needle 1 at the stitch part and is upwardly slanted by approximately 20 degrees toward the center of the circular knitting machine. If the yarn deflects and strays off point X, it comes back to point X along this slant thanks to the tension of the yarn.
The lower side of the second guide surface 54, the purpose of which is to prevent yarn from being routed to the back of cylinder needle 1, extends substantially parallel to needle dial D (see FIG. 5) and horizontally at about the same height as the height of the stitch bottom of the needle dial D. The second guide surface 54 continues from the first guide surface 53 and bends at an angle of approximately 90 degrees at the dashed and dotted line of FIG. 3 toward the yarn carrier 4.
FIG. 4 shows a knitting process of a double knit circular knitting machine (Model V-LEC6BSB, 38-inch, 20-gauge manufactured by Precision Fukuhara Works, Ltd.) for quilt knitting. At the knitting head of this machine, cylinder needle 1 that is inserted into needle cylinder S (see FIG. 5) and dial needle 2 that is inserted into needle dial D (see FIG. 5) are installed in the vertical direction and radial direction of the circular knitting machine respectively in such a way that they face each other. Movement line B2 shown in FIG. 4 shows an example of a movement line of cylinder needle 1, and movement line A2 shows an example of a movement line of dial needle 2.
At each feeder, a yarn carrier 4 for feeding knitting yarn to knitting needles is supported by a yarn carrier holder (not shown). The yarn carrier holder is mounted to a dial cam holder (not shown) or a yarn carrier ring (code 6 of FIG. 7).
As explained below, a quilted knit fabric is knitted by selecting cylinder needles 1 and dial needles 2 according to the desired jacquard pattern and inserting filler Y2 between needle cylinder S and needle dial D, thereby selectively connecting the front fabric N1 and back fabric N2.
In FIG. 4, at the first feeder F1, cylinder needles are selected to be in knit-welt positions according to the desired jacquard pattern. The L needles (low butt needles) of the dial are selected to be in support positions (actually selected to be in welt positions without being fed to the dial needle) where dial needles 2 are projected just a little to press the fabric in order to prevent the fabric from being raised together with cylinder needles 1 as cylinder needles 1 ascend, and the H needles (high butt needles) of the dials are selected to be in welt positions. First yarn Y1 (polyester 220dtex) is supplied from the yarn carrier 4 to the selected cylinder needles 1.
Between the first feeder F1 and the second feeder F2 a pipe yarn carrier 7 is installed, and by means of this yarn carrier 7, filler Y2 (polyester 660dtex) is supplied between verges S1 and D1 of the cylinder and the dial toward the next feeder.
At the second feeder F2, cylinder needles 1 are selected to be in knit-welt positions according to the desired jacquard pattern. The L and H needles 2 of the dial are both selected to be in knit positions. Third yarn Y3 (polyester 220dtex) is supplied from the yarn carrier 4 to the selected cylinder needles 1 and to all of the dial needles 2.
At the third feeder F3, cylinder needles 1 are selected to be in knit-welt positions according to the desired jacquard pattern. The H needles 2 of the dial are selected to be in support positions where dial 2 is projected just a little to press the fabric in order to prevent the fabric from being raised together with cylinder needles 1 as cylinder needles 1 ascend, and the L needles of the dial are selected to be in welt positions. Fourth yarn Y4 (rayon spun 20s) is supplied from the yarn carrier 4 to the selected cylinder needles 1.
Between the third feeder F3 and the fourth feeder F4, a dropped stitch preventive tool 5 for the fourth yarn Y4 that is fed at the third feeder F3 is installed.
The fourth yarn Y4 supplied at the third feeder F3 is guided near the intersection X of the first guide surface 53 and the second guide surface 54 of the dropped stitch preventive tool 5 installed between the yarn carrier 4 and the cylinder needle 1 that captures the yarn supplied from the yarn carrier 4, and maintains the same yarn feed angle regardless of the yarn selection that varies according to the desired jacquard pattern. Moreover, even if the fourth yarn Y4 makes a large swing, the second guide surface 54 that is positioned substantially parallel to the needle dial D prevents the fourth yarn Y4 from being routed to the back of the cylinder needle 1 and causing dropped stitches.
At the fourth feeder F4, cylinder needles 1 are selected to be in knit-welt positions according to the desired jacquard pattern. The L and H needles of the dial are both selected to be in knit positions. Fifth yarn Y5 (polyester 167dtex) is supplied from the yarn carrier 4 to the selected cylinder needles 1 and to all of the dial needles 2.
The above embodiment is about quilt knitting of a four-color jacquard using all the feeders from the first feeder F1 to the fourth feeder F4, and cylinder needles 1 are selected to be knit positions at least once at any of the feeders from the first feeder F1 to the fourth feeder F4.
A structure drawing of the quilted knit fabric according to this embodiment will now be described by reference to FIG. 6.
FIG. 6 shows arrangements of needles at each feeder. The lower series are arrangements of cylinder needles 1 and the upper series are arrangements of dial needles 2. The arrangements of dial needles 2 include two kinds of needles, the L needles and the H needles, which are arranged alternately and selected by 2-race cams. The arrangements of cylinder needles 1 include only one kind of needles, which are selected by computer.
At the first feeder F1, a front fabric N1 is jacquard knitted using cylinder needles.
At the second feeder F2, filler Y2 is inserted between dial D and cylinder S, and front fabric N1 is jacquard knitted using cylinder needles 1, and back fabric N2 is knitted using all dial needles 2.
At the third feeder F3, front fabric N1 is jacquard knitted using cylinder needles 1. As in this embodiment, if the front fabric N1 has long intervals of welts, dropped stitches are likely to occur. To avoid this, a dropped stitch preventive tool 5 is installed between the third feeder and the fourth feeder.
At the fourth feeder F4, front fabric N1 is jacquard knitted using cylinder needles 1, and back fabric N2 is knitted using all dial needles 2.

EMBODIMENT 2

In Embodiment 1 described above, the dropped stitch preventive tool 5 is installed only between the third feeder F3 and the fourth feeder F4. But when rayon spun yarn is used for the first yarn Y1, it is also possible to install a pipe yarn carrier 7A together with the dropped stitch preventive tool 5 as necessary between the first feeder F1 and the second feeder F2, as shown in FIG. 7. The pipe yarn carrier 7A is mounted by means of a pipe yarn carrier holder 71 that projects from the lower part of the dropped stitch preventive tool holder 55.

EMBODIMENT 3

As shown in FIG. 8, the lower side of the second guide surface 54B of dropped stitch preventive tool 5B can be formed of a linear part 56 such as wire to obtain the same effect.

EMBODIMENT 4

Although not shown in the drawings, the lower sides of the first guide surface and the second guide surface of the dropped stitch preventive tool can all be formed of linear parts such as wire to obtain the effect of this invention. (A shortcoming of this embodiment, however, is that yarn easily coils itself around such linear parts.)

EMBODIMENT 5

FIG. 9 shows (a) a side view and (b) a front view of a dropped stitch preventive tool 5C according to Embodiment 5 with its holder 55C attached to a knitting machine.
In this embodiment, rod 58C of the dropped stitch preventive tool 5C is mounted to the dropped stitch preventive tool holder 55C via screw 60C in such a way that it can move vertically and rotate. This dropped stitch preventive tool holder 55C is mounted to dial cam holder 6C or a yarn carrier ring (not shown) via screw 61 in such a way that it is adjustable in the left and right direction and in the depthwise direction.

Claims

A preventive tool (5) for preventing dropped stitches in a double knit circular knitting machine that performs knit and welt knitting with only cylinder needles, which is one process of knitting various fabrics, comprising:
a first guide surface (53) for preventing knitting yarn from deflecting in the radial direction of the circular knitting machine and coming off the guide surface, and a second guide surface (54, 54B) for preventing the same from deflecting in the vertical direction and coming off the guide surface.
A dropped stitch preventive tool according to Claim 1, in which:
the first guide surface (53) is installed between a yarn carrier (4) and a cylinder needle (1) that captures the yarn supplied from the yarn carrier (4), so that the yarn supplied from the feeder maintains substantially the same yarn-feed angle, and

the lower side of the second guide surface (54, 54B) extends substantially parallel to a needle dial (D) so as to prevent the yarn from being routed to the back of the cylinder needle (1).
A dropped stitch preventive tool according to Claim 1 or 2 that is adjustable vertically, horizontally and depthwise according to the approach angle of the knitting yarn.
A dropped stitch preventive tool according to any of Claims 1 to 3, in which
the first guide surface (53) is upwardly slanted by 10-30 degrees toward the center of the circular knitting machine,
the second guide surface (54) continues from the first guide surface (53) and bends at an angle of approximately 90 degrees toward the yarn carrier (4).
A dropped stitch preventive tool according to any of Claims 1 to 4, which is made of carbon tool steel and has a thickness of 0.1-0.3 mm.
A dropped stitch preventive tool according to any of Claims 1 to 3, in which the lower side of the second guide surface (54B) is formed of a linear part (56) such as wire.
A dropped stitch preventive tool according to any of Claims 1 to 6 in which the end of the first guide surface (53) is a protrusion (57) that extends downwards so that it prevents yarn from loosening and coming off the first guide surface (53).
A method for knitting a quilted knit fabric using a double knit circular knitting machine set up for rib gating, comprising:
a step for supplying first yarn (Y1) to cylinder needles (1) in knit-welt positions at the first feeder (F1), a step for feeding second yarn (Y2), which will be filler, from between the first feeder (F1) and the second feeder (F2) to between the cylinder verge (S1) and the dial verge (D1), a step for supplying third yarn (Y3) to cylinder needles (1) in knit-welt positions and to dial needles in knit positions (2) at the second feeder (F2), a step for supplying fourth yarn (Y4) to cylinder needles (1) in knit-welt positions at the third feeder (F3), and a step for supplying fifth yarn (Y5) to cylinder needles (1) in knit-welt positions and to dial needles (2) in knit positions at the fourth feeder (F4), characterized in that

the dropped stitch preventive tool (5, 5A, 5B) according to any of Claims 1 to 7 is installed between the third feeder (F3) and the fourth feeder (F4) so as to prevent dropped stitches of knitting yarn.
A method according to Claim 8 further provided with a dropped stitch preventive tool (5, 5A, 5B) along with a pipe yarn carrier (7) between the first feeder (F1) and the second feeder (F2) so as to prevent dropped stitches of knitting yarn.
A method according to Claim 8 or 9 in which the components of a knitting machine that rotates in the reverse direction are installed horizontally inverted.