US20160040330A1

US20160040330A1 - Apparatus and method for reducing torque in garments

Info

Publication number: US20160040330A1
Application number: US14/823,320
Authority: US
Inventors: James Larry Gunn
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-01-18
Filing date: 2015-08-11
Publication date: 2016-02-11

Abstract

A method of reducing torque in garments includes calculating a needle wale skew measurement for the fabric. A knitting machine can orient fabric along its negligible torque line. The knitting machine includes a cylinder having a plurality of needles for knitting the fabric, a take-down component for pulling the fabric from the cylinder, and the knitting machine is adapted for rotating the take-down component at a predetermined rotation ratio relative to rotation of the cylinder. The predetermined rotation ratio can be calculated using the needle wale skew measurement.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 13/947,458, filed Jul. 22, 2013, which claims priority to U.S. Provisional Patent Application No. 61/741,440, filed Jul. 20, 2012, and U.S. Provisional Patent Application No. 61/853,061, filed Mar. 28, 2013. All of said applications are incorporated herein by reference. In addition, U.S. patent application Ser. No. 12/930,777, filed Jan. 18, 2011, now abandoned, is incorporated herein by reference.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to an apparatus and method to reduce torque in fabric and garments. One embodiment of the invention comprises a textile apparel process to reduce and/or eliminate torque in garments made from single end spun commodity yarn.
Prior art attempts to address fabric torque, also referred to as fabric skew, include relatively inaccurate de-twisting at wet processing, and relatively expensive plied yarns. The prior art has not provided an efficient means to produce a skew specification, orient the fabric to an acceptable low minimal or negligible torque state, or non-destructive testing for torque.
Prior art processes attempt to address fabric torque at the pad or at slitting. Such processes have not been controllable to the level that yields fabric with acceptable or negligible torque thus fabric, cut parts and garments are produced that skew after wash and tumble drying. Current torque testing technology is not statistically representative or accurate and is wasteful. Prior art destructive testing for fabric skew can involve a very ambiguous process, because pass or fail depends on the chance that a single (statistically insignificant) sample randomly taken accurately represents the entire production order because of single sample destructive testing. Also, prior art tests typically allow for a significant amount of bow and skew that would be objectionable on higher cost garments. Thus today a significant volume of garments are objectionable after washing and tumble drying, because of fabric skew/torque. Current linear finishing technology does not allow the fabric to achieve the negligible torque state during processing. Today's quality assurance testing is limited and does not capture the variation within fabric lots. Today's quality assurance testing is limited and does not capture the variation within fabric lots. Improvement in linear finishing/extracting is desirable.

SUMMARY OF THE INVENTION

Needle skew measurement (NSPI) is a statistically accurate non-destructive method of evaluating an entire lot of fabric for torque/skew. One object of the present invention is to provide a method of establishing a torque/skew specification, orienting fabric to negligible torque, and non-destructive testing. Another object of the present invention is to provide an efficient textile manufacturing process that allows garments to be made from greige fabric and yield no torque garments, by orienting the fabric to negligible torque.
Another object of the invention is to change de-twisting of fabric to fabric needle skew (NS) orientation by using improved logic and/or smart/vision sensor/controller to control torsion (the twisting of fabric from the trailing end to cause orientation of needle wales to acceptable torque/seam deflection) of fabric coming to the pad spreader. Another object of the invention is to improve linear finishing/extracting using a logic and/or smart/vision sensor to control the turntable that is integrated with the pad.
Another object of the present invention is providing methods of making apparel from greige fabric with minimal torque. Yet another object of the invention is to provide a method of fabric production that allows for last minute dyeing decisions.
Yet another object of the invention is to provide a method of fabric production that reduces the amount of fabric dyed, reduces the cost of inventory and inventory obsolescence, and yields garments with high quality standards. Another object of the present is to provide means for non-destructive testing that eliminates the need for wash testing for shrinkage conformance.
These and other objects of the invention can be achieved in various embodiments of the invention disclosed below.
Knit fabric has a torque/skew condition that can be determined by yarn, stitch and knitting machine used. Natural skew in fabric can be measured after washing and tumble drying the fabric.
According to an embodiment of the invention, the needle skew can be measured as opposed to the edges of tubular fabric. This measure can be recorded in needles of skew per linear inch (needles of skew per inch with known stitches per inch) so that it can be translated back to greige fabric. This provides a skew specification (NSPI) that can be used to eliminate garment torque and test fabric by non-destructive means. Once the skew specification of a given fabric is determined, the fabric can be oriented to its known acceptable torque state during the knitting process, after knitting or during finishing or at cutting. Needle skew can be used to chart the entire lot of fabric such that it is a very statistically accurate measure of the fabric lot. In a 2000 yard lot of fabric, ten, fifteen, twenty-five (or as many desired with automation) random points can be measured with NS measurement as opposed to one or two samples with destructive testing.
Another embodiment of the invention comprises a knitting machine that orients fabric along its negligible torque line and the courses perpendicular to that negligible torque line. This allows fabric quality parameters (weight, shrinkage, skew, and bow) to be controlled at knitting through simple checks at predetermined points like the beginning of a roll with no waste created. The knitting machine can include a fabric take down that rotates at a different rate to the cylinder so that fabric is rolled up along its negligible torque line. The negligible torque state can also be achieved by orienting the fabric at other processes once the specification is determined.
Knit fabric that is oriented to negligible torque can have characteristics similar to plied yarn fabrics that have completely balanced twist or negligible torque. Thus, commodity yarns/fabrics can be used to replicate benefits of much higher cost yarns/fabrics.
An embodiment of the invention produces garments having acceptable appearance after wash by the consumer including apparel with side seams. Garment wash or garment dyed products can easily meet standards for torque, shrinkage, shape, hand, and fit. An embodiment of the invention can be used with open width or tubular goods, and can solve torque/skew on feed stripe knits.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 1A are schematic views showing stitches in the relaxed state angling around the fabric;

FIGS. 2 and 2A are schematic views showing stitches in the traditional knitted state, extending exactly vertical;

FIGS. 3-5 are schematic views illustrating a method for measuring needle wale skew and conducting a non-destructive test of fabric for correct needle skew orientation, according to a preferred embodiment of the invention;

FIG. 6 is a schematic view of a knitting machine, according to a preferred embodiment of the invention;

FIG. 7 is a schematic view of a wet processing system, according to a preferred embodiment of the invention;

FIG. 8 is a perspective view of a basket spreader, according to a preferred embodiment of the invention;

FIG. 9 is an environmental perspective view of the basket spreader of FIG. 8;

FIG. 10 is schematic view of a fabric tube; and

FIGS. 11-15 illustrate a method of making a garment according to another preferred embodiment of the invention; and

FIG. 16 is a chart illustrating results of testing for seam deflection/torque.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION AND BEST MODE

Torque or skew in fabric can be tested and predicted based on the yarn, stitch and knitting machine used, according to a preferred embodiment of the invention. FIGS. 1 and 1A show stitches 12 in a relaxed state, and illustrate how they angle around throughout the fabric 10. In comparison, FIGS. 2 and 2A show stitches 22 in the traditional knitted state in fabric 20, and illustrates precise vertical orientation of the stitches 22.
Garments have needle wale lines 11 that angle off from the vertical position when torque is controlled. Fabric made with the same yarn, stitch and machine consistently that is processed the same way will have the same skew potential.
According to a preferred embodiment of the invention, fabric torque/skew can be determined by performing a skew/torque measurement on tubular knit fabric that has been laundered to simulate the relaxed state of the fabric. The number of needle wales 11 that angle off the longitudinal edge 14 in a one inch segment 30 of length of the fabric 10 is counted and is referred herein as needle wale skew per inch. The fabric 10 shown in FIG. 3 has six needle wales 11 that angle off the vertical edge 14 in one inch of length 30 of fabric 10, thus yielding a needle wale skew per inch of six. Alternatively, the number of needle wales that angle off the vertical edge 14 in a six inch length of fabric 10 can be counted, and then divided by six to attain the needle wale skew per inch. A stitch glass or other magnifying device can be used to aid in the counting of the needle wales 11 on the fabric 10. We can measure needle skew (NS) as needle wales/linear needle wale distance, as an angle, or as a left to right distance amount per linear needle wale distance. That is, NS/inch (NSPI), angle of wales to fabric edge, or left or right measurement/linear measurement. NSPI measurement can be automated (camera and electronics) with a hand held unit or adapted to a process such as compacting.
A camera can be attached to a compactor to take images of fabric edge parallel to the fabric edge at predetermined points. Images can be forwarded to a quality assurance lab computer and monitor for analysis. A lab technician can pull up the images from a production order. The images are magnified to enhance needle skew definition and a grid is placed over the image on the monitor so that the angle of needle skew can be accurately analyzed. A production order will be passed or failed based on the standard compared to a minimum of ten points per lot instead of one to three fabric samples typically used today. Statistical accuracy of pass or fail can increase significantly, and there is no fabric waste.
The fabric 10 should be completely relaxed by laundering and tumble drying prior to measuring the needle wale angle to the vertical. The standard method is three wash and tumble dry cycles. The needle skew per course is calculated to determine the correlation of skew per course in greige or finished fabric. These processes provides the relationship between the traditional knitted state and the relaxed state after laundering and tumble drying, as illustrated by FIGS. 1 and 2. Traditional dyeing and finishing of greige fabric relaxes 25-30% of the torque that is present in greige fabric. For example, if greige fabric has eight NSPI when washed and tumble dried in the greige then the same fabric after dyeing and finishing will have approximately six NSPI after wash and tumble dry.
As shown in FIG. 4, the angle 40 of the needle wales 11 in relation to a vertical line 42 indicates the amount of natural skew/torque in the fabric 10. This measurement can be documented as part of the product specifications as needle wale skew per inch. This skew specification can be used to correctly orient the fabric 10 to eliminate torque and bow in garments.
Since this is a non-destructive test it can be performed randomly throughout the batch for ensuring process control. Various devices that can be developed based on the above described method to accurately and quickly determine accuracy of wale orientation. Templates with angles or measures can be used to quickly check fabric in many locations. The torque/skew specification angle 40 can be measured with a common protractor. Once the specifications (skew to balance torque) are known, calculations can be worked out to approximate the value for new fabrics given the yarn, stitch and knitting machine.
A measuring device for checking the fabric 10 for correct skew according to a preferred embodiment of the invention is illustrated in FIG. 5, and shown at reference numeral 50. The measuring device 50 can be comprised of plexi-glass other similar transparent material, and has a diagonal line 54 extending at the desired torque/skew specification angle 40. As such, the device 50 can placed upon the fabric 10, as shown in FIG. 5, and the number of that angle off the vertical edge 14 within the area defined by the diagonal line 54 can be counted to determine whether the fabric 10 has the desired torque/skew.
The replication of knitted stitches 22 in FIG. 2A shows the vertical stitch alignment of wales and horizontal alignment of courses in the traditional knitted state. The relaxed stitches 12 in FIG. 1A show the replication of stitches in fabric 10 that has been washed and tumbled dry. The known relationship between the knitted state 20 and relaxed state 10 is used to orient the fabric accurately on a knitting machine 60.
The end result is a greige fabric 10 that can be made into garments with negligible torque and minimal bow. The greige fabric garments can be garment washed, bleached, or dyed to complete the finishing process. Thus, all garments can be acceptable after wash by the consumer for skew and bow, and products that have side seams or garment wash can be successfully produced.
A knitting machine according to a preferred embodiment of the invention is illustrated in FIG. 6, and shown generally at reference numeral 60. The knitting machine 60 comprises a needle cylinder 62, and a take-up unit 70, as shown in FIG. 6. The cylinder 62 preferably has a diameter of thirty inches and 2088 needles. The take-up unit 70 comprises a take-down section 72 for pulling fabric off the cylinder 62, a roll-up section 74 that rolls up the finished fabric into rolls for transport, and a center driven take-up shaft 76 under constant spring tension positioned between the take-down 72 and roll-up 74.
The knitting machine 60 includes a variable take-up 70 to cylinder 62 rotation feature comprising two independent variable speed motor drives 68, 78. One motor drive 68 is operatively connected to the cylinder 60, and the other motor drive 78 is operatively connected to the take-up unit 70. The motor drives 68, 78 are electronically synchronized such that the take-down 72 turns at a predetermined speed ratio to the cylinder 62. The take-up 70 is driven with a coordinated but different ratio drive system 78, than the cylinder 62. This provides a means for inputting the appropriate ratio so that the fabric strand 10 is oriented with acceptable torque. The take-up 70 includes an electronic encoder 79 that detects the speed of the cylinder 62, and regulates the speed of the take-up 70 to account for any changes in the speed of the cylinder 62 to maintain the desired take-up 70 to cylinder 62 speed ratio.
The known skew/torque specification (by yarn, stitch and machine) can be used to determine the ratio of the take-up 70 to the cylinder 62, such that the resulting fabric oriented to negligible torque. Open width fabric can be slit along the negligible torque line in the greige state. The center driven take-up shaft 76 ensures that stitches and wales per inch remain consistent through the roll so that garments cut from this greige fabric will have the same garment dimensions before and after wash.
Fabric coming off the knitting machine 60 is oriented to negligible torque state prior to processing so all of the fabric knitted has negligible torque. Because the fabric is not linear finished fabric bow can be measured and controlled at knitting.
Since the fabric is rolled up with the edge along the negligible torque line, the edge for slitting on open width fabrics can be easily marked. This works especially well on feed stripes since the stripes can be straightened (and stripe matched) to this vertical line throughout the strand of fabric. With this method, feed stripe garments have acceptable stripe straightness and side seam location after wash. Feed stripes can be constructed so that the feed stripes are perpendicular to the negligible torque line that is aligned with the edge of the knit roll. Fabrics can be checked coming off the knitting machine 60 for course straightness (bow) by using a course maker (dyed yarn or marked yarn). The knitting machine can be equipped with a slitter and open width take up to prepare the fabric for open width cutting in the greige state.
The following examples illustrate a method of calculating the desired cylinder to take-up ratio according to a preferred embodiment of the invention.

Example 1

The appropriate take-up to cylinder ratio can be calculated by performing the following steps. The number of needles on the cylinder (2088) is divided by the needles skew per inch (eight) to yield a quotient (261). The number of yarn feeds going into the cylinder (120) is divided by the number of courses per inch (52) to yield a second quotient (2.307). The first quotient (261) is divided by the second quotient (2.307) to yield a third quotient (113). The third quotient (113) represents the number of cylinder revolutions. For Z-twist yarn, one revolution is added to the number of cylinder revolutions (113) to yield a sum (114), which represents the number of revolutions for the take-up, thereby yielding a desired cylinder to take-up rotation ratio of 113 cylinder revolutions for every 114 take-up revolutions. Accordingly, the motor drives 68, 78 and electronic encoder 79 of the knitting machine 60 are programmed to drive the take-up at 114 revolutions per every 113 revolutions of the cylinder 62. For S-twist yarn, one revolution is subtracted from the number of cylinder revolutions (113) to yield a difference (112), which represents the number of revolutions for the take-up, thereby yielding a desired cylinder to take-up rotation ratio of 113 cylinder revolutions for every 112 take-up revolutions. As such, the motor drives 68, 78 and electronic encoder 79 of the knitting machine 60 would be programmed to drive the take-up at 112 revolutions per every 113 revolutions of the cylinder 62.

Example 2

A Z twist 22/1 weight ring spun yarn knit on a four feed per diameter inch single jersey knitting machine results in fabric skew of 5.8 needles per inch. To relieve the torque in this fabric, the fabric tube is allowed to de-twist approximately twelve revolutions for each 100 yards. The ratio of cylinder to take-up turns would be 132.25:133.25 to achieve negligible torque. As such, the take-up 70 would make an extra revolution every 132.25 turns of the cylinder (or the take-up would turn 133.25 revolutions to each 132.25 revolutions of the cylinder).

Example 3

A Z twist 18/1 weight open end spun yarn knit on a four feeds per diameter inch single jersey knitting machine results in fabric skew of 2.8 needles per inch. The ratio of cylinder to take-up turns would be 164.77:165.77 to achieve negligible torque. The take-up would turn an extra revolution about every 164.77 turns of the cylinder.
Each fabric processed can have a specification for skew or negligible torque (angle of needles wales versus a vertical line). Fabric can be checked at any process or in garments for correct skew by using the stitch glass aligned to the vertical (folded edge on tubular). By counting the number of needle wales that angle out of the stitch glass on the fabric edge per inch you can establish a value for wale skew. Since this is a non-destructive test it can be performed randomly throughout the batch for ensuring process control. Once the specifications (skew to balance torque) are known tables can be worked out to approximate the value for new fabrics given the yarn, stitch and knitting machine.
Skew and shrinkage can be quickly checked by counting needle wales that angle off the edge, wales, and stitches per inch. There are devices to assist with this, so there is no reason to use the costly destructive wash testing method. Non destructive testing can be used, the test can be performed in seconds and multiple samples of in process and finished garments can be checked for statistically sound process control.
Fabric can be scanned with a hand held electronic device or manually count and measure needle wale skew, stitches, wales, and bow. Thus, pass/fail parameters can be easily determined and the data recorded by machine, batch or production order without the use of destructive testing. An electronic scanner can be used below the take down 70 on the knitting machine 60 to accurately check for quality parameters at the beginning of each roll.
Multi-weight fabrics can be made from commodity yarns having excellent quality characteristics (no torque, exceptionally low shrinkage, excellent drape, great hand, no linear finishing defects, consistent garment fit). Torque is negligible because the fabric is oriented to its torque specification on the knitting machine. Shrinkage is minimized by garment wash, bleach, or dye and tumble drying. Fabric drape and hand is enhanced by garment wash and tumble drying, and is also improved by being able to make lighter weight fabric and control quality parameters. Linear defects such as compactor sheen, phantom lines, finishing creases and processing holes are eliminated. Shape and fit of garments from this process can be excellent due to minimal torque, less bow, minimal shrinkage, and comfort of fabric.
Although the cost of dyeing garments instead of fabric may be slightly higher, there is a cost savings on fabric weight, lower off quality, dyeing less pounds of fabric, reduced waste, less destructive quality assurance testing, less lead time, lower obsolescence, and increased inventory turns. Also, garment dyeing has advanced and low liquor ratio garment dyeing is getting closer to the cost of fabric dyeing. Savings on fabric weight can be realized by knitting a lighter weight fabric and increasing the fabric weight by garment dye, bleach, or wash and then tumble drying. A traditional finished fabric that has thirteen percent (seven length by six width) additive total shrinkage can be knit ten percent lighter and bulked by this process to a shrinkage of less than three percent total. The resulting fabric weight savings would be about ten percent. The customer gets the same garment fit but does not get the bulkier fabric one would get after washing a traditional finished garment. Because of the above fabric weight savings, no dyed cutting or finishing waste and no dyeing of unbalanced components, there is a huge savings in material, dye, and chemical usage.
The textile apparel process is reduced to knit, cut, and sew. Dyeing and preparation for customer can be done to customer order or to finished garment inventory. Less lead time, lower inventory requirements (by storing some garment inventory as greige), less obsolescence (higher inventory requirements with dyed garments) reduced inventory investment can be realized. The cost of quality assurance is lower due to lower staffing requirements and less destructive testing is necessary.
There is an additional advantage of the knitting machine 60 orienting fabric to negligible torque state for traditional finishing. A problem with current textile finishing is that the fabric does not get oriented correctly resulting in variable torque and bow throughout the fabric lot. The knitting machine 60 orients the fabric to a negligible torque providing correct orientation and a pattern for how the needle wales should angle to achieve negligible torque. Therefore, new finishing devices can be adapted to properly orient fabric with traditional linear wet processing, drying, and compacting or calendaring.
Traditional linear finished fabric does not have the same torque/skew as cut to length, washed and tumble dried fabric without incorporating changes to existing equipment. If fabric is knitted on a knitting machine that orients the needle wales to a negligible torque position, traditional processing with length tension straightens the needle wale skew through the extraction/pad process. To accept enough needle wale skew for negligible torque at wet processing it is necessary to make changes to entry of the pad. An entry pre-spreader for the pad that will permit more needle wale skew to stay in the fabric through wet processing is needed. This device is referred to as a rotational spreader. The objective is to add a small amount of NSPI to achieve near negligible torque.
A pad spreader system according to a preferred embodiment of the invention is illustrated in FIG. 7, and shown generally at reference numeral 100. The pad spreader system 100 comprises a pad 102 for extracting water, a pre-spreader 104, a pair of idler turn bars 105, 106, ring guiders 108, a de-twisting device 110, and a wet box 112 on a turntable 114. The turn bars 105, 106 lower or raise to rotate the fabric tube 10, and can be adjusted to turn fabric 10 more or less to agree with negligible torque. The turn bars 105, 106 are positioned between the spreader 104 and the ring guiders 108 opening mechanisms. The turn bars 105, 106 raise the fabric tube up on one side and lower the fabric tube on the other side so that it rotates the fabric clockwise or counter clockwise on the second set of spreaders as needed to orient the fabric to negligible torque.
The fabric 10 may come to de-twisting 110 oriented to negligible torque or the de-twister 110 can be programmed to add needle wale skew so that the fabric 10 is in agreement with negligible torque specifications.
Using the known fabric needle wale torque/skew the fabric 10 can be oriented at wet processing to a negligible torque state. The needed needle wale skew can be added at the pad to achieve negligible torque in garments that are washed and tumbled dried. To achieve this amount of wale skew through the pad 102 the turn bars 105, 106 turn the fabric tube 10 clockwise or counter clockwise to orient fabric to negligible torque.
A basket spreader according to a preferred embodiment of the invention is illustrated in FIG. 8, and shown generally at reference numeral 200. The basket spreader 200 comprises a pair of S-shaped members 202, 204. As shown in FIG. 9, the basket spreader 200 can be used in front of a spreader on the pad 102, and has a rotation that encourages fabric 10 rotation prior to the fabric being spread to the width on the pad 102.
By testing the fabric and setting up a torque/skew specification, fabric coming to wet processing from the traditional knitted and dyed state would have wale skew added at the pad to equal negligible torque by devices that rotate (rotation spreader) the fabric tube correctly from the entry orientation.
Fabric may come to wet finishing with negligible skew (by orientation at knitting) and the turn bars 105, 106 can be used to rotate the fabric after opening to allow negligible skew through the pad 102. Without the turn bars 105, 106, wet processing can straighten the needle wales such that fabric will be under skewed (after wet processing) for negligible torque.
In addition, the turntable 114 at the extractor and turning device 105, 106 can add the needle skew needed based on stitches per inch, extractor speed and the current level of needle wale skew versus the known needle wale skew specification and force negligible skew through the pad 102.
A smart/vision sensor/controller to control the turntable 114 can achieve a high level of compliance as it does not introduce the variation that conventional sensors induce. Conventional sensors only de-twist back and forth S torsion then Z torsion, which can cause significant needle skew variation yielding significant torque variation. A conventional sensor calls for the turntable 114 to put the opposite torsion needed in fabric because it is merely reactionary. Testing has shown that most torque failures are caused by variation within the lot (see FIG. 16). NSPI below the solid line in FIG. 16 will fail seam deflection/torque because of low NSPI. Needle skew analysis has shown this solution.
It is possible to yield acceptable torque/seam deflection by manually controlling the torsion of fabric entering the extractor. Thus by changing the turntable sensor logic at the extractor, fabric can be produced with acceptable torque/seam deflection.
Alternatively, in the advanced state the extractor can control the needle skew by counting courses (camera, electronics and servo motor) and adjusting the needle wale skew to agree with known fabric skew specification. The turntable 114 and skew assist devices 105, 106 can be adjusted as the fabric 10 comes through the pad 102.
The amount of needle skew in fabrics oriented to negligible torque can be reduced by appropriately changing the yarn twist direction or the direction that a knitting machine turns. Slitting and moving one edge appropriately forward or backward can also reduce needle skew. Reduction in needle skew may be advantageous to traditional manufacturing or making garments from greige.
Washed and tumbled dried fabric provides the needle skew that is needed to manage torque through the processes. Washed and tumble dried (WTD) griege needle skew is higher (approximately 25-30% on ring spun) than in finished fabric because linear processes reduce the WTD skew in finished fabric. The needed needle skew (NS) can be used to produce negligible torque in finished fabric as a reference through the process. By associating needle skew with courses per inch (CPI) the needle skew value can be easily calculated for knitting, pre-extracting, post-extracting, post-drying, and after compacting.
The torque/skew specification (NSPI) provides a process control tool that can be used at any process. It can be used in combination with courses per inch (CPI) so that the torque/skew specification is stated as needle skew per inch with known courses, needle skew per course, or yards per complete wrap of a needle around the tube of fabric with known CPI. Once the torque/skew specification for WTD fabric of a given style is determined, it can be to measure control at any process.
Using needle skews (NSPI) to manage torque eliminates the need for destructive testing and wait time thus controlling torque within the process. This can be done using a stitch glass and other devices (angle measurement) to speed the quality assurance process so that multiple samples can be taken to ensure greater accuracy of results. Using NSPI to manage torque can be done with manual measurement and/or digital scanning of fabric for control.
For example, using the knitting machine 60 with a cylinder 62 having 2088 needles to make a fabric having a needle skew per inch of 7.5, a single needle will wrap all the way around the fabric tube in 7.73 yards. In 3.87 yards (139.32 inches) the needle creates a diagonal line 300 from one edge 302 to the other edge 304. Using the diagonal line 300 length and the width 302 of the fabric, the needle skew angle can be calculated, as shown in FIG. 10. For example, if the finished fabric has a width 302 of twenty-eight inches and the diagonal length 300 is 3.87 yards (139.32 inches), the fabric has a needle skew angle 306 of 11.4 degree angle. It should be noted that this is not the torque that would be expected on WTD fabric but the angle of the needle wales needed for zero torque or seam deflection in finished garments.
After a standard is established for NSPI, the seam deflection/torque remaining in finished fabric can be calculated without having to waste fabric and labor. A fabric has a standard NS of 6/inch after wash with 38 WPI and 54 CPI. If we get 4.5 NS per inch, 38 WPI, and 54 CPI at finishing then the fabric will torque/skew 1.5 NSPI after wash and tumble dry. On a thirty inch garment that would equal (1.5 NSPI×30 inches) 45 NS. At 38 WPI that would equal (45 NS/38 WPI) approximately 1.184 inches of torque/skew on the thirty inch garment after wash. Seam deflection on this thirty inch garment would be 1.184/30 or about 3.95% which would pass typical seam deflection standards.
FIGS. 11-15 illustrate a method for orienting NSPI traditional greige fabric at cutting according to another embodiment of the invention. By using the known NSPI and a parallelogram pattern, a garment 400 can be constructed that has perfectly oriented side seams after garment dye or wash. The greige garment 400 has side seams 416, 417 that angle down the garment after construction, but after the garment 400 is washed or garment dyed the side seams are vertically straight under the arms as desired. The needle wales will be vertical also, like more expensive ply balanced yarns.
The fabric 410 is knit on a traditional knitting machine with vertical needle wales. The fabric 410 comprises a back portion 411 having a neck hole 413 formed therein, a front portion 412 having a corresponding neck hole 414, and sleeve sections 421, 422.
The fabric 410 is opened on the knitting machine to reduce the cutting waste when cutting on a bias, as shown in FIG. 11. Needle skew measurement (specification) makes this process possible. The needle skew specification (NSPI) is used to adjust the angle (calculated by using two known sides of a right triangle) of the parallelogram pattern. The fabric 410 is cut in the parallelogram pattern, as shown in FIG. 11. Cut waste does not undergo finishing/dying, resulting in a cost savings.
The back portion 411 is flipped to face the front portion 412, as shown in FIGS. 12A and 12B. FIG. 12A illustrates a Z-twist construction, and FIG. 12B illustrates S-twist construction. The corners of the front and back portions 411, 412 are positioned together and the neck holes 413, 414 are aligned, as shown in FIG. 13, and the front and back portions 411 412 are seamed together. The sleeve sections 421, 422 can be sewn to the
The greige manufactured fabric 410 has side seams 416, 417 that are rotated at an angle in relation to the garment's tubular side edges 418, 419, respectively, as shown in FIGS. 13 and 14. The parallelogram pattern distorts the side seams 416, 417 on an angle that is equal to the natural torque that is in the greige fabric 410. The distortion is opposite the natural torque so that when the garment is processed (dyed and tumble dried) the side seams 416, 417 move to the vertical position under the arms (tubular side edges 418, 419, respectively), as shown in FIG. 15. If no dying is needed, the garment 400 can be washed and tumble dried, resulting in the side seams 416, 417 moving to the vertical position under the arms.
The garment 400 is dyed and tumble dried. After garment dyeing, the side seams 416, 417 are co-extensive with the substantially straight vertical tubular side edges 418, 419, respectively, and substantially perpendicular to the bottom hem of the garment, due to the relaxation of natural torque in the greige fabric 410. The angle used is equivalent to the natural torque specification.
Making garments from greige for garment dye is a major advantage over using traditional textile manufacturing and then dyeing the garment. The process is shorter and cheaper than normal garment dye, and has many advantages over traditional textile manufacturing, such as reduced inventory requirements and obsolescence, quicker replenishment from garments in the greige state, ability to dye all sizes and styles in a single dye lot, less dyeing requirements because cutting waste does not have to be dyed, and no shrinkage or torque.
A turntable can have a sensor that senses the build-up of torsion in fabric and sends a signal to the turntable control to react to this torsion by rotating in the direction needed to remove built-up torsion. A conventional turntable merely reacts to the torsion that is sensed by doing the opposite of what is sensed, although it can be programmed to have a bias for Z or S twist fabric.
Another embodiment of the invention comprises a smart turntable control process for de-twisting using needle skew measurement. Needle skew measurement provides accurate data to the user to determine how fabric needs to be de-twisted to prevent excessive high torque yardage from being processed. De-twisting control logic can be improved by using needle skew analysis data to program pad parameters (parameters control the reaction to sensor signals of torsion build-up).
For example, when running a Z twist fabric with high potential needle skew the turntable should be rotated almost consistently clockwise when observing from overhead. Clockwise rotation yields Z torsion, which is what the fabric needs to relax natural Z twist torque. For a given fabric, the needle skew analysis can determine how many net clockwise rotations are needed to relax the torque in a 1000 yard wet box of fabric. From measured NSPI, the number of needles in the cylinder, CPI (courses per inch), and the yardage of fabric, the number of turntable rotations needed to be in the acceptable range accurately can be calculated.
The turntable control can be given a bias for the correct torsion, which limits the wrong torsion and maximizes the correct torsion. Fabric needle skew is typically under skewed with conventional turntable control so the more that the correct torsion direction can be induced, the better control of torque yielded.
When running a Z twist fabric, the counter clockwise direction of rotation is limited and clockwise rotation increased, all while de-twisting the fabric strand. Turntable rotation is approximately eighteen to twenty revolutions per minute. Parameter one controls the number of rotations of the turntable before pausing once torsion is sensed. For example for parameter one, up to six seconds of clockwise rotation is allowed, but only two seconds of counter clockwise rotation before pausing. Parameter two controls the turntable rest time after clockwise or counter clockwise rotation. For example for parameter two, the turntable can be rested for two seconds after clockwise rotation and the turntable can be rested for five seconds after counter clockwise rotation. Parameter three is a time limit for switching direction of rotation. For example for parameter three, when there is a torsion signal, there is no switch from clockwise to counter clockwise for two seconds and there is no switch from counter clockwise to clockwise for 0.75 seconds.
The process provides a bias for inducing Z torsion, which is correct for Z twist fabric, and eliminates long yardage of Z twist fabric run with S torsion, which causes torque/seam deflection failures. For Z twist yarn, the smart sensor at the pad senses that it is running Z twist yarn, and can be programmed to maintain one to three turns of Z torsion throughout the entire lot to yield acceptable seam deflection/torque. S twist can be controlled as opposed to Z twist.
A vision sensor can control the fabric with consistent (e.g. one to three turns of torsion) Z torsion on Z twist fabric. The smart turntable control induces a bias for the correct torsion, which greatly improves the fabric over conventional generic control.
For Z twist yarn, a vision sensor inputs Z torsion to begin the lot and keeps a minimum of one-half and maximum of three Z torsion turns in the fabric between the sensor location and the fabric spreader. For S twist yarn, a vision sensor inputs S torsion to begin the lot and keeps a minimum of one-half and maximum of three S torsion turns in the fabric between the sensor location and the fabric spreader.
An apparatus and method for reducing torque in garments are described above. Various changes can be made to the invention without departing from its scope. The above description of the preferred embodiments and best mode of the invention are provided for the purpose of illustration only and not limitation—the invention being defined by the claims and equivalents thereof.

Claims

What is claimed is:

1. A method of producing a fabric having a desired torque comprising:

(a) calculating a needle wale skew measurement for the fabric to be produced;

(b) measuring torque by non-destructive testing means;

(c) providing a knitting machine comprising a cylinder having a plurality of needles for knitting the fabric and a take-down component for pulling the fabric from the cylinder, and wherein the knitting machine is adapted for rotating the take-down component at a predetermined rotation ratio relative to rotation of the cylinder; and

(d) calculating the predetermined rotation ratio based on the needle wale skew measurement.

2. The method of claim 1, wherein the step of calculating the needle skew measurement comprises determining a number of needle wales that run off a longitudinal side edge of the fabric within a predetermined length of the fabric.

3. The method of claim 2, wherein the step of calculating the needle skew measurement comprises washing and drying the fabric prior to determining a number of needle wales that run off a longitudinal side edge of the fabric within a predetermined length of the fabric.

4. The method of claim 2, wherein the predetermined length of fabric is the range of one to six inches.

5. The method of claim 1, further comprising the step of rotating the take-down component and the cylinder at the predetermined rotation ratio.

6. The method of claim 1, wherein the knitting machine comprises first and second variable speed motor drives, the first motor drive operatively connected to the cylinder, and the second motor drive operatively connected to the take-down component, and further wherein the motor drives are adapted to drive rotation of the cylinder and the take-down component at the predetermined rotation ratio.

7. The method of claim 6, wherein the knitting machine comprises means for electronically programming the first motor drive and the second motor drive whereby the cylinder and the take-down component rotate at the predetermined rotation ratio.

8. The method of claim 6, wherein the knitting machine further comprises an electronic encoder operatively connected to the cylinder and the take-down component, whereby the electronic encoder detects the rate of rotation of the cylinder, and adjusts the rate of rotation of the take-up component to maintain the cylinder and the take-down component at the predetermined rotation ratio.

9. The method of claim 6, wherein the knitting machine comprises:

(a) a roll-up component for receiving fabric from the take-down component and rolling the fabric up into a roll for transport; and

(b) a center driven take-up shaft positioned between the take-down and roll-up components.

10. The method of claim 1, wherein the needle wale skew measurement comprises the number of needle wales of skew per linear inch of the fabric.

11. The method of claim 10, wherein the step of calculating the predetermined rotation ratio comprises:

(a) dividing a total number of needles on the cylinder by the needle wales of skew per linear inch of the fabric to yield a first quotient;

(b) dividing a total number of yarn feeds into the cylinder by a total number of courses per inch of the fabric to yield a second quotient;

(c) dividing the first quotient by the second quotient to yield a third quotient, said third quotient representing a number of cylinder rotations; and

(d) adding one to said number of cylinder rotations to yield a sum, said sum representing a number of take-down component rotations, wherein the number of cylinder rotations to the number of take-down component rotations provides the predetermined rotation ratio.

12. The method of claim 10, wherein the step of calculating the predetermined rotation ratio comprises:

(d) subtracting one from said number of cylinder rotations to yield a difference, said difference representing a number of take-down component rotations, wherein the number of cylinder rotations to the number of take-down component rotations provides the predetermined rotation ratio.

13. The method of claim 1, further comprising the step of providing a water processing system comprising first and second moveable turn bars providing mechanical assistance in rotating the fabric clockwise or counter clockwise to orient the fabric to negligible torque.

14. A method of making a garment comprising:

(a) providing a piece of fabric;

(b) calculating a needle wale skew measurement for the fabric; and

(c) cutting the fabric in a substantially parallelogram shape based on the needle skew measurement of the fabric.

15. The method of claim 14, wherein the piece of fabric comprises a front portion and a back portion, and further comprising the step of seaming the front portion and the back portion together.

16. The method of claim 15, wherein the piece of fabric comprises first and second side seams that extend at an angle in relation to tubular side edges of the fabric that is equal to the natural torque in the fabric.

17. The method of claim 16, further comprising the step of dyeing the fabric, wherein after the dyeing of the fabric the first and second side seams are substantially co-extensive with the tubular side edges of the fabric.

18. The method of claim 16, further comprising the step of tumble drying the fabric, wherein after the tumble drying of the fabric the first and second side seams are substantially co-extensive with the tubular side edges of the fabric.

19. A method of producing a fabric having a desired torque comprising:

(a) providing a turntable and a sensor operatively connected to the turntable, wherein the sensor is adapted for sensing torsion in fabric on the turntable and comprises a computer processor device programmable to control the turntable to minimize torsion;

(b) calculating a needle wale skew measurement for the fabric to be produced; and

(c) programming the sensor based on the needle wale skew measurement for the fabric to be produced.

20. The method of claim 19, wherein the sensor is programmed to maintain one to three turns of Z torsion throughout Z twist fabric, and one-half to three turns of S torsion throughout S twist fabric.