US3831444A

US3831444A - Yarn quality assessment method and apparatus therefor

Info

Publication number: US3831444A
Application number: US00326695A
Authority: US
Inventors: T Sasaki; K Kuroda
Original assignee: Kurashiki Spinning Co Ltd
Current assignee: Kurabo Industries Ltd; Kurashiki Spinning Co Ltd
Priority date: 1972-01-26
Filing date: 1973-01-26
Publication date: 1974-08-27
Anticipated expiration: 1991-08-27
Also published as: DE2303607C3; DE2303607A1; DE2303607B2; IT977676B; FR2174560A5

Abstract

A method and apparatus for assessing knitting quality of yarn which comprises a plurality of elements which operatively cooperate so that some prediction can be made about the knitting quality of the yarn by the detection of the accumulated value of the resistances to various forces as a yarn winding tension, and by the comparison of the data with the respective standard value, an evaluation of the yarn can be made easily and simply before the yarn is knitted.

Description

United States Patent [191 Sasaki et a1.

[451 Aug. 27, 1974 YARN QUALITY ASSESSMENT METHOD AND APPARATUS THEREFOR Inventors: Toshiro Sasaki, Osaka; Katsuaki Kuroda, Kyoto, both of Japan Kurashiki Boseki Kabushiki Kaisha (a/k/a Kurabo Industries Ltd.), Kurashiki-shi, Okayama-ken, Japan Filed: Jan, 26, 1973 Appl. No.: 326,695

Assignee:

Foreigi Application Priority Data Jan. 26, 1972 Japan 47-10153 June 16, 1972 Japan 47-60660 US. Cl. 73/160, 73/9 Int. Cl. G011 5/06 Field of Search 73/160, 9, 95.5

References Cited UNITED STATES PATENTS 10/1965 Schlatter 73/160 3,726,137 4/1973 Demon 73/160 FOREIGN PATENTS OR APPLICATIONS 842,919 7/1960 Great Britain 73/9 Primary Examiner-Richard C. Queisser Assistant ExaminerDenis E. Corr Attorney, Agent, or Firm-Wenderoth, Lind & Ponack [57] ABSTRACT 9 Claims, 10 Drawing Figures YARN QUALITY ASSESSMENT METHOD AND APPARATUS THEREFOR The present invention relates to a method and apparatus for determining the quality of yarn or the like used in the production of natural and/or synthetic fabrics. More particularly the invention relates to a method and apparatus whereby the quality of a yarn, etc., as based on the results of a plurality of normal industrial tests, such as unwinding, needle-to-yarn, yarnto-yarn frictional resistance tests, can be determined in one single operation.

As is well known, in textile fabric production use is made of yarns or threads which have a variety of characteristics, and which are subjected to a variety of preliminary processes, such as mercerising, waxing, etc., and there is also a considerable variety of composition of yarns, which may be, for example, 100 percent cotton, or varying blends of cotton or other materials. Tensile stresses and other forces that yarns are able to bear obviously vary from yarn to yarn according to composition and preliminary treatment, and may also vary from yarns that have the same composition and have received the same preliminary treatment. A constant problem, therefore, in industry, is to determine the quality of a yarn that is to be used, for example, in a knitting mill, in order to avoid stoppages due -to breakage, etc., and to ensure excellent quality and smooth operation on a mass-production basis. By quality is meant the knittablity of yarns, that is the stresses they can withstand and the ease or difficulty withwhich they can be knitted or woven. This assessment of yarn quality is made on the basis of a number of criteria and yarns are generally classified as good (i.e., they knit smoothly and produce finished goods without flaws), medium (i.e., knitting operation can proceed but is usually attended by some difficulty and requires fairly constant adjustments to be made inorder to produce finished goods), or poor (i.e., either that knitting is impossible, or even if it is possible, the finished goods produced are unsaleable). The reason why a number of different criteria for assessing yarn quality is necessary, is that in practical operation, in passing through a knitting machine, yarn is subject to not one but a number of different tensile forces and resistances. These forces and resistances generally include;

1. Unwinding resistance (produced when a yarn is unwound from a cheese, or cone, etc.)

2. Yarn-to-yarn frictional force (also termed crossover resistance or friction, and meaning the mutual frictional resistance offered between two lengths of one and the same yarn at a point where the yarn is crossed on itself) 3. Needle-to-yarn frictional force (i.e., frictional resistance between a yarn and a needle through which it is threaded) 4. Yarn bending moment (i.e., the force imposed on a yarn by bending it sharply once or repeatedly) 5. Yarn tensile strength and elongation at the breaking point 6. Youngs Modulus of initial tension 7. Yarn unevenness (U%).

As far as a particular yarn is concerned, more than one of these resistances and forces is present, but since they are imposed at various points over the length of the same be represented conventionally as one single force, and assessment of yarn quality requires the attention of skilled operators to carry out various tests to determine a yarns qualities with respect to individual resistances, and forces, and then combine the results of tests in a manner previously determined on the basis of experience, in order to classify the yarn as good, medium. or poor. The various factors to be considered and their different correlations for different yarns make assessment of yarn quality in this manner exceedingly complex, and because the assessment is so dependent on the accuracy of individual tests, the testing must be entrusted to skilled workmen, and even if test results are accurate, assessment is rendered difficult because of the fact that what may be a satisfactory value of, for example, needle-to-yarn frictional resistance for a yarn in one situation may not be satisfactory for another yarn, or for the same yarn in another situation. Such a procedure therefore, is obviously time-consuming, and expensive, since it requires skilled operators and a variety of equipment, and also, the mere fact that there are a plurality of tests increases the possibility of error, and the procedure is far from ideal for a mass-production industry such as textile manufacturing.

It is an-object, therefore, of this invention to provide a method and apparatus wherein. a yarn to be tested is unwound from a cheese or cone, passed through a unit where cross-over friction, yarn to needle friction, and bending resistance are generated, and then wound up again at a constant speed by a take-up reel, and the total resistive force representing the above-mentioned cross-over friction, yarn-to-needle friction and bending resistance, is measured at the take-up point and the measured value is compared with standard values obtained when-yarns of known qualities in the same manner, thus making it possible, by a simple and single operation, to classify a yarn into one of three classes, that are good, medium, or poor.

Another object of the invention is to provide a yarn quality assessment method and apparatus wherein a yarn or similar material to be tested is unwound from a cheese or cone, passed through a means for generating unwinding resistance, through a means for generating cross-over (i.e., yarn to yarn) frictional resistance, yarn to needle frictional resistance, and bending resistance and then wound up again at a constant speed by a take-up means and wherein there is provided a detection means for mesuring a tensile force which represents the accumulative value of at least one or more of the above-mentioned resistances. The detection means consists essentially of a floating pulley which is subject to an upwardly acting force provided by the said accumulative tensile force and to which is attached a set weight, it being observed to what position the floating pulley moves relative to a previously determined set level.

A further object of the invention is to provide a yarn quality assessment method and apparatus which comprise a floating pulley for the purpose of measuring an accumulative tensile force on a tested yarn, as described above, and which further comprise a means for continuously varying the weight acting downwards on the floating pulley, said means essentially comprising a freely suspended chain the position of one end of which can be adjusted in such a manner as to change the fraction of the weight of the chain that is imposed on the floating pulley, thus making it possible to assess yarn quality over a continuous range; in other words by a single, simple apparatus and method the invention makes it possible not only to classify yarns broadly into three classes, good, medium, poor, but also to assess yarns much more closely by observation of the movement of a floating pulley.

These and other features and objects of the present invention will become apparent from the following full description taken in conjunction with preferred embodiments thereof and with reference to the attached drawings, in which;

FIG. 1 is a perspective view of one preferred embodiment of a yarn quality assessment apparatus according to the invention,

FIG. 2 is a perspective view, on an enlarged scale, of a movable guide pulley employed in the apparatus of FIG. 1,

FIG. 3 is a perspective view, on an enlarged scale, of a needle holder employed in the apparatus of FIG. 1,

FIG. 4 is a perspective view, on an enlarged scale, of a floating pulley employed in the apparatus of FIG. 1,

FIG. 5, (a) and (b), is a graph showing the position of the floating pulley varying due to the influence of the accumulated resistances applied to a yarn,

FIG. 6 is a schematic diagram showing essential portions of another embodiment of a yarn quality assessment apparatus according to the present invention,

FIG. 7, (a) and (b), is a partially schematic diagram similar to FIG. 6 for illustrating an alternative method of passing a yarn through needles, and

FIG. 8 is a partially schematic diagram showing an essential portion of a further embodiment of a yarn quality assessment apparatus according to the present invention.

Before the description of the present invention proceeds, it is to be noted that like parts are, for the sake of brevity, designated by the like reference numerals throughout the several views of the accompanying drawings.

Referring first to FIGS. 1 to 4, the equipment has a flat base 1. On the base 1 there is mounted a vertical panel 2, and adjacent to one side of the panel 2 there is an upright stand 3, which constitutes a support for a cone 4 of yarn, wool, silk or other material it is desired to test (hereinbelow abbreviated to yarn). The initial point of feed-in of yarn to be tested from the cone 4 to the equipment of the panel 2 (described in further detail below) is a guide pulley 7; yarn unwound from the cone 4 is led to this initial guide pulley 7 by means of a unwinding guide arm 5 on which is mounted a lead-in pulley 6. On one end 5a of the guide arm 5 there is mounted a pivot pin 50, which is slidably fitted into a guide groove Zn on the back, near the top and parallel to the upper edge of the panel 2. The guide arm 5 extends upwards and outwards with respect to the panel 2 (as seen from the front, obliquely upwards to the left), and the above-mentioned pulley 6 is mounted at the outer end 5b of the guide arm 5. The guide arm 5 is free to move laterally in either direction, since the pivot pin 50 is slidably fitted in the panel guide groove 2a, and also the pivot pin 5c permits adjustment of the angle at which the guide arm 5 projects from the panel 2; the range of this adjustment is such that the height of the arm end 512, and hence the pulley 6, above the base 1 can be varied by any amount up to about 100 cm. Yarn from the cone 4 on the stand 3 is unwoumd,- led upwards, passed over the pulley 6, and thence led downwards and onto the guide pulley 7; in this manner, unwinding resistance of yarn fed to the guide pulley 7 is generated at the pulley 6. It is preferable to set the height of the pulley 6 to within about 20 cm above the imaginary apex of the yarn cone; by setting the pulley 6 to various'heights it is also possible to determine the optimum height for positioning an unwinding guide in an actual knitting machine. The shape of the cone changes knitting qualities, of course, for the same yarn, and if it is desired to disregard unwinding resistance and assess knitting qualities from other yarn characteristics only, this can be achieved by interposing a yarn tensioner feed device or magneto tensor between the cone 4 and pulley 6.

There are six guide pulleys mounted on the front of the panel 2 and all are level with one another along a line that is in the upper portion and parallel to the top of the panel 2. From left to right (that is in the direction of yarn travel) the pulleys are the above-mentioned first guide pulley 7, a second guide pulley 8, a third guide pulley 9, a fourth guide pulley 10, a fifth guide pulley l1, and a sixth guide pulley 12. The

pulleys

8 and 9 are movable pulleys; which, respectively, are attached to

brackets

8d and 9d, which are dependent from

vertical support shafts

8a and 9a; the

support shafts

8a and 9a are themselves supported by

bearings

8b and 9b connected to the panel 2; the

shafts

8a and 9a are provided with cam plates 8c and which, by engagement with cam portions formed in the

bearings

8b and 9b, permit the

pulleys

8 and 9 to be turned through For either pulley 8 or pulley 9, if a yarn is first passed over the pulley and then the pulley is turned once, clockwise as seen from above, the yarn crosses itself, and thus turning the pulley produces the crossover friction of a yarn, that is the friction generated between one length and another of the same yarn.

Since all the

pulleys

6, 7, 8, 9, 10, 11 and 12 are part of an equipment for testing yarn qualities, it is obviously desirable that they react accurately to yarn tensions, etc., and be uninfluenced by external factors, and to this end, in the present embodiment, all the pulleys are provided with hearings to keep rotational friction to a minimum. Of course, if resistance increases uniformly in all pulleys, calculations are not affected, and it is also possible to use open type bearings. However, from the point of view of pulley service, economy and similar considerations, sealed grease bearings are preferable. Also, if it is more convenient, the

pulleys

6 and 7 can be simple guide pulleys, since very little tension is imposed on yarn between these points, and the pulleys may even be non-rotating.

Fixed to the front of the panel 2, on a level with one another and on a line that is below and parallel to the line of the above-mentioned guide pulleys, there are three needle holders, 13, l5 and 17. The positions of the holders l3, l5 and 17 lie, respectively, between the first guide pulley 7 and second guide pulley 8, between the second guide pulley 8 and third guide pulley 9, and between the third guide pulley 9 and fourth guide pulley 10. Each holder comprises a fixed plate (130, 15a, 17a), and a movable plate (13b, 15b, 17b) attached thereto, between which a needle is held, the needles held by the

holders

13, 15 and 17 being respectively a first needle 14, a second needle 16, and a third needle 18. The

needles

14, 16 and 18 therefore lie on a line that is below and parallel to the line on which lie the

pulleys

7, 8, 9, 10, 11 and 12. Yarn unwound from the cone 4 is passed over the lead-in pulley 6, passed onto the first guide pulley 7, threaded through the first needle 14, passed over the movable second guide pulley 8, threaded through the second needle 16, passed over the movable third guide pulley 9, threaded through the third needle 18, and passed on to the fourth guide pulley 11; the subsequent path of the yarn will be described later. There is resistance generated at various points on the path of the yarn thus passed over pulleys and threaded on needles. These resistances are: unwinding resistance at the lead-in pulley 6, frictional resistance between the yarn and the first, second and

third needles

14, 16, and 18, and yarn bending resistance at the points where it bends at the first, second and third, needles 14, 16 and 18, and also, if the

moveable pulleys

8 and 9 are turned as described above, there is cross-over frictional resistance adjacent to the guide pulleys 8 and 9. Since these various resistance are imposed successively on one and the same yarn, their effects are accumulative, and add together to present a single take up resistance at the th guide pulley ll. Tension in the yarn as it passes through the 1st needle 14 is comparatively small, and variations in tension are liable to cause the yarn to jump the hook, and it is therefore preferable to provide the first needle 14 with a further clip or blocking portion 19 which is applied after the needle latch is closed.

There is formed in the front surface of the panel 2 a narrow, vertical guide groove 27. The guide groove 27 lies on a line at a position between imaginary vertical lines passing through the fifth and sixth guide pulleys l1 and 12, and the top thereof is located at a point that is below the line on which the

pulleys

7, 8, 9,10, l 1 and 12 lie, and it extends to a point approximately level with the

needle holders

13, and 17. At the top of the guide groove 27 there is fixed a support arm 28a which extends perpendicularly from the front surface of the panel 2. The arm 28a supports a narrow, vertical guide rail 28 that is opposite and parallel to the guide groove 27. One end, 21a, see FIG. 4, of a guide rod 21 is slidably inserted in the guide groove 27, and the other end, 21b, is slidably inserted in the guide rail 28. The guide rod 21 can either be straight or it can have the shape of a square-bottomed U. In the latter case, an attachment portion 24 is fixed to, or forms a downward extension from, the rod 21 near its end 21b (that is the outer end with respect to the panel 2). The attachment portion 24 curves inwards (i.e., towards the panel 2) and its end 24a lies beneath the center of the middle portion 210 of the rod 21. To the attachement portion end 24a there is attached a downwardly looped, flexible chain 23, the other end of which is attached to a fixable support rod 32 (described later). The central portion 210 of the guide rod 21 passes through the bottom por tion of a stepped bracket-shaped attachment portion 26, which is for attachment of weights 25 of varying values. Fixed to the upper portion of the step-shaped attachment portion 26 there is a floating pulley 20, which is positioned with its hypothetical turning axis parallel to the middle portion 210 of the guide rod 21. The configuration of these various elements is such that the center of the floating pulley 20, the center of the guide rod middle portion 21c, the weight 25, and'the attachment portion 24 end 24a all lie on the same-vertical line. Alternatively, if the rod 21 is straight, it can be passed through the floating pulley 20, along the axis thereof, and the

attachment portions

24 and 26 formed integrally therewith.

Positioned on the opposite side of the panel 2 to the first guide, pulley 7 and at a pointbelow the level of the

needle holders

13, 15 and 17, there is a traverse rod 29, and positioned vertically below the traverse rod 29 there is a take up reel 30, which possesses a cut-off notch 30a, for cutting off yarn when the reel 31 is fully wound. The traverse rod 29 and take-up reel 30 are both driven by a motor 31 that is located within the panel 2. The speed of the motor 31 can be adjusted to any desired value, for example, by a slide contact device for control by changing impressed voltage, and the motor 31 can be caused to run constantly at the speed selected. In other words, rotational speed of the takeup reel 30 can be controlled by the motor 31, and the speed of the reel 30 can be determined by means of a stroboscope, and any adjustments made when required.

As described earlier, yarn is unwound from the cone 4, passed over the lead-in pulley 6, and then led, via the

needles

14,16 and 18, and pulleys 7, 8, 9 and 10, to the fifth guide pulley 11. From the guide pulley 11 the yarn is led down, passed round and under the floating pulley 20, led up to and passed over the sixth guide pulley12, led down and across to, and passed around the traverse rod.29, and thence led down and-attached to the takeup reel 30. The floating pulley 20 is free to ride up or down since the ends-2la and 21b of the guide rod can slide within the guide groove 27 and guide rail 28, and therefore the downward force applied to the floating pulley 20 must be such as to balance the take-up resistance composed of the accumulated resistances from pulley 6 through pulley -11. Put another way, if the downward force applied to the floating pulley 20 is greater than the force of the accumulative take-up resistance the floating pulley 20 will sink, and if it is less, the floating pulley 20 will rise. It is, of course, possible to set upper and lower limits to such up and down movement of the floating pulley 20 by means of stops suitably located in the guide groove 27 and rail 28.

The tested yarn is traversed very slowly from the 6th guide pulley 12 and wound on the take-up reel 30. The speed of travel of theyarn depends, of course, on the peripheral speed of the reel 30, which in turn depends on the rotational speed of 'the reel 30. In this embodiment, fouryarn speeds are employed, the four speeds being 10, 25, 50, and l0Om/min., it being also possible to-obtain other speeds if required. The speed normally employed is that of 25m/min, which approximates the speed of needle operation in practical knitting machines; the other speeds are selected for severe comparative testing of materials. For a given rotational speed of the reel 30, the peripheral speed, and hence the yarn speed, increases with the amount of yarn wound on the reel 30, and therefore the yarn is cut by the cut-off notch3la whenthe yarn wound thereon has reached a set amount. Alternatively, the speed at which yarn is led away from the testing equipment can be kept constant by taking the yarn out through a pair of rollers and taking it up at some further stage.

The above-mentioned fixable support rod 32, to which one end of the chain 23 is attached, is slidably fitted in a vertical guide slot 33 which is formed in the front of the panel 2 parallel to the guide groove 27. The fixable support rod 32 passes through the slot 33 and has attached to its other end inside the panel 2 a windup chain or similar means by which the location of the rod 32 in the slot 33 can be arbitrarily fixed. Such fixing means can be, for example, a chain 36 which is at tached at one end to the inside end of the support rod 32 and at the other end to a winch which is controlled by a wheel 34 at the front of the base 1; turning the wheel 34 in one direction winds in the chain 36 and raises the support rod 32, and turning the wheel 34 in the opposite direction unwinds the chain 36 and allows the support rod 32 to be lowered. The chain 23 is attached to and hangs freely between the floating pulley attachment portion 24 and the support rod 32, and the amount of weight the chain 23 imposes on either the attachment 24 (and hence on the floating pulley 20) or the support rod 32 depends on the length of chain between the lowest point of the chain 23 and the attachment portion end 24a or the outer end of the support rod 32. These lengths can be varied as required by varying the height of the support rod 32 in the guide slot 33 by the means described above; in other words, the weight imposed by the chain 23 on the support rod 32 or, acting through the connection portion 24, on the floating pulley 20 can be varied as required. The weight of the chain 23 can be even over its length, or if more convenient, its weight can be steadily increased over its length; in either case the principles described above are still applicable.

Beside the guide slot 35 there is a scale 33, which, for any position of the support rod 32, gives a reading of the total weight, including that of the pulley 20 itself, imposed downwards on the floating pulley 20. This weight acting downwards on the floating pulley 20 varies with the height of the support rod 32 and is countered by the force of the accumulative take-up resistance at the 5th guide pulley 11, and the position of the floating pulley 20 (which can move up and down with its guide rod 21 guided in the groove 27 and rail 28) depends on the difference between these upwardly and downwardly acting forces. In other words, by observing to what point (i.e., to what scale 35 reading) the support rod 32 must be moved to produce a downwardly acting weight to bring the floating pulley guide rod 21 to a set lower limit or stop, it is possible to determine the take-up tension of a yarn being tested.

The equipment described above can, of course, be provided with various accessories, such as an attached or mounted plumb-line and adjustable feet on the base 1, to ensure that the panel 2 is vertical, or upper or lower display lamps that are actuated when the floating pulley 20 reaches set upper or lower limits, or a warning buzzer for when the floating pulley 2O exceeds set limits; also, for special testing it is possible to pass yarn through or past a tensioner prior to feed in to the equipment, or in cases where not enough tension to be detected is generated, a gauged tensioner can be interposed between the lead-in pulley 6 and 1st guide pulley 7; contrariwise, interchanging tensioners interposed between the pulley 6 and pulley 7 provides a comparision check of tensioners as well as of testing yarn quality. If a yarn being tested breaks, the motor should be stopped to stop the yarn travel. Similarly, interchanging needles used for the same yarn gives a comparison check of needles as well as testing the yarn.

A cheese or cone of a yarn to be tested is placed on the stand 3, led up to the pulley 6 on the unwinding guide arm 5, where unwinding resistance is produced, threaded onto the guide pulleys and through the needles to produce friction, bending and needle resistance, and, where the moveable pulleys are turned around, cross-over resistance, passed under the floating pulley on which is imposed a downwardly acting force to balance the accumulative resistance force, and wound up by the take-up reel. Even if the speed of the take-up reel is constant, the position of the floating pulley does not stay fixed, but varies due to the influence of changing resistances, particularly unwinding resistance. This variation of the position of the floating pulley is illustrated in FIG. 5(a), although there is variation it is generally evenly distributed above and below a set point, which is the position at which the force of the accumulated resistance and the weight of the suspended chain balance; this is because, with the support rod 32 fixed in any particular position the end of the chain 23 attached to the rod 32 is also fixed, while the other end attached to the attachment portion 24a is free to move as the floating pulley 20 moves up or down, and if the accumulative resistance force increases and raises the floating pulley 20, the attachment portion 24 end of the chain 23 is also raised and the lendth of the chain 23 on the floating pulley 20 side, and hence the weight imposed by the chain 23 on the floating pulley 20, is automatically increased, and similarly, there is an automatic decrease in the weight imposed by the chain 23 on the pulley 20 when the accumulative resistance force decreases and allows the floating pulley 20 to move down.

For any particular yarn, therefore the floating pulley 20 has a point that represents a point of stability, and so one method of determining the total take-up tension of a yarn is to adjust the position of the support rod 32 so that the point of stability of the pulley 20 is stably settled at an intermediate point of the groove 27 and the rail 28, and then take a reading of the position of the support rod 32 from the scale 35 indicating the weight imposed on the pulley 20, that is the force of the accumulative take-up tension. When this reading is taken it can be compared with set values, for assessing the yarn as good, medium or poor. Therefore, a method of assessing yarn quality is to observe the up and down movement of the pulley 20 and note the approximate center point of this up and down movement; adjust the position of the support rod 32 until the center point of the up and down movement of the pulley 20 is settled at a certain predetermined position; and then take a reading of the position of the support rod 32 from the scale 35. In this method the scale is calibrated with weights imposed on the pulley 20 at every position of the support rod 32 while the pulley 20 is settled at a certain predetermined position. Another method of determining the total accumulative take-up tension of a yarn is to note at what sale 35 reading the support rod 32 must be placed for the support arm 21 of the floating pulley to settle at a bottom stop. It should be noted here that the amount the pulley 20 moves up and down varies in a cycle, and the bottom stop selected should be level with the highest one of the bottom points of the downward movement; the movement of the pulley 20 is indicated by the heavy line in FIG 5(b). In this method the scale is calibrated with weights imposed on the pulley 20 at every position of the support rod 32 while the pulley 20 is settled at the bottom stop. It was found experimentally that if the amplitude of the up and down movement of the pulley 20 is less than 5 cm, that the same assessment of yarn quality is obtained if a weight 25 is used alone, without using the chain 23; the quality of the yarn being tested can be assessed by using a set weight W, as shown in FIG. 6.

Thus, a yarn is unwound and passed through portions where friction and bending are caused, and then brought to point where the various resistances act accumulatively, and by determining the weightimposed on a chain, and comparing the value to standard values it is possible to'determine the total take-up resistance of the yarn. The resistance thus measured is a sum total of friction between parts of the yarn, friction between the yarn and needles, and bending resistance, and therefore represents a value that gives a direct assessment of the qualities of the yarn foruse in a practical knitting machine.

Amethod for suchcomparison is to'previously determine classes of yarn quality, such as good, medium, and poor, based on factors such as excellent articleratio, occurrence of breaks or flaws, etc., as encountered in actual industrial operations; then determine a standard value for making an assessment of yarn quality asmentioned hereinafter, by means of measuring yarnsas to which results in practical knitting are already known, by the device of the present invention, without using the chain 23, but by only setting the pulley 20. It is necessary to find out the amount of weight 25 to satisfy the conditions that the pulley is settled onthe bottom stop by observing a good quality yarn, is moving up and down between the upper and bottom stops by observing a medium quality yarn, and rises to settle under the upper stop by observing a poor quality yarn. Accordingly, this makes it possible to obtain an assessment of yarn quality by means of comparing the standard value with the amount of tension measured withrespect to yarns of various kinds. It is of course necessary to previously determine a number of different standards to correspond to different knitting conditions and different types of yarn. v

With the device of the invention when observing without using the chain 23 but only the setting pulley 20, it is not only possible to classify yarn tested into the three qualities good, medium, or poor, but also possible to make finer assessments, since the floating pulley 20 risig from the bottom stop sometimes indicates that yarn quality is getting somewhat worse than a good quality yarn, and the floating pulley 20 moving down from the upper stop sometimes indicates that yarn quality is getting somewhat better than a poor quality yarn.

With the present device it is also possible, by crossing yarn over itself after it has passed throughthe needles, to produce cross-over resistance adjacent to the needles. This increases contact of the yarn with the needles, and therefore increased tension is produced closer to the movable pulleys, and this extra tension caused by the needles is effective for detecting, for example, yarn unevenness.

Also, in cases where there are problems of too much tension being generated, it is possible to eliminate crossover resistance by simply not turning the moveable pulleys; in this case the accumulated resistance consists of abrasion between yarn and needles, bending moment, and unwinding resistance, and is still applicable to industrial practice.

The invention therefore provides a device for determining yarn quality on the basis of bending moment and various friction or other resistances, and the invention eliminates the necessity for making'separate tests, but makes it possible to obtainan assessment that is the equivalent of many tests in a simple rapidprocess.

An explanation of a second embodiment of the invention .is'given below with reference to FIG. .6.

In the-equipment of the-secondembodiment pulleys '7, 8, 9 and '10, are mounted evenlyspaced on the front of the upper portion-of a vertical panel section P and ina straight line that is belowand parallel to the line of the

pulleys

7, 8, 9 and '10, there are mounted three needle holders I13, '15 and 17, which are of conventional design .to permiteasy interchanging of needles 14, '16 and 18 of various gages; the needle holder 13 lies between

pulleys

7 and 8, the holder 15 lies between

pulleys

8 and 9, and the holder 17 lies between pulleys 9 and '10. Nextto and aligned with the panel section P thereis a small vertical panel section O which is'the same height as the panel section P but narrower, being about one quarter of the width of the latter width. Near thetop of-the panel section Q are mounted two pulleys 11 and -12 on a line that is parallel to the top of the panel section Q (and also of panel P) Below and between the pulleys 11, l2-there is provided a'floating pulley 20. Nextto the panel section 0 by the side further away from the panel section-P, there is placed a take-up unit 30 which is for winding 'in yarn at a constant speed. Adjacenttothe lead+in side of the panel section P, that-is the pulley 7 side and opposite to the panel section Q side, there is provided a stand 3, and above the stand 3 and on approximately the same level as the

pulleys

7,8,9 and 10 there is provided a pulley '6 which-is designed for'minimum rotational friction, usingany conventional means such as bearings,'Snell wire, etc., and which is a guide for controlling the unwinding of yarn. Between the pulley 6 and the pulley 7 there is provided a yarn tensioner 41 for use when required.

A cone or cheese 4 of a yarn A to be tested is placed on the stand 3 and the yarn A is unwound,,led upwards, passed over the pulley'6, through the tensioner 41, over pulley 7, through needle 14, over pulley 8, through needle 16, over pulley 9, through needle 18, over pulley 10, over pulley ll, underthe floating pulley 20, over pulley l2, andthen led down and attached to the takevup unit 30.

In the section P the

pulleys

8 and 9 can be optionally turned, so as to generate yarn cross-over friction. The path of the yarn A through the various parts of the section P is subject to various resistances and forces, which include frictional resistance, bending, needle to yarn resistance, and, if the yarn A is crossed on itself,

cross-over resistance; these resistances are additive and when the yarn A comes to the section Q are combined to represent a single tensile force. The purpose of the section Q is to determine the value of this single tensile force, and this is achieved by hanging a weight W of a standard value on the floating pulley 20, and

.then observing to what position the floating pulley 20 ,moves. To assist thisobservation there are provided two stops, or stop marks,42 and 43, on the front of the section 0 and on the path of the .up and down move- .ment of the floating pulley 20. The stop 42 is a lower stop mark, the stop 43 is an upper stop mark. If the force of the yarn tension is greater than half the sum of the weight of the pulley '20 and of the standard weight W, the floating pulley 20 rises to the upper stop 43; if

the tensile force is smaller than the above-mentioned value, the pulley 20 moves down to the lower stop 42; and if the tensile force and the downward force of the combined weight of the pulley 20 and weight W are approximately equal, the pulley 20 moves between the upper and

lower stops

43 and 42. The value of the weight W is determined in reference to standard yarns; that is, yarns of a previously determined quality are run through the sections P and Q and it is then observed what weight W brings the pulley 20 to what positions, in order to determine standard reference stop positions and values of the weight W. Thereafter, to assess quality of a yarn on the basis of bending, needle to yarn, and cross-over frictional resistance, it is merely necessary to observe to what position the floating pulley 20 moves with a weight W attached, and the yarn can be immediately classed as poor, medium, or good.

An alternative method of passing a yarn through the section P is, as illustrated in FIG. 7, not to turn the

pulleys

8 and 9 but to cross the yarn over itself at the points where it is passed through the needles, this method (shown in FIG. 70) being useful for detection of yarn unevenness; or in cases where there is a problem of too much resistance, the yarn can be passed through the section P without being crossed over itself at any point (as shown in FIG. 7b). In the section Q the tensile force can of course be mesured directly by means of a spring balance W instead of the weight W, as illustrated in FIG. 8. In this case, the resistance accumulated on the yarn which acts as taking-up tension of the yarn is measured directly by the spring balance W.

Classification of yarns, etc., by the equipment of the present invention and by the actual knitting processes correspond exactly, as is shown in the Comparison Table l. The materials tested were 100 percent cotton yarn, cotton and acryl blends of different count, numbers, and mercerised yarn; also test materials which had the same count number but which had had different treatment (mercerising, softening), were used. The items marked A are unmercerised thread, and the items marked AA are the same items subsequently waxed.

Two methods of assessing the quality of a material are, as described earlier, to use a weight only and not the chain 23, in which case a yarn can be classed as good, medium or poor, or to use the chain 23 attached to the floating pulley in which case yarn quality can be assessed over a continuous range as well as into the same three classes, good, medium, and poor.

In the second method, since assessment is continuous, it is possible to assess quality by a quantified scale.

The yarn take-up speed in both methods was 50 m/min., and the results obtained are shown in Table l where they are compared with results obtained by actual knitting machine operation. It is seen that there is an extremely close match between the sets of results. Thus classification of yarn and similar materials is the same as that obtained in actual industrial processes, but

the invention produces this same classification without the necessity of carrying out a series of separate tests, but in one simple, quickly completed operation which does not require skilled workmen. The invention thus speeds and simplifies yarn classification and is therefore of great advantage in industry.

Although the present invention has been fully de-.

scribed with reference to the accompanying drawings in connection with the preferred embodiments thereof,

various changes and modifications will be apparent to those skilled in the art. Therefore, the present invention is not to be limited thereby and such changes and modifications should be construed as included within the scope of the present invention unless otherwise they depart therefrom.

TABLEI w Cross-over Abrasion Friction Between Yarn yp Force and Knitting Needle Bending 0f Unwinding Between Moment No. mp Resist- Yarn and Friction Gauge of X 10- Yarns ance (g.) Ymlgi Force (g.) Knitting Needles (gem) 1A Cotton 0.38 11.7 31.5 18 1.31 2AA & Mercerized 0.35 9.5 24.0 18 1.31 3 Yarn 30/2 0.30 9.2 22.8 18 1.30 4 0.38 9.7 20.9 18 1.74 5 0.47 *18.1 *49.3 18 *4.19 6 0.44 *15.2 *42.5 18 *2.20 7 *0.98 11.2 *41.5 18 *2.27 g

8A 100% Cotton & 0.32 10.7 26.5 18 0.97 9AA Mercerized 0.30 8.9 22.8 18 0.97 10 Yarn 40/2 0.35 9.1 18.4 18 1.20 11 0.25 9.7 22.7 18 1.14 12 0.40 11.7 *27.1 18 *l.80

13A 100% Cotton 0.25 10.2 25.8 26 0.78 14 & Mercerized 0.28 8.7 19.6 26 0.83 15 Yarn 56/2 0.25 10.0 *24.8 26 0.85 16 0.24 7.7 20.8 26 0.89

17A Blended Yarn 0.30 11.7 23.4 18 1.16 18 of Cotton & 0.33 9.7 20.3 18 1.13 Acrylic 32/2 0.44 14.5 *29.7 18 1.19

20 Blended Yarn 0.31 9.0 16.5 18 0.97 21 of Cotton 8L 0.26 8.3 17.9 18 0.93 22 Acrylic 32/42 0.39 10.2 *26.4 18 0.94

TABLE 1Continued Tensile Tensile Initial Yarn Valuation Valuation No strength elongation youngs unevenness according by the (g) modulus to actual invention (g/ knitting 1A 827 6.4 40.6 8.5 Acceptable Acceptable 2AA 827 6.4 40.6 Excellent Excellent 3 833 4.8 63.0 8.6 Excellent Excellent 4 902 4.6 67.2 8.4 Acceptable Acceptable 5 l 141 6.2 61.0 8.2 Not acceptable *Not acceptable 6 1043 4.0 87.l 8.6 Not acceptable *Not acceptable 7 977 5.1 63.6 9.0 Not acceptable *Not acceptable 8A 589 6.3 39.9 8.6 Acceptable Acceptable 9AA 589 6.3 39.9 Excellent Excellent 10' 604 4.4 64.4 9.] Excellent Excellent 1 1 773 5.5 64.4 8.5 Acceptable Acceptable 12 586 5.7 45.9 9.5 Not acceptable *Not acceptable 13A 399 5.3 45.6 10.9 Acceptable Acceptable 14 424 4.0 67.9 1 1.5 Acceptable Acceptable 15 548 4.6 70.2 10.8 Not acceptable *Not acceptable 16 444 4.0 66.0 10.6 Excellent Excellent 17A 432 8.8 23.7 9.6 Acceptable Acceptable 18 423 5.7 31.2 9.2 Acceptable Excellent 19 414 5.7 30.1 9.1 Not acceptable *Not acceptable 20 428 6.1 32.4 8.5 Excellent Excellent 21 404 5.7 31.8 9.2 Excellent Excellent 22 399 4.9 36.5 9.1 Not acceptable Not acceptable TABLE 2 mulated resistance on the yarn is detected by detecting the position of the free end of a chain when the other Yarn Gauge number d end of the chain is suspended from the yarn which has number of knitting Loa ttl d in a fix d osition K' d of am count needle Se 6 e p m y 4. A method according to claim 1, wherein the accu- 1 3 & 30/2 18 mulated resistance on the yarn is detected by detecting m the position of a floating pulley around which the yarn do. 40/2 18 60 is run and to which. is connected one end of a chain the 56/2 26 4O other end of which 18 kept ata fixed position.

5. An apparatus for assessing. the knitting quality of Blended Yam 9 yarn comprising a means for leading yarn from a cheese 32/2 80 or cone or similar device in an unwinding direction, Cotton & Acyrlic means for winding in said yarn at a constant speed, a 32/42 18 60 40 means between said leading means and said winding What is claimed is:

l. A method for assessing the knitting quality of yarn and similar materials comprising placing a cone or similar mass of yarn the quality of which is to be assessed in a fixed position, passing said yarn in an unwinding direction from said cone and successively through a means for imposing resistances on said yarn including yarn to yarn frictional resistance, yarn to needle frictional resistance, and bending resistance, and then winding said yarn up at a constant speed by a take up means for unwinding the yarn from the cone for imposing an unwinding resistance thereon and imposing yarn to yarn frictional resistance, yarn to needle frictional resistance and bending resistance on said yarn, and detecting at a point between the last of said resistance means and take up means the yarn tensile force representing the accumulative value of said resistance imposed on said yarn, and comparing the detected value with previously detemiined standard values.

2. A method according to claim 1, wherein the accumulated resistances on the yarn is detected by placing a weight on said yarn and comparing the movement of said weight between predetermined limits due to yarn tensile force with the similar movement of said weight for a good quality yarn.

3. A method according to claim 1, wherein the accumeans for generating resistances to be imposed on said yarn including yarn to yarn frictional-resistance, needle to yarn frictional resistance and bending resistance in a yarn passed therethrough, a detecting means between said resistance generating means and said winding means for detecting a yarn tensile force representing the accumulative value of said resistances including unwinding resistance imposed on said yarn, and a means operatively associated with said detecting means for measuring said accumulative tensile force detected by said detecting means in comparison with a previously determined standard value.

6. An apparatus according to claim 5, wherein said detecting meanscomprises a floating pulley which is suspended on said yarn on which said accumulative tensile acts upwards, and said measuring means comprises a weight attached to said floating pulley so as to urge it downwardly and vertically spaced limit'means' between which said weight moves.

7. An apparatus according to claim 5, wherein said detecting means comprises a floating pulley which is suspended on the yarn to detect said accumulative tensile force.

8. An apparatus according to claim 5, wherein said. detecting means comprises a floating pulley which is; suspended on said yarn on which said accumulative tensile force acts upwards, and said measuring means 9. An apparatus according to claim 5, wherein said generating means includes at least one pulley for guiding the yarn and at least one needle held by a holder through which the yarn is passed, both said pulley and needle being respectively fixed at certain positions.

Claims

1. A method for assessing the knitting quality of yarn and similar materials comprising placing a cone or similar mass of yarn the quality of which is to be assessed in a fixed position, passing said yarn in an unwinding direction from said cone and successively through a means for imposing resistances on said yarn including yarn to yarn frictional resistance, yarn to needle frictional resistance, and bending resistance, and then winding said yarn up at a constant speed by a take up means for unwinding the yarn from the cone for imposing an unwinding resistance thereon and imposing yarn to yarn frictional resistance, yarn to needle frictional resistance and bending resistance on said yarn, and detecting at a point between the last of said resistance means and take up means the yarn tensile force representing the accumulative value of said resistance imposed on said yarn, and comparing the detected value with previously determined standard values.

3. A method according to claim 1, wherein the accumulated resistance on the yarn is detected by detecting the position of the free end of a chain when the other end of the chain is suspended from the yarn which has settled in a fixed position.

4. A method according to claim 1, wherein the accumulated resistance on the yarn is detected by detecting the position of a floating pulley around which the yarn is run and to which is connected one end of a chain the other end of which is kept at a fixed position.

5. An apparatus for assessing the knitting quality of yarn comprising a means for leading yarn from a cheese or cone or similar device in an unwinding direction, means for winding in said yarn at a constant speed, a means between said leading means and said winding means for generating resistances to be imposed on said yarn including yarn to yarn frictional resistance, needle to yarn frictional resistance and bending resistance in a yarn passed therethrough, a detecting means between said resistance generating means and said winding means for detecting a yarn tensile force representing the accumulative value of said resistances including unwinding resistance imposed on said yarn, and a means operatively associated with said detecting means for measuring said accumulative tensile force detected by said detecting means in comparison with a previously determined standard value.

6. An apparatus according to claim 5, wherein said detecting means comprises a floating pulley which is suspended on said yarn on which said accumulative tensile acts upwards, and said measuring means comprises a weight attached to said floating pulley so as to urge it downwardly and vertically spaced limit means between which said weight moves.

8. An apparatus according to claim 5, wherein said detecting means comprises a floating pulley which is suspended on said yarn on which said accumulative tensile force acts upwards, and said measuring means comprises a freely suspended chain, one end of which is attachEd to said pulley, and a means that can be moved and fixed and to which the other end of said chain is attached so as to vary the fraction of the weight of said chain imposed downwardly on said floating pulley.

9. An apparatus according to claim 5, wherein said generating means includes at least one pulley for guiding the yarn and at least one needle held by a holder through which the yarn is passed, both said pulley and needle being respectively fixed at certain positions.