CA1112524A - Slubbed open end spun yarn - Google Patents

Abstract

Abstract of the Disclosure A method of making slub or thick and thin yarns with twist variation on open end spinning machines by changing the speed of the yarn as it exits from the rotor of the open end spinning machine. The method produces a unique slub yarn which has a portion of high twist adjacent the slub in the yarn which has lower yarn twist.

Description

-~ This is a divisional of Canadian Application Serial No. 324,046 filed March 23rd, 1979.
This invention relates to open end spun yarn of staple fibre having thick and thin portions along the length thereof. Such yarn may be made with twist ~ " ' .
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variation on open end spinning machines by rapid-ly changing the speed of the yarn as it exits from the rotor, In that yarn size is dependent on yarn exit speed from the rotor, rapid change in exit speed produces abrupt changes in yarn size. Special ,varn guide movements may be utilized to change the length of yarn path between the rotor and the constant s?eed delivery rolls. Yarn is alternately stored and ~ ..
; 10 released by guide move~ents. When the yarn path is lengthened (i,e. excess yarn stored), velocity from the rotor must increase and a li~hter weight or finer yarn is made. While not essential, this motion is usually relatively slow and of a rela-tively long duration so that the velocity increase ~ is small; this results in a section of yarn only '~ slightly finer than the normal base yarn, and the ~ length of the fine section is relatively long, .
I~hen the yarn path is shortened (i.e. the excess yarn released from storage), the yarn velocity from the rotor is reduced and a heavier weight or courser yarn or slub is made, This motion is usually fast and OL a brief time period so that a large and abrupt reduction in yarn velocity from the rotor is achieved; this produces a slub or short section of ~larn much courser than nor-,' mal. There are various combinations o' velocity ' changes (above and ~clow normal velocity), and ; ti~es of the velocity changes which can be used : `~

. ., to produce thick and thin yarns of long or short sect~ons.
Open end or break spinning involves a number of well known steps. Staple fibers in the form ~ 5 of sliver are fed into a drafting zone which may - either be similar to the multiple pairs of nip rolls with fiber-control aprons as used very con-ventionally in ring spinning machines, or, more usually, consist of a high speed combing roll or . .
- 10 beater roll which has many protrustions of pins or wires similar to card clothing. ~he high tip speed of the combing roll protrusions accelerate the fibers through a partial peripheral path of the combing roll, tends to straighten and paraL-lelize them, separates them from surrounding . ,!
~ fibers, and drafts the relatively large, slow ~;
; moving ~undle of fibers in the sliver to a relatively fine stream of fibers moving at high velocity. With the aid of air flow, the fibers pass from the combing roll across a "break" to -~ the "open end" of the rapidly rotating end of a forming yarn, to which they attach themselves.
The classic open end spinning scheme involves a ~: .
simple means of rotating only the forming end of yarn; this is possible in that the growing or forming end of the yarn is open, i.e. there are ~ discrete spaces between the individual fibers -~ moving toward the end of yarn. Rotating only the tip end of the yarn requires relatively little power and can be done at very high speeds. In ~ractice, the twisting of tne end of yarn is achieved by collecting the fibers on the inside face of a high sp~ed rotor and forming the twist-ed yarn as it peels off toward the center of the S rotor. The yarn is then removed from the rotor axially through a doff tube by the nip action or a pair of delivery rolls through which the yarn passes as it goes on to a take-up package.
The velocity of removal of yarn from the rotor is selected so as to produce a yarn com-posed of the desired average number of fibers per cross section, (i.e. the desired yarn weight).
Normally, an effort is made to control carefully and uniformly botn the rate of input of fibers to the rotor as well as output velocity of yarn ; fromthe rotor; this is done to produce yarns with maximum uniformitv of size. This invention is for a system designed to purposely vary the out-put velocity of the yarn from the rotor so as to produce yarn with purposeful variations in uni-formity and twist. This may be a gradual and/or subtle variation of yarn size to yield a unique "nervous or flutter" look in the fabric made from the yarn,or it may have abrupt variations result-ing in thick and thin yarns which shows gross diameter differences when put into fabric.
The minimum length slub capable of being produced by this invention is essentially the length of the inside circumference of the rotor "
5~4 and is achieved by momentarily reducing yarn exit velocity from the rotor to zero. During this moment, the fibers continue to enter the rotor and build up in the rotor as an embryo varn sec-,, tion. Also, during this moment of zero yarn ve-locity, the section of yarn between the peel-off point (where the yarn joins the fibers in the . -:
rotor) and the doff tube is continually twisted by the rotation of the rotor. This results in . .
-; 10 the unique yarn construction where the neck or : . -section of yan~ immediately preceeding the slub ` has an unusually high number of turns or twists per unit length of yarn. This high twist neck may be weaker than either the normal yarn or the ; 15 slub and appears to be finer because it is more dense, although it is essentially the same weight : per unit length as the normal base yarn. During . . .
the moment of the zero yarn velocity, the twist buildup in the neck may contract the yarn slight-.:;
ly and cause it to pull away rom the peel-off point and may form a small amount of additional yarn even though the exit yarn velocity is essentially zero.
After the moment of zero velocity, the exit Z5 yarn speed rapidly accelerates back to normal - velocity. The accumulation of fibers is pulled through from the rotor as it continues to rotate and twist is inserted into the slub. The slub has ' ..
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5~ 25~4 a minimum 'heoretical length equivalent to the length of the rotor circumference.
In that the twist is inserted as the slub ~arn is produced at the ~eel-off point, it : 5 possesses good tensile strength. Slub yaxns made on ring spinning e~uipment often have lower twist per unit length resulting in abnormally low tensile strength in the slub as well as low density in the slub, both of which often causes 13 difficulty in weaving and knitting. It is im-portant in this invention that a moment of normal yarn velocity exist following the zero velocity slub forming so that the slub is removed at near normal speed to assure adequate twist in the slub.
Next, the yarn velocity may again be reduc-ed to zero to form another slub. Or, as is neces-sitated by the particular yarn storage device des-; cribed in this invention, the yarn velocity is increased above normal and a section of fine or light ~eight yarn is produced due to more rapid removal of yarn from the rotor. While the veloc-ity increase could be great, this is not usual in that a great reduction in yarn weight results in a great reduction in yarn tensile stre~gth which is normally undesirable. A slight increase in yarn velocity for a period of time greater than ~he zero velocity time, produces a slightly finer yarn whose length is greater than the slub ':

' : ` `, length. This fine yarn possesses fewer turns of twist ~er unit length; this may contribute some-what more to reduced tensile stren~th.
; ~hile the high velocity time period can be followed im~ediately b~y a low or zero velocit~y time, a time period of normal velocity will allow ; normal weight yarn to be produced following the fine yarn. This usually is a choice of esthetics rather than physical performance.
Thus, the invention in one aspects provides - an open end spun yarn of staple fibers having portions of incr2ased weight along the ; length thereof comprising: an elongated length of soun staple fibers having first spaced por-tions of higher weight than second portions of said open end spun yarn and third portions next adjacent to said first spaced portions and hav-lng a higher twist than said first and said second portior.s.
The various features and advantages of the invention will become readily apparent as the specification proceeds to describe preferred embodiments of the invention with reference to the accompanying drawings, in which:
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Figure 1 is a front elevation view of an open end spinning machine incorporating the novel slub producing device;
Figure 2 ls a side elevation view or the open end spinning machine shown in Figure 1, and Figure 3 is a schematic representative of the slub ;0 yarns produced on the open end spinning machine shown ~` in Figures 1 and 2.

Looking now to the drawings, the invention will be described in detail. Figures 1 and 2 -. represent several positions of an open end spinn-ing frame lC with each position being supplied roving or sliver 12 from a supply can (not shown3.
The roving 12 is delivered into the housing 14, which contains the conventional combing roll and rotor (not shown), to be acted upon by the rotor to produce the spun yarn 16. From the rotor in the housing 14, the yarn 16 exits through the doff tube 18 and passes over the pulley 19 on the lever arm 20 to the nip of rolls 21 and ~3 through the guide 24. From the nip or delivery rolls 20 and 24 the yarn passes through the conventional ends-down detector 26 to the take-up roll 28 driven by the surface drive roll 29.
As discussed previously, it is desired to oroduce slub or heavy weight yarn portions in the yarn being spun. Basically, this is accom-; 20 plished ~y alternately increasing and decreasing '.:
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the length of the yarn path from the doff tube lO
to the take-up roll 28. To accomplish this vari-.:~ ation in the length of the yarn, the levex member or arm 20 is pivotally mounted at each spindle ~osition to the brackets 30. Looking at Figure

2, it can be seen that the spun yarn 16 passing over the pulley 19 travels a shorter path when : the lever arm 20 is in the (solid line) down posi-'- tion rather than when the lever arm 20 is in the up (dotted line) position. The pivotal movement ,~ of the lever arm 20 is controlled by the pulley chain 32 connected to the pulley 34, which, along with the lever arm 20 are fixed to the shaft 36 rotably mounted on the brackets 30. The upper end of the chain 32 passes over an idler pulley 38 and is connected to the reciprocating rod 38 by means of a clamp 40, as hereinafter explained, the rod 38 is reciprocated by the double acting air piston 42. Air is supplied to and returned ~; 20 from the air c~ylinder 42 by conduits 44 and 46 through suita~le flow valves or regulators 48.
~ Air under pressure is supplied from conduit 50 : through a suitable pressure regulator 5 to the multi-way solenoid operated flow control device 54 which controls the flow of air in the conduits 44 and 46 to the air piston as well as through : exit conduits 58 and 60. The device 54 is electrically controlled from a random signal generator 56 powered by an external source of ,~ .

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,'"'`' : electricity. ~andom signal generator 56 can be of any suitable type such as a continuous ~ag-netic type player with random signals on the tape or a multiple shift register type. Flow valves l 5 or regulators 48 operate undirectionally so : - that flow of air to the air piston is un- :
modulated but can ~e modulated in the reverse : direction to the flow control device 54 to ex-` haust the supplied air through either conduit 53 or 60 depending on the selected position of the :: solenoids in flow control device 54.
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The sliver 12 of staple fibers such as acrylic, polyester, polyester-cotton, polyester-rayon, cotton or rayon is supplied from the sliver cans (not shown) over a suitable guide 58 . into the rotor (not shown) in the housing 14 of the open-end spinning machine 10. As discussed ::~ previously the spun yarn 16 rom the doff tube 18 ,~:: 20 is delivered to the feed rolls 21 and 23 over the ,.. :.
: pulley guide 19, from whence it is delivered to , ~. . .
~i the take-up roll 28. The feed rolls 21 and 23 ., ::
~,. are driven at a constant speed and, for the sake ~: of discussion, assume that the lever 20 is in the ''!.;.:'' 25 down position (solid line position is ~igure 2) and nor~al twist, normal weight open end spun yarn l: . 16 is being produced. Then, as the rod 38 (Figure ;~''''' 1) is pulled to the left by air cylinder 42, the , .. .:

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l~ver arm 20 is Pivoted upward towards the dot-ted line position by the pulley chain 32. Since the feed rolls 21 and 23 are driven at a con-stant speed and the rotor of the open end spin-ning machine rotates at a constant speed, the velocity of the yarn from the doff tube 18 will increase due to the longer yarn path as the lever 20 pivots uPwardly resulting in the production of a finer or lighter weight yarn, as indicated at 60 in Figure 3. Then at the appropriate time, a signal from the random sig~al generator is deliv-ered to the flow control device 54 and air is delivered suddenly into the left hand side of the air cylinder 42 through conduit 44 while air is exhausted through conduit 46 to cause the air cylinder 42 to rapidly move the rod 38 to the right. This ra~id movement of the rod 38 causes the lever 20 to pivot rapidly down to the solid line position to momentarily reduce the yarn exit velocity from the doff tube 18 to substantially zero. During the period of zero yarn exit ve-locity, fibers continue to accumulate in the rotor until pulled out by the action of the feed rolls 21 and 23. The y~rn 16 pulled out has a nec~ portion 6' of high twist, substantially normal weight, ~ust prior to the twisted slub ~ortion 64 of high weig'nt, ~Ihich has accumulated during the period of zero exit velocity~ Then the random signal generator 56 delivers another ~Z~ 4 signal to the flow control device to reverse the action of the air cylinder 42 and the cycle starts all over again.
It should be kept in mind that the timing of the signals from the random si~nal generators are not usually equally spaced so that the slubs 64 generated are not evenly spaced throughout the yarn 16 produced. Further, it is obvious that adjustments to the slub producing mechanism, such as length of lever 20 or position and/or location of pulley 19, can be made to vary the characteristics of the yarn ?roduced.
The following examples are characteristics of the capabilities of the above described apparatus:

EX~'IPLE 1 : Apparatus similar to that shown in Figures 1 and 2 was installed on a Platt model 885 open end spinning machine with a 51 mm I.D. (2.15 inch) ; 20 rotor producing 10.75's cotton count (c.c.) yarn from 64 grain/yd., 1 1/2 denier x 9/16 inch bright rayon staple fiber. The guide arm was 5 inches long and was intermittently raised and lowered ~: from a lo~er position essentially vertical so that the yarn guide was disengaged from the yarn, to a position slightly higher than the horizontal.
This increased the yarn path for about seven inches normal to about 19 inches for a yarn stor-age oi about 12 inches. The input air pressure .

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from the regulator to the air valves was 60 PSIG.
~ ~low valve settings were adjusted so that the - arm moved up slowly in about three seconds but down quickly in about 0.1 second or less. The arm paused in the down position ror about 0.5 - seconds and in the u~ position for random tlmes averaging about one second. A solid state ran-dom signal generator activated the system to 12-14 cycles per minute average. The rotor speed was 38,500 RPIl, the combing roll speed was 4,900 ~; RPM, the draft was 83, and the yarn twist averag-ed 13.1 TPI. The yarn produced has excellent . .
slubs about six inches long with a primar~ i~eignt of three to three and one-half times the average weight of the base yarn as measured on a modified Uster Uniformitv Analyzer. Slubs were randomly spaced along the length of the yarn, spacing varying for approxi.mately 135 to 335 inches a-part. The skein tensile strength of the slub yarn averaged about 150 pounds when measured on the Scott Tester as compared with about 200 pounds Cor the same yarn construction made smooth without slubs. The ends down rate dur-ing spinning was only slightly higher than the smooth yarn. ~he slub yarn was used to weave a drapery fabric.

EXA~LE 2 A rayon yarn similar to them of Example 1 was made on the same equipment but with the 5~4~

~ando~ Signal Generator adjusted to give about 24 cycles per minute. The up movement consumed above 1.5 seconds, the pause in the up position varied from 0 to about 1.0 second or less; and the pause at the bottom of the stroke was about 0.3 seconds;
the average time per total cycle was about ~.4 seconds.
The yarn ran good with ends-down rate accept-able although higher than normal smooth yarns.
The yarn was measured on the Uster and found - to contain primary slubs 3.1 to 3.8 times the weight of the yarn average, and with secondary slubs 3.9 to 4.8 times the weight of the yarn average. The primary slub is the average of the majority of the approximately six inches long torpedo shaped slub; the secondary slub is the ., small accumulation of excess fibers which often i occur along the primary slub causing a small but noticeable "nub" of larger size and higher weight.

EX~MPLE 3 A rayon yarn was made on the apparatus sim-ilar to that of Example 1 but with the arm inter-mittently raised to a position about 30 above - 25 the horizontal (to l'2 o'cloc~'l) and the signal timing and air pressure adjustments made to cause the arm to mo~e up in about 2.6 seconds, to pause up for zero to about 2.6 seconds, to come .
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down very abruptly and pause down for during a - period of about 0.4 seconds. This produced a yarn with slubs, randomly spaced having a weight about four times normal weight per unit length.
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the length of this yarn. It was evident that there is a high twist neck adjacent to each slub ; and each slub had a twist less than the twist of the high twist neck. This characteristic was true of all the yarns in the above examples.
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In the description of the invention, the ' terms normal twist, normal weight and normal ..
yarn diameter refers to open end yarn spun when the lever arm ~0 is in the solid position after the yarn velocity has stabilized or the lever arm 20 is in some other position and has remained in ; such position long enough for the yarn velocity to stabilize. These conditions are true since the speed of the feed rolls 21 and 23 and the speed of the rotor on the housing 14 are contin-- uous and constant. The slub yarn of Figure 3 is produced when the yarn path is being altered.
- The yarn of Figure 3 is the preferred configura-tion and includes a section of normal yarn 59 between the fine yarn 60 and the neck yarn 62 by sta~ilizing the position of the lever arm 20 for a pre-determined period of time. The critical relationship in the yarn is that the yarn :

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produced has a high twlst, normal welght portion . 62 next adjacent to a lower twist, higher weight slub portion 64. In the preferred form of the :
. invention the relative diameter of the yarn por-tions shall such that the diameter of portion `~ 59 is normal, the diameter of the portion 60 is .. smaller than normal, the diameter of the portion ,. 62 be smaller than normal and the diameter o~
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. yarn portion 64 be larger than normal.
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: 10 In the ?referred form of the invention shown ri~ :.
in ~igures 1~3, when the end i5 pieced-up after a ::. . break, or upon start-up, an operator has to place , ~`~.: the yarn 16 onto the ~ulley 19 but it is contem-t::: plated that th.e pulley could be replaced by a . 15 U-shaped hook guide which, in the down stride of ~' the arm 20 will ~ush the yarn outwardly off the hook until it slips over the edge thereof and fall into the bottom of 'he U-shape and then, from there on out will act in the sa~e manner as the :: 20 pulley 19. This hook guide eliminates the manual ;-:
: operation of placing t~e yarn into or onto the `:i. guide upon start-up.
: It can be seen that a novel apparatus has been described which will produce a novel slub . 25 open-end spun yarn with a minimum amount of modi-~: fication to the basic open-end spinning apparatus.
Although I have described specifically the . preferred embodiments of my invention, I contem-,~ plate that changes may be made without departing . .
' ' ~lZS24 -^- from the sco?e or spirit o' my invention, and I
- desire to be limited onlv by the scope or the .i; claims.
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Claims (4)

WHICH IS CLAIMED IS:

1. An open end spun yarn of staple fibers having portions of increased weight along the length thereof comprising: an elongated length of spun staple fibers having first spaced por-tions of higher weight than second portions of said open end spun yarn and third portions next adjacent to said first spaced portions and hav-ing a higher twist than said first and said second portions.

2. The open end spun yarn of Claim 1 where-in said first spaced portions have a twist lower than said second portion.

3. The open end spun yarn of Claim 1 where-in the diameter of the first portions is greater than the diameter of the second portions and the diameter of the second portions is greater than the diameter of the third portions.

4. The yarn of Claim 1 wherein said yarn includes fourth portions having a weight and a twist less than said second portion.