WO2008131252A1

WO2008131252A1 - Compact continuous over end take-off (oeto) creel with tension control

Info

Publication number: WO2008131252A1
Application number: PCT/US2008/060865
Authority: WO
Inventors: Thomas W. Manning; Ronald D. Bing-Wo
Original assignee: Invista Technologies S.A.R.L.
Priority date: 2007-04-20
Filing date: 2008-04-18
Publication date: 2008-10-30
Also published as: US20080283653A1; EP2139800A1; MX2009011342A; CN101678989A; JP2010526000A

Abstract

A compact continuous over end take-off creel system (100' ' ') with a tension control apparatus (110-3) permits unwinding of high tack elastomeric threads from multiple thread packages (105). Thread tension is monitored and controlled through a variable speed motor of a driven take-off roll (130) to maintain continuous operation of the creel system by avoiding breakage of elastomeric threads. Separate motors and thread tension sensors (117), optionally in combination with pretensioners (113A), may be used for groups of threads or for individual threads.

Description

COMPACT CONTINUOUS OVER END

TAKE-OFF (OETO) CREEL WITH

TENSION CONTROL

FIELD OF THE INVENTION

[0001 ] The present invention relates to yam or fiber unwinding devices, and more specifically to a method and apparatus designed to continuously deliver as-spun over-end-take-off yarn to downstream manufacturing equipment at targeted average tension levels and minimal tension variations of a plurality of elastomeric yarns or fibers being transported to the downstream manufacturing equipment. It should be noted that the terms "yarn," "thread" or "fiber" are used interchangeably throughout this document.

BACKGROUND OF THE INVENTION

[0002] The most common method of unwinding yarn, thread or fiber from a cylindrical mandrel (or "tube" or "package") in manufacturing processes is referred to as "rolling takeoff. When the package is exhausted the empty mandrel must be removed and a new package installed. This operation requires shutting down the manufacturing line causing unproductive downtime.

[0003] Another background art example of a method for unwinding yarns from package(s) held on a creel is the over-end-take-off (OETO) method. The OETO method allows for continuous operation of the unwinding process since the terminating end of the yam of an active package is attached to the leading end of the yam of a standby package. In the OETO method, after the active package is fully exhausted, the standby package becomes the active package. However, a drawback of the OETO method is that unacceptable yarn tension variations can occur during the unwinding process. [0004J In a background art example of a system and apparatus that implements the OETO method, elastomeric fibers are passed through the system before being fed to a manufacturing line. This background art OETO system has a rack structure that holds the creels of active packages and standby packages, a relaxation section and motor driven nip rolls. The relaxation section is located between an active package and the nip rolls of the OETO system. The relaxation section helps to suppress the unacceptable yarn tension variations discussed above by providing some slack in the yarn being unwound.

[0005] However, background art OETO systems that include such a relaxation section have problems with fibers or yarns that exhibit high levels of tack (i.e., yarns having particularly high cohesive forces). Moreover, yarns with high levels of tack also display unusually high variations in frictional forces and yarn tension levels as the active package is unwound from the creel.

[0006J In addition, the slack in the yarn provided by the relaxation section can vary, and excess yarn can be unwound from the active package. This excess yarn can be drawn into the nip rolls and wound upon itself leading to entanglement or breakage of the yarn. Use of yarns with high levels of tack further contributes to the possibility of the excess yarn adhering together and adhering to the nip rolls. The entanglement or breakage of yarns during the unwinding process requires the manufacturing line to be stopped_^ delays the unwinding process and increases the cost of manufacturing.

[0007] Background art OETO apparatus are typically configured such that the yarn horizontally traverses the relaxation section. In this configuration, the yarn travels through nip rolls with axes that are vertical. However, with such a vertical configuration for the axes of the nip rolls, the yarn located in the relaxation section between the active package and the nip rolls tends to sag. As a result, the yarn position on the nip rolls can become unstable, and interference and entanglement can occur between adjacent yams. Each of these problems would require the manufacturing line to be stopped. [0008] Furthermore, some manufacturing applications (e.g., diaper manufacturing) require the use of as-spun fiber that is substantially finish-free. Such finish-free yarns also exhibit the problems associated with high levels of tack discussed above.

[0009] The problems discussed above make applying OETO methods and apparatus particularly difficult when processing yarn with a high level of tack. Background art OETO apparatus have attempted to address these problems in the unwinding process by: (1) using yarns with anti-tack additives applied prior to winding; and/or (2) using rewound packages, where an active package is unwound and then rewound on a different creel to create a rewound package. Both of these approaches add additional expense to the manufacturing and unwinding processes.

[00010] As a result of the problems discussed above, OETO apparatus of the background art have been designed to take into account the difficulties due to the relaxation section, high levels of tack and breakage in yarns unwound with the OETO method. As an example, U.S. Pat. No. 6,676,054 (Heaney et al.), which is wholly owned by the assignee of the present application, discloses an OETO method and apparatus for unwinding elastomeric fiber packages with high levels of tack from a package. In particular, the OETO apparatus of Heaney et al. proposes that a minimum distance exists between a fiber guide and the fiber package. Heaney et al. states that minimum distances less than 0.41 meter can result in undesirably large tension variations. These variations can cause process control difficulties and can also lead to yarn breakages.

[00011] Further, Heaney et al. states that distances longer than 0.91 meter make the unwinding equipment less compact and ergonomically less favorable. As the level of tack exhibited by the fiber increases, the minimum allowable distance, d, increases. For yarns with tack levels greater than about 2 grams and less than about 7.5 grams, d is preferably at least about 0.41 meter; and for fibers with tack levels greater than about 7.5 grams, d is preferably at least about 0.71 meter. In view of such minimum distance requirements for high tack yarns, OETO apparatus typically require a frame with a large footprint that can take up significant floor space in a manufacturing environment. Additional examples of background art references are given by U.S. Patent Application Publication Nos. US 2005/0133653 (Heancy et al.) and US 2006/001 1771 (Manning, Jr. ct. al.), each of which is incorporated by reference herein.

[00012] Therefore, there continues to be a need in the art for an OETO apparatus for unwinding yarns with high levels of tack that avoids the problems of entanglement, breakage, larger equipment footprint and increased manufacturing costs as compared to the methods and apparatus of the background art. Processing high tack, elastomeric threads or fibers is particularly problematic when such as-spun thread or fiber is substantially finish-free, as is common for the elastomeric threads or fibers used to make diapers and other personal care products. Hence, there remains a need in the art for an OETO apparatus for unwinding yarns with or without anti-tack additives that can be implemented in a relatively small footprint. Therefore, a fast and reliable method of unwinding and feeding high tack elastomeric thread or fiber from a package to a manufacturing system is still needed in the art.

SUMMARY OF THE INVENTION

[00013] One embodiment of the invention is an OETO creel system, comprising: a support frame with a plurality of thread guides; at least one pivoting leg connected to the support frame; a plurality of package holders affixed to the at least one pivoting leg with each holder configured to hold one or more packages of thread, with each said package of thread located on a rotational axis configured to allow the thread to unwind through one of the plurality of thread guides; and a plurality of drive and tension control apparatus connected to the support frame, with each of said apparatus configured to unwind a thread from one of the plurality of packages of thread.

[00014J In the embodiment of the OETO creel system discussed above, each drive and tension control apparatus comprises: a pretensioner and associated guide roll configured to guide the unwinding thread through a thread path of the drive and tension control apparatus; at least one eyelet configured to prevent tangles of the thread; a horizontal driven take-off roll configured to move the thread through the drive and tension control apparatus; a variablc-spccd motor configured to drive the horizontal driven take-off roll and control thread tension; a thread tension sensor through which the unwinding thread passes; a tension controller device configured to at least one of increment, maintain and decrement a speed of the variable-speed motor in accordance with a feedback signal from the tension sensor; and at least one guide roll configured to output the thread from the tension control apparatus; wherein the pretcnsioner and guide roll are located before the horizontal driven take-off roll, and the tension sensor is located after the horizontal driven take-off roll, and wherein the speed of the variable- speed motor is varied to maintain thread tension values within a predetermined range of thread tension by the tension controller device.

[00015] Another embodiment of the invention is a drive and tension control apparatus for a thread unwinding system, comprising: a pretensioner and guide roll configured to guide the thread through a thread path of the drive and tension control apparatus; at least one eyelet configured to prevent tangles of the thread; a driven takeoff roll configured to move the thread through the drive and tension control apparatus; a variable-speed motor configured to drive the driven take-off roll and control thread tension; a tension sensor configured to determine the tension on the thread; a tension controller device configured to at least one of increment, maintain and decrement a speed of the variable-speed motor in accordance with a feedback signal from the tension sensor; and at least one guide roll configured to output the thread from the tension control apparatus, wherein the pretensioner and guide roll is located before the driven take-off roll and the tension sensor is located after the driven take-off roll.

[00016] Yet another embodiment of the invention is a method for controlling thread tension in an elastomeric thread unwinding system for unwinding a plurality of threads concurrently, comprising: unwinding each elastomeric thread from a thread packaging with an associated driven take-off roll for said thread, which roll is driven by a variable-speed motor; guiding each elastomeric thread with an individual pretensioner and associated guide roll into a tension and control apparatus; passing each elastomeric thread through an associated tension sensor; determining whether one or more threads are broken; determining whether one or more threads arc moving and measuring the tension of each of the moving threads; determining whether any of the moving threads have a tension that is out-of-range relative to predetermined tension values; at least one of incrementing and decrementing the speed of the respective driven take-off roll for a respective moving thread when the tension of said respective moving thread is out-of-range relative to the predetermined tension value for said moving thread, and at least one of the number of increments and decrements is below a first correction threshold; determining whether an average tension for the respective moving thread is out-of-rangc relative to the predetermined tension value for said moving thread; at least one of incrementing and decrementing the speed of the respective driven take-off roll when the average tension of said respective moving thread is out-of-range and at least one of the number of increments and decrements is below the second correction threshold; and setting an alarm when one or more of the threads are at least one of broken, not moving and out-of-range and above the first or second correction threshold.

[00017] In addition, in embodiments of the invention guide rolls may be located before and after the driven take-off roll, the tension sensor may be located after the driven take-off roll, wherein the speed of the variable-speed motor can be maintained or varied to maintain thread tension values within a predetermined range of thread tension by the tension controller device, and wherein a distance between the tension sensor and the horizontal driven takeoff roll may be fixed and minimized to avoid errors in the thread tension variations related to distance.

[00018J Further, in embodiments of the invention each drive and tension control apparatus further comprises an idler configured to dampen tension variations in the thread, wherein the idler is located adjacent to the horizontal driven take off roll. In addition, each drive and tension control apparatus further comprises a plate eyelet configured to pass the thread to the drive and tension control apparatus.

[00019] Moreover, in embodiments of the invention, each of the plurality of drive and tension control apparatus may be spaced apart vertically on the support frame in order to unwind each of the threads individually from a respective package of the plurality of packages. In addition, The OETO creel system the plurality of drive and tension control apparatus are configured in parallel on the support frame to unwind each of the threads individually from a respective package of the plurality of packages.

BRIEF DESCRIPTION OF THE DRAWINGS

[00020J Several embodiments of the invention will now be further described in the following more detailed description of the specification when read with reference to the accompanying drawings in which:

[00021] FIG. 1 is an exemplary perspective view showing an embodiment of the invention for continuous unwinding of yarns using OETO.

[00022] FIG. 2 is a top plan view of the embodiment shown in FIG. 1.

[00023] FIG. 3A is a perspective view showing an exemplary embodiment of the invention that includes tension control.

[00024] FIG. 3B is a perspective view showing another exemplary embodiment of the invention that includes tension control.

[00025] FIG. 3C is yet another perspective view showing yet another exemplary embodiment of the invention that includes tension control.

[00026] FIG. 4A is a top plan view of the embodiment shown in FIG. 3 A.

[00027] FIG. 4B is a top plan view of the embodiment shown in FIG. 3B.

[00028] FIG. 4C is a top plan view of the embodiment shown in FIG. 3C.

[00029] FIG. 5 is a view in front elevation of yet another exemplary embodiment of the invention that includes tension control, wherein each of four thread groups has a drive and tension control apparatus and shares a single driven take-off roll.

[00030] FIG. 6 is a top plan view of the system shown in FIG. 5. [00031] FIG. 7 is a right side elevational view of the four thread drive and tension control apparatus shown in FIGs. 5 and 6.

[00032] FIG. 8 is a perspective view showing an exemplary embodiment of a single thread drive and tension control apparatus.

[00033] FIG. 9 is a perspective view of another exemplary embodiment of a drive and tension control apparatus that includes a separate variable-speed motor and a corresponding separate tension sensor for each individual thread.

[00034] FIG. 10 is an enlarged front elevational view of yet another embodiment of a single thread drive and tension control apparatus.

[00035] FIG. 11 is a right side elevational view of the drive and tension control apparatus shown in FIG. 10.

[00036] FIG. 12 is a top plan view of the single thread drive and tension control apparatus shown in FIG. 10.

[00037] FIG. 13 is an enlarged front elevational view of yet another exemplary embodiment of a single thread drive and tension control apparatus.

[00038] FIG. 14 is a top plan view of the third embodiment of the single thread drive and tension control apparatus shown in FIG. 13.

[00039] FIG. 15 is an exemplary enlarged front elevational view of yet another embodiment of a single thread drive and tension control apparatus.

[00040] FIG. 16 shows an exemplary flow diagram for a tension control/trim algorithm of the method of monitoring threads or fiber tension that may be used in association with embodiments of the invention as shown in FIG. 3A to FIG. 3C.

[00041] FIG. 17 schematically illustrates the fiber unwinding test equipment used to obtain the data in Examples 1-5. [00042J FIG. 18 plots test results of delivered tension as measured over time when a yarn package was unwound using an OETO system embodiment of invention shown in FIG. 3B.

DETAILED DESCRIPTION OF THE INVENTION

[00043] The apparatus for unwinding yarns allows for the cost efficient use of an OETO method with rewound yarn and/or as-spun OETO yarn with anti-tack additives. Yarn without anti-lack additives may also be as-spun OETO if tension control equipment is used. In particular, the apparatus continuously unwinds as-spun OETO yarns and delivers a relatively constant yarn tension in a relatively small footprint. This provides for improved efficiency in manufacturing processes.

[00044] FIG. 1 is an exemplary perspective view showing an embodiment of an invention for continuous unwinding of yarns disclosed by the present inventors in US 2006/001 1771. FIG. 1 shows a system 100 with two pivoting legs 141, 113 that are connected to a central portion 109 at pivot points 103 shown in FIG. 1 as two parallel posts, with bridging supports therebetween. A central support frame 108 extends from one side of system 100 in the embodiment shown in FIG. 1.

[00045] The two pivoting legs 141, 113 contain a plurality of pivoting yarn holding arms 120 (see FIG. 2). The pivoting yarn holding arms 120 hold creels for up to eight packages 105 on each of the pivoting legs 141, 113. Each of the packages 105 may be either active packages or standby packages. Referring to FIG. 2, the pivoting legs 141, 113 of the system 100 are set at acute angles (8₁,8₂) relative to the legs of the central portion 109 in order to provide a versatile and small footprint for the system 100. The acute angles (8₁,8₂) are in the range of 0° to 90°. As a result, the system 100 can be configured with various orientations of the two pivoting legs 141, 113 to optimize space on a manufacturing floor.

[00046] In addition, FIG. 1 shows a drive control assembly 110 that is attached to the central support frame 108 of the system 100. The drive control assembly 110, as shown in FIG. 1, further comprises a drive motor 112, a drive roll 114, an electrical control box 118, a separator roll 122, second thread guides 126, break sensors 128, and third thread guides 132. Multiple drive control assemblies 107 may be used to support individual yarns provided by each package 105. Thread guides 138, 132, 126 direct individual yarns from the packages to the drive rolls 114 in drive control assembly 110. A non-limiting example value for the number of first thread guides 138, second thread guides 126, break sensors 128 and third thread guides 132 is eight. The electrical control box 118 provides power supplies, terminal blocks that provide interface connections for signals to components, servo drive motors for yarn speed control, relays, motor controllers, a break detector interface, digital-to-analog converters, analog-to-digital converters and other interface electronics in support of the monitoring and operation of the above-discussed components of the frame 100. The frame 100 of FIG. 1 can be used with all embodiments of the invention.

[00047] A non-limiting example of an active and a standby package 105 is a full 3 kg creel package of a wound fiber or yarn. While not wishing to be limited, an exemplary yarn for OETO unwinding is spandex (segmented polyurethane), such as LYCRA® sold by INVISTA SARL (formerly DuPont). The active and standby packages 105 typically occupy either of two adjacent pivoting yarn holding arm 120 positions on the small footprint frame 100. The pivoting yarn holding arms 120 pivot for easy access to the active and standby packages 105. The pivoting yarn holding arms 120 hold regular yarn tube cores (e.g., as-spun OETO material).

[00048] FIG. 2 is a top plan view of the apparatus for unwinding yarns shown in FIG. 1. As can be seen in FIG. 2, the frame 100 is designed to provide a versatile configuration and a small footprint by placing the two pivoting legs 141, 113 of the frame 100 that hold the packages 105 at angles (9i,0₂) relative to the central support frame 108. Since the two legs 141, 113 can be moved and because the frame 100 has a small footprint, the apparatus takes up less floor space in a manufacturing environment. In addition, pins 103 can be removed from the central portion 109 to allow further reduction in the size of the unwinding apparatus. That is, with the removal of the appropriate pins 103 at the top and bottom of the central portion 109, either one of the two pivoting legs 141, 113, may be removed from the compact OETO unwinding apparatus frame 100 and with the other pivoting leg 141, 113 set at a 90° angles αi,c-₂ the apparatus or creel could have a smaller footprint on the manufacturing floor. The remaining reference numbers shown in FIG. 2 have been discussed above in FIG. 1.

[00049] FIG. 3A is another exemplary embodiment of a compact OETO creel system 100' that includes tension control. FIG. 4 is a top plan view of the system shown in FIG. 3A. The concept of net tension control for a thread group may be further explained using the diaper manufacturing as a thread manufacturing system example. Thread groups may be supplied to a diaper or other manufacturing process. For example, a first thread group may provide the elastic feature for the right leg portion of a diaper, and a second thread group may provide the elastic feature for the left leg portion. During manufacturing, the tension of the elastic feature for the right or left leg portion may no longer be at an acceptable level due to tension variations in the thread. The compact OETO creel system 100' enables the tension of the first thread group or the second thread group to be adjusted independently of the other thread group in order to correct any such variations.

[00050] As can be seen in FIG. 3A, the system 100' is designed to provide a versatile configuration and a small footprint by placing the two pivoting legs 141, 113 of the system 100' that hold the packages 105 at angles (θi.θ_∑ as shown in FIG. 4) relative to the central support frame 108. Since the two legs 141, 113 can be moved and because the system 100' has a small footprint, the system takes up less floor space in a manufacturing environment. In addition, pin 103 can be removed from the central portion 109 to allow further reduction in the size of the creel system. That is, with the removal of the appropriate pins 103 at the top and bottom of the central portion 109, either one of the two pivoting legs 141, 113, may be removed from the compact OETO creel system 100' and with the other pivoting leg 141, 113 set at a 90° angles αi,c.₂ the creel system could have a smaller footprint on the manufacturing floor. In addition, an electrical control box 118, as discussed above in FIG. 1 can be used with this system 100' to support the operation of the creel system. Further, any remaining reference numbers shown in FIG. 3A- FIG. 3C can be defined by the discussion above of FIG. 1. Moreover, the central support frame 108 of FIG. 3A to FIG. 3C and the tension control apparatus 110 of FIG. 5 to FIG. 15 can be used all embodiments of the invention.

[00051] Referring still to FIGs. 5 to IS, in operation, a diaper machine or other thread processing manufacturing system may provide a signal to the tension controller 119 of the drive and tension control apparatus 110-lA and 110-lB, as shown for example in FIG. 5 and FIG. 8, respectively. This signal provides an indication of what speed the motor should operate at to provide the necessary elongation to achieve a desired tension. The signal from the thread processing system is typically based on industry standards that have been created indicating the theoretical amount of elongation necessary to achieve a desired tension. This input signal from the thread processing system is referred to as the tension set point and initially dictates the speed of the driven take-off roll 111 of the drive and tension control apparatus 110-lA and 110-1 B, as shown in FIG. 5 and FIG. 8, respectively.

[00052] According to a preferred embodiment, a user may enter a desired tension range that is to be maintained for the thread group directly into tension controller device 119. The tension controller device receives input signals from the tension sensors 115-115"' representative of the thread tension. Tension controller device 119 uses these input signals to determine whether the tension level of the thread 102-102'" coming off driven take-off roll 111 can be maintained because it is within the desired tension range, or whether the tension needs to be increased or decreased. Variable-speed motors 127 of the drive and tension control apparatus 110-lA and 110- IB, as shown in FIG. 5 and FIG. 8, respectively, will maintain a speed until tension controller device 119 outputs a signal indicating that the net tension is outside the desired range based on a signal received from the tension sensors 115-115'". The output signal from tension sensors 115-1 15" will override an input signal from the thread processing manufacturing system and change the speed of the variable speed motor 127 of the drive and tension control apparatus 110-1 until the speed is within the desired range. That is, the speed of motors 127 will be adjusted to correct for variations in tension that occur during unwinding or the thread feeding process.

[00053] If the tension controller device 119 determines that the thread tension after driven take-off roll 111 is too high, the tension controller device 119 will increase the speed of motor 127. Alternatively, if the tension controller device 119 determines that the thread tension after driven take-off roll 111 is too low, the tension controller device 119 will decrease the speed of motor 127.

[00054] As described above, the compact OETO creel system 100' may be configured to look at a signal from a thread processing manufacturing system as well as a signal from the tension sensor 115 in determining the appropriate speed for motor 127, as shown in FIG. 6 to FIG. 8. In alternative embodiments, the drive and tension control apparatus 110-lA or 110-lB of the compact OETO creel system 100' may be configured to look only at a signal from tension sensors 115-115'" (i.e., an averaged tension feedback signal) in determining the appropriate speed for motor 127. Further, the compact OETO creel system 100' may include multiple sensors positioned throughout the system that determine the appropriate speed of motor 127.

[00055] FIG. 3B and FIG. 3C are other exemplary embodiments of a compact OETO creel systems 100" and 100'", respectively, that include tension control. FIG. 4B and FIG. 4C are top plan views of the systems shown in FIG. 3B and FIG. 3C, respectively. The operation and components of these embodiment are similar to those of FlG. 3A with like components sharing the same reference numbers between these and other descriptive figures below. However, the drive and tension control apparatus 110-2 and 110-3 of FIG. 3B and FIG. 3C, respectively, are dedicated to individual threadlines 102. The configuration and operation of various embodiments of drive and tension control apparatus 110-2 and 110-3 of FIG. 3B and FIG. 3C, respectively, are further discussed in the following paragraphs.

[00056J As can be seen in FIG. 3B and FIG. 3C the creel systems 100", 100'" are also designed to provide a versatile configuration and a small footprint by placing the two pivoting legs 141, 113 of the system 100" that hold the packages 105 at angles Θi,θ₂ relative to the central support frame 108. Since the two legs 141, 113 can be moved and because the system 100" has a small footprint, the system takes up less floor space in a manufacturing environment. In addition, pins 103 can be removed from the central portion 109 to allow further reduction in the size of the creel system. That is, with the removal of the appropriate pins 103 at the top and bottom of the central portion 109, either one of the two pivoting legs 141, 113, may be removed from the compact OETO creel system 100" and with the other pivoting leg 141, 113 set at a 90° angles oti,α₂ the creel system could have a smaller footprint on the manufacturing floor. In addition, an electrical control box 118, as discussed above in FIG. 1 can be used with either system 100", 100'" to support the operation of the creel system. Further, any remaining reference numbers shown in FIG. 3B to FIG. 3C can be defined by the discussion above of FIG. 1. Moreover, the tension control apparatus of FIG. 5 to FIG. 15 is applicable to all embodiments of the invention.

[00057] FIG. 5 is an exemplary enlarged front elevational view of a four thread drive and tension control apparatus 110-1 mounted on the system 100'. The tension controller device 119 further comprises a graphical display 151, a keyboard 123 for data entry and control, and alarm lights 125 to indicate alarm conditions to the operator. Static guides 128 and captive rolling guides 129 that are external to the drive and tension control apparatus II 0-1 are also shown in FIG. 5.

[00058] As shown in FIG. 5, guide systems 112A, 112B are used to direct the threads toward the drive and tension control apparatus 110-lA. In particular, when the compact OETO creel system 100' is feeding multiple threads, the multiple guide systems 112A, 112B may be needed to direct the threads to drive and tension control apparatus 110-1 A so that the threads do not tangle. Preferably the thread path for each thread is isolated relative to the other threads, but multiple threads may be in contact with the driven take-off roll 111 as will be discussed below.

[00059] However, in alternative embodiments, the use of guide systems can be minimized or may be avoided by taking threads directly from guide 138 to driven take-off roll 111. Λs shown in FIG. 5, guide system 112A, 112B includes a series of contact points. Given the possible high tack level of the clastomeric fiber or thread, contact points are likely to undesirably add tension to the thread before reaching drive and tension control apparatus 110-1 A. As can be appreciated by those having ordinary skill in the art, it is generally preferable to stretch the thread with drive and tension control apparatus 110-1 A before tension is added to the thread since any tension added to the thread before the thread reaches drive and tension control apparatus 110-1 A will be amplified by the drive and tension control apparatus 110-1 A.

[00060] According to one embodiment, as shown in FIG. 5, each thread group 102-102'" is driven by a separate drive and tension control apparatus 110-lA with a separate driven take-off roll 111. Thread groups may be supplied to a diaper machine to provide the elastic band features near the open end of the legs. For example, a first thread group may provide the elastic feature for the right leg portion, and a second thread group may provide the elastic feature for the left leg portion. During manufacturing, the tension of the clastic feature for the right or left leg portion may no longer be at an acceptable level due to tension variations in the thread. The compact OETO creel system 100' enables the tension of the first thread group or the second thread group to be adjusted independently of the other thread group in order to correct any such variations.

100061] In particular, FIG. 5 and FIG. 8 show an exemplary enlarged front elevational view of a multiple thread drive apparatus 110-1 A and a single thread drive 110-1 B and tension control apparatus, respectively. The drive and tension control apparatus 110-1 A, 110-1 B comprising a driven take-off or driven take-off roll 111, guide rolls 113A-113E, a tension sensor 115, breakage sensors 117, motor 127 and a tension controller device 119. Optionally, a motion sensor 116 may also be included. The tension controller device 119 further comprises a graphical display 151, a keyboard 123, and alarm lights 125.

[00062] While diaper manufacture has been described herein, thread groups may be supplied by the OETO creel system to other thread processing manufacturing systems. In operation, the diaper machine or other thread processing manufacturing system is likely to provide a signal to the tension controller 119, as shown in FIG. 5 to FIG. 8 of the drive and tension control apparatus 110-1 A and 110-1 B, respectively, indicating what speed the motor 127 should operate at to provide the necessary elongation to achieve a desired tension. The signal from the thread processing system is typically based on industry standards that have been created indicating the theoretical amount of elongation necessary to achieve a desired tension. This input signal from the thread processing system is referred to as the tension set point and initially dictates the speed of the driven take-off roll 111 of the drive and tension control apparatus 110-1 A, 110-lB.

[00063] According to another embodiment, a user may enter a desired tension range that is to be maintained for the thread group directly into the keyboard 123 of the tension controller device 119. The tension controller device 119 receives input signals from the tension sensor 115 representative of the thread tension. Tension controller device 119 uses these input signals to determine whether the tension level of the thread coming off driven take-off roll Ul can be maintained because it is within the desired tension range, or whether the tension needs to be increased or decreased.

[00064] FIG. 6 shows a top view of the drive and tension control apparatus 110-lA. The drive and tension control apparatus 110-1 A has driven take-off roll 111, guide rolls 113A-113A¹" to 113E-113E'", a tension sensors 115-115'", motion sensors 116-116'", breakage sensors 117-117"' and a tension controller device 119. In FIG. 6, a variable-speed motor 127 of the drive and tension control apparatus UO-IA will maintain a speed until tension controller device 119 outputs a signal indicating that the net tension is outside the desired range based on a signal received from the tension sensors 115-115'". The output signal from tension sensors 115-115'" will override an input signal from the thread processing system and change the speed of the variable speed motor 127 of the drive and tension control apparatus 110-1 A until the speed is within the desired range. That is, the speed of motor 127 may be adjusted to correct for variations in tension that occur during unwinding or the thread feeding process. [00065] If the tension controller device 119 determines that the thread tension after driven take-off roll 111 is too high, the tension controller device 119 will increase the speed of motor 127. Alternatively, if the tension controller device 119 determines that the thread tension after driven take-off roll 111 is too low, the tension controller device 119 will decrease the speed of motor 127.

[00066] As described above, the compact OETO creel system 100' may be configured to look at a signal from a manufacturing system as well as a signal from the tension sensor 115 in determining the appropriate speed for motor 127. In alternative embodiments, the drive and tension control apparatus 110-lA, 110-lB of the compact OETO creel system 100' may be configured to look only at a signal from tension sensor 115 (i.e., a tension feedback signal) in determining the appropriate speed for motor 127. Further, the compact OETO creel system 100' may include multiple sensors that sense tension or other parameters from which the system may adjust the appropriate speed of motor 127.

[00067] FIG. 7 shows a top plan view of a driven roll and tension control apparatus 110-A of a thread group being supplied to an application of the thread processing system. In addition, the compact OETO creel system 100' may provide for a separate net tension control of a second thread group being supplied to a second application of the thread processing system. As used herein, net tension refers to the resultant tension of the group of threads passing over the same driven take-off roll 111. By controlling the net tension of a first thread group, and separately controlling the net tension of a second thread group, tension variations for each thread group may be corrected where background art unwinding devices/thread feeding systems typically could not make such a correction.

[00068] FIG. 8 is an exemplary enlarged perspective view of a single thread drive and tension control apparatus 110- 1 B. The drive and tension control apparatus 110-1 B comprising a driven take-off roll 111, guide rolls 113A-113E, a tension sensor 115, breakage sensor 117, motor 127 and a tension controller device 119. Optionally, a motion sensor (not shown) may also be included. The tension controller device 119 further comprises a graphical display, a keyboard, and alarm lights.

[00069J FIG. 9 is a perspective view of another exemplary embodiment of a drive and tension control apparatus 110-2A that includes a separate variable-speed motor 227 and a corresponding separate tension sensor 215 for each individual thread. Such a system may advantageously correct variations in each active thread package. According to one embodiment, the speed of motor 227 is controlled without receiving input from a thread processing system. That is, the motor speed is based solely on tension feedback detected by tension sensor 215 and recognized by tension controller device 219. Alternatively, the speed of motor 227 may be controlled by receiving input from a thread processing system in addition to tension feedback detected by tension sensor 215. In addition, when only a single thread is being driven by driven take-off roll 211, the guide system for a thread feeding system may be simplified as compared to a system using multiple threads, wherein thread paths must be kept separate.

[00070] When only a single thread is being driven by driven take-off roll 211, the guide system for a thread feeding system may be simplified as compared to a system using multiple threads wherein thread paths must be kept separate. For example, a guide system having only a static guide, such as a ceramic eye, through which the thread passes after coming off a package, and a first guide roller to direct the thread towards driven take-off roll 211.

[00071] In one embodiment of the single thread configuration of FIG. 9, the control of the speed of motor 227 is based solely on tension feedback. In this case, the changes in speed are likely to occur more frequently and in larger increments/decrements than a thread feeding system controlled by a tension set point provided by a thread processing system in combination with tension feedback, as discussed above. In particular, a large decrement in the speed of motor 127 may cause slack in the thread before reaching driven take-off roll 211 which may lead to a subsequent slippage of the thread around driven take-off roll 211.

[00072J To reduce the likelihood of such slack in the thread before reaching driven take-off roll 211, a prctensioncr may be used in the first guide roll 213A. Background art pretensioners rely on friction between the thread and the pretensioner to maintain tension in the thread feeding system and avoid slack in the thread. However, such friction-type pretensioners are not applicable to elastomeric threads where tack is an issue.

[00073] Accordingly, pretensioner guide roll 213A uses a pretensioner which otherwise hinders the speed of rotation of the guide roll. In one embodiment of the invention for pretensioner guide roll 213A, a magnet is positioned adjacent to pretensioner guide roll 213A and a material that is coupled to the guide roll. The material to be coupled to the guide roll is, for example, a ferrous metal such as steel. The magnetic force slows the rotational speed of the pretensioner guide roll 213A and thereby maintains the tension and eliminates slack in the thread without relying on friction.

[00074] Moreover, as shown in FIG. 9, after the thread is directed around pretensioner guide roll 213A, the thread is wrapped around driven take-off roll 211. The wraps of the thread around driven take-off roll 211 may either be directly adjacent to one another or spaced out across the driven take-off roll 211. A tension sensor 215 is positioned after driven take-off roll 211. The guide roll 213B is located after driven take-off roll 211. In addition, the tension sensor 215 may also be simplified because only a single thread is being used.

[00075] FIG. 10 is an exemplary enlarged front elevational view of yet another embodiment of a single thread drive and tension control apparatus 110-2 A. As shown in FIG. 10, after the thread is directed around pretensioner guide roll 213A, the thread is wrapped around driven take-off roll 211. The wraps of the thread around driven take-off roll 211 may either be directly adjacent to one another or spaced out across the driven take-off roll 211. In particular, the thread is wrapped around driven take-off roll 211 at an angle sufficient to minimize slippage and low enough to avoid tangling. The angle at which the thread is wrapped around driven take-off roll 211 is referred to as a "first wrap angle." The first wrap angle (θj) may be approximately between 2 degrees and 360 degrees. The first wrap angle (θι) may vary depending on the type of elastomeric thread of fiber being used and the corresponding level of tack. According to one embodiment, the thread is wrapped around driven take-off roll 211 at the first wrap angle (θ[) of approximately 270 degrees. The first wrap angle (θ|) can be obtained by the proper positioning of guide rolls 213A, driven take-off roll 211, and tension sensor 215.

[00076] The tension sensor 215 is positioned after driven take-off roll 211. The guide roll 213B is located after driven take-off roll 211. The thread maintains a second wrap angle (Θ₂) across tension sensor 215 that provides an accurate and consistent measurement of the thread tension in the range of 0 to 180 degrees of circumference. The thread is pressed against the thread guides before and after the tension sensor to guarantee a consistent second wrap angle (Θ₂). The second wrap angle (83) can be obtained by the proper positioning of guide rolls 213B, driven take-off roll 211, and tension sensor 215. A tension controller device 219 monitors the thread tension measured by tension sensor 215 and at least one of increments, maintains or decrements the speed of the variable-speed motor 227.

[00077] FIG. 11 is a right side elevational view of the drive and tension control apparatus 110-2A shown in FIG. 10. As shown in FIGs. 10 and 11, after the thread is directed around the driven take-off roll 211 which is driven by motor 227, the thread passes through the tension sensor 215 and out of the apparatus via guide roll 213B. [00078] FIG. 12 is a top plan view of the single thread drive and tension control apparatus shown in FIG. 10. As shown in FIG. 12, after the thread is directed around pretensioner guide roll 213A, the thread is wrapped around driven take-off roll 211. The wraps of the thread around driven take-off roll 211 may either be directly adjacent to one another or spaced out across the driven take-off roll 211. A tension sensor 215 is positioned after driven take-off roll 211. The guide roll 213B is located after driven take-off roll 211.

[00079] FIG. 13 is an enlarged front elevational view of yet another exemplary embodiment of a single thread drive and tension control apparatus 110-2B. As shown in FIG. 13, after the thread is directed around pretensioner guide roll 313A, the thread is wrapped around driven take-off roll 311 which is driven by motor 327. The wraps of the thread around driven take-off roll 311 may either be directly adjacent to one another or spaced out across the driven take-off roll 311. In particular, the thread is wrapped around driven take-off roll 311 at an angle sufficient to minimize slippage and low enough to avoid tangling. The angle at which the thread is wrapped around driven take-off roll 311 is referred to as a "first wrap angle." The first wrap angle (αi) may be approximately between 2 degrees and 360 degrees. The first wrap angle (ot|) may vary depending on the type of elastomeric thread of fiber being used and the corresponding level of tack. According to one embodiment, the thread is wrapped around driven take-off roll 311 at the first wrap angle (θi) of approximately 270 degrees. The first wrap angle (θj) can be obtained by the proper positioning of guide rolls 313A, driven take-off roll 311, and tension sensor 315.

[00080] As shown in FIG. 13, a tension sensor 315 is positioned after driven take-off roll 311. The guide roll 313B is located after driven take-off roll 311. The thread maintains a second wrap angle (Θ₂) across tension sensor 315 that provides an accurate and consistent measurement of the thread tension in the range of 0 to 180 degrees of circumference. The thread is pressed against the thread guides before and after the tension sensor to guarantee a consistent second wrap angle (θ_∑). The second wrap angle (Θ2) can be obtained by the proper positioning of guide roll 313B, driven take-off roll 311 and tension sensor 315. A tension controller device 319 monitors the thread tension measured by tension sensor 315 and at least one of increments, maintains or decrements the speed of the variable-speed motor 327.

[00081] FIG. 14 is a top plan view of the third embodiment of the single threads drive and tension control apparatus 110-2B shown in FIG. 13. As shown in FIG. 14, after the thread is directed around pretensioner guide roll 313A, the thread is wrapped around driven take-off roll 311. A tension sensor 315 is positioned after driven take-off roll 311. The guide roll 313B is located after driven take-off roll 311. A tension controller device 319 monitors the thread tension measured by tension sensor 315 and at least one of increments, maintains or decrements the speed of the variable-speed motor 327.

[00082] FIG. 15 shows yet another exemplary embodiment of a drive and tension control apparatus 110-3 that includes a separate variable-speed motor 427 and a corresponding separate tension sensor 415 for each individual thread. Such a system may advantageously correct variations in each active package. According to one embodiment, the variable-speed of motor 427 is controlled without receiving input from a thread processing system. That is, the motor speed is based solely on tension feedback detected by tension sensor 415 and recognized by tension controller device 419. Alternatively, the variable speed of motor 427 may be controlled by receiving input from a thread processing system in addition to tension feedback detected by tension sensor 415. In addition, as discussed above, when only a single thread is being driven by driven take-off roll 411, the guide system for a thread feeding system may be simplified as compared to a system using multiple threads, as shown in the background art of FIG. 1 and the embodiment of the invention in FIG. 3A.

[00083] When only a single thread is being driven by driven take-off roll 411, the guide system for a thread feeding system may be simplified as compared to a system using multiple threads wherein thread paths must be kept separate. For example, a guide system having only a static guide, such as a ceramic eyelet plate 403, through which the thread passes after coming off a package, and a first eyelet 430 and a second eyelet 432 that direct the thread towards driven take-off roll 411.

[00084] In one embodiment of the single thread configuration of FIG. 15, the control of the variable speed of motor 427 is based solely on tension feedback. In this case, the changes in speed are likely to occur more frequently and in larger increments/decrements than a thread feeding system controlled by a tension set point provided by a thread processing system in combination with tension feedback, as discussed above. In particular, a large decrement in the speed of motor 427 may cause slack in the thread before reaching driven take-off roll 411 which may lead to a subsequent slippage of the thread around driven take-off roil 411.

[00085] To reduce the likelihood of such slack in the thread before reaching driven take-off roll 411, a combination of a guide roll 422 and prctensioncr 420 is used. A non-limiting example of such a pretensioncr is Model No. JH-703A from Da Kong Enterprise Co., Ltd, Chung Shan Road, Chang Hua City 500, Taiwan. Background art pretensioners rely on friction between the thread and the pretensioner to maintain tension in the thread feeding system and avoid slack in the thread. However, such friction-type pretensioners usually are not applicable to elastomeric threads where tack is an issue.

[00086] Pretensioner 420 hinders the speed of rotation of the guide roll 422. As shown in FIG. 15, after the thread is directed around the guide roll 422, the thread is wrapped around driven take-off roll 411. The wraps of the thread around driven take-off roll 411 may either be directly adjacent to one another or spaced out across the driven take-off roll 411. A tension sensor 415 is positioned after driven takeoff roll 411. The guide roll 413B is located after driven take-off roll 411 and the tension sensor 415. In addition, the tension sensor 415 may also be simplified because only a single thread is being used. [00087] The drive and tension control apparatus 110-3 in FIG. 15 includes a separate variable-speed motor 427 and a corresponding separate tension sensor 415 for each individual thread. Such a system may advantageously correct variations in each active package. According to one embodiment, the speed of motor 427 is controlled without receiving input from a thread processing system. That is, the motor speed is based solely on tension feedback detected by tension sensor 415 and recognized by tension controller device 419. Alternatively, the speed of motor 427 may be controlled by receiving input from a thread processing system in addition to tension feedback detected by tension sensor 415. In addition, when only a single thread is being driven by driven take-off roll 411, the guide system for a thread feeding system may be simplified as compared to a system using multiple threads, wherein thread paths must be kept separate.

[00088] As compared to the previous embodiments of the OETO creel system with drive and tension control apparatus, the guides have been changed from rollers/pigtails to eyelets (e.g., 430, 432). The use of eyelets reduces the chance of tangles, trapping or breaking due to ballooning of the thread between a package and the first guide. Embodiments of the invention may use individual eyelets and plates. Preferably embodiments of the invention use a single plate 403 with holes/eyelets, as shown in FIG. 15.

[00089] As discussed above, the friction prctenstoner (e.g., 420 in FIG. 15) provides a consistent minimum tension on the threads that reduces initial tension variation caused by potential plucking from the package. With plucking, there is the possibility of momentarily dropping the tension to zero which would introduce a spike leading to a break - even with overall threadline tension control.

[00090] In particular, as compared to the previous embodiments of the invention and the background art, the driven roll 427 has an idler 421 attached, as shown in FIG. 15. The idler 421 provides for further dampening of the tension variation prior to tension sensor 415. Though FIG. 15 shows one wrap of the thread, several wraps may be used to further increase threadline and driven roll contact surface area for the thread that improves the "pulling" and "dampening" fluctuations that result from the increase or incrementing and decrease or decrementing the variable speed control of motor 427.

[00091] In addition, as shown in FIG. 3C, tension control apparatus 110-3 are mounted back-to-back which increases the space between tension control panels for easier string-up and reduces the chance of threadline/threadline interference. This makes it easier to work with the system components mounted at extremely low levels (e.g., floor level) or high levels (e.g., requiring a step stool or ladder).

[00092] FIG. 16 shows a flow diagram for a method for controlling thread tension in an elastomcric thread unwinding system that unwinds a plurality of threads concurrently. Step 1600 is unwinding each elastomeric thread from a thread package with an associated driven take-off roll for said thread, which roll is driven by a variable-speed motor. In step 1601, a guiding of each elastomeric thread with an individual pretensioner and associated guide roll into a tension and control apparatus occurs. Passing each elastomeric thread through an associated tension sensor occurs in step 1602 and determining whether one or more threads are broken occurs in step 1603 of FIG. 16, the method determines whether any of the threads or fibers is broken. When a broken thread or fiber is detected, a BREAK ALARM is set in step 1605 and the algorithm is stopped at step 1627A.

[00093] When no broken threads or fibers are detected in step 1603, the method determines whether the threads or fibers are moving in step 1604 of FIG. 16. When the threads or fibers are not moving, a MOTION ALARM is set in step 1609 and the algorithm is stopped at step 1627B. When the threads or fibers are moving, a measurement of the tension of the moving threads or fibers occurs in step 1611.

[00094] In step 1612 of FIG. 16, the method determines whether any of the individual thread or fibers has a tension that is outside of a predetermined range. The predetermined range is preferably defined by at least one of the mean or average range tension, as determined in step 1623, and is compared to maximum tension as disclosed in TABLE 1 to TABLE 5 below. Alternatively, any acceptable predetermined range of tensions may be used with the thread feed processing system. When an out-of-range value of tension is detected, a TENSION ALARM is set in step 1613.

[00095] In accordance with whether the out-of-range tension is above or below the predetermined range, the motor speed is decremented or incremented, respectively, in step 1614 of FIG. 16. The number of increments and decrements in the motor speed over the course of the algorithm arc stored in step 1620. When an individual thread or fiber tension has a value that is out-of-range, the method determines whether the number of increment/decrement steps that is stored in step 1620 exceeds a correction threshold in step 1629.

[00096] When no out-of-range tension values are detected for the individual threads or fibers, the method determines an average value for the tension of multiple threads or fibers in step 1615 of FIG. 16. In addition, the average value for the threads or fiber tension is stored in step 1617.

[00097] In step 1618 of FIG. 16, the method determines whether the average value for the threads or fiber tension is outside of a predetermined range. The predetermined range is preferably defined by at least one of the mean range tension and maximum tension as disclosed in TABLE 1 to TABLE 5 below. When an average value for the thread or fiber tension has a value that is out-of-range, the method determines whether the number of increment decrement steps, previously stored in step 2320, exceeds a correction threshold in step 1629.

[00098] The correction threshold is a predetermined value that is entered in the algorithm at initialization and may be updated in real-time. The predetermined value is a maximum number of corrections that are to be allowed by the algorithm before operator intervention is suggested. The values for the predetermined value of the correction threshold may be different in terms of the number of decrements and the number of increments that are determined to exceed the threshold.

[00099] When the correction threshold has been exceeded, by either or both the number of increments or decrements, a TENSION UPDATE alarm is set in step 1625 and the algorithm is stopped at step 1627C. When the algorithm is stopped at either of steps 1627A, 1627B or 1627C, as discussed above, the operator can read the alarm status of the equipment and take the appropriate steps to intervene and correct the process.

[000100] When the average value of the yarn, thread or fiber tension is not out-of-range, the method maintains the motor speed, as indicated in step 1621 and returns to step 1603 to repeat the above discussed trim tension monitoring algorithm. The above-discussed algorithm may be applied to one or more yarn, thread or fiber being delivered by an OETO creel or drive and tension control apparatus.

[000101] The following examples include experiments with Lycra® XA® spandex fibers having no topically applied finish and provide information on the performance of embodiments of the invention.

EXAMPLE 1

[000102] The test equipment used in obtaining the data for this and the following examples, could be configured in various ways, such as optionally including or excluding certain design elements and changing the sequence of certain elements. The equipment configuration employed for examples 1 to 5 is shown in FIG. 17, which has been adapted from U.S. Patent No. 6,676,054 (Heaney et al.). The equipment, as shown in FIG. 17, was comprised of the following elements: fiber package 10, static guide 20, first, driven roll 30, tension sensor 40, and driven take-up rolls 50. [000103] The test equipment geometry and other experimental test conditions are summarized below:

[000104] The distances between the static guide and the first driven roll, between the first driven roll and the tension sensor and between the first driven roll and the take-up roll were 0.22, 1.94 and 2.1-3.4 meters, respectively. In this example, the first driven roll, having a diameter of 8.89 cm. was not grooved. The threadline was maintained in the horizontal plane (relative to ground), and its directional change within that horizontal plane as it passed through the static guide, was maintained constant at 0°. The distance between the package and first guide was varied. The lhreadline was wrapped 360° around the first driven roll. The threadline draft was controlled at 2.15 x. by maintaining the surface speeds of the first roll at 93.4 meter/min, and the surface speed of the take-up rolls at 294.3 meters/min.

[000105] Tension data (expressed in grams) were collected with a Model PDM-8 data logger, and a Model TE-200-C-CE-DG sensor (Electromatic Equipment Co.). All tension measurements were averaged over five-minute run time using a data sampling frequency of approximately 82 samples/sec.

[000106] "Mean range tension" was determined as follows: within every 1.25-second interval of the tension measurement, the minimum and maximum tension levels were recorded (yielding 103 data points). Mean range tension was calculated by averaging the differences (between the minimum and maximum values) over the 5-min run.

[000107] The fiber evaluated in this test was as-spun Lycra® XA® spandex (a registered trademark of INVlSTA SARL, formerly E.I. du Pont de Nemours and Company) having a linear density of 620 dtex (decigram per kilometer). [000108] TABLE 1 shows the thread line tension variations, as measured at the sensor, as the distance, d, between the package and the static guide was varied over a distance between about 0.25 and 0.81 meter.

TABLE 1

Distance Means Range Tension Max. Tension

(meter) (grams) (grams)

0.27 16.90 50.00

0.28 17.60 50.00

0.30 17.80 50.00

0.33 16.30 50.00

0.36 1630 49.00

0.38 14.50 50.00

0.41 13.70 48.40

0.43 13.30 38.00

0.46 12.40 37.10

0.48 12.20 44.70

0.51 1 1.60 36.30

0.53 1 1.60 36.70

0.56 1 1.60 30.40

0.58 1 1.80 32.60

0.61 10.00 28.80

0.64 1.0.60 34.30

0.66 10.60 25.30

0.69 10.40 34.30

0.71 10.60 29.80

0.74 10.00 28.40

0.76 10.40 29.40

0.79 10.80 27.80

0.80 10.80 34.50

[000109] TABLE 1 demonstrates that thread line tension (expressed either as the mean range or the maximum tension) decreases as the distance between the package and the static guide is increased. Minimum tensions, not shown in the table ranged from about 0.6 to 1.4 grams. Unexpectedly, it has been discovered that there is a minimum distance of about 0.41 meter below which the absolute level of tension and the tension variability (as observed by plotting, for example, maximum tension versus distance) rises to an unacceptably high level identifiable by the occurrence of threadline breakages which are usually preceded by a relatively abrupt increase in mean range tension. EXAMPLE 2

[0001 10] The same test equipment as described in EXAMPLE 1 , but configured to more closely correspond to the preferred embodiment of the OETO unwinder design shown in FIG. 17 was utilized. The equipment had the following elements in the order in which they were encountered by the moving threadline: fiber package, captive rolling guide, static guide, captive rolling guide, first, driven roll, captive rolling guide, tension sensor, and driven take-up rolls.

[000111] The distances between the static guide and the first driven roll, between the first driven roll and the tension sensor, and between the first driven roll and tlie take-up rolls were 0.43, 0.51 and 2.43 meters, respectively. The first driven roll was a single roll having a single groove with a depth of 0.38 mm. The threadline was again maintained in the horizontal plane. The distance between the package and the static guide was held constant at 0.65 meter while the angle, θ, was varied. Threadline draft was maintained at 4 x by controlling the first driven roll and the take-up rolls, respectively, at surface speeds of 68.6 and 274.3 meters/min.

[0001 12] In addition to monitoring threadline tension as in EXAMPLE 1, tension spikes were also recorded. "Tension spikes" are the average number of sudden increases in tension greater than 25 grams above baseline tension in a 5-min period.

[0001 13] Various as-spun Lycra® XA® spandex fibers, exhibiting different levels of tack, were evaluated. Tack levels were characterized by measuring the OETO tension (in grams) by the following method: The fiber package and a ceramic pig tail guide were mounted 0.61 meter apart, such that the axes of each were directly in line. The fiber is pulled off the package over end at a threadline speed of 50 meters/min, through the guide, and through a tension sensor. [000114] TABLE 2 shows the threadline tension variations as the angle θ increased; where θ is defined as the acute angle made by the intersection of the imaginary lines corresponding, respectively, to the rotational axis of the package and the central axis of the static guide orifice that is perpendicular to the plane of the orifice.

TABLE 2

Mean Max.

Angle Range Tension Tension

Fiber (decree) Tension (g) (grams) Spikes Tack

T- 127 0 38.4 174.9 56

620 dtex 5 40.8 176.5 85

Lot 9291 1 1 BROKE

Merge 1 Y331 22 BROKE

45 BROKE

T- 127 0 16.5 1 18.4 0

620 dtex 5 17.3 1 19.2 0

Lot 021 1 1 1 17.3 122.4 0

Merge 16398 22 18.8 124.7 0

45 20.4 131.8 0

57 25/1 138.0 1

67 29.0 149.0 9

77 30.6 156.9 1 1

90 35.3 167.9 14

T- 162B 22 32.9 171.8 16 1 1.368

800 dtex 45 40.8 198.4 53

Lot 0205 57 44.7 >200 72

Merge 16525

T-162C 22 25.9 159.2 0 7.02

800 dtex 45 29.8 176.5 4

Lot 0020 57 31.4 169.4 24

Merge 16600

[0001 15] Examination of the data in TABLE 2 reveals an unexpected relationship between threadline tension and the angle between the centerlines of the package and the static guide. As the angle increases so does thread line tension, and tension spikes occur more frequently. At sufficiently large angles, thread line breakage can occur. The sensitivity of thread line tension to the angle traversed by the thread line as it passes through the guide is dependent upon the properties of the fiber. The data of Table 2 indicates that fibers characterized by higher tack exhibit higher sensitivity of thread line tension with respect to this angle. For some fibers that exhibit an exceptionally high level of tack, the angle above which thread line breakage cannot be avoided is less than about 10°.

EXAMPLE 3

[000116] This series of runs, using the test equipment described previously and configured as in EXAMPLE 2, evaluated the effect of angle on threadline tension for fibers of different tack levels. The distance, d, between the package and the static guide was maintained constant at 0.65 meter. Threadline draft was maintained at 4x by controlling the first driven roll and the take-up rolls, respectively, at surface speeds of 68.6 and 274.3 meters/min. All other experimental conditions were as described for EXAMPLE 2. The data are summarized in TABLE 3.

TABLE 3

Mean Max.

Angle Range Tension Tension

Fiber (decree) Tension (g) (grains) Spikes Tack

T-162C 0 25.1 164.7 2 7.02

800 dtex 5 25.1 157.7 0

Merge 16600 11 27.5 156.9 0

Lot 0020 22 28.2 160.0 0

45 36.9 182.8 16

57 42.4 196.1 59

67 47.8 >200.0 127

77 BROKE

T-162C 0 18.8 150.6 0 1.408

As-spun 5 15.7 142.8 0

840 den 11 17.3 143.5 0

Merge 16795 22 14.9 140.4 0

Lot 1019 45 14.9 138.8 0

57

67 15.7 140.4 0

90 17.3 145.1 0

T- 162 B 0 29.0 171.8 13 11.368

800 dtex 5 32.2 172.6 10

Merge 16525 1 1 36.1 184.3 42

Lot 0205 22 39.2 >200.0 43

45 52.6 >200.0 126

57 BROKE

[0001 17] The high tack fibers tested in this series of runs are the same as two of the fibers tested in EXAMPLE 2. Comparison of the data for these same fibers in TABLE 2 and TABLE 3, shows that thread line tension increases with increasing angle, and thread line breakage may occur at excessively high angles. (In contrast, fibers containing finish can be run at angles of up to and including 90° with no increase in thread line tension, no occurrence of tension spikes and no thread line breaks. When Lycra® XA® T-162C fiber, 924 dtex den, merge 16795(lot 1019), finish, having a tack of 1.406, was run at angles of 0-90°, there was no threadline tension increase and no tension spikes.) [0001 18] These data demonstrate that limiting the angle the thread line traverses as it passes through the first static guide provides uninterrupted manufacturing processing even for high tack fiber threadlines.

EXAMPLE 4

[0001 19] This series of runs using the test equipment described previously and configured as in EXAMPLE 2, evaluated the effect of the distance, d, between the package and the static guide on threadline tension for fibers of different tack levels. The angle, θ, was maintained constant at 22°. The threadline draft was controlled at 4x and the take-up speed at 274.3 meters/min.

TABLE 4

Mean Max.

Distance Range Tension Tack

Fiber (meter) Tension (g) (grams) (grams)

T-I 62 C 0.20 56.5 >200 7.02

As-spun 0.30 44.7 200.0

720 den 0.41 32.2 182.0

Merge 16600 0.51 32.2 174.9

Lot 0020 0.61 31.4 181.2

0.71 29.0 173.3

0.81 29.8 178.8

0.91 32.2 173.3 π

1.02 29.0 167.9

T-162 B 0.20 BROKE BROKE 1 1.368

As-spun 0.30 57.3 >200

720 den 0.41 56.5 >200

Merge 16525 0.51 55.7 >200

Lot 0205 0.61 56.5 200.0

0.71 56.5 200.0

0.81 48.6 200.0

0.91 50.2 200.0

1.02 52.6 200.0 [000120] The test results for these fibers in TABLE 4 show the minimum distance between the package and the fixed guide below which the lhreadline tension and mean range tension increase unacceptably. The value of this minimum depends upon the tack level of the fiber being tested. In contrast, there is essentially no effect of package-to-static guide distance on the lower tack Lycra® spandex. These results reinforce the difficulty in maintaining smoothly running process conditions with high tack fibers. The OETO creel system allows successful control of processes utilizing such fibers.

EXAMPLE 5

[000121] A test of the operation of embodiments of the invention was conducted under commercial production conditions using fibers that were characterized by different levels of tack. TABLE 5 summarizes these test results. Data were obtained as in previous examples, except that each of the tension measurements reported is the average of a minimum of 4 separate measurements, each measurement consisting of one tube running for a 10-min period. Similarly, each number of tension spikes, as reported in TABLE 5, is the average number of spikes greater than 25 grams above baseline tension in a 10-min period. Measurements were made on packages that were nearly full (surface) or nearly empty (core). Core measurements are those with about 1.6-cm thickness of thread or fiber remaining on the tube. Of the 5 as-spun fibers run, 4 ran with no operational problems. One fiber sample, Merge 1 Y331, did result in an unacceptable occurrence of tension spikes. That fiber demonstrated an unusually high level of tack, even for as-spun fiber, as evidenced by the fact that the mean range tension was over 60% higher than that of the fiber exhibiting the next highest level of tack.

TABLE 5

Mean

Linear Fiber Range Max.

Density Location Speed Fiber Tension Tension Tension

Fiber (dtex) on Tube (ft/min) Draft (grams) (grams) Spikes

Merge 16398 620 Surface 274.3 4X 12.3 10016 0

Merge 16398 620 Surface 121.9 4X 12.5 96.1 0

Merge 16398 620 Core 274.3 4X 17.5 1 10.7 0

Merge 16398 620 Core 121.9 4X 16.3 104.1 0

Merge 1Y331 620 Surface 274.3 4X 28.6 151.4 18

EXAMPLE 6

[000122] FIG. 17 below shows some exemplary test results that represent typical values collected running a full package from beginning to end on an embodiment of the invention similar to that shown in FIG. 3B. Without controlling tension or adding anti-tack additives, an increasing tension profile typically develops due to high yarn tack forces nearer to the tube core leading to over elongation of the yarn causing a break. The presence of varying yarn tension within the supply package is compensated for in the tension controlled yarn delivery system of FIG. 3B as is demonstrated by the fairly consistent value of tension shown in FIG. 17. It should be noted that though the parameters for tension control were not optimized for this test, the tension stays consistent, as indicated by the fairly level nature of the graph in FIG. 17. The yarn used for this test was 680 dtx T262 made on the 312th day of 2005. The Appendix contains the test data plotted which as shown varies approximately between 90 and 95 g.

[000123] The foregoing description illustrates and describes the present invention. Additionally, the disclosure shows and describes only the preferred embodiments of the invention, but, as mentioned above, it is to be understood that the invention is capable of use in various other combinations, modifications, and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein, commensurate with the above teachings and/or the skill or knowledge of the relevant art. The embodiments described hercinabove are further intended to explain best modes known of practicing the invention and to enable others skilled in the art to utilize the invention in such, or other, embodiments and with the various modifications required by the particular applications or uses of the invention. Accordingly, the description is not intended to limit the invention to the form or application disclosed herein. Also, it is intended that the appended claims be construed to include alternative embodiments.

APPENDIX

Time Sample Point Tension Measured (lO sec int) (g)

1 94.1

2 93.8

3 95.7

4 92.6

5 95

6 91.6

7 94.9

8 93.1

9 93.4

10 92.1

11 94.9

12 90

13 90.9

14 91

15 92.2

16 92

17 95.3

18 90.2

19 94.9

20 92.8

21 95.9

22 93.6

23 96.9

24 95.5

25 94.1

26 94.1

27 93.8

28 93.6

29 91.9

30 92.8

31 94

32 96.2

33 93.5

34 93.5

35 94.7

36 95.7

37 94.7

38 92.8

39 95.4

40 91.2

41 91.8

42 93.1

43 94.2

44 89.8 45 92.7

46 95.7

47 94.1

48 96.7

49 90.3

50 93.9

51 96.6

52 90.8

53 92.6

54 92.5

55 90.4

56 96.2

57 89.9

58 96.9

59 96.3

60 95.2

61 96.1

62 94.1

63 95

64 95.1

65 91

66 90.9

67 91.1

68 93.4

69 94.4

70 92.5

71 94

72 90.5

73 92.4

74 93

75 89.6

76 92.8

77 93.4

78 91.2

79 96.9

80 91.8

81 92.2

82 92.4

83 94.8

84 94.6

85 93

86 94.3

87 93.4

88 97.6

89 94.5

90 94.9

91 94

92 92.6

93 93.5

94 94.8

95 94.8

96 90.1 97 90.6

98 94

99 95.6

100 91.7

101 92.6

102 96.3

103 89.3

104 91.7

105 93.3

106 94.4

107 95.8

108 93.7

109 94.7

110 95

111 94.8

112 94.2

113 94.3

114 93

115 92.4

116 92.8

117 90.3

118 94.1

119 90.4

120 93.7

121 94.3

122 90.2

123 92

124 93.8

125 94

126 93.2

127 92

128 92

129 95.6

130 93.2

131 96.2

132 96.8

133 95

134 95

135 94.6

136 93.6

137 92.6

138 94.2

139 87.8

140 94.6

141 90.6

142 93.2

143 91.3

144 93

145 94.1

146 94.5

147 91.4

148 92.4 149 90.2

150 91.3

151 92.5

152 88

153 94.2

154 93.7

155 94.2

156 94.6

157 90.6

158 92.6

159 90.6

160 91

161 92.2

162 95.4

163 95

164 92.7

165 90.4

166 92.7

167 88.4

168 92.4

169 93.3

170 90.3

171 92.7

172 90.7

173 94.1

174 94.3

175 96.8

176 94.9

177 92

178 94

179 93.4

180 92

181 95.1

182 94.1

183 90.2

184 93.7

185 95.4

186 95

187 93.3

188 96.4

189 94.5

190 94.3

191 96.4

192 94.7

193 92.5

194 95.6

195 94.9

196 91.6

197 91.6

198 92.3

199 92.7

200 89.7 201 91

202 96

203 91.2

204 93.9

205 94.9

206 92.3

207 94.1

208 90.2

209 89.2

210 92.1

211 94.9

212 92.7

213 91

214 93

215 95

216 95.2

217 92.3

218 93

219 93.3

220 95.3

221 92.8

222 92

223 94.4

224 92.8

225 92.8

226 95.2

227 94.5

228 91.9

229 95.3

230 91.2

231 92.7

232 92.8

233 95.7

234 90.7

235 92.8

236 93.9

237 96.2

238 91.6

239 93.5

240 92.7

241 92.1

242 95.7

243 90.8

244 96.3

245 95.2

246 92.3

247 93.4

248 86.6

249 92.3

250 96.3

251 92.6

252 92 253 94.9

254 918

255 89.4

256 96.7

257 91.7

258 94.2

259 92.8

260 95.2

261 92.1

262 92.3

263 95.1

264 95.8

265 94

266 96.6

267 92.6

268 91.7

Claims

CLAIMSWhat is claimed is:

1. An OETO creel system, comprising: a support frame with a plurality of thread guides; at least one pivoting leg connected to the support frame; a plurality of package holders.affixed to the at least one pivoting leg with each holder configured to hold one or more packages of thread, with each said package of thread located on a rotational axis configured to allow the thread to unwind through one of the plurality of thread guides; and a plurality of drive and tension control apparatus connected to the support frame, with each of said apparatus configured Io unwind a thread from one of the plurality of packages of thread, wherein each drive and tension control apparatus comprises:

a pretensioner and associated guide roll configured to guide the unwinding thread through a thread path of the drive and tension control apparatus; at least one eyelet configured to prevent tangles of the thread; a horizontal driven take-off roll configured to move the thread through the drive and tension control apparatus; a variable-speed motor configured to drive the horizontal driven take-off roll and control thread tension; a thread tension sensor through which the unwinding thread passes; a tension controller device configured to at least one of increment, maintain and decrement a speed of the variable-speed motor in accordance with a feedback signal from the tension sensor; and at least one guide roll configured to output the thread from the tension control apparatus; wherein the pretensioner and guide roll are located before the horizontal driven take-off roll, and the tension sensor is located after the horizontal driven take-off roll, and wherein the speed of the variable-speed motor is varied to maintain thread tension values within a predetermined range of thread tension by the tension controller device.

2. The OETO creel system of claim 1 , wherein each drive and tension control apparatus further comprises an idler configured to dampen tension variations in the thread, wherein the idler is located adjacent to the horizontal driven take off roll.

3. The OETO system of claim 1 , wherein each drive and tension control apparatus further comprises a plate eyelet configured to pass the thread to the drive and tension control apparatus.

4. The OETO creel system of claim 1, wherein the thread is an elastomeric thread.

5. The OETO creel system of claim 4, wherein each of the plurality of drive and tension control apparatus are spaced apart vertically on the support frame in order to unwind each of the threads individually from a respective package of the plurality of packages.

6. The OETO creel system of claim 4, wherein the plurality of drive and tension control apparatus are configured in parallel on the support frame to unwind each of the threads individually from a respective package of the plurality of packages.

7. The OETO creel system of claims 5 or 6, wherein a first wrap angle of the thread around the driven take-off roll is in the range between about 2 and 360 degrees.

8. The OETO creel system of claims 5 or 6, wherein a first wrap angle of the thread around the driven take-off roll is approximately 270 degrees.

9. The OETO creel system of claims 5, 6, 7 or 8, wherein the drive and tension control apparatus further comprises a second wrap angle of the thread around the tension sensor that is in the range between about O and 180 degrees.

10. The OETO creel system of claim 9, wherein the pretensioner creates pretension in the unwinding thread by moving a magnet positioned adjacent to the guide roll to induce movement of a ferrous material coupled to the guide roll.

1 1. Λ drive and tension control apparatus for a thread unwinding system, comprising: a pretensioner and guide roll configured to guide the thread through a thread path of the drive and tension control, apparatus; at least one eyelet configured to prevent tangles of the thread; a driven take-off roll configured to move the thread through the drive and tension control apparatus; a variable-speed motor configured to drive the driven take-off roll and control thread tension; a tension sensor configured to determine the tension on the thread;

a tension controller device configured to at least one of increment, maintain and decrement a speed of the variable-speed motor in accordance with a feedback signal from the tension sensor; and at least one guide roll configured to output the thread from the tension control apparatus, wherein the pretensioner and guide roll is located before the driven takeoff roll and the tension sensor is located after the driven take-off roll.

12. The drive and tension control apparatus of claim 1 1, further comprising an idler configured to dampen tension variations in the thread, wherein said idler is located adjacent to the driven take-off roll.

13. The drive and tension control apparatus of claim 1 1 , further comprising a plate eyelet configured to pass thread input to the drive and tension control apparatus.

14. The drive and tension control apparatus of claim 1 1 , wherein the speed of the variable-speed motor is varied to maintain thread tension values within a predetermined range of thread tension by the tension controller device.

15. The drive and tension control apparatus of claim 14, wherein a distance between the tension sensor and the driven take-off roll is minimized to avoid errors in the thread tension variations related to distance.

16. The drive and tension control apparatus of claim 1 1, wherein the thread is an clastomeric thread.

17. The drive and tension control apparatus of claim 16, wherein a first wrap angle of the thread around the driven take-off roll is in the range between about 2 and 360 degrees.

18. The drive and tension control apparatus of claim 15, wherein a first wrap angle of the thread around the driven take-off roll is approximately 270 degrees.

19. The drive and tension control apparatus of claim 16 or claim 17, wherein a second wrap angle of the thread around the tension sensor is in the range between about 0 and 180 degrees.

20. A method for controlling thread tension in an elastomeric thread unwinding system for unwinding a plurality of threads concurrently, comprising: unwinding each elastomeric thread from a thread packaging with an associated driven take-off roll for said thread, which roll is driven by a variable- speed motor; guiding each elastomeric thread with an individual pretensioner and associated guide roll into a tension and control apparatus; passing each elastomeric thread through an associated tension sensor; determining whether one or more threads are broken; determining whether one or more threads are moving and measuring the tension of each of the moving threads; determining whether any of the moving threads have a tension that is out- of-range relative to predetermined tension values; at least one of incrementing and decrementing the speed of the respective driven take-off roll for a respective moving thread when the tension of said respective moving thread is out-of-range relative to the predetermined tension value for said moving thread, and at least one of the number of increments and decrements is below a first correction threshold; determining whether an average tension for the respective moving thread is out-of-range relative to the predetermined tension value for said moving thread; at least one of incrementing and decrementing the speed of the respective driven take-off roll when the average tension of said respective-moving thread is out-of-range and at least one of the number of increments and decrements is below the second correction threshold; and setting an alarm when one or more of the threads are at least one of broken, not moving and out-of-range and above the first or second correction threshold.

21. The method of claim 20, further comprising: passing each elastomeric thread over an associated idler configured to dampen tension variations in said thread.