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

Abstract

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

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 to 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 0 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. 
     
     
         11 . 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 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 take-off roll and the tension sensor is located after the driven take-off roll.   
     
     
         12 . The drive and tension control apparatus of  claim 11 , 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 11 , 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 11 , 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 11 , wherein the thread is an elastomeric 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.