Tension controlled thread feeding system

Abstract

A system, apparatus and method for tension control in a thread feeding system that provides a fast and reliable method for feeding high tack elastomeric thread or fiber from a package to a thread processing system. A drive and tension control apparatus at least one of increments, maintains or decrements the speed of a driven take-off roll when the tension is out of a predetermined range of operation. A tension controller devices measures tension and determines whether the average tension for the moving threads is out-of-range relative to the predetermined tension values for the threads. Alarms and other indicators may also be used to determine the threads are at least one of broken, not moving and out-of-range for tension control.

1 . A thread feeding system comprising: 
 a support frame;    a fiber package holder affixed to said support frame for holding a package of thread about a rotational axis such that at least one thread can unwind from the package in a direction defining an acute angle with the rotational axis of the package;    a driven take-off roll for unwinding thread from the package at a predetermined take-off rate:    a first static guide for directing fiber unwound from the fiber package, said first static guide positioned on said frame such that; 
 a distance (d) from the first static guide to the end of the package facing the first static guide, measured on the line defined by the rotational axis of the package, is equal to: 
 at least about 0.41 meter for thread with tack of greater than about 2 grams OETO and less than about 7.5 grams OETO; or from about 0.71 meter to about 0.91 meter for fiber with tack greater than about 7.5;  
 
 an angle (θ), defined by the intersection of imaginary lines corresponding, respectively, to the rotational axis of the package and the central axis of the first static guide inlet orifice that is equal to: 
 0° to about 30° for threads with tack greater than about 2 grams OETO and less than about 7.5 grams OETO; or  
 0° to about 10° for threads with tack levels greater than about 7.5 grams OETO; and  
 
   a drive and tension control apparatus for sensing and controlling the speed of the driven take-off roll,    wherein the drive and tension control apparatus controls the speed of a variable-speed motor for the driven take-off roll by determining whether at least one of the mean tension and maximum tension is within a predetermined range of thread tension values.    
     
     
         2 . The thread feeding system of  claim 1 , wherein the thread is an elastomeric thread.  
     
     
         3 . The thread feeding system of  claim 1 , wherein a first wrap angle of the thread around the driven take-off roll is in the range between 2 and 360 degrees.  
     
     
         4 . The thread feeding system of  claim 1 , wherein a first wrap angle of the thread around the driven take-off roll is approximately 270 degrees.  
     
     
         5 . The thread feeding system of  claim 1 , wherein the drive and tension control apparatus further comprises guide rolls and a tension sensor, and wherein a second wrap angle of the thread around the tension sensor is in the range between 0 and 180 degrees.  
     
     
         6 . The thread feeding system of  claim 5 , wherein a guide roll that precedes the driven take-off roll is a pretensioner guide roll.  
     
     
         7 . The thread feeding system of  claim 6 , wherein the pretensioner guide roll creates pretension from the thread by using a magnet positioned adjacent to the pretensioner guide roll and a ferrous material coupled to the guide roll.  
     
     
         8 . The thread feeding system of  claim 7 , wherein the ferrous material is at least one of metal and steel.  
     
     
         9 . A drive and tension control apparatus comprising: 
 guide rolls configured to guide at least one thread through a thread path of the drive and tension control apparatus;    a driven take-off roll configured to move the at least one thread through the drive and tension control apparatus;    a variable-speed motor configured to drive the driven take-off roll;    a tension sensor configured to determine the tension on the at least one thread;    a tension controller device configured to at least one of increment, maintain and decrement a speed of the variable-speed motor,    wherein the guide rolls are located before and after the driven take-off roll, the tension sensor is located after the driven take-off roll, and wherein the speed of the variable-speed motor is maintained within a predetermined range of thread tension values by the tension controller device.    
     
     
         10 . The drive and tension control apparatus of  claim 9 , wherein the thread is an elastomeric thread.  
     
     
         11 . The drive and tension control apparatus of  claim 9 , wherein a first wrap angle of the thread around the driven take-off roll is in the range between 2 and 360 degrees.  
     
     
         12 . The drive and tension control apparatus of  claim 9 , wherein a first wrap angle of the thread around the driven take-off roll is approximately 270 degrees.  
     
     
         13 . The drive and tension control apparatus of  claim 9 , wherein the drive and tension control apparatus further comprises guide rolls and a tension sensor, and wherein a second wrap angle of the thread around the tension sensor is in the range between 0 and 180 degrees.  
     
     
         14 . The drive and tension control apparatus of  claim 13 , wherein a guide roll that precedes the driven take-off roll is a pretensioner guide roll.  
     
     
         15 . The drive and tension control apparatus of  claim 14 , wherein the pretensioner guide roll creates pretension from the thread by using a magnet positioned adjacent to the pretensioner guide roll and a ferrous material coupled to the guide roll.  
     
     
         16 . The drive and tension control apparatus of  claim 15 , wherein the ferrous material is at least one of metal and steel.  
     
     
         17 . A method for controlling thread tension in a thread feeding system, comprising: 
 determining whether threads are broken;    determining whether threads are moving;    measuring the tension 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 a driven take-off roll when the tension is out of range and at least one of the number of increments and decrements is below a correction threshold;    determining whether an average tension for the moving threads is out-of-range relative to the predetermined tension values for the threads;    at least one of incrementing and decrementing the speed of a driven take-off roll when the tension is out of range and at least one of the number of increments and decrements is below a correction threshold; and    setting an alarm when the threads are at least one of broken, not moving and out-of-range and above a correction threshold,    wherein the value that determines that the tension is out-of-range are in accordance with predetermined tension values for the threads.