Patent Publication Number: US-2012025004-A1

Title: Donning and doffing yarn tubes using magnetic force

Description:
TECHNICAL FIELD 
     This application relates generally to textile machines. More specifically, this application relates to a method and apparatus for donning and doffing yarn tubes mounted on a creel using magnetic force. 
     SUMMARY 
     In aspects of present disclosure, a device for mounting spools on a creel is disclosed including a base frame having two distinct positions, one each for donning and doffing thread from a yarn spool. The device further includes at least one pivot arm configured to receive the yarn spool. The pivot arm is configured to swing between the two positions. At least one magnetic component may be used to hold the pivot arm at one of the positions. 
     In further aspects of the present disclosure, a creel for use with a textile machine is disclosed including a rack structure with multiple base frames attached to the rack structure, each base frame configured to support at least one pivot arm for holding a yarn tube. The pivot arm is further configured to swing between two distinct positions on the base frame and be held in one of the two distinct positions using a magnetic component. 
     In still further aspects of the disclosure, a method of donning and doffing yarn tubes on a creel including moving a pivot arm having a yarn spool mounted on it, held at a doffing position by a magnetic force on a base frame to a donning position on the base frame, replacing the yarn spool, and returning the pivot arm to the doffing position to be securely held at the doffing position by the magnetic force. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings, when considered in connection with the following description, are presented for the purpose of facilitating an understanding of the subject matter sought to be protected. 
         FIG. 1  is an example environment where a creel may be deployed; 
         FIG. 2A  shows a top view of an example base frame for holding yarn tubes on a creel; 
         FIG. 2B  shows a perspective view of the example base frame of  FIG. 2A ; and 
         FIG. 3  is a flow diagram showing an example process for donning and doffing yarn tubes mounted on a creel. 
     
    
    
     DETAILED DESCRIPTION 
     While the present disclosure is described with reference to several illustrative embodiments described herein, it should be clear that the present disclosure should not be limited to such embodiments. Therefore, the description of the embodiments provided herein is illustrative of the present disclosure and should not limit the scope of the disclosure as claimed. In addition, while following description references yarn, it will be appreciated that the disclosure may be used with other types of threads, strings, ropes, and the like, which may be used in creating fabrics, meshes, nets, and similar material. 
     Briefly described, a method and a device are disclosed for donning (putting on) and doffing (taking off) of yarn (or other types of threads) tubes or spools mounted on a creel (yarn spool holding rack used in textile industry). A base frame may be used to support pivoted arms on which yarn tubes are mounted for use with various textile machines, such as a fabric weaving machine or carpet tufting machine. The thread spool may be in at least one of two positions: donning position and doffing position. In the doffing position the thread may be fed to the textile machine for weaving, while in the donning position the thread spool may be manually or automatically replaced by another thread spool, for example to change thread type or color or to refill/replace an empty spool. The pivoted arms may be held in either the donning or doffing positions with magnetic force for precise, secure, and easy positioning of the pivoted arms. 
     A textile machine is supplied with threads for weaving a fabric. The fabric may be any kind of mesh weaved from various kinds of threads or yarns. The yarn or threads also may be used for other operations such as carpet tufting. Generally, the threads for weaving or other operations are supplied to the textile machines via spools, bobbins, or tubes wrapped with yarn or thread. These yarn tubes are mounted on a support arm attached to a frame on a creel, a rack for holding such yarn tubes and feeding textile machines. A regular part of the textile manufacturing process is the replacement of yarn tubes. The yarn tubes may have to be replaced for various reasons, such as running out of yarn, changing type or color of yarn, and the like. To replace the yarn tube, the arm on which the yarn tube is mounted is generally moved to a donning position away from a working or doffing position. Traditionally, the arm supporting the spool is fixed in a position by spring tension, latch, spring-loaded rod and hole/slot, or other similar mechanical devices, which are deactivated by force and/or by two-handed operation to unlock the arm before it can be moved to a different position for donning or doffing. Such devices are cumbersome to operate and often cause injuries, such as carpel tunnel injury, to operators because of the repetitive nature of the operation of these devices. 
       FIG. 1  is an example environment where a creel may be deployed. A textile machine  102  consumes threads  104  unwound from yarn tube  106  mounted on creel  108  via base frame  110 . Textile machine  102  pulls yarn from yarn tube  106  for weaving. The yarn tubes are mounted on pivot arms attached to base frame  110 , which arms can swing between two positions of donning and doffing. Creel  108  may include a rack structure for attaching multiple base frames. Base frame  110  may be attached to creel  108  by bolts, weld, or other mechanical interfaces such as tongue-and-groove, or any other suitable mechanical interface that can securely attach base frame  110  to creel  108 . Generally, multiple base frames are attached to a creel to form a spool rack for simultaneously handling multiple yarn tubes. 
     Textile machine  102  consumes threads  104  while yarn tubes  106  are in the doffing position. At some point during the textile manufacturing process, one or more of the yarn tubes  106  may need to be replaced. At such point in the process, the arm supporting yarn tube  106  is moved to the donning position for removal and replacement. In one embodiment, a natural magnet is used to hold the arm in the donning and/or doffing positions. The arm is simply pulled off the magnet for moving it to the other position, as further described in detail below. 
       FIG. 2A  shows a top view of an example base frame for holding yarn tubes on a creel. In one embodiment a base frame  210  is used to support pivot arms (or arms)  202   a  and  202   b . Arm stops  208 ,  216 ,  218 , and  228  are used to limit the motion of the pivot arms. Magnet support blocks  206 ,  212 ,  220 , and  224  are used to support arm magnets  204 ,  214 ,  222 , and  226 , respectively. Pivot arms  202   a  and  202   b  can swing between two positions each about pivot points  230  and  232 , respectively. Pivot arm  202   a  may move to position  202   c  and pivot arm  202   b  may move to position  202   d  for donning or doffing, depending on how base frame  210  is mounted on the creel. In some embodiments, the pivot arms are made of ferromagnetic material, such as steel, to be attracted by the arm magnets and be held in place. In other embodiments, the pivot arms are made of several parts including a shaft and a base. The shaft used for receiving yarn spool may be made of non-ferromagnetic metals such as aluminum, or composite materials, such as plastics, attached to a separate part, such as a steel base or block. The steel base serves the purpose of being attracted to the arm magnets while the non-ferromagnetic materials make the arm lighter in weight. The non-ferromagnetic shaft may generally be less expensive and be replaceable when worn out or damaged, while the steel base is permanently attached to base frame  210  at the pivot points. In some embodiments, only two arm magnets are used on base frame  210 , one each for the doffing position of each of the two pivot arms, while in other embodiments, four arm magnets may be used, one for each of the donning and doffing positions of the two arms. 
     In some embodiments, base frame  210  supports a single pivot arm  202   a , while in other embodiments base frame  210  supports multiple pivot arms. For example, an extended base frame may support two, four, six, or any odd or even numbers of pivot arms in various geometric configurations suitable for mounting on a creel. 
     In some embodiments, arm magnets may be natural magnets, while in other embodiments, the arm magnets may be electromagnets. In various embodiments, electromagnets may be turned off to release the pivot arms for swinging to the other position with little force needed from the operator. In such embodiments, the electromagnets are turned back on to hold the pivot arms securely in the appropriate positions. In some embodiments, the electromagnets may be turned on and off by a control button located in the proximity of each particular pivot arm for controlling the arm magnet for the particular pivot arm. In other embodiments, the control button may be used to control a group of pivot arms, for example, a row or column of pivot arms in certain geometric configurations of the base frame. 
       FIG. 2B  shows a perspective view of the example base frame of  FIG. 2A . In this embodiment, base frame  210  supports two pivot arms  202   a  and  202   b , which can move to positions  202   c  and  202   d , respectively. Only two arm magnets  204  and  222 , supported by magnet support blocks  206  and  220 , respectively, are employed to hold the pivot arms in the doffing position during consumption by the textile machine. 
     In operation, with continued reference to  FIG. 2B , at the time of replacing a yarn tube, a creel operator forces a pivot arm, for example, pivot arm  202   a , off arm magnet  204  at the doffing position and swings the pivot magnet to the donning position  202   c . Once pivot arm  202   a  is separated by a small distance, typically on the order of a few tenths of an inch, from arm magnet  204  holding it in place at the doffing position, the pivot arm swings freely without any exertion from the creel operator. This is in contrast with pivot arms held in the doffing position by a spring where the tension on the pivot arm increases as it is separated from the doffing position to replace the yarn tube. The creel operator may now easily swing the pivot arm to the donning position to replace the yarn tube mounted on pivot arm  202   a  with another yarn tube and return pivot arm  202   a  to its original doffing position where the arm is attracted and held in place again by the magnetic force from arm magnet  204 . Typically, the moving of the pivot arm is done by a single hand and a use of both hands is not necessary. In the case that an electromagnet is used, the creel operator turns off the electromagnet first before moving the pivot arm to the donning position. 
       FIG. 3  is a flow diagram showing an example process for donning and doffing yarn tubes mounted on a creel. With reference to  FIGS. 2A and 3 , the process starts at block  300  and proceeds to block  310  where the pivot arm is held in place at the doffing position by magnetic force generated by a natural magnet or an electromagnet. The process proceeds to block  320 . 
     At block  320 , the pivot arm may be moved to the donning position by overcoming or removing the magnetic force holding the pivot arm, for example, pivot arms  202   a  and  202   b , in the doffing position. As discussed previously, the magnetic force holding the pivot arm in the doffing position may be generated by a permanent magnet or an electromagnet. The process proceeds to block  330 . 
     At block  330 , in some embodiments, the pivot arm may be held in place at the donning position, using magnetic force generated by magnets installed at the donning position, for the replacement of a yarn tube. In other embodiments, the pivot arm may simply be held in the donning position manually, without the use of magnetic force, for replacing the yarn tube. Once the pivot arm is separated by a small distance, typically on the order of a few tenths of an inch, from the magnet holding it in place at the donning or the doffing positions, the pivot arm swings freely without any exertion from the creel operator. Next, the process proceeds to block  340 . 
     At block  340 , the creel operator may replace the yarn tube mounted on the pivot arm. The process proceeds to block  350  next. 
     At block  350 , in some embodiments, the pivot arm may be held in place at the donning position, using magnetic force generated by magnets installed at the donning position, for the replacement of a yarn tube. In other embodiments, the pivot arm may simply be held in the donning position manually, without the use of magnetic force, for replacing the yarn tube. In embodiments where magnetic force is used at the donning position, once the pivot arm is separated by a small distance, typically on the order of a few tenths of an inch, from the magnet holding it in place at the donning positions, the pivot arm swings freely without any exertion from the creel operator. The creel operator may move the pivot arm to the doffing position where it is attracted and held in place by magnetic force to supply yarn to the textile machine from the newly replaced yarn tube. Next, the process proceeds to block  360 . 
     At block  460 , the process terminates. 
     While the present disclosure has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this disclosure is not limited to the disclosed embodiments, but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.