Patent Grant
7731119
1. Field of the Invention
The present invention relates to a thread delivery system or fiber unwinding device, and more specifically to a compact creel system or device for continuous delivery of threads or fibers to a downstream fiber manufacturing process or device.
2. Description of Background Art
Creels are well known in the background art and support packages upon which thread, fiber or yarn is wound for delivery to an associated manufacturing device such as a loom or a diaper machine (note: the terms “thread,” “fiber” and “yarn” are used interchangeably throughout this document). The most common method of unwinding yarn from a cylindrical mandrel (i.e., a “package”) on a creel in manufacturing processes is referred to as “rolling take-off” (RTO) method. In the RTO method, when an active package is exhausted the empty cylindrical mandrel must be removed and a new or standby package is installed. The step of removing the empty mandrel in the RTO method typically requires shutting down the manufacturing process. This shut down of the manufacturing process in the problem of unproductive downtime on a manufacturing line using the RTO method.
In contrast to the RTO method discussed above, an over end take-off (OETO) method allows continuous operation of a manufacturing process. In the OETO method, the terminating end of the fiber wound on the active package is attached to the leading end of the fiber wound on the standby package. Once the active package is completely exhausted, the standby package becomes the new active package without any interruption in the manufacturing process. In this manner, a rather continuous feed of fiber to the manufacturing process is provided.
Background art creels have been provided with various horizontal and vertical arrangements of packages to take advantage of the OETO method. For example, U.S. Pat. Nos. 3,693,904 and 4,450,876 disclose horizontal arrangements of yarn packages configured in pairs for supplying an associated manufacturing process. U.S. Pat. Nos. 3,236,265; 4,358,068; and 4,648,564 disclose vertical arrangements of yarn packages configured in pairs for feeding associated manufacturing process machinery such as looms or diaper machines.
However, with the advent of higher speed manufacturing processes, a configuration of two yarn packages tied together has become increasingly insufficient to supply the associated machinery, and creels with arrangements of four yarn packages tied together have been provided. For example, U.S. Pat. No. 4,545,547 discloses a creel commonly known as a “carousel creel” which includes four yarn packages are configured horizontally and tied together. Moreover, U.S. Pat. Nos. 5,613,643 and 6,634,585 disclose creels using a large number of packages to continuously feed a high speed manufacturing process. However, a problem with carousel and other creels that handle a large number of packages is that the fibers must undergo several changes in direction as it is fed from the packages to other associated machinery. Each time the fiber changes direction, particularly sharply, the chances of a fiber break are greatly increased because of the increased tension resulting from the changes in direction. Fiber breaks with such creels also cause interruptions in the manufacturing process and lead to the problem of unproductive downtime discussed above.
An additional problem with creels using multiple packages is related to the size of the yarn packages which can be provided and supported on a creel. That is, the amount of yarn is limited due to practicalities such as weight and space occupied by the package. For example, typical yarn packages of up to 12″ in diameter are utilized to provide a large amount of yarn to a high speed manufacturing process such as a diaper machine. However, a large number of packages of this size package can take up a lot of valuable manufacturing floor space when used with creel configurations of the background art.
To handle the problem due to the size of the multiple packages needed, background art creels for the OETO method are typically configured with the active package and standby package positioned at acute angles (i.e., less than 90°) relative to one another. However, as noted above, a problem with OETO creels with this type of configuration is the valuable floor space they take up in the manufacturing environment. In addition, unacceptable variations in threadline tension are common with these background art creels when using the OETO method.
U.S. Pat. No. 5,566,574 discloses a method for feeding fiber to a textile machine by utilizing a braking member and actuator to adjust the tension and feed rate of the thread or fiber in an attempt to address the tension problems discussed above. However, the '574 patent does not disclose the concept of utilizing a variable speed electrical motor for a driven roll, where the speed of the motor is determined based on a range of desired thread tensions and could improve the performance of the manufacturing process.
Further, manufacturing processes using an elastomeric thread or fiber like Spandex, which has a unique inherent finish texture that differs from threads or fibers used in the textile industry, requires an electrical motor feeding device that allows the Spandex to remain in contact with the driven feed roll attached to the motor. Furthermore, Spandex has a higher tensile strength specification and other characteristics that differ from fibers used in the textile industry. For example, threads or fibers typically used in the textile industry are specified in the range of 50-100 decitex (decigrams per kilometer) and tend to operate at lower rotation speeds of 1-50 feet/minute when being unwound from a package as compared to those used for elastomeric threads which typically are specified in the range of 600-1500 decitex and with higher rotation speeds of 300-400 feet/minute. Moreover, the '574 patent is not directed to operate with or feed systems that require high tack, elastomeric threads such as Spandex.
The aforementioned problems make the continuous processing of high tack, elastomeric fibers particularly problematic. Fiber tack and its associated problems have been addressed by using topical fiber additives (e.g., prior to winding) or by unwinding the package and re-winding it on a new mandrel. However, both approaches add additional expense to the manufacturing process. Furthermore some applications (e.g., manufacturing of diapers and other personal care products) require the use of as-spun thread or fiber that is substantially finish-free and, consequently, exhibits high tack.
Therefore, there is a need in the art for creels that: (1) allow packages to be changed without interrupting the manufacturing process; (2) hold a large number of packages for feeding fiber to high speed manufacturing processes in a relatively compact footprint; (3) minimize the changes in direction of the fiber during delivery to eliminate breaks and minimize tension; (4) provide a fast, reliable and continuous method of unwinding, feeding and delivering high tack elastomeric fibers from a package to a high speed manufacturing process.
The present invention compact creel using the OETO method that accommodates an increased number of packages in a relatively small footprint while providing a straight in-line delivery path in which fiber bends and changes in direction are minimized. In addition, the present invention is a system, apparatus and method for tension control in a fiber feeding system that provides a fast and reliable method for feeding high tack elastomeric thread or fiber from a package to a manufacturing process. Furthermore, the present invention provides a method and apparatus for changing packages on a creel without interrupting the manufacturing process. In particular, the compact creel of the present invention provides for continuous operation of unwinding and fiber delivery by allowing a standby package to be loaded on the same mandrel as an active package that is presently being unwound.
One embodiment of the present invention is a method for positioning and loading at least one new standby package on a mandrel of a creel while an active package is being unwound, comprising: sliding a new standby package onto the mandrel adjacent to at least one of an active package and a standby package; tying a leading fiber end of the new standby package to a trailing fiber end of the at least one of an active package and standby package; inserting a mandrel core holder and an end pivot stud of a package change fixture into the mandrel and creel frame, respectively; releasing the package support assembly and pivoting the package support assembly away form the mandrel; pivoting the package change fixture, the mandrel, the mandrel support bar, and packages upward at least 10° until the end of the mandrel support bar disengages a mandrel support bolt; removing the mandrel support bar from the creel frame and form slots in the mandrel; pivoting the package change fixture, mandrel, and packages until the package change fixture contacts and is aligned with the creel frame; sliding the standby package onto the mandrel at least until the new standby package contacts at least one of the active package and a standby package and further sliding the new standby package to eject an exhausted core of an old active package from the end of the mandrel; reinserting the mandrel support bar through the slots in the mandrel and into the support bar slots of the creel frame; pivoting the package change fixture, mandrel 7 and packages upward at least 10°; pushing the mandrel support bar into the creel frame until the mandrel support bar is aligned with the mandrel support bar bolt; pivoting the package change fixture, mandrel 7 and packages back down to a normal operating position; and removing the package change fixture by pulling outward until the pivot stud and the mandrel core holder are disengaged from the creel frame and mandrel, respectively.
Another embodiment of the present invention is a method for positioning and loading at least one new standby package on a mandrel of a creel while an active package is being unwound comprising: sliding the new standby package onto the mandrel and adjacent to at least one of a standby package and an active package; tying a tail end of the fiber of at least one of an active package and a standby package to the lead end of the fiber of the new standby package; attaching a package change fixture to a creel frame to support the mandrel; inserting a mandrel core holder of the package change fixture into the mandrel and locking the mandrel core holder in place to support the packages and mandrel; releasing a package support assembly from the mandrel and pivoting the package support assembly away from the mandrel; sliding the new standby package along the mandrel until contacting at least one of the active package a standby package, and further sliding the new standby package until an exhausted core is ejected; reconnecting the package support assembly to support and secure the mandrel; unlocking the mandrel core holder of the package change fixture from the mandrel; and removing the package change fixture from the mandrel and creel frame.
Another embodiment of the present invention is a method for monitoring and adjusting the net tension of a fiber group or the tension of a single fiber by at least one of increasing, maintaining or decreasing the tension on the fiber group or fiber.
Yet another embodiment of the present invention is an apparatus for unwinding an elastomeric fiber, comprising: a creel frame; a plurality of mandrels; a plurality of active packages; at least one new standby package; a plurality of drive and tension control assemblies; a package support assembly; a package change fixture; and an electronics cabinet, wherein at least one of the plurality of active packages and the at least one new standby package are configured in-line on at least one of the plurality of mandrels, and the at least one new standby package is positioned and loaded on one of the plurality of mandrel one of the plurality of active packages is being unwound.
With reference to
In addition, the interior of the mandrel 7 is configured to accommodate the insertion of a package change fixture 21 that allows positioning and loading of at least one standby package 6 on each mandrel 7 of the creel while fiber is being unwound from an active package 5. For example, by making the mandrel 7 hollow, the mandrel can accommodate the insertion of a package change fixture. Further the compact creel system 1 includes a tray 9 that can catch the exhausted core 8 of an active package 5 for later disposal.
Further,
The drive and tension control assembly 13 of
In addition,
In addition, the interior of the mandrel 7 is configured to accommodate the insertion of a package change fixture 21 that allows positioning and loading at least one standby package 6 on each mandrel 7 of the compact creel while fiber is being unwound from an active package 5. For example, this may be accomplished by making the mandrel 7 hollow. Further, the compact creel system 1 may include trays 9 (not shown) that can catch an exhausted core 8 of a previously active package 5 for later disposal.
Further,
The drive and tension control assembly 13 of
In addition,
In addition, as shown in
An exemplary method for operating the compact creel system 1 of both embodiments of the present invention comprising: a) placing active packages 5 and standby packages 6 on their respective mandrels 7; b) tying the lead end of a fiber from each standby package 6 to a tail end of a fiber of a corresponding active package 5 located on the same mandrel 7; c) directing the leading fiber end of each active package 5 through the respective static guide 27 and pre-tensioning guide roll 29 of the drive assembly 13 that corresponds to each mandrel 7 and then through a wrap of 270° or less around a driven roll 25 of the drive and tension control assembly 13 configured to control tension in the fiber to be within predetermined tension ranges; causing the fiber to be engaged by a take-up device (i.e., not shown in
In particular, repeating steps a) through e), as required, allows continuous operation of the compact creel system 1. The compact size of the creel system 1 allows a large number of yarns to be delivered from a small footprint that takes up a reduced amount of space on the manufacturing floor in comparison to background art creel systems.
In addition, as shown in
In addition, as shown in
According to a preferred embodiment, a user enters a desired tension range that is to be maintained for the thread directly into tension controller device 35. The tension controller device receives input signals from the tension sensor 31 representative of the thread tension. Tension controller device 35 uses these input signals to determine whether the tension level of the thread coming off driven take-off roll 25 can be maintained because it is within the desired tension range, or whether the tension needs to be increased or decreased. Variable-speed motor 33 of the drive and tension control assembly 13 will maintain a speed until tension controller device 35 outputs a signal indicating that the net tension is outside the desired range based on a signal received from the tension sensor 31. The output signal from tension sensor 31 will override an input signal from a manufacturing process and change the speed of the variable speed motor 33 of the drive and tension control assembly 13 until the speed is within the desired range. That is, the speed of variable speed motor 33 will be adjusted to correct for variations in tension that occur during unwinding or the thread feeding process.
Table 1 shows examples of thread line tension variations, as measured at a sensor, as the distance, d, between the package and a static guide was varied over a distance between about 0.25 and 0.81 meter. These thread line tension variations are examples that may be used to determine a desired or predetermined range of tensions for the present invention.
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.
If the tension controller device 35 determines that the thread tension after driven take-off roll 25 is too high, the tension controller device 35 will increase the speed of motor 33. Alternatively, if the tension controller device 35 determines that the thread tension after driven take-off roll 25 is too low, the tension controller device 35 will decrease the speed of motor 33.
As described above, drive and tension controller assembly 13 may be configured to look at a signal from a manufacturing process device as well as a signal from the tension sensor 31 in determining the appropriate speed for motor 33. In alternative embodiments, the drive and tension control assembly 13 of the manufacturing process may be configured to look only at a signal from tension sensor 31 (i.e., a tension feedback signal) in determining the appropriate speed for motor 33. Further, a large compact creel system may include multiple sensors positioned throughout the system that determine the appropriate speed of the motor 33.
According to a preferred embodiment, the speed of motor 33 is controlled without receiving input from an external manufacturing processing system (e.g., a diaper machine). That is, the motor speed is based solely on tension feedback detected by tension sensor 31 and recognized by tension controller device 35.
In addition, to reduce the likelihood of slack in the thread before reaching driven take-off roll 25, a pretensioner may be used in the pretensioner guide roll 29. 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. Accordingly, pretensioner guide roll 29 uses a pretensioner which otherwise hinders the speed of rotation of the pretensioner guide roll 29. In a preferred embodiment for pretensioner guide roll 29, a magnet is positioned adjacent to pretensioner guide roll 29 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 29 and thereby maintains the tension and eliminates slack in the thread without relying on friction.
When no broken threads or fibers are detected in step 3203, the method determines whether the threads or fibers are moving in step 3204 of
In step 3212 of
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 3214. The number of increments and decrements in the motor speed over the course of the algorithm are stored in step 3220. 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 3220 exceeds a correction threshold in step 3218.
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 3215 of
In step 3218 of
The correction threshold is a predetermined value that is entered in the trim tension algorithm 3201 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.
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 3225 and the tension trim algorithm 3201 is stopped at step 3227C. When the tension trim algorithm 3201 is stopped at either of steps 3227A, 3227B or 3227C, as discussed above, the operator can read the alarm status of the equipment and take the appropriate steps to intervene and correct the process.
When the average value of the thread or fiber tension is not out-of-range, the method maintains the motor speed, as indicated in step 3221 and returns to step 3203 to repeat the above discussed trim tension monitoring algorithm.
The foregoing description of the present invention provides illustration and description, but is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The scope of the invention is defined by the claims and their equivalents.
The foregoing figures show particular compact creel systems used to feed elastomeric threads to a manufacturing process such as a diaper or textile machine. However, it should be understood that the present invention is not limited to the configuration of the creel systems shown. Alternative unwinder systems also fall within within the scope of the present invention even if they vary from the creel systems shown in a variety of ways not limited to but at least including: (1) number of threads being fed; (2) types of packages supported; (3) positioning and use of guide and rack frame members; and (4) number and type of drive and tension control systems. In particular, the present invention is suitable for use with any creel system where it would be desirable to monitor and control the tension of elastomeric or other types of thread in order to minimize tension variations in the thread from being introduced into a manufacturing process.
In addition, though the figures illustrate a particular compact creel system that uses the OETO method for unwinding a package, it should be understood that the present invention is equally suitable for use with creel systems that do not use the OETO method. In particular, the present invention applies to all creel systems where a tension monitoring and tension adjusting system can be used to enhance efficiency and/or quality of thread processing systems using elastomeric or other types of threads.
Further, the written description of the preferred and other exemplary embodiments discusses the applicability of the present invention for providing elastomeric thread to manufacturing processing in the form of a diaper manufacturing system. In particular, the application is preferably directed at the task of supplying elastomeric thread to be used for the elastic band features present near the open end of the legs of the diaper. While the present invention is discussed in a diaper manufacturing environment, such discussions are not intended to be limiting and is included for exemplary purposes only. It will be understood by those skilled in the art after reading the description that the present invention is equally suitable for use for any other manufacturing process that utilizes an elastomeric thread.
Further, though only a few exemplary embodiments of the present invention have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible in these embodiments (e.g., types of rack systems, guide systems, drive systems, and control systems; sizes, structures, shapes and proportions of the various elements and mounting arrangements; and use of materials in terms of combinations and shapes) without materially departing from the novel teachings and advantages of the present invention.
Furthermore, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating configuration and arrangement of the preferred and other exemplary embodiments without departing from the spirit of the inventions as expressed herein.
This application claims benefit of priority from Provisional Application No. 60/724,796 filed Oct. 11, 2005.
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| Number | Date | Country | |
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| 20070084960 A1 | Apr 2007 | US |
| Number | Date | Country | |
|---|---|---|---|
| 60724796 | Oct 2005 | US |
