Title of Invention

YARN WITHDRAWAL DEVICE FOR CONTINUOUSLY UNWINDING A YARN

Abstract

NO.1593/CHENP/2005 ABSTRACT YARN WITHDRAWAL DEVICE FOR CONTINUOUSLY UNWINDING A YARN The invention relates to a yam withdrawal device for making available a yam adapted for continuous unwinding, as well as a texturing machine with a yam withdrawal device. In the art, the yam withdrawal device comprises at least one feed yam package and a reserve yam package, whose leading and trailing yam ends are knotted together. The transition of the yam being unwound from the feed yam package to the reserve yam package is detected by a sensor. This occurs by a movable yam guide, which moves during the transition from an inactive position to a signaling position. To prevent the movable yam guide from rebounding, this yam guide or an element connected thereto are provided with a second degree of freedom of movement. A correspondingly shaped curve coordinates the two degrees of freedom of movement such that after the rebound the movement is of such a kind that a departure from the signaling position is geometrically not possible. Figure 2.

Full Text

The invention relates to a yam withdrawal device for continuously unwinding a yam, as well as a texturing machine with the yam withdrawal device of the invention. Yam withdrawal devices of this type are disclosed in WO 00/21866 A2. To ensure a continuous operation in a yam treating process, wherein a yam is unwound from a feed package and further processed, the trailing yam end of the feed yam package is joined to the leading yam end of a reserve yam package. In this connection, the joining occurs such that after having completely unwound from the feed yam package, the yam continues to unwind with no trouble from the reserve yam package. Normally, the joining occurs by knotting or splicing. A thick place that forms in the yam as a result thereof, represents an unavoidable decrease in quality in the subsequent process. For this reason WO 00/21866 A2 proposes to detect the transition from the feed yam package to the reserve yam package with the use of a sensor and to respond thereto in the treatment process. This is accomplished by a sensor, which is provided between the packages, and by means of a movable yam guide, whose movement is released by the yarn change between the packages, and whose position is detected. The problem that arises in this process is that the fast advancing yarn accelerates the movable yarn guide from an inactive position to a signaling position in a very short period of time to a very high speed. In so doing, it is possible that in the signaling position the yarn guide is reflected on its stop, and drops back to its inactive position. While it is possible to detect and electronically store this short stay, it is not desired from the viewpoint of faster and easier operability and operational safety in the event of electrical breakdowns that the yarn guide be in its released state in the inactive position. Obvious attempts of solving the problem, such as, for example, softly absorbent stop materials, bring no results. This also applies to bulk material fillings, which are integrated into the yarn guide, or other additional masses that are applied for purposes of damping. The reason is to be found in that because of the small mass of the yarn guide in combination with a high speed, a slight, undamped residual energy will already suffice to reflect the yarn guide into its inactive position. Consequently, likewise other obvious solutions, such as bistable layers with the aid of permanent magnets, have brought no results. Likewise air damping and electromagnetically operating dampers are unsuited to bring about the required high damping forces. In this instance, one may consider as additional problem the fact that the speed, at which the yarn guide moves to the signaling position, varies very greatly. For this reason, it is hardly possible to adjust, for example, a friction brake such that it is equally reliable in operation both at high and at low speeds of the yarn guide. It is therefore an object of the invention to make available a yarn withdrawal device with a movable yarn guide, which reliably prevents the yarn guide from rebounding even at varying speeds. This object is accomplished by the invention in that a sensor includes a means, which prevents because of its geometry the yarn guide from rebounding to its inactive position. The advantage of the invention lies in that irrespective of the speed, at which the yarn guide is moved to its signaling position, it is prevented from rebounding, and thus operates in a reliably manner. This is accomplished in that a second degree of freedom of movement is created in addition to the movement of the yarn guide from its inactive position to its signaling position. As a result of correspondingly coordinating the second degree of freedom of movement with the first degree of freedom of movement, it is accomplished that the movement of the yarn guide from its inactive position to its signaling position turns out to be different than in the opposite direction. This recognition is used in the construction of the yarn withdrawal device according to the invention for blocking the return path of the yarn guide after rebounding. In a variant of the yarn withdrawal device according to the invention, the second degree of freedom of movement is realized by a pawl, which is capable of overshooting a notch in the direction of the signaling position at a high speed of the yarn guide, whereas it blocks the movement in the opposite direction. This pawl may be integrated both into the stationary part of the sensor and directly into the yarn guide. At a standstill, the blockage must be capable of reversing itself or be manually releasable. In another, preferred variant, the yarn guide itself is movable in two degrees of freedom of movement. The yarn guide cooperates with a curve, which coordinates the degrees of freedom of movement of the yarn guide. This curve is shaped such that while moving from its inactive position to its signaling position, the yarn guide initially advances along first portion of the curve. Upon arrival at the signaling position, the yarn guide is moved because of its speed and mass moment of inertia along a second portion of the curve, which blocks a return to the inactive position. In a further development of this variant, the second part of the curve is shaped such that it permits the yarn guide to move along this curve several times, and thus decreases its kinetic energy by friction. In the ideal case, the second portion of the curve includes a circular guideway, which repeatedly returns the yarn guide to the end position, so that it does not leave the signaling position. Once the yarn guide is inactive, an operator changing the feed yarn packages can easily return it along the first part of the curve to its inactive position. The yarn withdrawal device is used in a texturing machine for texturing and winding yarns, with the texturing machine unwinding the yam from the yarn withdrawal device via a feed system. In the following an embodiment is described in greater detail with reference to the attached drawings, in which: Figure 1 shows a yarn withdrawal device of the invention as well as a schematic view of the texturing machine; Figure 2 shows a variant of the sensor of the yarn withdrawal device; and Figure 3 shows a further variant of the sensor of the yarn withdrawal device. Figure 1 illustrates a yarn withdrawal device 1 and a schematic view of a texturing machine 10-17. In the yarn withdrawal device 1, a continuous yarn 2 is made available. To this end, the yarn 2 is unwound via a yarn guide 9 from a feed yarn package 4.1, which is provided in a first creel position 3.1. During the winding of the feed yarn package, a trailing yarn end 5.1 of the feed yarn package 4.1 was guided from the interior of the package out of the stroke range and can therefore be joined by means of a tie 5.3 to the leading yarn end of a reserve yam package 4.2, which is provided in a second creel position 3.2. Once the feed yarn package 4.1 is completely unwound, the connection of the trailing yarn end 5.1 to the leading yarn end 5.2 tensions, so that the yarn 2 is pulled out of a sensor 6. This occurrence is detected by the sensor 6 and supplied as a signal 7 to a signal processing unit 8. After leaving the yarn withdrawal device 1, the yarn 2 is initially advanced in the texturing machine by a first feed system 10, which also builds up the necessary yarn tension for withdrawing the yarn. In the texturing machine, the yarn is initially heated in a heater 11, and cooled in a cooling rail 12 such that it sets a twist, which is imparted to the yarn 2 by the texturing unit 13. Subsequently, the yarn is withdrawn by a second feed system 14, heated one more time in a second heater 15, and advanced via a third feed system 16 to a takeup unit 17. The takeup unit 17 comprises a yarn traversing device 17.1, which reciprocates the yarn 2 transversely to the axis of a package 17.3, and a drive roll 17.2, which presses the yarn 2 against the package 17.3, while driving it at the same time. It is obvious that a tie 5.3 advancing through the process represents an imperfection in the textured yarn. For this reason, it is important to detect with a sensor a tie 5.3 that has passed through the process, and to respond accordingly. This may be done in that a package 17.3 having been produced at this point in time is classified faulty, or also that the package 17.3 is doffed at this point in time, so that the imperfect length of the yarn 2 is not wound. Figure 2 is a detail view of the sensor 6. The sensor 6 essentially comprises an insertion slot 19 arranged in a yarn guide support 18, and a yarn guide 20. The yarn guide 20 is supported for rotation about an axis of rotation 21. In the Figure, the yarn guide 20 is shown in an inactive position 20.1. The yarn 2 is inserted behind the yarn guide 20 such that a tensioning of the yarn, as it occurs during a transition of the yarn from the feed yarn package 4.1 to the reserve yarn package 4.2 of Figure 1, pulls the yarn 2 out of the insertion slot 19 and, in so doing, entrains the yarn 20 from its inactive position 20.1 to a signaling position 20.2. This change in position is detected by a switch 28. Representative of other switch principles, such as optical, inductive, or capacitive switches, the Figure shows a mechanical cam switch. In the illustrated embodiment, the tip of the yam guide 20 is fork-shaped. This has the advantage that during the insertion of the yarn 2 into the slot 19, the yarn guide 20 is moved in one step together with the yarn 2 from its signaling position 20.2 to its inactive position 20.1. The following describes the movement of the yarn guide 20 during the transition of the yarn 2 from the feed yarn package 4.1 to the reserve yarn package 4.2. Because of the yarn tension, the yarn 2 is laterally pulled out of the insertion slot 19. At high yarn speeds of several hundred meters per minute, very high accelerations act upon the yarn guide 20. The yarn guide 20 rotates at a high speed about the axis of rotation 21 in the direction of its signaling position 20.2. A pawl 22 that is pushed by means of a spring 23 against a curve 26 overshoots a notch 27. The steep slope on the backside of the notch 27 prevents the pawl 22 from overshooting the notch in the opposite direction, and thus prevents the yarn guide 20 from rebounding to its inactive position 20.1. A system comprising a tension spring 25 and a mass 24 that is additionally arranged in the yarn guide 20, and which accommodates the pawl 22 and pawl spring 23, causes the pawl 22 to cooperate with the curve 26 only at high speeds. Because of the friction between the mass 24 and the yarn guide 20, the mass is unable to return to its inactive position during the rebound. Only when the yarn guide 20 has come to a standstill, will the mass 24 and thus the pawl 22 be pulled back. The operator will then be able to move the yarn guide 20, as has been described above, to its inactive position 20.1. While not described in greater detail, it is likewise possible to integrate the pawl 22 into the stationary yarn guide support 18. Likewise possible is an integration of the described elements, namely pawl 22, pawl spring 23, mass 24, and spring 25 into the yarn guide 20, for example, by flexible solid-body joints. Figure 3 is a detail view of another variant of the sensor 6. In this embodiment, the yarn guide 20 connects to the support 18 by means of a turning and sliding joint 29. A cam 30 that is guided in a curve 31 coordinates the rotational and the translational degree of freedom. The curve 31 is divided into a first portion 31.1 for the movement of the yarn guide 20 from its inactive position 20.1 to its signaling position 20.2 and a second portion 31.2 for moving the yarn guide 20 after reaching the signaling position 20.2. Based on the description of Figure 2, the movement of the yarn guide 20 during a yarn change is described. Starting from its inactive position 20.1, the yarn guide initially performs a movement, which is defined by the advance of the cam 30 in the first portion 31.1 of the curve 31. In Figure 3, this is a pivotal movement about the pivot of the turning and sliding joint 29. This will apply, until the signaling position 20.2 is reached. In this position, the cam 30 enters the second portion 31.2 of the curve 31. The second portion 31.2 of the curve 31 represents a circular guideway. This circular guideway is configured such that while it allows the yarn guide 20 to rebound in an orderly fashion, it prevents the yarn guide 20 from leaving the area of the signaling position 20.2. Instead, the cam 30 advances along the circular guideway once or several times, and in so doing, it decreases the kinetic energy of the yarn guide. Based on the circular movement of the cam 30, the yarn guide 20 performs a combined pivotal/sliding movement with a small amplitude. As a result of the sliding movement in the turning and sliding joint 29, energy is removed from the yarn guide 20 because of friction. Because of the smaller space availability, the cam is ideally made truncated, with that, it is possible to achieve a great flexural strength of the cam despite its small structural shape. 1 Yarn withdrawal device 2 Yarn 3.1 First creel position 3.2 Second creel position 4.1 Feed yarn package 4.2 Reserve yarn package 5.1 Trailing yarn end 5.2 Leading yarn end 5.3 Tie 6 Sensor 7 Signal 8 Signal processing unit 9 Yarn guide 10 First feed system 11 Heater 12 Cooling rail 13 Texturing unit 14 Second feed system 15 Second heater 16 Third feed system 17 Takeup unit 17.1 Yam traversing device 17.2 Drive roll 17.3 Package 18 Yarn guide support 19 Insertion slot 20 Yarn guide 2 0.1 Inactive position 20.2 Signaling position 21 Axis of rotation 22 Pawl 23 Pawl spring 24 Mass 25 Tension spring 2 6 Curve 27 Notch 28 Switch 29 Turning and sliding joint 3 0 Cam 31 Curve 31.1 First portion of the curve 31.2 Second portion of the curve WE CLAIM 1. Yam withdrawal device (1) for continuously unwinding a yam (2), with at least two creel positions (3.1, 3.2), wherein one of the creel positions (3.1) mounts a feed yam package (4.1) and the other creel position (3.2) a reserve yam package (4.2), wherein the yam (2) is unwound from the feed yam package (4.1) and from the reserve yam package (4.2), and wherein a trailing yam end (5.1) of the feed yam package (4.1) is knotted to the leading yam end (5.2) of the reserve yam package (4.2) by a tie (5.3), wherein a sensor (6) is provided between the two creel positions (3.1, 3.2), which detects and signals the transition from the yam of the feed yam package (4.1) to the yam of the reserve yam package (4.2), and wherein the sensor (6) comprises a yam guide (20) that is movable by the yam transition from an inactive position (20.1) to a signaling position (20.2), and a position sensor (28) that detects the position of the yam guide (20), characterized in that the sensor (6) comprises a means, which prevents during the yam transition a reflection of the yam guide (20) from the signaling position (20.2) in the direction of the inactive position (20.1). 2. Yam withdrawal device as claimed in claim 1, wherein the means for preventing the reflection makes available on the yam guide (20) or an element connected to the yam guide (20) a second degree of freedom of movement in addition to the first degree of freedom of movement of the yam guide (20) between the inactive position (20.1) and the signaling position (20.2), and that the first degree of freedom of movement and the second degree of freedom of movement are coordinated with each other in such a manner that they prevent the reflection of the yam guide (20) from the signaling position (20.2) in the direction of the inactive position (20.1). 3. Yam withdrawal device as claimed in claim 2, wherein the second degree of freedom of movement is produced by a pawl (22), which is capable of overshooting a notch (27) during the movement of the yam guide (20) in the direction of the signaling position (20.2), and which blocks in the direction of the inactive position (20.1). 4. Yam withdrawal device as claimed in claim 3, wherein the pawl (22) is arranged on the yam guide (20). 5. Yam withdrawal device as claimed in claim 3, wherein the pawl (22) is arranged on the stationary part of the sensor (6). 6. Yam withdrawal device as claimed in claim 2, wherein the yam guide (20) is adapted for moving in the first and the second degree of freedom of movement, and that a curve (31) coordinates the degrees of freedom of movement in such a manner that during the movement of the yam guide (20) to the signaling position (20.2), a first porfion (31.1) of the curve is traversed, and that a rebound of the yam guide (20) results in traversing a second portion (31.2) of the curve, the second portion (31.2) of the curve being shaped such that the mass forces of the yam guide prevent it from reaching the inactive position (20.1). 7. Yam withdrawal device as claimed in claim 6, wherein the second portion (31.2) of the curve is shaped such that it is traversed several times. 8. Yam withdrawal device as claimed in claim 6, wherein the second portion (31.2) of the curve corresponds to a circular guideway. 9. Texturing machine for texturing and winding a yam with at least one feed system (10) which unwinds the yam from a yam withdrawal device (1), characterized in that the yam withdrawal device (1) is a yam withdrawal device as claimed in any one of the preceding claims.

Documents:

1593-chenp-2005 abstract duplicate.pdf

1593-chenp-2005 abstract.jpg

1593-chenp-2005 abstract.pdf

1593-chenp-2005 correspondence -others.pdf

1593-chenp-2005 correspondence -po.pdf

1593-chenp-2005 description (complete) duplicate.pdf

1593-chenp-2005 description (complete).pdf

1593-chenp-2005 drawings duplicate.pdf

1593-chenp-2005 drawings.pdf

1593-chenp-2005 form-1.pdf

1593-chenp-2005 form-18.pdf

1593-chenp-2005 form-26.pdf

1593-chenp-2005 form-3.pdf

1593-chenp-2005 form-5.pdf

1593-chenp-2005 pct search report.pdf

1593-chenp-2005 pct.pdf

1593-chenp-2005 petition.pdf