YARN WINDING APPARATUS
Field of the Invention
The present invention relates to a yarn winding apparatus that winds a yarn around a winding tube while traversing the yarn.
Background of the Invention
A yarn winding apparatus generally has a winding tube rotational-driving device that rotationally drives a winding tube around which a yarn is wound and a traverse device that traverses the yarn being wound around the winding tube. In the yarn winding apparatus, the yarn may fail to be traversed because, for example, the yarn slips off the traverse device. In this case, an abnormal winding state such as straight winding may occur. To detect the abnormal winding state, a known method determines the diameter of a winding package formed by winding the yarn around the winding tube. The Unexamined Japanese Patent Application Publication (Tokkai-Hei) No. 10-72168 discloses a winder (yarn winding apparatus) having a friction drum that rotates a traverse winding package (winding tube). The friction drum has a traverse groove and also serves as a traverse device that uses the groove to traverse the yarn while the traverse winding package is being rotationally driven. The winder calculates the diameter of the traversed winding package from the angular speed of the friction drum and the angular speed of the traverse winding package.
Summary of the Invention
A main object of the present invention is to improve the above-described winding apparatus to provide a yarn winding apparatus that can quickly and accurately detect the abnormal winding state of the package such as straight winding.
A yarn winding apparatus according to the present invention comprises a winding tube rotational-driving device, a traverse device, a yarn splicing device, a package diameter measuring means, a package diameter predicting means, and a winding state detecting means. The winding tube rotational-driving device rotationally drives a winding tube around which a yarn unwound from a supplying bobbin is wound. The traverse device traverses the yarn while the yarn is being wound around the winding tube. The yarn splicing device splices a supply-side yarn end to a winding-side yarn end. The package diameter measuring means measures actual diameter of a winding package formed by winding the yarn around the winding tube. The package diameter predicting means uses the actual diameter measured by the package diameter measuring means as a reference diameter to calculate predicted diameter of the winding package for a time point after the measurement of the reference diameter. The winding state detecting means detects a winding state of the winding package at a certain time in accordance with the actual diameter measured at a certain time by the package diameter measuring means and the predicted diameter calculated for the same certain time by the packagediameter predicting means. When winding of the yarn around the winding tube is suspended and subsequently resumed, the package diameter predicting means updates the reference diameter used as the reference for the calculation of the predicted diameter to the actual diameter measured by the package diameter measuring means at the time of resumption of the winding of the yarn.
The yarn winding apparatus according to the present invention compares the actual diameter with the predicted diameter at all times during winding. The yarn winding apparatus can thus quickly detect abnormal winding state. Furthermore, when suspending and subsequently resuming the winding of the yarn around the winding tube, the yarn winding apparatus updates the reference diameter used to determine the predicted diameter to the actual diameter measured at the time of resumption of the winding of the yarn. Thus, the accuracy of the predicted diameter, which is calculated in accordance with the actual diameter, can be increased. This makes it possible to accurately detect that the abnormal winding state resulting from straight winding or the like is occurring on the winding package.
Furthermore, preferably, the winding state detecting means compares the actual diameter measured by the package diameter measuring means with the predicted diameter measured by the package diameter predicting means, and when the actual diameter is greater than the predicted diameter by at least a predetermined value, the winding state detecting means determines that the winding state of the winding package is abnormal and stops driving of the winding tube
rotational-driving device. This prevents a possible situation in which the abnormal winding state such as straight winding excessively increases the diameter of the winding package, which thus contacts and damages a traverse guide of the traverse device. Furthermore, the detection can be quickly performed to reduce possible damage to the winding package.
Moreover, the package diameter predicting means preferably calculates the predicted diameter of the winding package by multiplying double diameter of the yarn by a predetermined correction coefficient for each of all traverse operations performed since the update of the reference diameter and adding sum of the values obtained to the reference value. That is, the predicted diameter of the winding package is obtained by multiplying double the diameter of the yarn by the predetermined correction coefficient for each of all the traverse operations performed since the update of the reference diameter and adding the sum of the values obtained to the reference value. The predetermined correction coefficient is set by considering a variation in the diameter of the yarn wound around the winding tube, the variation being caused by the tension of the yarn, a contact pressure on the yarn, or the like. Thus, the predicted diameter of the winding package can be accurately calculated to reduce possible erroneous detections of the winding state.
Additionally, preferably, when the winding state detecting means detects that the actual diameter measured by the package diameter measuring means is smaller than the predicted diameter calculated by the package diameter predicting means,
the package diameter predicting means updates the reference diameter to the actual diameter. This makes it possible to accurately detect that the abnormal winding state resulting from straight winding or the like is occurring on the winding package.
Other features, elements, processes, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.
Brief Description of the Drawings
Figure lisa schematic front view and a block diagram showing a yarn winding unit in an automatic winder according to an embodiment of the present invention.
Figure 2 is a flowchart showing how the state of winding a yarn into a package is detected.
Figure 3 is a diagram showing a temporal variation in the diameter of the winding package.
Detailed Description of the Preferred Embodiment
An embodiment of the present invention will be described. First, with reference to Figure 1, a yarn winding unit 2 (yarn winding apparatus) in an automatic winder 1 will be described. The yarn winding unit 2 winds a yarn 4 unwound from a supplying bobbin 3, around a winding tube 6 while allowing a
traverse device 5 to traverse the yarn 4, to form a winding package 7 of a predetermined length and a predetermined shape. Figure 1 shows only one yarn winding unit 2. However, the automatic winder 1 is composed of a large number of the yarn winding units 2 arranged on a machine body (not shown in the drawings) in a 1 ine.
The yarn winding unit 2 comprises a cradle 8 removably supporting the winding tube 6, and a contact roller 9 that is rotationally driven by the winding tube 6 or a winding package 7 in contact with a peripheral surface of the winding tube 6 or a peripheral surface of the winding package 7. The cradle 8 is configured to be able to rotatably support the winding tube 6 at opposite ends thereof by sandwiching the winding tube 6 between opposite portions of the cradle 8. Furthermore, the cradle 8 is configured so as to be tiltable around a swinging shaft 10 and to be able to swing to absorb an increase in the diameter of the winding package 7 resulting from winding of the yarn 4 around the winding tube 6.
A winding tube driving motor 41 (winding tube rotational-driving device) is attached to one of the portions of the cradle 8 which sandwich the winding tube 6 therebetween and the cradle 8 is thus configured so that the winding tube driving motor 41 rotationally drives the winding tube 6 to wind the yarn 4 around the winding tube 6. A motor shaft of the winding tube driving motor 41 is coupled to the winding tube 6 so as not to be rotatable relative to the winding tube 6 when the winding tube 6 is gripped by the cradle 8. Actuation of the winding tube driving motor 41 is controlled by a winding tube driving control section 42. The
winding tube driving control section 42 receives signals from a unit control section 50 described below to control operation and stoppage of the winding tube driving motor 41.
A package rotation speed sensor 43 is attached to the cradle 8. The package rotation speed sensor 43 detects the rotation speed of the winding tube 6 held by the cradle 8. Rotation speed detection signals for the winding tube 6 are transmitted from the package rotation speed sensor 43 to the winding tube driving control section 42 or the unit control section 50. Moreover, the rotation speed detection signals are also transmitted to a traverse control section 46 described be 1ow.
A package diameter sensor 44 (package diameter measuring means) such as an angle sensor or the like is attached to the cradle 8. The package diameter sensor 44 is configured to be able to measure the diameter of the winding package 7, which is formed by winding the yarn 4 around the winding tube 6 held by the cradle 8, by detecting the swing angle of the cradle 8. This measuring method enables the diameter of the winding package 7 to be measured accurately and also when winding is stopped. The diameter of the winding package 7 measured by the package diameter sensor 44 is transmitted to the unit control section 50 and transferred from the unit control section 50 to the winding tube driving control section 42.
The traverse device 5 is provided close to the contact roller 9. The traverse device 5 traverses the yarn 4 being wound around the winding tube 6. The traverse device 5 includes a traverse guide 11 provided so as to be reciprocatable in a
traverse direction and a traverse guide driving motor 45 as a driving means for reciprocatably driving the traverse guide 11.
The traverse device 5 has the traverse guide 11 formed, like a hook, at the tip end of an elongate arm member 13 configured capable of swinging around a support shaft. The traverse device 5 is configured to reciprocate and swing the arm member 13 using a traverse guide driving motor 45 as shown by an arrow A in Figure 1. Specifically, the traverse device 5 is configured such that a motor shaft of the traverse guide driving motor 45 is coupled to a base end of the arm member 13, and rotated forward and backward to reciprocate the traverse guide 11.
Actuation of the traverse guide driving motor 45 is control led by the traverse control section 46. The traverse control section 46 receives signals from the unit control section 50 to control operation and stoppage of the traverse guide driving motor 45. Furthermore, the traverse device 5 includes a traverse guide position sensor 47 such as a rotary encoder. The traverse device 5 is thus configured to be able to detect the position of the arm member 13 (or the position of the traverse guide 11) to transmit a position signal to the traverse control section 46.
Next, the yarn splicing device 14 and the yarn clearer 15 will be described.
The yarn winding unit 2 is configured such that the yarn splicing device 14 and
the yarn clearer 15 are disposed in this order in a yarn traveling path between
the supplying bobbin 3 and the contact roller 9; the yarn splicing device 14 is
closer to the supplying bobbin 3.
When the yarn clearer 15 detects a yarn defect and cuts the yarn 4, or when replacing the supplying bobbin 3, or when doffing a fully wound package 7 and placing an empty bobbin, the winding of the yarn 4 is suspended once. When resuming the winding of the yarn 4 after such suspension, the yarn splicing device
14 splices a lower yarn at the supplying bobbin 3 side and an upper yarn at the
winding package 7 side.
The yarn clearer 15 detects thickness defects in the yarn 4. The yarn clearer
15 is configured to use an appropriate sensor to detect the thickness of the yarn
4 passing though a detection portion of the yarn clearer 15 and then to use an
analyzer 23 to analyze a signal from the sensor to detect a yarn defect such as
slab. The yarn clearer 15 also has a cutter 16 that cuts the yarn 4 immediately
after the yarn defect has been detected.
An upper yarn catching and guiding portion 20 is provided above the yarn splicing device 14 to suck, catch, and guide the upper yarn at the winding package 7 side to the yarn splicing device 14. The upper yarn catching and guiding portion 20 is configured like a pipe and capable of swinging up and down around a shaft 21. The upper yarn catching and guiding portion 20 has a mouth 22 on a tip end thereof. A lower yarn catching and guiding portion 17 is provided below the yarn splicing device 14 to suck, catch, and guide the lower yarn at the supplying bobbin 3 side to the yarn splicing device 14. The lower yarn catching and guiding portion 17 is also configured 1 ike a pipe and capable of swinging up and down around a shaft 18. The lower yarn catching and guiding portion 17 has a suction port 19 on a tip
end thereof. An appropriate negative pressure source is connected to the upper yarn catching and guiding portion 20, and the lower yarn catching and guiding portion 17 to generate suction effect at the mouth 22 and the suction port 19.
In general, the yarn winding unit 2 in the automatic winder 1, the splicing device 14 splices the yarns 4 from a plurality of the bobbins 3 to wind the resulting yarn into one winding package 7. Thus, while the yarn 4 is being wound around the winding tube 6, when the supplying bobbin 3 becomes empty and the supply of the yarn 4 is disrupted, the winding of the yarn 4 around the winding tube 6 is stopped. Furthermore, the reciprocation of the traverse guide 11 is stopped. Then, a supplying bobbin supply device (not shown in the drawings) replaces the empty supplying bobbin with another supplying bobbin, and the yarn splicing device 14 performs a yarn splicing operation. Then, the winding of the yarn 4 around the winding tube 6 and the reciprocation of the traverse guide 11 are resumed.
Furthermore, once the full package 7 is formed, the rotation of the winding tube 6 is stopped to stop the further winding of the yarn 4 around the winding tube 6, and the reciprocation of the traverse guide 11 is also stopped. The full package 7 is removed from the cradle 8 and conveyed on a conveyor (not shown in the drawings). Meanwhile, a new winding tube 6 is set to the cradle 8 from which the full package 7 has been removed. Subsequently, the winding tube 6 is rotationally driven to resume the winding of the yarn 4 and the reciprocation of the traverse guide 11. As described above, the supplying bobbin 3 and the full package 7 are automatically replaced, and the splicing of the upper yarn and the
lower yarn, which is required to resume the winding of the yarn, is automatically performed by the yarn splicing device 14. That is, the yarn winding unit 2 automatically carries out the above-described series of steps without the intervention of any operator.
If the yarn 4 slips off the traverse guide 11, the yarn 4 is wound around the winding tube 6 without being traversed. Then, straight winding is formed at a specific position on the winding tube 6. If the yarn 4 is continuously wound around the winding tube 6 with the straight winding uncorrected, an extremely thick straight winding portion is formed at the specific portion. The extremely thick straight winding portion may contact and damage the traverse guide 11. Thus, the automatic winder 1 according to the present embodiment has a configuration that detects the winding state of the yarn 4 into the winding package 7 to determine whether or not an abnormal winding state such as straight winding is occurring.
In the present embodiment, the winding tube driving control section 42 and the traverse control section 46 are configured on the basis of microcomputers. The winding tube driving control section 42 and the traverse control section 46 each include a central processing unit (CPU) as arithmetic means, a read only memory (ROM) and a random access memory (RAM) as storage means; the central processing unit, the read only memory, and the random access memory are not shown in the drawings. Furthermore, the unit control section 50 also includes a CPU, a ROM, and a RAM (not shown in the drawings).
The ROM of the unit control section 50 stores control software that operates
hardware such as the CPU which is provided in the unit control section 50, as a package diameter predicting section 51 and a winding state detecting section 52. The package diameter predicting section 51 (package diameter predicting means) calculates the predicted diameter of the winding package 7 formed by winding the yarn 4. When the diameter of the yarn 4 is defined as Dy, a reference diameter is defined as DO, a correction parameter is defined as G (<1), and the number of traverse operations performed during a certain period of time is defined as Y, the predicted diameter Db of the winding package 7 is calculated by the following formula: [Formula 1]
The reference diameter DO refers to the diameter of the winding package 7 measured by the package diameter sensor 44 at the time of the start of winding before the package diameter predicting section 51 calculates the predicted diameter of the winding package 7. That is, the reference diameter DO is updated to the diameter of the winding package 7 measured by the package diameter sensor 44 at the time of start of winding or under predetermined conditions. Furthermore, when the yarn 4 is wound into the winding package 7, the yarn 4 is slightly crushed by tension occurring in the yarn 4, the state of twist in the yarn 4, the contact pressure of the contact roller 9 on the winding package 7. Thus,
the diameter Dy of the yarn 4 is multiplied by the correction parameter G to calculate the diameter of the crushed yarn 4. The correction parameter G may have a fixed value or a value varying with lot or yarn type.
The winding state detecting section 52 (winding state detecting means) compares the actual diameter Da of the winding package 7 measured by the package diameter sensor 44 with the predicted diameter Db of the winding package 7 calculated by the package predicting section 51. When a case in which the difference (actual diameter deviation) AD is greater than an allowable diameter deviation DC occurs at least a limiting allowable number of consecutive times Z, the unit control section 50 transmits a stop signal to the winding tube driving control section 42 and the traverse control section 46 to stop the winding of the yarn 4 around the winding tube 6 and the reciprocation of the traverse guide 11. The allowable diameter deviation DC is the limiting allowable value of the difference between the actual diameter Da and the predicted diameter Db which value can be considered to indicate that the abnormal state such as straight winding is not occurring.
Next, with reference to Figure 2, a description will be given of a series of operations performed for detecting the winding state of the yarn 4 into the package 7. Figure 2 is a flowchart showing how the winding state of the yarn 4 into the winding package is detected. In a process shown in Figure 2, the actual diameter Da of the winding package 7 is compared with the predicted diameter Db for each traverse operation. When the state in which the difference (actual diameter
deviation) AD is greater than the allowable diameter deviation DC occurs the limiting allowable number of consecutive times Z, a detection is made that the abnormal winding state such as straight winding is occuring. Then, the winding of the yarn 4 around the winding tube 6 and the reciprocation of the traverse guide 11 are stopped.
First, a determination is made as to whether or not the winding tube 6 has been rotationally driven by the winding tube driving motor 41 and the winding of the yarn 4 around the winding tube 6 has been started (start of winding operation) (step SI). If the winding of the yarn 4 around the winding tube 6 has just been started (step SI: Yes), the winding state detecting section 52 clears the number of times of exceedances X and the number of times of traverse operations Y to an initial state, that is, sets both numbers to zero (step S2). Then, the package diameter sensor 44 measures the actual diameter Da of the winding package 7 to update the reference diameter DO to the actual diameter Da (step S3). If the winding of the yarn 4 around the winding tube 6 has not just been started (step SI: No), a determination is made as to whether or not the yarn 4 is being wound around the winding tube 6 (step S4). If the yarn 4 is not being wound around the winding tube 6, that is, if the winding of the yarn 4 has been suspended (step S4: No), the process returns to step SI. The case in which the winding of the yarn 4 has been started includes the case in which the yarn has been cut upon detection of a yarn defect by the yarn clearer 15, the case in which the supplying bobbin 3 is replaced, the case in which the winding operation manually stopped using a
unit switch has been resumed, or the case in which upon the cutting of the yarn 4 for replacement of the full package 7 or the like, the yarn splicing device 14 has performed the yarn splicing operation, which is followed by the resumption of the winding operation.
If the yarn 4 is being wound around the winding tube 6 (step S4: Yes) or after the reference diameter DO is updated to the actual diameter Da in step S3, the winding state detecting section 52 determines whether or not one traverse operation has been performed (the traverse guide 11 has performed one traverse operation ) (step S5). If the traverse guide 11 has not performed one traverse operation (step S5: No), the winding state detecting section 52 waits for the traverse guide 11 to perform one traverse operation. If the traverse guide 11 has performed one traverse operation (step S5: Yes), the winding state detecting section 52 adds one to the number of traverse operations Y (step S6). The package diameter sensor 44 measures the actual diameter Da of the winding package 7 (step S7). The package diameter predicting section 51 calculates the predicted diameter Db of the winding package 7 (step S8).
Then, the winding state detecting section 52 calculates the actual diameter deviation AD from AD = Da - Db (step S9), and compares the actual diameter deviation AD with the allowable diameter deviation DC (step S10). If the actual diameter deviation AD is greater than the allowable diameter deviation DC (step S10: Yes), the winding state detecting section 52 adds one to the number of exceedances X (step Sll), and compares the number of exceedances X with the

limiting allowable number of times Z (step SI2). If the number of exceedances X is equal to or smaller than the limiting allowable number of times Z (step S12: No), the process returns to step SI. If the number of exceedances X is greater than the limiting allowable number of times Z (step S12: Yes), the winding state detecting section 52 detects that the abnormal winding state such as straight winding is occurring. Then, the unit control section 50 transmits the stop signal to the winding tube driving control section 42 and the traverse control section 46 to stop the winding of the yarn 4 around the winding tube 6 and the reciprocation of the traverse guide 11 (step S14). In other words, when the case in which the actual diameter deviationAD is greater than the allowable diameter deviation DC occurs the limiting allowable number of consecutive times Z, the winding state detecting section 52 detects that the abnormal winding state such as straight winding is occurring, to stop the winding of the yarn 4 around the winding tube 6 and the reciprocation of the traverse guide 11. In this case, an alarm device (not shown in the drawings) may be provided which notifies the operator that the winding of the yarn 4 around the winding tube 6 and the reciprocation of the traverse guide 11 have been stopped due to the occurrence of the abnormal winding state such as straight winding.
Furthermore, if the actual diameter deviation AD is equal to or smaller than the allowable diameter deviation DC (step S10: No), the winding state detecting section 52 clears the number of exceedances X to the initial state, that is, sets the number to zero (step S14). The winding state detecting section 52

compares the actual diameter Da of the winding package 7 measured in step S7 with the predicted diameter Db of the winding package 7 calculated in step S8 (step S15). If the actual diameter Da is equal to or greater than the predicted diameter Db (step S15: No), the process returns to step SI. If the actual diameter Da is smaller than the predicted diameter Db (step S15: Yes), the winding state detecting section 52 updates the reference diameter DO to the actual diameter Da of the winding package 7 measured in step S7 (step S16). The process then returns to step SI. When the yarn 4 continues to be wound into the winding package 7 with the actual diameter Da remaining smaller than the predicted diameter Db, that is, in the state of Da