Title of Invention

"A METHOD FOR CONTROLLING OPERATION OF AN AUTOMATIC YARN WINDING MACHINE"

Abstract

To provide an automatic winding machine wherein even if a yarn splicing operation is carried out during the reduction of pressurizing tension at the tine of winding yarn splicing, the subsequent winding tension can be naintained at an appropriate value depyarn spl icing on the amount of remaining yam. In an automatic winding machine including a tension apparatus 2 that can adjust pressurizing tension by reducing it at a predetermined rate at the tine of winding yarn splicing, a rapid pressure reduction pattern used after a yarn splicing operation during pressure reduction at the tine of winding yam splicing is different fron a rapid pressure reduction pattern used after the yarn splicing operation during normal winding.

Full Text

The present invention relates to a method for controlling operation of an automatic yarn winding machine. Field of the Invention The present invention relates to an automatic winding machine wherein an adjustment value for a tension apparatus for adjusting winding tension is set higher than a reference value upon activation of the rotation of a driving drum and is reduced as the amount of remaining yarn on a yarn supply bobbin decreases, and wherein the automatic winding machine executes rapid winding at a constant winding tension from the beginning of the winding of the yarn supply bobbin to its end. Bacground of the Invention The spun bobbins produced by a spinning machine are supplied to an automatic winding machine in a subsequent step where a yarn is wound onto a package of a predetermined shape that can hold a predetermined amount of yarn thereon, while removing defects from the yarn. In the automatic winding machine, the yarn unwound from the spun bobbin passes through a balloon controller and a tension apparatus and is checked by a slab catcher for defects while being wound around a package rotating on a traverse drum. During winding, the yarn is cut when the slab catcher detects the yarn defect and after removal of the defective portion of the yarn, the yarn on the package side and the yarn on the spun bobbin side are spliced together. The tension apparatus is controlled so that during the unwinding of the spun bobbin, the pressurizing tension is controlled so as to become slightly higher than a reference value as winding begins, then to decrease down to the reference value, and to decrease at a predetermined rate relative to the reference value from the start of a decrease in the amount of remaining yarn until winding is complete. Mien the slab catcher detects the yarn defect near the winding end of the spun bobbin and winding is restarted after a yarn splicing operation, the pressurizing tension is returned to the value used at the start of winding and is gradually reduced relative to the reference value. In such a case, however, the value does not decrease down to the pressurizing tension used at the winding end, thereby increasing the winding tension at the winding end to disturb the shapes of the packages. It is thus an object of the present invention to solve this problem to provide an automatic winding machine wherein even if the yarn splicing is executed while the pressurizing tension is decreasing toward the winding end, the subsequent winding tension can be maintained at an appropriate value depending on the amount of the remaining yam. Summary of the Invention To achieve the said objective this invention provides a method for controlling operation of an automatic yarn winding machine having a tension apparatus, a winding drum drive, a supply bobbin, a splicing device for splicing yarn ends, and a tension controller for controlling the tension apparatus to apply tension to the yarn during a winding operation comprising: setting a yam tension reference pattern in the controller during a normal winding operation which is reduced during a reduction period when the remaining amount of yam on the supply bobbin reaches a predetermined amount; setting a tension adjustment value in the controller higher than the reference value which has a particular return pattern to the reference pattern upon activation of rotation of the winding drum drive and after a splicing operation; and setting a tension adjustment value in the controller having a different return pattern after a splicing operation during the reduction period. The above method further comprises: setting a yarn tension reference pattern in the controller during a normal winding operation which is reduced during a reduction period when the remaining amount of yarn on the supply bobbin reaches a predetermined amount; setting a tension adjustment value in the controller higher than the reference value which returns to the reference pattern upon activation of rotation of the winding drum drive and after a splicing operation; storing the value of the tension apparatus immediately before a splicing operation during the reduction period; and returning the tension adjustment value in the controller during the reduction period to a value based upon the stored value after the end of the splicing operation. The value based upon the stored value is the stored value. The above method includes the step of providing a set value of the reference pattern in the controller during the reduction period, determining whether yam splicing occurs before or after the set value, and using different tension adjustment value return patterns for cases in which the yarn splicing occurs before or after the value of tension of the tension apparatus reaches the set value. Brief Description of the Accompanying Drawings The invention will now be described with reference to the accompanying drawings. Figure 1 describes the adjustment of pressuring tension accoridng to the present invention. Figure 2 described the adjustment of pressuring rension used after a yarn splicing operation during pressure reduction at the time of winding ending according to the present invention. Figure 3 describes another example of the adjustment of pressuring. tension used after a yam splicing operation during pressure reduction at the winding ending in Figure 2. Figure 4 describes yet another example of the adjustment of pressurizing tension used after a yarn splicing operation during pressure reduction at the time of winding ending in Figure 2. Figure 5 approximately shows an automatic winding machine according to the present invention. Detailed Description of the Preferred Embodiment One preferred embodiment of the present invention is described in detail with reference to the attached drawings. First, the basic configuration of an automatic winding machine according to the present invention is described with reference to Figure 5. A Yarn Y unwound and drawn from a spun bobbin B passes through a bal loon controller 1 and a tension apparatus 2 and is checked by a slab catcher 4 with a cutter 3 for defects while being wound around a package P rotated by a traverse drum 5. The traverse drum 5 is rotated by a drum driving motor 6 that is driven by an inverter 7 having a variable output frequency. Based on an instructed frequency value 9 from a control apparatus 8, the inverter 7 drives the drum driving motor 6 at the instructed rotation speed. During winding, any variation in the thickness of the yarn passing through the slab catcher 4 is input to a clearer controller 11 as an electric signal 10, and the clearer controller 11 compares the variation with a reference value to determine that a defective portion has passed if the result of the comparison exceeds a set tolerance. Then, the clearer controller 11 immediately outputs a driving instruction signal to the cutter 3 of the slab catcher 4, which then operates to conpulsorily cut the yarn. In response to the cutting of the yarn, a yarn forward (FW) signal 13 from the slab catcher 4 is turned off to allow the yarn cut to be detected, and the clearer controller 11 issues a stop instruction to the drum driving motor 6 via the control apparatus 8 to stop the rotation of the drum 5. Subsequently, an operation to splice the yarns on the spun bobbin B side and the yam on the package P side together, is performed. First, when the cutter 3 of the slab catcher 4 cuts the yarn Y, the yarn on the package P side (upper yam) is wound around the package P, while the yarn on the spun bobbin B side (lower yarn) is trapped by a yarn trap 14. During this yarn splicing operation, for the upper yarn, a suction mouth 15 rotational ly moves upward around a shaft 16 as shown by the arrow so as to be located close and opposite to the circumferential surface of the package P, and the traverse drum 5 is inverted to capture the end of the upper yarn located on the circumferential surface of the package P. The suction mouth 15 is subsequently rotationally moved downward to guide the upper yarn to a yarn splicing apparatus 17. For the lower yarn, a relay pipe 18 rotationally moves downward around a shaft 19 to capture the lower yarn trapped by the yarn trap 14, and is then rotationally moved upward to guide the lower yarn to the yarn splicing apparatus 17. After the upper and lower yarns have been guided to the yarn splicing apparatus 17, they are spliced together and the traverse drum 5 is rotated to start winding again. In addition, during winding, the rotation of the traverse drum 5 is detected by a rotation sensor 20 and the detected value is input to the control apparatus 8 via the clearer controller 11, and based on the rotation speed of the traverse drum 5, the control apparatus 8 calculates the length of the yarn wound around the package P to cause specified-length winding of the package P to be effected. Furthermore, the control apparatus 8 calculates the amount of remaining yarn from initial winding of the spun bobbin B until its end during the unwinding of the spun bobbin B, to output a value for the pressurizing tension to the tension apparatus 2 from the start of winding to its end. In this case, the balloon controller 1 is controlled to gradually lower from initial winding of the spun bobbin B until its end during the unwinding of the spun bobbin B, in order to maintain the diameter of a balloon at a constant value during unwinding. Figure 1 shows the variation in the control of pressurizing tension carried out by the tension apparatus 2 over time, from initial winding of the spun bobbin B until its end during the unwinding of the spun bobbin B. First, from initial winding tO (hiring unwinding, the pressurizing tension (voltage) is kept higher than a reference value S by X and is reduced down to the reference value S using a first inclination a when the yarn forward (FW) signal is turned on. The reference value S is input and set by an operator and the period of time during which the pressurizing tension is maintained at the reference value S is called "normal winding." The inclination a is set so that the pressure reduction period becomes equal to the time required until a predetermined speed (winding speed) is reached since the traverse drum 5 (the package P) begins to rotate. The difference (X in Figures 1 ~3) between the reference value and the maximum value during clamping is set to be constant despite changes in yarn type, yarn count and reference value S. When the pressurizing tension is applied at the reference value and a yarn defect is found at a time tl during winding, the yarn is cut, the value of the pressurizing tension becomes zero, and the upper and lower yarns are guided to the yarn splicing apparatus 17 as described above. Subsequently, at a time t2, the pressurizing tension is set higher than the reference value S by X, as during initial winding. The yarn splicing (air injection) is started and once the yarn splicing has been completed, winding is started. When it is detected at a time t3 that the signal FW from the slab catcher 4 is turned on, the value is reduced with the inclination a to effect normal winding with the pressurizing tension set at the reference value S. Subsequently, the amount of remaining yarn on the spun bobbin B decreases, and during a period of time Z between a winding end te and the point of time when the balloon controller 1 shown in Figure 5 reaches the lowest point, or the point of time t4 when the amount of remaining yarn on the spun bobbin B is determined to reach a predetermined value based on the rotation speed of the traverse drum 5, the pressurizing tension is gradually reduced from the reference value S to the minimum pressurizing tension value U using a second inclination b until the amount of remaining yarn becomes zero at te. In this case, the pressurizing tension is set at the minimum value instead of zero because if it is set at zero, the yarn flaps on the tension apparatus 2 during yarn travelling resulting in unstable winding tension. According to the present invention, the value of the pressurizing tension is adjusted so that if the slab catcher 4 detects a yarn defect and executes a yarn splicing while the pressurizing tension is being reduced at a predetermined rate (the gentle inclination b) at the winding end (the period Z), the pressurizing tension is set at the minimum value U when the amount of the remaining yarn on the spun bobbin B becomes zero. Specifically, the rapid pressure reduction pattern used after the yarn splicing operation during reduction at the winding end (the period Z) is different from the rapid pressure reduction pattern used after the yarn splicing operation during normal winding. Ihis adjustment is described with reference to Figure 2. During the reduction of pressurizing tension relative to the reference value S using an inclination b gentler than the first inclination a since the point of time t4 when the amount of the remaining yarn becomes a predetermined value (or the balloon controller 1 reaches the lowest point), a yarn defect is found at a time t5 when the yarn is cut, the value of pressurizing tension becomes zero, and the upper and lower yarns are guided to the yarn splicing apparatus 17. Subsequently, at a time t6, the pressurizing tension (S+X) is set higher than the reference value S by X as in the winding start, and yarn splicing (air injection) is started and completed, and then, when the signal FW from the slab catcher 4 is turned on at a time t7, the conventional technique reduces the voltage with the first inclination a, and when the reference value S is reached, reduces it with the second inclination b, as shown by the alternating long and short dashed line. Hie conventional technique, however, results in a high value of the pressurizing tension even at the winding end te when the amount of the remaining yarn becomes zero and fails to allow the minimum value U to be reached. Consequently, the winding tension at the winding end increases and cannot be maintained at a constant value, thereby disturbing the shape of the package. Thus, as shown in Figure 2, the present invention stores the value of the pressurizing tension V at the time t5 when a yarn defect has been found, and when the signal FW is turned on, reduces the pressurizing tension from the maximum value (S+X) obtained during clamping to the stored value V obtained at the time t5 when the yarn defect has been found, using a first inclination a that enables more rapid pressure reduction than a second inclination b. The present invention further reduces the pressurizing tension from the value V using the second inclination b to achieve the minimum pressurizing tension value U at the winding end te, thereby enabling winding tension to be maintained at an approximately constant value as in techniques without the yarn splicing, even if the yarn splicing is carried out during the pressure reduction with the second inclination b at the winding end. In Figure 2, a conventional rapid pressure reduction period A after a yam splicing operation is set equal to the time required to increase the winding speed and the pressurizing tension is reduced to the value V stored with the inclination a, so a pressure reduction period B is longer than the time required to increase the winding speed. Thus, even after the increase in the winding speed, the rapid pressure reduction continues for a small amount of time (the period C). The pressurizing tension, however, should be inherently gradually reduced during the period C which is very short, so the variation of winding tension is not significantly affected. This prevents the shape of the package from being disturbed and thus improves its quality. Figure 3 shows an example a rapid pressure reduction pattern used after the completion of the yarn splicing operation during the period Z. In Figure 3, the present invention stores the value of the pressurizing tension V at the time t5 when a yarn defect has been found, and when the signal FW is turned on, reduces the pressurizing tension from the maximum value (S+X) obtained during clamping to the stored value V obtained at the time t5 when the yarn defect was found, using a third inclination c that enables more rapid pressure reduction than a second inclination b. Thus, the minimum value of the pressurizing tension U can be achieved at the winding end te, thereby enabling winding tension to be maintained at an approximately constant value as in the techniques without the yarn splicing, even if the yarn splicing is carried out during the pressure reduction with the second inclination b at the winding end. In this case, the pressure reduction time can be set equal to the time required to increase the winding speed using the inclination c enabling more rapid pressure reduction than the inclinations a and b. Although the embodiments in Figures 2 and 3 have been described in conjunction with the stored value of the pressurizing tension V as a target value for rapid pressure reduction with the first inclination a or the third inclination c, the present invention is not limited to the stored value V but may use a value higher or lower than the stored value V by some predetermined amount. That is, the pressurizing tension after a yarn splicing operation may be adjusted based on the stored value of the pressurizing tension. Figure 4 shows another example of a rapid pressure reduction pattern used after the end of the yarn splicing operation during the period Z. Figure 4 shows an example in which a value T smaller than the reference value S is set for the pressure reduction period Z at the winding end, and in which a different rapid pressure reduction pattern (a target value) is used after the end of the yarn splicing operation depending on whether the yarn splicing is executed before or after the set value T is reached with the inclination b. In this case, if the yarn splicing is carried out before the set value T has been reached, the pressurizing tension is reduced down to the tension value stored with the steep inclination a (or the inclination c), as in the examples in Figures 2 and 3. If, however, the yarn splicing is carried out after the set value T has been exceeded, the steep inclination a (or the inclination c) may be used to reduce the pressurizing tension down (below the stored tension value) to a preset lower limit R (the lower limit R may be slightly higher than or equal to the minimum value of pressurizing tension U). Since the unwinding tension of the spun bobbin particularly increases rapidly immediately before the winding end during the pressure reduction period Z at the time of the winding end, the tension can be maintained at a more appropriate value until the winding end by setting the value T for the pressure reduction at the time of the winding end and using different pressure reduction patterns (specifically, changing the target values while maintaining the same inclination) depending on whether the yarn splicing is executed before or after the set value T is reached, as described above. The pressure reduction patterns according to the present invention are not limited to the above embodiments, a range of other variations is possible. An arbitrary pressure reduction pattern can be used as long as winding tension is maintained at an approximately constant value from the tension value used immediately before the start of a yarn splicing operation until the minimum value of pressurizing tension U at the time of winding end instead of rapidly reducing pressurizing tension down to the reference value S for normal winding and further reducing it with the second inclination b as in the prior art. In brief, this invention provides the following effects. Even if the yarn splicing is carried out during pressure reduction at the time of winding end, the winding tension can be maintained at an approximately constant value until the winding end.

Documents:

3007-del-1998-abstract.pdf

3007-del-1998-correspondence-others.pdf

3007-del-1998-correspondence-po.pdf

3007-del-1998-description (complete).pdf

3007-del-1998-drawings.pdf

3007-del-1998-form-1.pdf

3007-del-1998-form-19.pdf

3007-del-1998-form-2.pdf

3007-del-1998-form-3.pdf

3007-del-1998-form-4.pdf

3007-del-1998-form-6.pdf

3007-del-1998-pa.pdf

3007-del-1998-petition-137.pdf