Multiple twister

Abstract

 In an individual-spindle-drive type double twister comprising a spindle motor 3 for each spindle that drives a spindle shaft 1 and twists a yam Y that forms a balloon around a yarn supplying package P while simultaneously winding the yarn, a yarn tension detection device 11 for outputting a tension detection signal depending on the variation of the tension of the travelling yarn Y while in contact with the yarn Y is provided adjacent to a balloon guide 5 that converges the balloon, on the downstream side of the balloon guide 5, and a display device 16 is also provided to display uniformity (p) and temporal waveforms as information indicating the temporal variation of the tension detection signal. The present invention thus enables even a small variation in balloon tension to be accurately recognized and also enables inappropriately produced packages to be identified.

Description

Field of the Invention

[0001] The present invention relates to a multiple twister, which twists a yarn that forms a balloon around a yarn supplying package while simultaneously winding the yarn, ant in particular, to a multiple twister capable of detecting the variation of balloon tension accurately.

Background of the Invention

[0002] One example of a conventional multiple twister is a double twister, wherein a rotating disc rotating with a spindle makes a single rotation to apply two twists to a yarn that balloons around a yarn supplying package. In such a double twister, a yarn released from the yarn supplying package moves downward through a central shaft and then passes through a path in a rotating disc to exit the disc through a hole formed therein. Subsequently, a predetermined amount of yarn is wound around a storage section of the rotating disc (for example, the yarn is wound once), and forms a balloon between the rotating disc and a balloon guide located above the yarn supplying package while being simultaneously twisted.

[0003] During twisting, the angle (storage angle) at which the yarn is wound around the storage section varies due to the vertical movement of a release point on the yarn supplying package or a decrease in a diameter of the yarn supplying package. The variation of this angle is preferably small, but becomes large if the tension applied by a tension applying device arranged inside of the central shaft of the yarn supplying package is inappropriate. Thus, during initialization, an operator actually operates the multiple twister and adjusts the tension applying device so as to render the magnitude of the variation appropriate while using a stroboscope to check the variation of the storage angle.

[0004] During the adjustment of the tension applying device, however, it is very troublesome to check the variation of the storage angle using the stroboscope. In addition, in the multiple twister, in which a large number of twisting and winding spindles are installed in a line, it is difficult to manually adjust the tension applying devices for all spindles reliably, and adjustments may be forgotten or be incorrect. In such a case, twisting and winding is carried out using the tension applying devices that are still inappropriately adjusted, resulting in unacceptable wound packages. It is difficult to visually detect unacceptable packages, which may be delivered to a post-process and create a serious problem.

[0005] The present invention is provided in view of these problems, and its object is to provide a multiple twister capable of accurately recognizing even a small variation in balloon tension and also identifying inappropriately produced packages.

Summary of the Invention

[0006] The present invention is a multiple twister, which twists a yarn that forms a balloon around a yarn supplying package while simultaneously winding the yarn, characterized in that a yarn tension detection device for outputting a tension detection signal depending on the variation of the tension of a travelling yarn while in contact with the yarn is provided adjacent to a balloon guide that converges a balloon, on the downstream side of the balloon guide. According to the present invention, the contact-type yarn tension detection device is provided adjacent to the balloon guide that converges a balloon, on the downstream side of the balloon guide, without an object between the device and the balloon guide that may come in contact with the yarn. Consequently, a small variation in tension caused by the balloon can be detected accurately.

[0007] The multiple twister comprises a display device for displaying information indicating the temporal variation of the tension detection signal. According to this aspect of the present invention, an operator can watch a display screen of the display device during twisting and winding or after the completion of winding to recognize the temporal variation of the tension detection signal easily. Thus, the operator can refer to the display screen to easily adjust the tension applying device and recognize unacceptable packages. Uniformity, which is calculated based on the magnitude of a deviation from a mean value, is used as the information indicating the variation of the tension detection signal. This enables the variation alone to be accurately recognized despite a decrease in balloon tension caused by a decrease in the supplied yarn diameter.

[0008] The multiple twister comprises an error determination section for outputting an error signal based on the magnitude of the variation of the tension detection signal. According to this aspect of the present invention, if a yarn cut or another mechanical error increases the variation of the balloon tension beyond an appropriate value, this can be automatically detected.

[0009] Once the error signal has been generated, the operator can recognize this situation when the machine is stopped or an alarm is issued.

[0010] The error determination section samples the tension detection signal at intervals of a predetermined number of cycles and constantly compares the preceding sampling value with the latest one for error determination. According to this aspect, an error is determined based on the comparison with the preceding sampling value to enable an error such as a yarn cut to be accurately determined despite a variation in balloon tension value caused by a decrease in the supplied yarn diameter.

[0011] The multiple twister comprises a drive motor for each spindle that drives a spindle shaft to twist a yarn and a control section, so that the drive motor is stopped based on the error signal generated by the error determination section.

[0012] According to this aspect of the present invention, by stopping, based on the variation of the balloon tension, only spindles (rotating discs) in which an error has occurred, the yarn can be reliably prevented from being wound around a peripheral region without employing a drop wire, which is conventionally used. The elimination of the need for the drop wire can simplify the apparatus and eliminate the problem of the drop wire jumping up due to the travelling vibration of the yarn, particularly if the yarn, is thin.

Brief Description of the Drawing

[0013] 

Figure 1 is a schematic drawing showing a double twister according to the embodiment of the present invention.

Figure 2 is an explanatory drawing showing an example of the displayed temporal variation of a tension detection signal.

Figure 3 is a schematic sectional view showing a yarn tension detection device.

Detailed Description of the Preferred Embodiments

[0014] An embodiment of the present invention is described below with reference to the drawings, but the present invention is not limited to this embodiment. In this embodiment, a double twister in which a spindle shaft makes a single rotation to apply two twists is described as an example of a multiple twister for rotating a spindle to twist a yarn while winding it. Figure 1 is a schematic drawing showing a double twister according to the embodiment of the invention. Figure 2 is an explanatory drawing showing an example of the displayed temporal variation of a tension detection signal. Figure 3 is a schematic sectional view showing a yarn tension detection device.

[0015] As shown in Figure 1, the double twister according to this embodiment uses an individual-spindle-drive type system in which each spindle shaft 1 comprises a drive motor 2 that can be individually driven and stopped. The double twister is composed of a plurality of spindles installed in a line as shown in Figure 1. Each spindle has a twisting unit U for twisting a yarn Y and a winding device W for winding the twisted yarn Y above the twisting unit U.

[0016] In the twisting unit U, P is a yarn supplying package placed on a stationary disc 3, and during twisting, the stationary disc 3 and the yarn supplying package P are kept stationary by a magnetic attraction means (not shown in the drawings). 4 is a rotating disc, located below the stationary disc 3, that rotates integrally with a spindle shaft 1. The yarn Y is released from an outer layer on the yarn supplying package P, passes through the central shaft of the yarn supplying package P, jumps sideways from the rotating disc 4, and reaches a balloon guide 5 above the yarn supplying package P. That is, the yarn Y is twisted while forming a balloon between a yarn outlet of the rotating disc 4 and the balloon guide 5.

[0017] After leaving the yarn outlet of the rotating disc 4, a predetermined amount of the yarn Y is wound around the storage section of the rotating disc 4 and is then ballooned. The angle (storage angle) at which the yarn is wound around the rotating disc 4 periodically increases and decreases due to the vertical movement of a release point on the yarn supplying package P. In addition, the storage angle generally tends to gradually decrease with decreasing yarn supplying package diameter. Thus, the variation of tension depending on the magnitude of release resistance from the yarn Y is absorbed by the variation of the storage angle to prevent yarn cats during twisting.

[0018] A tension applying device (not shown in the drawings) capable of adjusting tension applied to the yarn Y is provided in the central shaft of the yarn supplying package P. The tension applying device comprises, for example, a plurality of tensor balls for applying tension to the yarn Y and is configured as a tensor unit that can be installed in and removed from the central shaft of the yarn supplying package P. The tension applying device can be adjusted by, for example, increasing or reducing the number of tensor balls or changing the size of the balls. To obtain a normal-quality wound package Pw, the tension applying device must apply an appropriate tension depending on winding conditions such as the diameter of the yarn supplying package P and the thickness of the yarn Y. By providing an appropriate tension value using the tension applying device, the variation of tension (storage angle) during twisting can be minimized to produce a high-quality wound package Pw.

[0019] The yarn Y twisted by the twisting unit U is wound around the wound package Pw via a feed roller 6 by means of the winding device W. Despite its particularly high tension on the upstream side caused by a balloon, the feed roller 6 feeds the yarn at a predetermined speed to maintain the winding tension on the downstream side at an appropriate value. In the winding device W, the yarn Y is traversed by a traverse guide 7 while being wound around the wound package Pw, which is rotated while abutting on the winding drum 8. The wound package Pw is supported by a rolling cradle arm 9 so as to contact and leave the winding drum 8. By operating an actuator 10 such as an air cylinder, the cradle arm 9 can be rolled upward to separate the wound package Pw from the winding drum 8. An urging means such as a spring (not shown in the drawings) is provided to return the wound package Pw to an abutting state.

[0020] On a yarn traveling path between the balloon guide 5 and the feed roller 6, a yarn tension detection device 11 for detecting the tension of the traveling yarn Y is provided adjacent to the balloon guide 5 on its downstream side. The yarn tension detection device 11 is of a contact type that detects tension while constantly in contact with the traveling yarn Y, and outputs to a signal processing section 12 a tension detection signal depending on the variation of the tension of the target yarn Y. The signal processing section 12 has an analog/digital converter, a central processing unit, and a storage device for storing programs and parameters, and executes predetermined processing based on the tension detection signal from the yarn tension detection device 11 as described below. An appropriate number of guides are provided between the yarn tension detection device 11 and the feed roller as required.

[0021] As shown in Figure 3, the yarn tension detection device 11 has a guide section 111 that comes in contact with the traveling yarn Y, a guide support 112 attached to the tip of the guide section 111, an elastic sensor substrate 113, and a circuit board 114. The guide support 112 is supported perpendicularly to the sensor substrate 113 at its proximal portion so that the displacement of the guide section 111 is transmitted to the sensor substrate 113 via the guide support 112. Distortion detection elements 115, each having a resistance value varying in proportion to the amount of distortion, are affixed to the sensor substrate 113 at appropriate positions. The circuit board 114 is electrically connected to the sensor substrate 113 by a connection section 116 so that the variation of the resistance value of the distortion detection element 115 can be obtained from the circuit board 114 as the variation of the voltage. The sensor substrate 113 and the circuit board 114 are covered with a case 117 so that the guide support 112 protrudes out through an opening 118 in the case 117. The height of the opening 118 is slightly greater than the diameter of the guide support 112 so as to allow the guide support 112 to be displaced.

[0022] The tension of the yarn Y engaging with the guide section 111 is detected while the yarn Y is being bent into a V-shape using the guide section 111 as a bending section. The detected tension is output to the external signal processing section 12 via the circuit board 114 as a tension detection signal. The guide section 111, which is the yarn contact section of the yarn tension detection device 11, is located adjacent to the balloon guide 5 that acts as a balloon converging section, on the downstream side of the balloon guide 5, so that no member comes in contact with the yarn Y between the balloon guide 5 and the guide section 111. Thus, the variation of tension caused by a balloon is accurately converted into the displacement of the guide member 111.

[0023] The signal processing section 12 has a uniformity calculation section 13, a waveform generation section 14, and an error determination section 15, and is connected to a display device 16 via a communication line. The uniformity calculation section 13 calculates uniformity, which is an index indicating the magnitude of a deviation from a mean value, for tension detection signals from the yarn tension detection device 11. The uniformity may be a CD value (%), which is the ratio of a standard deviation to a mean value, or a U value (%), which is the ratio of a mean value deviation to a mean value.

[0024] The waveform generation section 14 generates displayed waveform data indicating temporal variations occurring during the latest predetermined time period, for tension detection signals from the yam tension detection device 11.

[0025] The waveform data comprises the tension, shown as the vertical axis, and the time, shown as the horizontal axis, and is output to the display device 16 connected to the signal processing section 12 via the communication line, together with the uniformity determined by the uniformity calculation section 13. The display device 16 displays a spindle number (p), a uniformity (CV value) (q), and a temporally varying waveform on the same screen according to a predetermined operation by an operator, as shown in Figure 2. The uniformity and temporally varying waveform on the display screen 16 are automatically updated at predetermined time intervals.

[0026] A signal processing section 12 is provided for each spindle, with a single display device 16 connected to the plurality of signal processing sections 12 via the communication line. For example, a display device 16 can be provided at the end of each multiple twister. The display device can collect uniformity and waveform data from the plurality of signal processing sections 12 to display them in appropriate forms according to predetermined operations. That is, as shown in Figure 2, the display device can not only display the spindle number (p), the uniformity (CV value) (q), and a temporally varying waveform for each spindle, but can also simultaneously display the uniformity for the plurality of spindles on the same screen together with the spindle numbers. Thus, the tension applying device can be simply adjusted while comparing the uniformity values for the plurality of spindles.

[0027] Thus, by observing on the display screen the uniformity and waveform, which are information indicating the temporal variation of the tension detection signal, the operator can easily adjust the tension applying device and recognize from the temporal variation of the tension detection signal that the wound package Pw is unacceptable due to an error in tensor ball adjustments. As is seen in Figure 2, a yarn cut reduces the tension detection signal rapidly.

[0028] The error determination section 15 determines whether the tension is abnormal, based on the tension detection signal from the yarn tension detection device 11. If so, the error determination section immediately outputs an error signal to the actuator 10 and a motor control section 17. In addition, if the error determination section 15 determines that the detected tension is abnormal, it transmits the details of the error and the relevant spindle number via the communication line to the display device 16, which then displays the details to the operator.

[0029] The motor control section 17 controls the rotational driving of the drive motor 2 and can control the motor so as to accelerate or stop rapidly or to maintain a constant speed. A rotation speed detector (not shown in the drawings) is provided in the drive motor 2, and the motor control section 17 regulates a drive signal to maintain the drive motor at a predetermined rotation speed based on the detected rotation speed. Upon receiving an error signal from the signal processing section 12, the motor control section 17 immediately stops the drive motor 2 rapidly. Since the spindle is stopped while the actuator 10 is in operation and while the package Pw remains lifted, the operator can easily recognize the occurrence of an error even from a remote position.

[0030] The error determination section 15 samples tension detection signals from the yarn tension detection device 11 at intervals of a predetermined number of cycles to compare the preceding sampling value with the latest one in order to determine errors. By the above comparison process, errors can be accurately determined despite any variation of the mean value of detected tension due to a decrease in yarn supplying diameter (weight). Specifically, the error determination section 15 determines that the spindle is normal if the latest sampling value falls within a preset range from the preceding sampling value, and that the spindle is abnormal if the value deviates from this range.

[0031] In addition, the error determination section 15 determines the error that occurs when a value calculated by the uniformity calculation section 13 exceeds a preset value. Instead of depending solely on the signal processing section 12 for each spindle, errors can also be determined based on the mean of the uniformity values for the plurality of spindles that are collected by the display device 16 or another host device. That is, a spindle can be determined to be abnormal when the uniformity for this spindle deviates from the mean value for the plurality of spindles by a predetermined amount. Alternatively, by setting first and second thresholds such that normal ranges of different sizes are formed, yarn cuts can be determined based on the larger first threshold, while yarn cuts can be predicted or unacceptable packages can be determined based on the smaller second threshold. In any error determination method, the set value used to determine errors may be transmitted to the signal processing sections 12 of all spindles via the communication line by simply setting it at one position.

[0032] In addition, the error determination section 15 is designed to execute no error determinations when the tension is unstable (during the acceleration of the spindle shaft 1). That is, the error determination section 15 is designed to stop error determination processing from the start of winding until a predetermined amount of time has passed (region A in Figure 2) and to start the above error determination a predetermined amount of time after the start of winding (region B in Figure 2). This configuration simplifies signal processing and prevents erroneous determinations.

[0033] As described above, this embodiment detects the yarn tension at the position adjacent to the balloon guide 5 that converges a balloon, on its downstream side, thereby enabling the variation of the balloon tension to be detected accurately. That is, nothing comes in contact with the yarn Y on the downstream side of the balloon guide 5 between the balloon guide 5 and the yarn contact section of the yarn tension detection device 11, so the variation of the balloon tension can be sensitively transmitted to the yarn contact section of the yarn tension detection device 11, while the yarn Y is not subjected to friction before reaching the yarn tension detection device 11. The balloon guide 5 may operate as the yarn contact section of the yarn tension detection device 11, but the structure of the yarn tension detection device can be simplified by providing the yarn tension detection device 11 on the yarn traveling path and away frown the balloon guide 5 as in the above example.

[0034] By detecting the variation of the balloon tension accurately, this data can be used to automatically determine unacceptable wound packages Pw resulting from large variation of the balloon tension during winding or after the completion of winding. In addition, by using this data to display information indicating the temporal variation of the tension detection signal, the operator can watch this display screen in order to adjust the tension applying device easily. Furthermore, unacceptable packages resulting from large variation of the balloon tension can be easily recognized in order to monitor the package quality during twisting executed by the multiple twister.

[0035] Due to the above configuration, the present invention provides the following effects.

[0036] In the multiple twister which twists a yarn that forms a balloon around a yarn supplying package while simultaneously winding the yarn, the yarn tension detection device for outputting the tension detection signal depending on the variation of the tension of a travelling yarn while in contact with the yarn is provided adjacent to the balloon guide that converges a balloon, on the downstream side of the balloon guide. Thus, since the contact-type yarn tension detection device is provided on the downstream side of the balloon guide and does not come in contact with the yarn, the variation of tension caused by a balloon can be detected sensitively. Consequently, the variation of the balloon tension can be detected accurately and whether the variation is appropriate can be determined accurately.

[0037] The multiple twister comprises a display device for displaying information indicating the temporal variation of the tension detection signal. Thus, the operator can watch the waveform on the display device in order to recognize a small variation in balloon tension easily and accurately. As a result, the operator can refer to the display screen to easily adjust the tension applying device without using a stroboscope to check for the variation of the amount of yarn wound, as is necessary in the prior art. In addition, the operator can easily recognize unacceptable packages resulting from large variation of the balloon tension, based on the information on the variation shown on the display screen.

[0038] The multiple twister comprises an error determination section for outputting an error signal based on the magnitude of the variation of the tension detection signal. This configuration enables the automatic detection of unacceptable packages and yarn cuts resulting from mistakes in adjusting the tension applying device.

[0039] The error determination section samples the tension detection signal at intervals of a predetermined number of cycles and constantly compares the preceding sampling value with the latest one for error determination. Consequently, errors can be accurately determined despite large variation of the balloon tension value.

[0040] The multiple twister comprises a drive motor for each spindle that drives a spindle shaft to twist a yarn and a control section, in order to stop the drive motor based on the error signal generated by the error determination section. As a result, individual spindles (rotating discs) in which an error has occurred can be immediately stopped to reliably prevent the yarn from being wound around a peripheral region without using a drop wire as is required in the prior art.

Claims

1. A multiple twister which twists a yarn that forms a balloon around a yarn supplying package while simultaneously winding the yarn, characterized in that a yarn tension detection device for outputting a tension detection signal depending on the variation of the tension of a travelling yarn while in contact with the yarn is provided adjacent to a balloon guide that converges a balloon, on the downstream side of the balloon guide.

2. A multiple twister as in Claim 1, characterized by comprising a display device for displaying information indicating the temporal variation of said tension detection signal.

3. A multiple twister as in Claim 2, characterized in that said display device displays, as information indicating the temporal variation of said tension detection signal, a uniformity that is calculated based on the magnitude of the variation relative to a mean value.

4. A multiple twister as in Claim 3, characterized in that said display device can display on the same screen uniformity values for a plurality of spindles with their spindle numbers.

5. A multiple twister as in Claim 2 or Claim 3, characterized in that said display device can display the information indicating the temporal variation of said tension detection signal for any individual spindle or for a set of a plurality of sets of predetermined spindles by switching between the plurality of the sets.

6. A multiple twister as in Claim 5, characterized in that said display device displays on the same screen both the uniformity calculated from said tension detection signal and a temporally varying waveform created from said tension detection signal with their spindle numbers.

7. A multiple twister as in Claim 6, characterized in that the uniformity and temporally varying waveform displayed on the screen of said display device are automatically updated at predetermined time intervals.

8. A multiple twister as in any one of Claims 1 to 7, characterized by comprising an error determination section for outputting an error signal based on the magnitude of the variation of said tension detection signal.

9. A multiple twister as in Claim 8, characterized in that said error determination section samples said tension detection signal at intervals of a predetermined number of cycles and constantly compares the preceding sampling value with the latest one for error determination.

10. A multiple twister as in Claim 8 or Claim 9, characterized in that said error determination section stops error determination processing from the start of winding until a predetermined amount of time has passed so as not to execute error determinations during activation when the tension is unstable.

11. A multiple twister as in any one of Claims 8 to 10, characterized by comprising a drive motor for each spindle that drives a spindle shaft to twist a yarn and a control section, so that said drive motor is stopped based on said error signal generated by said error determination section.

Drawing