Control method for a centrifugal spinning machine

Abstract

Provided is a control method for a centrifugal spinning frame that prevents a residual yarn from being layered with a subsequent yarn in a can even when the winding of the yarn fails. The control method for the centrifugal spinning frame includes a spinning process that spins a yarn supplied from a drafting device into a can, a winding process that winds the yarn spun into the can in a bobbin, and an inspection process that inspects, after the spinning process and the winding process are completed and before a next spinning process is started, whether there is a residual yarn in the can for each spool, and operates a roving supply stopper for a spool determined to have the residual yarn in the inspection process in such a manner that the yarn is not spun into the can in the next spinning process.

Description

Technical Field

[0001] This invention relates to a control method for a centrifugal spinning machine. Background Technology

[0002] In a centrifugal spinning frame, the yarn stretched by the drafting device is guided into a can through a guide tube. The introduced yarn is then spun out from the end of the guide tube and layered on the inner wall of the can. Afterward, the yarn is wound back into the bobbin inside the can. If, for some reason, the winding process fails, yarn that should have been wound back into the bobbin remains in the can at the end of the winding process. In this specification, the yarn remaining in the can at the end of the winding process is referred to as "residual yarn".

[0003] If residual yarn remains in the can at the end of the rewinding process, the yarn spun into the can during the subsequent spinning process (hereinafter referred to as "subsequent yarn") will be layered on top of the residual yarn. Therefore, the thickness of the yarn cake formed on the inner wall of the can will be thicker than usual. As a result, there are concerns that the yarn guide tube may come into contact with the yarn cake during the spinning process, and that the bobbin inserted into the can for rewinding may also come into contact with the yarn cake.

[0004] Therefore, for example, Patent Document 1 describes a technique in which, when yarn is spun from the end of the yarn guide tube, the phenomenon that the rotational frequency of the yarn strands rotating around the yarn guide tube decreases due to the presence of residual yarn is used to check whether there is residual yarn in the container. Specifically, the rotational frequency of the yarn strands is detected during the yarn spinning process, and the detected rotational frequency is compared with a target value to check whether there is residual yarn in the container.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2001-81634

[0006] However, in the technology described in Patent Document 1, the rotational frequency of the yarn strands cannot be detected unless it actually occurs after the yarn spinning process has begun. Therefore, if residual yarn is present in the spool, the yarn spun to detect the rotational frequency of the yarn strands will be layered on top of the residual yarn. Thus, as described above, there is a concern that the guide tube may come into contact with the yarn package, and the bobbin may come into contact with the yarn package. Furthermore, even if rewinding is performed onto the bobbin, residual yarn and subsequent yarn will be mixed together on the bobbin. Therefore, during the subsequent winding process, when the yarn is wound from the bobbin, the residual yarn and subsequent yarn become entangled, resulting in unusable yarn, i.e., "waste yarn." Summary of the Invention

[0007] This invention was made to solve the above-mentioned problems. Its purpose is to provide a control method for a centrifugal spinning machine that can prevent residual yarn from being stacked with subsequent yarn in the tank even if the yarn rewinding fails.

[0008] This invention relates to a control method for a centrifugal spinning frame, wherein the centrifugal spinning frame comprises multiple spindles, each spindle comprising: a drafting device having a back roller pair, a middle roller pair, and a front roller pair arranged sequentially from upstream to downstream in the roving transport direction, wherein the roving is lengthened by rotating the back roller pair, the middle roller pair, and the front roller pair respectively; a roving supply stop device that stops the supply of roving to the drafting device; and a can that rotates at a predetermined speed. The control method for the centrifugal spinning frame comprises... The process includes: a spinning process, in which yarn supplied from the drafting device is spun into the aforementioned tank; a rewinding process, in which the yarn spun into the aforementioned tank is rewound into a bobbin; and an inspection process, in which, after the aforementioned spinning process and the aforementioned rewinding process are completed, and before the next aforementioned spinning process begins, each of the aforementioned spindles is inspected for residual yarn in the aforementioned tank, and for the aforementioned spindles that are determined to have residual yarn in the aforementioned inspection process, the roving supply stop device is activated such that yarn is not spun into the aforementioned tank in the next aforementioned spinning process.

[0009] In the control method of the centrifugal spinning machine of the present invention, it is also possible that, in the above-mentioned inspection process, the inside of the tank is photographed by a camera, and the image data obtained by the above-mentioned photograph is processed to determine whether there is residual yarn in the tank.

[0010] In the control method of the centrifugal spinning machine of the present invention, it is also possible that, when it is determined in the inspection process that there is residual yarn in the can of any of the spindles, before the roving supply stop device is operated for the spindles for which residual yarn is determined, the rear roller pair and the middle roller pair are rotated by a predetermined amount in the opposite direction to the roving transport for all the spindles.

[0011] In the control method of the centrifugal spinning machine of the present invention, the operation of the centrifugal spinning machine may be stopped when it is determined in the above inspection process that the number of times the above residual yarn is found in the above tank occurs continuously N times (N is an integer greater than 2).

[0012] In the control method of the centrifugal spinning machine of the present invention, the operation of the centrifugal spinning machine may be stopped when it is determined in one of the above-mentioned inspection processes that the number of spindles containing the above-mentioned residual yarn in the above-mentioned tank exceeds a preset upper limit value.

[0013] According to the present invention, even if the rewinding of the yarn fails, the residual yarn can be prevented from being stacked with the subsequent yarn inside the can. Attached Figure Description

[0014] Figure 1 This is a simplified diagram illustrating an example of the configuration of a centrifugal spinning machine according to an embodiment of the present invention.

[0015] Figure 2 This is a block diagram illustrating an example of the configuration of a drive control system for a centrifugal spinning machine according to an embodiment of the present invention.

[0016] Figure 3 This is a flowchart illustrating the control method of a centrifugal spinning machine according to an embodiment of the present invention.

[0017] Figure 4 This diagram illustrates a specific example of the operation of a centrifugal spinning machine when the control method of the centrifugal spinning machine according to an embodiment of the present invention is applied.

[0018] Figure 5 This diagram illustrates a specific example of the operation of a centrifugal spinning machine when the control method of the centrifugal spinning machine according to an embodiment of the present invention is applied.

[0019] Figure 6 This diagram illustrates a specific example of the operation of a centrifugal spinning machine when the control method of the centrifugal spinning machine according to an embodiment of the present invention is applied.

[0020] Figure 7 This diagram illustrates a specific example of the operation of a centrifugal spinning machine when the control method of the centrifugal spinning machine according to an embodiment of the present invention is applied.

[0021] Figure 8 This diagram illustrates a specific example of the operation of a centrifugal spinning machine when the control method of the centrifugal spinning machine according to an embodiment of the present invention is applied.

[0022] Figure 9 This diagram illustrates a specific example of the operation of a centrifugal spinning machine when the control method of the centrifugal spinning machine according to an embodiment of the present invention is applied.

[0023] Figure 10 This diagram is used to illustrate the technical significance of reversing the back roller pair and the middle roller pair.

[0024] Figure 11 This diagram is used to illustrate the technical significance of reversing the back roller pair and the middle roller pair.

[0025] Figure 12 This diagram is used to illustrate the technical significance of reversing the back roller pair and the middle roller pair.

[0026] Figure 13 This diagram is used to illustrate the technical significance of reversing the back roller pair and the middle roller pair.

[0027] Explanation of reference numerals in the attached figures

[0028] 1…Centrifugal spinning frame; 2…Drafting device; 3…Roving supply stop device; 4…Yarn guide tube; 5…Tank; 7…Inspection device; 8…Wedge; 15…Rear roller pair; 15a…Rear upper roller; 15b…Rear lower roller; 16…Middle roller pair; 17…Front roller pair; 9…Roving; 20…Yarn; 31…Camera; 32…Image processing unit; 61-63…Spindles. Detailed Implementation

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0030] <Structure of a Centrifugal Spinning Frame>

[0031] First, the structure of the centrifugal spinning machine according to an embodiment of the present invention will be described.

[0032] Figure 1 This is a simplified diagram illustrating an example of the configuration of a centrifugal spinning machine according to an embodiment of the present invention.

[0033] like Figure 1 As shown, the centrifugal spinning frame 1 includes: a drafting device 2, a roving supply stop device 3, a yarn guide tube 4, a can 5, a bobbin support 6, and an inspection device 7. These components together form a single spindle, which is a unit of spinning. The centrifugal spinning frame 1 has multiple spindles, but each spindle shares a common structure; therefore, the structure of a single spindle will be described here.

[0034] (Stretching device)

[0035] The drafting device 2 is a device that draws the roving 9, which will become the yarn material, into a yarn of a specified thickness. The drafting device 2 is configured to use multiple roller pairs consisting of a back roller pair 15, a middle roller pair 16, and a front roller pair 17. The multiple roller pairs are arranged in the order of back roller pair 15, middle roller pair 16, and front roller pair 17 from the upstream side to the downstream side in the roving transport direction.

[0036] The rear roller pair 15 consists of an upper rear roller 15a and a lower rear roller 15b. The upper rear roller 15a and the lower rear roller 15b are in contact with each other at a specified pressure. The upper rear roller 15a is the driven roller, and the lower rear roller 15b is the driving roller. Therefore, the upper rear roller 15a rotates as the lower rear roller 15b rotates.

[0037] The middle roller pair 16 consists of an upper middle roller 16a and a lower middle roller 16b. The upper middle roller 16a and the lower middle roller 16b are in contact with each other at a specified pressure. The upper middle roller 16a is the driven roller, and the lower middle roller 16b is the driving roller. Therefore, the upper middle roller 16a rotates as the lower middle roller 16b rotates. A belt pair 19 is wound around the middle roller pair 16. The belt pair 19 consists of a top belt 19a and a bottom belt 19b. The top belt 19a is wound around the upper middle roller 16a, and the bottom belt 19b is wound around the lower middle roller 16b.

[0038] The front roller pair 17 consists of a front upper roller 17a and a front lower roller 17b. The front upper roller 17a and the front lower roller 17b are in contact with each other at a specified pressure. The front upper roller 17a is the driven roller, and the front lower roller 17b is the driving roller. Therefore, the front upper roller 17a rotates as the front lower roller 17b rotates.

[0039] Each roller pair 15, 16, and 17 is rotated by the drafting drive unit, described later. The drafting drive unit causes the rear roller pair 15, the middle roller pair 16, and the front roller pair 17 to rotate at a predetermined speed. Here, if the rotational speed of each roller pair 15, 16, and 17 is defined in terms of rotational speed per unit time (rpm), then the rotational speed of the middle roller pair 16 is higher than that of the rear roller pair 15, and the rotational speed of the front roller pair 17 is higher than that of the middle roller pair 16. In this way, the rotational speeds of each roller pair 15, 16, and 17 are different. Utilizing this difference in rotational speed, the drafting device 2 draws the roving 9 to a finer length. The yarn 20, drawn to a predetermined thickness by the drafting device 2, is supplied from the drafting device 2 to the yarn guide tube 4 through the suction tube 22.

[0040] (Roving supply stop device)

[0041] The roving supply stop device 3 has a wedge 8 that is configured to move forward and backward relative to the rear roller pair 15 of the drafting device 2. The roving supply stop device 3 causes the wedge 8 to be squeezed between the two rollers constituting the rear roller pair 15, namely between the upper rear roller 15a and the lower rear roller 15b, thereby stopping the supply of roving 9 to the drafting device 2.

[0042] If the roving supply stop device 3 is actually activated, the wedge 8 moves forward relative to the rear roller pair 15. As a result, the wedge 8 is squeezed between the rear upper roller 15a and the rear lower roller 15b. Therefore, the rotation transmitted from the rear lower roller 15b to the rear upper roller 15a is cut off by the wedge 8. Furthermore, the roving 9 is clamped between the rear upper roller 15a and the wedge 8. Therefore, even if the rear lower roller 15b rotates, no conveying force is applied to the roving 9. Thus, the supply of the roving 9 to the drafting device 2 stops.

[0043] (yarn guide tube)

[0044] The yarn guide tube 4 guides the yarn 20 supplied from the drafting device 2 via the suction tube 22 into the tank 5. The yarn 20, stretched by the drafting device 2, is introduced into the suction tube 22 via the suction tube 22, for example, after being introduced by a rotating airflow. The yarn guide tube 4 is formed as a long, thin tube. When the yarn guide tube 4 is cut in a direction orthogonal to its length, it has a circular shape. The yarn guide tube 4 is coaxially disposed with the tank 5 on the downstream side of the drafting device 2. The lower part of the yarn guide tube 4 is disposed inside the tank 5. A yarn discharge port 4a is formed at the lower end of the yarn guide tube 4. The yarn 20 introduced into the yarn guide tube 4 is spun out from the yarn discharge port 4a of the yarn guide tube 4. The yarn guide tube 4 is configured to be movable in the vertical direction by a yarn guide tube drive unit described later.

[0045] (Can)

[0046] The canister 5 is used for forming the yarn cake 24 and rewinding the yarn 20. The canister 5 is cylindrical. The canister 5 is configured to rotate about its central axis. The central axis K of the canister 5 is configured to be parallel to the vertical direction. Therefore, one side of the canister 5 along the central axis is the upper side, and the other side is the lower side. The canister 5 is rotated by a canister drive unit described later. An opening 5a is formed at the lower end of the canister 5. The yarn cake 24 is a stack of yarn 20 formed on the inner wall 5b of the canister 5.

[0047] (Bollard support section)

[0048] The bobbin support 6 supports the bobbin 25. The bobbin support 6 is configured to move vertically via the bobbin drive unit described later. The bobbin support 6 has a bobbin base 26 and a bobbin mounting part 27. The bobbin base 26 is formed in the shape of a plate. The bobbin mounting part 27 is fixed to the bobbin base 26.

[0049] The bobbin mounting section 27 is the part that mounts the bobbin 25 so that it can be easily installed and removed. The bobbin mounting section 27 is configured to be coaxial with the yarn guide tube 4 and the tank 5, facing each other along the central axis of the tank 5. Furthermore, the bobbin mounting section 27 is positioned below the yarn guide tube 4. Therefore, if the bobbin 25 is mounted on the bobbin mounting section 27, the bobbin 25 is configured to face the yarn guide tube 4 along the central axis K of the tank 5.

[0050] (Inspection device)

[0051] The inspection device 7 checks whether there is residual yarn inside the tank 5. The inspection device 7 has a camera 31 for taking pictures and an image processing unit 32. The camera 31 takes pictures of the inside of the tank 5 and outputs the image data obtained by the pictures. The image processing unit 32 performs image processing on the image data output from the camera 31, thereby determining whether there is residual yarn inside the tank 5. The inspection device 7 with camera 31 and image processing unit 32 can be provided with the same number of spindles as the centrifugal spinning machine 1, or a single inspection device 7 can be provided for multiple spindles.

[0052] In this embodiment, as an example, a structure is adopted in which one inspection device 7 is provided for multiple spindles. In this case, it is necessary to use one inspection device 7 to take pictures of the inside of the can of all spindles. Therefore, in this embodiment, the inspection device 7 is installed on a mobile wagon (not shown) so as to be able to check the presence or absence of residual yarn in the cans 5 of all spindles. The multiple spindles of the centrifugal spinning machine 1 are arranged side by side along the long side of the machine frame of the centrifugal spinning machine 1. Therefore, the wagon is configured to be able to move along the side by side direction of the multiple spindles of the centrifugal spinning machine 1.

[0053] A camera 31, mounted on the truck, is positioned under the canisters 5 of each spindle as the truck moves, and sequentially photographs the interior of each canister 5. Meanwhile, an image processing unit 32 acquires the image data output from the camera 31 and performs image processing. If, at this time, there is residual yarn inside the canister 5 as captured by the camera 31, this will be reflected in the image data output from the camera 31, for example... Figure 1 As shown, a predetermined amount of brightness difference is generated at the boundary P between the inner wall 5b of the can 5 and the residual yarn 20. Therefore, when the image processing unit 32 performs image processing on the image data, it determines that there is residual yarn if there is a portion where the predetermined amount of brightness difference is generated, and determines that there is no residual yarn if there is no portion where the predetermined amount of brightness difference is generated.

[0054] Figure 2 This is a block diagram illustrating an example of the configuration of a drive control system for a centrifugal spinning machine according to an embodiment of the present invention.

[0055] like Figure 2 As shown, the centrifugal spinning machine 1 includes: a control unit 50, a drafting drive unit 51, a wedge drive unit 52, a yarn guide tube drive unit 53, a can drive unit 54, a bobbin drive unit 55, and a freight car drive unit 56.

[0056] (Control Department)

[0057] The control unit 50 provides unified control over the overall operation of the centrifugal spinning frame 1. The control unit 50 is electrically connected to the drafting drive unit 51, wedge drive unit 52, yarn guide tube drive unit 53, can drive unit 54, bobbin drive unit 55, and freight car drive unit 56. Additionally, an inspection device 7 is electrically connected to the control unit 50. The drafting drive unit 51, yarn guide tube drive unit 53, can drive unit 54, bobbin drive unit 55, and freight car drive unit 56 are each configured for a given number of spindles, while multiple wedge drive units 52 are configured in a one-to-one correspondence with multiple spindles.

[0058] (Traction Drive Unit)

[0059] The drafting drive unit 51 rotates the rear roller pair 15, the middle roller pair 16, and the front roller pair 17 at predetermined speeds. The drafting drive unit 51 is driven based on control commands given to it from the control unit 50, thereby causing the rear roller pair 15, the middle roller pair 16, and the front roller pair 17 to rotate.

[0060] (Wedge drive unit)

[0061] The wedge drive unit 52 actuates the wedge portion 8 of the roving supply stop device 3. The wedge drive unit 52 is driven based on control commands issued from the control unit 50, thereby causing the wedge portion 8 to move forward or backward relative to the rear roller pair 15. When the control unit 50 activates the roving supply stop device 3, it drives the wedge portion 8 forward via the wedge drive unit 52; when the roving supply stop device 3 is deactivated, it drives the wedge portion 8 backward via the wedge drive unit 52.

[0062] (Yarn guide tube drive unit)

[0063] The yarn guide tube drive unit 53 actuates the yarn guide tube 4. The yarn guide tube drive unit 53 is driven based on the control command given to the yarn guide tube drive unit 53 from the control unit 50, thereby causing the yarn guide tube 4 to move in the vertical direction.

[0064] (Tank drive unit)

[0065] The can drive unit 54 rotates the can 5. The can drive unit 54 is driven based on the control command given to the can drive unit 54 from the control unit 50, thereby causing the can 5 to rotate about the central axis K of the can 5 as the center of rotation.

[0066] (Bollard drive unit)

[0067] The bobbin drive unit 55 actuates the bobbin 25. The bobbin drive unit 55 is driven based on the control command given to the bobbin drive unit 55 from the control unit 50, thereby causing the bobbin 25 mounted on the bobbin mounting unit 27 and the bobbin stand 26 to move together in the vertical direction.

[0068] (Truck Drive Unit)

[0069] The truck drive unit 56 moves the truck. The truck drive unit 56 is driven based on control commands given to it from the control unit 50, thereby causing the inspection device 7 to move together with the truck.

[0070] (Inspection device)

[0071] The inspection device 7 notifies the control unit 50 of the inspection results obtained using the camera 31 and the image processing unit 32. Each of the multiple spindles in the centrifugal spinning machine 1 is assigned its own unique identification information. In contrast, the inspection device 7 uses the camera 31 to photograph the inside of the jar 5 of each spindle by moving the freight car, and the image processing unit 32 processes the resulting image data. At this time, the image processing unit 32 determines whether there is residual yarn in the jar 5 for each spindle. Then, if the image processing unit 32 detects a spindle with residual yarn in the jar 5, it notifies the control unit 50 of the identification information of the detected spindle as the inspection result. Furthermore, if there is no residual yarn in the jar 5 of any spindle, that is, if the rewinding of all spindles is successful, the image processing unit 32 notifies the control unit 50 of this information as the inspection result.

[0072] <Operation of a centrifugal spinning machine>

[0073] Next, the basic operation of the centrifugal spinning machine according to the embodiment of the present invention will be described.

[0074] First, the processes performed on the centrifugal spinning machine 1 include at least a spinning process in which the yarn 20 supplied from the drafting device 2 is spun into the drum 5, and a winding process in which the yarn 20 spun into the drum 5 is wound back into the bobbin 25. The operation of the centrifugal spinning machine 1 in the spinning and winding processes will be described below. Furthermore, both the spinning and winding processes are performed while the drum 5 is rotating at a predetermined speed. Therefore, when the centrifugal spinning machine 1 begins operation, the control unit 50 issues a control command to the drum drive unit 54, thereby causing the drum 5 to rotate at a predetermined speed and move to the spinning process in this state.

[0075] (Spinning process)

[0076] First, the control unit 50 sends a control command to the drafting drive unit 51, thereby causing the rear roller pair 15, the middle roller pair 16, and the front roller pair 17 to rotate at predetermined speeds. As a result, the roving 9 is conveyed by the rotation of each roller pair 15, 16, and 17. At this time, the middle roller pair 16 rotates at a higher speed than the rear roller pair 15, and the front roller pair 17 rotates at a higher speed than the middle roller pair 16. Thus, the roving 9 is drawn to a predetermined thickness by the difference in rotational speeds of each roller pair 15, 16, and 17.

[0077] The yarn 20, stretched by the drafting device 2, is introduced into the yarn guide tube 4 through the suction tube 22. The yarn 20 introduced into the yarn guide tube 4 is spun out from the yarn outlet 4a of the yarn guide tube 4, and is pressed tightly against the inner wall 5b of the tank 5 by the centrifugal force generated by the rotation of the tank 5. In addition, the yarn 20 is twisted by the rotation of the tank 5.

[0078] Next, the control unit 50 sends a control command to the guide tube drive unit 53, causing the guide tube 4 to repeatedly move up and down in a predetermined cycle, and displacing its position relatively downward. This results in a predetermined amount of yarn 20 being stacked on the inner wall 5b of the tank 5. Consequently, a yarn cake 24 is formed on the inner wall 5b of the tank 5. At this time, the control unit 50 sends a control command to the drafting drive unit 51, thereby cutting the yarn. Specifically, the control unit 50 sends a control command to the drafting drive unit 51 in a manner that keeps the rotation of the front roller pair 17 continuing while stopping the rotation of the rear roller pair 15 and the middle roller pair 16 simultaneously. This cuts the yarn in front of the front roller pair 17. The spinning process is then complete.

[0079] (Rewinding process)

[0080] First, the control unit 50 drives the can 5 to rotate at a predetermined speed via the can drive unit 54, and sends a control command to the bobbin drive unit 55, thereby moving the bobbin platform 26 upward. At this time, the bobbin 25 moves upward together with the bobbin platform 26. Additionally, the bobbin 25 enters the can 5 through the opening 5a. Thus, the bobbin 25 is inserted into the can 5. Furthermore, the control unit 50 sends a control command to the guide tube drive unit 53 to move the guide tube 4 upward without the bobbin 25 inserted into the can 5 contacting the guide tube 4.

[0081] Next, the control unit 50 drives, for example, a stylus drive unit (not shown) to bring the stylus into contact with the inner wall 5b of the can 5, thereby stripping the yarn 20 wound on the lower end side of the yarn cake 24 from the inner wall 5b of the can 5. The yarn 20 that has left the inner wall 5b of the can 5 is then wound onto the bobbin 25, thus initiating the rewinding of the yarn onto the bobbin 25.

[0082] Next, if all the yarn 20 forming the yarn cake 24 is wound back onto the bobbin 25, the control unit 50 sends a control command to the bobbin drive unit 55, thereby causing the bobbin platform 26 to move downward. As a result, the bobbin 25 with the yarn 20 wound back, i.e., the full bobbin 25, is removed from the tank 5. This concludes the rewinding process.

[0083] However, when the spinning and rewinding processes described above are performed sequentially, there are cases where yarn rewinding fails for various reasons. If yarn rewinding fails, all or part of the yarn 20 forming the yarn cake 24 becomes residual yarn and remains in the jar 5. Therefore, if the spinning process is performed again with residual yarn in the spindles in the jar 5, subsequent yarns will be stacked on top of the residual yarn. Therefore, in the embodiment of the present invention, the centrifugal spinning frame 1 is controlled as follows.

[0084] Figure 3This is a flowchart illustrating the control method of a centrifugal spinning machine according to an embodiment of the present invention. The control method of the illustrated centrifugal spinning machine is performed under the control of the control unit 50.

[0085] First, the control unit 50 sets the value of variable M to 1 as an initial value (step S1). Variable M is an integer of 1 or more representing the number of times each process is performed; M=1 refers to the 1st time, M=2 refers to the 2nd time, and M=3 refers to the 3rd time. Therefore, for example, if M=1 represents the current time, then M=2 represents the next time. Furthermore, if M=2 represents the current time, then M=1 represents the previous time, and M=3 represents the next time. This consideration remains the same when variable M is 4 or higher.

[0086] Next, the control unit 50 begins the first spinning process (step S2). In the first spinning process, the operation of the roving supply stop device 3 is released in all spindles. With the roving supply stop device 3 released, the wedge 8 is positioned in the position retracted from the rear roller pair 15.

[0087] Next, the control unit 50 determines whether the first spinning process is complete (step S3).

[0088] Next, if the control unit 50 determines in step S3 that the first spinning process has ended, it performs the first rewinding process (step S4). The rewinding process is performed in parallel in all spindles.

[0089] Next, the control unit 50 performs the first inspection process (step S5). In this process, the inspection device 7 checks for the presence of residual yarn. Specifically, the control unit 50 issues a control command to the truck drive unit 56, causing the inspection device 7 to move along with the truck. The inspection device 7 then checks for residual yarn in the jars 5 of each spindle and notifies the control unit 50 of the inspection results.

[0090] Next, based on the inspection results notified from the inspection device 7, the control unit 50 determines whether there is a spindle with residual yarn in the tank 5 among the multiple spindles (step S6). If the inspection results notified from the inspection device 7 contain identification information for more than one spindle, the control unit 50 determines it as yes in step S6; if the inspection results do not contain identification information for any spindle, the control unit 50 determines it as no in step S6.

[0091] In step S6, if it is determined that there are spindles with residual yarn, the control unit 50 issues a control command to the drafting drive unit 51, thereby rotating the back roller pair 15 and the middle roller pair 16 by a predetermined amount in the opposite direction to the direction of roving transport (hereinafter also referred to as "reverse rotation") for all spindles (step S7). After reversing the back roller pair 15 and the middle roller pair 16, the rotation of the back roller pair 15 and the middle roller pair 16 is temporarily stopped. The technical significance of reversing the back roller pair 15 and the middle roller pair 16 in step S7 will then be explained.

[0092] Next, the control unit 50 operates the roving supply stop device 3 only for spindles determined to have residual yarn in the inspection process of step S5, so as not to spin yarn 20 into the tank 5 in the next spinning process (step S8). Specifically, the control unit 50 operates only the roving supply stop device 3 of the spindles identified by the identification information of the spindles included in the inspection results from the multiple roving supply stop devices 3 corresponding to multiple spindles. In addition, the control unit 50 gives a control command to the wedge drive unit 52 corresponding to the roving supply stop device 3 of the spindle identified by the identification information. As a result, in the drafting device 2 of the spindle identified by the identification information, the wedge 8 moves forward relative to the rear roller pair 15. Therefore, the wedge 8 is squeezed between the rear upper roller 15a and the rear lower roller 15b that constitute the rear roller pair 15.

[0093] In addition, in step S6 above, if the control unit 50 determines that there are no spindles with residual yarn, the process moves from step S6 to step S9.

[0094] Next, the control unit 50 determines whether the number of times the yarn residue in the tank 5 is determined to exist in the inspection process of step S5 occurs consecutively N times (step S9). The number of times the yarn residue in the tank 5 is determined to exist in the inspection process of step S5 refers to the number of times the rewinding failed in the rewinding process of step S4. N is an integer greater than or equal to 2, and this value is preset to take into account the impact of rewinding failures on productivity. For example, the value of N is set in the range of 3 or more and less than 5.

[0095] If the determination in step S9 is yes, the control unit 50 stops the operation of the centrifugal spinning machine 1 (step S10). When the centrifugal spinning machine 1 stops, the rotation of the tumbler 5 stops in all the spindles. Furthermore, from the start of the first spinning process until the centrifugal spinning machine 1 stops, the tumbler 5 continues to rotate at a predetermined speed. Therefore, the spinning process, the rewinding process, and the inspection process are all performed without stopping the rotation of the tumbler 5.

[0096] On the other hand, if the determination in step S9 is negative, the control unit 50 returns to step S2 after incrementing the value of variable M (step S11).

[0097] Next, the control unit 50 begins the second spinning process in step S2. At this time, if residual yarn remains in the jar 5 of any spindle during the completion of the first rewinding process, the second spinning process begins while the roving supply stop device 3 of that spindle is operational. Therefore, the supply of roving 9 to the drafting device 2 is stopped in the spindle where the roving supply stop device 3 is operational. Therefore, even when the second spinning process begins, yarn 20 is not spun into the jar 5 from spindles containing residual yarn. Therefore, there is no situation where subsequent yarn is layered on top of residual yarn in the jar 5.

[0098] Determine whether the second spinning process is complete (step S3).

[0099] Next, after the second rewinding process (step S4), the control unit 50 performs a second inspection process (step S5). Regardless of whether there is residual yarn in the jar 5, the second rewinding process is performed on all spindles. At this time, there are cases where rewinding fails in the first rewinding process but succeeds in the second. For example, the identification information for a spindle that failed to rewind in the first rewinding process is "007," and there is a case where the second rewinding process is successful in the spindle identified by this identification information "007." In such a case, at the end of the second rewinding process, there is no residual yarn in the jar 5 of the spindle identified by the identification information "007." Therefore, in the second inspection process performed after the second rewinding process, the inspection result notified to the control unit 50 from the inspection device 7 does not include the identification information "007." Therefore, in the spindle identified by the identification information "007", the third spinning process begins, and yarn 20 is spun into tank 5.

[0100] On the other hand, there are also cases where rewinding fails in the first rewinding process and fails again in the second rewinding process, i.e., there are cases where rewinding fails multiple times consecutively. For example, the identification information of the spindle that failed to rewind in the first rewinding process is "003", and there are cases where the spindle identified by the identification information "003" fails to rewind again in the second rewinding process. In such cases, at the stage after the second rewinding process, there is residual yarn in the jar 5 of the spindle identified by the identification information "003". Therefore, in the second inspection process performed after the second rewinding process, the inspection result notified to the control unit 50 from the inspection device 7 includes the identification information "003". In this case, after the control unit 50 determines that it is true in step S6, it reverses the back roller pair 15 and the middle roller pair 16 in step S7, and then, in step S8, it activates the roving supply stop device 3 of the spindle identified by the identification information "003". Therefore, in the spindle identified by the identification information "003", the supply of roving 9 to the drafting device 2 is stopped by the roving supply stop device 3, so there is no situation where yarn 20 is spun into the tank 5 in the third spinning process.

[0101] Next, use Figures 4-9 Specific operational examples of a centrifugal spinning machine when the control method of the centrifugal spinning machine according to the embodiments of the present invention is described.

[0102] Here, we will take three spindles from the multiple spindles of the centrifugal spinning frame 1 as an example for explanation. These three spindles are further divided into spindle 1 61, spindle 2 62, and spindle 3 63. Spindle 1 61 has a yarn guide tube 4-1 and a canister 5-1, spindle 2 62 has a yarn guide tube 4-2 and a canister 5-2, and spindle 3 63 has a yarn guide tube 4-3 and a canister 5-3.

[0103] First, at the stage after the first spinning process is completed, such as Figure 4 As shown, yarn cakes 24-1, 24-2, and 24-3 are formed in the jars 5-1, 5-2, and 5-3 of each spindle 61, 62, and 63, respectively. Yarn cake 24-1 is formed from yarn 20-1 layered on the inner wall of jar 5-1. Yarn cake 24-2 is formed from yarn 20-2 layered on the inner wall of jar 5-2, and yarn cake 24-3 is formed from yarn 20-3 layered on the inner wall of jar 5-3.

[0104] Next, after the first rewinding process is completed, such as... Figure 5As shown, in the first spindle 61, yarn 20-1 is wound back onto bobbin 25-1, and in the third spindle 63, yarn 20-3 is wound back onto bobbin 25-3. Conversely, in the second spindle 62, due to the failure of the winding process, yarn 20-2 is not wound back onto bobbin 25-2, and yarn cake 24-2 remains on the inner wall of tank 5-2. At this time, the yarn 20-2 forming yarn cake 24-2 inside tank 5-2 is equivalent to residual yarn.

[0105] Next, in the first inspection process, such as Figure 6 As shown, by moving camera 31 in the direction of the arrow in the figure, camera 31 sequentially photographs the cans 5-1, 5-2, and 5-3 of each spindle 61, 62, and 63. At this stage, only cannula 5-2 of spindle 2 62 contains residual yarn 20-2. In the first inspection process, it was determined that there was no residual yarn in cannula 5-1 of spindle 1 61 and cannula 5-3 of spindle 3 63, but it was determined that there was residual yarn in cannula 5-2 of spindle 2 62 due to the presence of yarn 20-2. Therefore, in spindles 1 61 and 3 63, the roving supply stop device 3 (see reference) is activated. Figure 1 None of them work, and in the second spindle 62, the roving supply stop device 3 works.

[0106] Therefore, in the second spinning process, as Figure 7 As shown, yarn 20-1 is spun into tank 5-1 using guide tube 4-1 in spindle 1, and yarn 20-3 is spun into tank 5-3 using guide tube 4-3 in spindle 3. In contrast, in spindle 62, roving supply stop device 3 is activated, so no yarn is spun into tank 5-2.

[0107] Afterwards, at the stage where the second spinning process has ended, such as Figure 8 As shown, yarn cakes 24-1, 24-2, and 24-3 are formed in the jars 5-1, 5-2, and 5-3 of each spindle 61, 62, and 63, respectively. Yarn cakes 24-1 and 24-3 are formed in the second spinning process, while yarn cake 24-2 is formed in the first spinning process.

[0108] Next, after the second rewinding process is completed, such as... Figure 9As shown, in the first spindle 61, yarn 20-1 is wound back onto bobbin 25-1. Similarly, in the second spindle 62 and the third spindle 63, yarns 20-2 and 20-3 are wound back onto bobbins 25-2 and 25-3, respectively. In this case, in the second spindle 62, after a failed winding in the first winding process, winding is successful in the second winding process. Therefore, in the third spinning process, yarns 20-1, 20-2, and 20-3 are spun into jars 5-1, 5-2, and 5-3 in any of the three spindles 61, 62, and 63.

[0109] Next, the technical significance of reversing the back roller pair 15 and the middle roller pair 16 in step S7 above will be explained.

[0110] First, in the spinning process, when the yarn package 24 is finished forming and the yarn is cut, the rotation of the front roller pair 17 is maintained, while the rotation of the rear roller pair 15 and the middle roller pair 16 is stopped. Therefore, in the drafting device 2 after the yarn is cut, as... Figure 10 As shown, the tip 9a of the roving 9 is located in front of the front roller pair 17. If the next spinning process is carried out in this state, then in the spindle where the roving supply stop device 3 is operating, as... Figure 11 As shown, the middle roller pair 16 and the front roller pair 17 rotate while the wedge 8 is squeezed between the upper rear roller 15a and the lower rear roller 15b. Therefore, the roving 9 is pulled and cut between the rear roller pair 15 and the middle roller pair 16. As a result, there is a concern that the cut end portion 9b of the roving 9 may be carried by the rotation of the middle roller pair 16 and the front roller pair 17 and enter the tank 5. Furthermore, although the roving 9 entering the tank 5 can be discarded, this deteriorates the raw material allocation, leading to a decrease in productivity. Additionally, if the rotation of the rear roller pair 15 is stopped and the yarn is cut while the front roller pair 17 and the middle roller pair 16 are kept rotating, the reversal of the rear roller pair 15 and the middle roller pair 16 is not required. However, in this case, the yarn cutting position is inconsistent between spindles, resulting in a decrease in rewind success rate and spinning start success rate, thereby reducing productivity.

[0111] Conversely, if the rear roller pair 15 and the middle roller pair 16 are reversed in step S7 above, then as follows: Figure 12 As shown, the roving 9 returns to the upstream side of the roving transport direction. At this time, the control unit 50 preferably controls the rotation of the rear roller pair 15 and the middle roller pair 16 via the drafting drive unit 51 in such a way that the tip 9a of the roving 9 moves from the position in front of the front roller pair 17 to the position in front of the middle roller pair 16. Thus, as Figure 13As shown, when the wedge 8 is squeezed between the upper rear roller 15a and the lower rear roller 15b by the operation of the roving supply stop device 3, the roving 9 will not be cut even if the middle roller pair 16 and the front roller pair 17 rotate. Therefore, it is possible to prevent the cut end portion 9b of the roving 9 from entering the tank 5. In addition, the amount of rotation when the rear roller pair 15 and the middle roller pair 16 are reversed is at least enough to avoid Figure 11 The amount of that coarse yarn cut to 9 is sufficient.

[0112] <Effects of the Implementation Method>

[0113] The control method for a centrifugal spinning frame according to an embodiment of the present invention includes an inspection process that checks each spindle for residual yarn in the hopper 5 after the spinning and rewinding processes have ended and before the next spinning process begins. Furthermore, a structure is employed to operate the roving supply stop device 3 such that for spindles determined to have residual yarn in the inspection process, yarn 20 is not spun into the hopper 5 in the next spinning process. Therefore, even if a spindle has residual yarn in the hopper 5 due to a rewinding failure in the rewinding process, yarn 20 will not be spun into the hopper 5 from that spindle in the next spinning process. Thus, even in the event of a yarn rewinding failure in any spindle, the accumulation of residual yarn with subsequent yarn in the hopper 5 can be prevented.

[0114] Furthermore, in this embodiment of the invention, the structure employs a method where a camera 31 photographs the interior of the can 5, and the resulting image data is processed to determine whether there is residual yarn inside the can 5. This allows for the determination of the presence of residual yarn inside the can 5 without contact with it. Therefore, the inspection process can be performed without causing the yarn cake 24 to collapse due to contact with residual yarn. Additionally, during the inspection process, even without stopping the rotation of the can 5, the presence of residual yarn inside the can 5 can be accurately determined by utilizing the brightness difference generated at the boundary between the inner wall 5b of the can 5 and the residual yarn.

[0115] Furthermore, in the embodiment of the present invention, the structure employed is such that, when it is determined during the inspection process that residual yarn exists in the jar 5 of any spindle, for the spindle determined to have residual yarn, before activating the roving supply stop device 3, all spindles are rotated by a predetermined amount in the opposite direction to the roving transport direction. Thus, even if a spindle fails to rewind during the rewinding process and has residual yarn in the jar 5, the roving 9 can be pre-returned to the upstream side of the roving transport direction without being cut in the drafting device 2 at the start of the next spinning process.

[0116] Furthermore, in an embodiment of the present invention, the structure employed is such that when it is determined in the inspection process that residual yarn in the jar 5 occurs N times consecutively, the operation of the centrifugal spinning machine 1 is stopped. Thus, when rewinding fails multiple times consecutively in the rewinding process, the operation of the centrifugal spinning machine 1 is stopped when this consecutive number reaches N times, thereby suppressing a decrease in productivity.

[0117] <Examples of variations, etc.>

[0118] The scope of the present invention is not limited to the above-described embodiments, but also includes various modifications and improvements made within the scope of deriving the definite effects obtained from the constituent elements of the invention and their combination.

[0119] For example, in the above embodiment, the camera 31 takes a picture of the inside of the can 5, but it is not limited to this. The camera 31 can also take pictures of the bobbins 25 that have finished the rewinding process in each spindle and have been taken out of the can 5. In this case, the amount of yarn rewound in the bobbins 25 that have been successfully rewound and the bobbins 25 that have failed to be rewound are actually different from those of the bobbins 25. Therefore, even when the camera 31 takes pictures of the bobbins 25 that have been taken out of the can 5, the difference in the amount of yarn, etc., can be detected by image processing, thereby determining whether there is any residual yarn in the can 5. In addition, when the rewinding is successful in the rewinding process, there is an area on the upper end of the bobbin 25 that is the rewinding terminal side where the yarn 20 is thinly wound by one or several layers. Therefore, the area can also be photographed by camera 31, and the brightness or color difference between the case where the yarn 20 is thinly wound and the case where the yarn 20 is not wound can be detected by image processing, thereby determining whether there is residual yarn in the tank 5.

[0120] In addition, the inspection process does not necessarily require the use of camera 31 and image processing unit 32. For example, a contact sensor can be used to contact the inner wall 5b of tank 5 to determine the presence or absence of residual yarn.

[0121] Furthermore, in the above embodiment, when it is determined in the inspection process that the number of times residual yarn is found in the tank 5 occurs consecutively N times, the operation of the centrifugal spinning machine 1 is controlled to stop. However, the present invention is not limited to this. For example, the operation of the centrifugal spinning machine 1 may also be controlled to stop when the number of spindles with residual yarn in the tank 5 (in other words, the number of spindles that failed to be rewound in the Mth rewound process) J exceeds a preset upper limit value in an inspection process performed after the Mth rewinding process. When this control method is adopted, for example, even if a certain number of spindles among the multiple spindles of the centrifugal spinning machine 1 fail to be rewound consecutively, the operation of the centrifugal spinning machine 1 continues as long as the number of spindles with residual yarn in the tank 5 is determined in one inspection process to not exceed the upper limit value. Therefore, even if a few spindles fail to be rewound consecutively, and the impact of stopping the operation of the centrifugal spinning machine 1 once would significantly reduce productivity, the operation of the centrifugal spinning machine 1 can continue without stopping. Furthermore, the value of J mentioned above can be determined by counting the amount of identification information contained in the inspection results.

[0122] The roving supply stopping device is not limited to having a wedge configured to move forward and backward relative to the back roller pair, and squeezing the wedge between the two rollers constituting the back roller pair, thereby stopping the supply of the roving relative to the drafting device. For example, other known structures, such as holding and cutting the roving located upstream of the back roller, may also be used.

Claims

1. A control method for a centrifugal spinning machine, wherein, The centrifugal spinning machine has multiple spindles. Each of the plurality of spindles has: A drafting device having a back roller pair, a middle roller pair, and a front roller pair arranged sequentially from the upstream side to the downstream side in the roving transport direction, which stretches the roving by rotating the back roller pair, the middle roller pair, and the front roller pair respectively. A roving supply stopping device that stops the supply of the roving to the drafting device; and The tank rotates at a specified speed. The control method for the centrifugal spinning machine is characterized by having: The spinning process spins the yarn supplied from the drafting device into the tank; The rewinding process involves rewinding the yarn spun into the jar back into the bobbin; and The inspection process, which occurs after the spinning and rewinding processes are completed and before the next spinning process begins, involves checking for any remaining yarn in the can that should be rewound to the bobbin for each spindle. For a spindle that is determined to have residual yarn during the inspection process, the spindle is moved to the next spinning process while the roving supply stop device is operating, so that no yarn is spun into the tank in the next spinning process.

2. The control method for a centrifugal spinning machine according to claim 1, characterized in that, In the inspection process, the inside of the can is photographed by a camera, and the image data obtained by the photograph is processed to determine whether there is any residual yarn inside the can.

3. The control method for a centrifugal spinning machine according to claim 1, characterized in that, If, during the inspection process, it is determined that there is residual yarn in the can of any of the spindles, before the roving supply stop device is activated for the spindles where residual yarn is determined to be present, the rear roller pair and the middle roller pair are rotated by a predetermined amount in the opposite direction to the direction during roving transport for all the spindles.

4. The control method for a centrifugal spinning machine according to claim 2, characterized in that, If, during the inspection process, it is determined that there is residual yarn in the can of any of the spindles, before the roving supply stop device is activated for the spindles where residual yarn is determined to be present, the rear roller pair and the middle roller pair are rotated by a predetermined amount in the opposite direction to the direction during roving transport for all the spindles.

5. The control method for a centrifugal spinning frame according to any one of claims 1 to 4, characterized in that, If, during the inspection process, it is determined that the number of times the residual yarn is found in the tank occurs consecutively N times, the operation of the centrifugal spinning machine is stopped, where N is an integer greater than or equal to 2.

6. The control method for a centrifugal spinning frame according to any one of claims 1 to 4, characterized in that, If, during the first inspection process, it is determined that the number of spindles containing residual yarn in the tank exceeds a preset upper limit, the operation of the centrifugal spinning machine is stopped.

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