Yarn joining system and method for joining auxiliary yarn at spinning station of ring spinning machine requiring maintenance

Abstract

A yarn joining system for threading and joining an auxiliary yarn (1), comprising a yarn handling tool (6) attached to a computer-controlled robotic or robotic arm (7), a yarn nozzle (9) located on a yarn outlet of the yarn handling tool (6), the device comprises a yarn handling tool (6), yarn holding means (16) arranged on the yarn handling tool (6) to be able to form a threading portion of an auxiliary yarn (1), and processing and control means configured to provide an activation signal to driving means of a robotic arm (7) to cause the yarn handling tool (6) to perform a threading operation and a coupling operation, the system further comprises a yarn feeding device (10) arranged and configured for feeding a length ("L0", "L1") of the auxiliary yarn (1) to a yarn conveying path external to the yarn handling tool (6) during operation of the yarn handling tool (6) by the robotic arm (7).

Description

Technical Field

[0001] The present invention generally relates to a yarn coupling system for coupling auxiliary yarns when a yarn break occurs at a spinning station of a ring spinning machine. The present invention also relates to a method for automatically coupling auxiliary yarns at a spinning station. Background Art

[0002] Known yarn coupling systems perform automatic coupling of broken ends of yarn. When yarn breakage occurs on a ring spinning machine, the broken ends of the yarn are wound on bobbins after the breakage. In these systems, an automatic yarn handling device is used to detect the broken ends of the yarn via a suction tube connected to a vacuum source. The suction tube is mounted on an automatic service station that is arranged to be able to shift along a row of spinning stations and selectively stop at a selected spinning station that requires maintenance operations.

[0003] In the above-mentioned known yarn connection system, in order to resume spinning after a yarn break, the yarn end is sucked into a vacuum tube, via which the yarn end is positioned relative to the bobbin, and then the threading operation is performed by a threading part that forms the yarn end. The threading part is positioned at the flange of the ring, and the wire loop on the ring of the spinning machine is set to move via compressed air so that the wire loop is placed on the threading part of the yarn end and the yarn end is threaded into the wire loop. Once threaded, the yarn end is positioned via the same suction tube, so that the yarn end is connected to the roving emitted from the roving output roller.

[0004] The yarn coupling system for handling the broken ends of the yarn has the disadvantage that the broken ends are difficult to detect when the yarn breaks after a bobbin change (unbobbin) when the spindle tube is still without yarn. Likewise, the broken ends are difficult to detect if they remain wound on the part of the spindle tube that is located below the spindle track of the spinning machine. This happens when two spinning stations require maintenance operations at the same time, and the automatic service station needs more time to assist the second spinning station, so that a large part of the spindle tube of the second spinning station is without yarn on the spindle track.

[0005] In order to solve the disadvantages of yarn joining systems that deal with broken ends of yarn, known joining systems have been developed to improve the joining process by feeding the free end of the auxiliary yarn to the spindle tube of the rotating spindle where the free end is to be wound. These known yarn joining systems can save the step of detecting the broken end of the yarn.

[0006] JP03199436A discloses a known yarn coupling system, which has an automatic maintenance station, which can be positioned at a spinning station, for supplying the free end of an auxiliary yarn from an auxiliary yarn source to a rotating spindle, which has a spindle tube, and the spindle tube provides a winding surface for winding the free end of the auxiliary yarn. The free end of the auxiliary yarn is supplied by a yarn feeding nozzle, which pushes the free end of the auxiliary yarn to the spindle tube of the rotating spindle together with air. The system is also provided with a finger-like element, which is used to fix the auxiliary yarn on the outside of the yarn feeding nozzle when the free end of the auxiliary yarn is wound on the spindle tube to form a threading part. For this purpose, an automatic manipulator is provided to manipulate the yarn feeding nozzle and the finger-like element to perform the threading operation. Once threaded, the yarn end of the auxiliary yarn is positioned to be used to couple the yarn end to the roving emitted from the front roller of the drafting assembly via another finger-like element.

[0007] The yarn coupling system disclosed in JP03199436A has several disadvantages. One of the disadvantages is that the winding operation of the free end of the auxiliary yarn on the spindle tube fails due to the poor adhesion of the free end of the auxiliary yarn to the surface of the spindle tube, especially when there is no yarn on the spindle tube after unwinding. Another disadvantage is that the threading operation takes place while the spindle tube is kept rotating in order to maintain appropriate tension on the auxiliary yarn outside the yarn feed nozzle and prevent the threaded part from sagging. However, it has been found in practice that the threading operation is even more difficult and complicated to perform by rotating the spindle tube, because threading requires high precision when positioning the yarn.

[0008] Therefore, it is necessary to provide an alternative technology that compensates for the defects found in the related art, which is achieved by providing a yarn coupling system and a method for coupling auxiliary yarns, which overcomes the above-mentioned shortcomings and thus provides a system as follows: the system has a fast and reliable yarn threading operation and coupling operation, and has improved reliability in the winding operation of the free end of the auxiliary yarn, even in the case of an empty spindle tube. Summary of the invention

[0009] To this end, the present invention relates in a first aspect to a yarn coupling system for coupling auxiliary yarns at a spinning station requiring maintenance of a ring spinning machine, the yarn coupling system comprising:

[0010] - a yarn manipulation tool attached to a computer controlled mechanical or robotic arm,

[0011] - drive devices for robot arms,

[0012] - a yarn delivery channel located inside the yarn manipulation tool, which is used to deliver the auxiliary yarn from the yarn inlet to the yarn outlet,

[0013] - a yarn nozzle, which is located at the yarn outlet of the yarn manipulation tool,

[0014] - a yarn holding device, which is arranged on the yarn manipulation tool so as to be able to form a threading portion of the auxiliary yarn on the outer side of the yarn nozzle, and

[0015] - a processing and control device configured to: when the free end of the auxiliary yarn is wound on the spindle and the rotation of the spindle is stopped, provide an enabling signal to the drive device of the robot arm so that the yarn manipulation tool performs the threading operation and the coupling operation,

[0016] Among them, the system also includes:

[0017] - a yarn delivery path located outside the yarn manipulation tool, the yarn delivery path being used to deliver the auxiliary yarn from the auxiliary yarn source to the yarn inlet of the yarn manipulation tool, and

[0018] A yarn feeding device arranged and configured for feeding a length of auxiliary yarn to a yarn delivery path outside the yarn manipulation tool during operation of the yarn manipulation tool via the robot arm.

[0019] Due to the defined characteristics, the present invention provides a yarn connecting system, in which both the threading operation and the connecting operation are manipulated via a yarn manipulation tool attached to a robot arm of an automatic maintenance station, and in which the yarn feeding device is arranged and constructed to feed a length portion of the auxiliary yarn to a path located outside the yarn manipulation tool during the operation of the yarn manipulation tool via the robot arm.

[0020] It has been found that during operation the auxiliary yarn outside the yarn manipulation tool can relax, twist and wind upon itself, resulting in yarn curling which changes the yarn curl and impedes threading and binding.

[0021] In the system claimed for protection, the yarn feeding device feeds a length portion of the auxiliary yarn to a path outside the yarn manipulation tool, which length portion of the auxiliary yarn acts as a yarn buffer and helps improve the manipulation of the auxiliary yarn outside the yarn manipulation tool by preventing curling and twisting when a robotic arm or a computer-controlled mechanical arm moves to thread and connect the yarn.

[0022] According to a second aspect, the invention relates to a method for coupling an auxiliary yarn at a spinning station of a ring spinning machine requiring maintenance, the method comprising the following steps:

[0023] a) feeding a first length portion of the auxiliary yarn to a yarn delivery path external to a yarn manipulation tool driven by a robotic arm,

[0024] b) bringing the yarn handling tool close to the spindle tube of the spindle that needs maintenance,

[0025] c) advancing a first length of the auxiliary yarn to the yarn outlet of the yarn manipulation tool so that the free end of the auxiliary yarn is wound around the rotating spindle tube,

[0026] d) after the free end of the auxiliary yarn has been wound onto the rotating spindle, stopping the rotation of the rotating spindle,

[0027] e) After step d), the second length portion of the auxiliary yarn is fed to the yarn delivery path outside the yarn manipulation tool, and the second length portion of the auxiliary yarn is increased or decreased when the robotic arm moves the yarn manipulation tool for threading and coupling.

[0028] In contrast to known coupling methods, in the claimed method a first length of auxiliary yarn is fed to the yarn path outside the yarn manipulation tool in order to precisely prepare the yarn length for being advanced and wound onto the spindle tube.

[0029] When the free end of the auxiliary yarn is wound, the rotation of the rotating spindle is stopped and the second length of the auxiliary yarn is fed along the yarn path outside the yarn manipulation tool. The back and forth movement of the yarn manipulation tool via the robot arm causes the second length of the auxiliary yarn to grow or shorten, thereby allowing the threading and coupling operations to be performed without yarn sagging. In this way, the reliability and accuracy of the threading and coupling operations are significantly improved.

[0030] For one embodiment, the yarn feeding device of the claimed system is preferably configured to feed a length portion of the auxiliary yarn under tension, and steps a) and e) of the claimed method are preferably performed by respectively feeding a first length portion of the auxiliary yarn under tension and a second length portion of the auxiliary yarn under tension.

[0031] Advantageously, the yarn coupling system comprises a yarn buffer mechanism and a control unit for the yarn buffer mechanism, wherein the yarn buffer mechanism forms a yarn buffer for the auxiliary yarn between the yarn manipulation tool and the auxiliary yarn source along the yarn delivery path outside the yarn manipulation tool.

[0032] It has been discovered that yarn buffers help improve manipulation of secondary yarns external to the yarn manipulation tool by preventing curling and twisting as a robotic arm or computer controlled mechanical arm moves to perform threading and splicing.

[0033] For the preferred embodiment, the yarn buffer mechanism is configured to form a yarn buffer of the tensioned auxiliary yarn to more effectively counteract curling and twisting of the auxiliary yarn length along a path outside the yarn manipulation tool.

[0034] For a preferred embodiment including a yarn buffer mechanism, a method of coupling an auxiliary yarn is claimed, in which method:

[0035] - step a) comprises: forming a yarn buffer including a first length portion of the auxiliary yarn along the yarn delivery path outside the yarn manipulation tool,

[0036] - step c) comprises: advancing a first length of the auxiliary yarn of the yarn buffer to the yarn nozzle of the yarn manipulation tool, thereby winding the free end of the auxiliary yarn of the yarn buffer onto the rotating spindle tube, and

[0037] - Step e) comprises:

[0038] i. forming a yarn buffer comprising a second length of auxiliary yarn, and

[0039] ii. Maintaining the second length of the auxiliary yarn of the yarn buffer in elastic tension as the second length of the auxiliary yarn grows or shrinks as the robotic arm moves the yarn manipulation tool to perform threading and joining operations.

[0040] Advantageously, the yarn handling and control device is configured to provide, at an initiating step of a joining cycle, a signal to a control unit of the yarn buffer mechanism to cause the yarn buffer mechanism to form a yarn buffer comprising a predetermined length of the auxiliary yarn.

[0041] Due to these features, a predetermined length portion of auxiliary yarn can be fed between the auxiliary yarn source and the yarn inlet of the yarn manipulation tool along a path outside the yarn manipulation tool. The predetermined length portion of the auxiliary yarn is arranged to be advanced to the rotating spindle at the initiation step of the coupling cycle. Depending on the type of yarn, the length of the yarn to be advanced may be different. Since the length portion of the auxiliary yarn to be advanced is prepared by the yarn buffer mechanism, the manipulation of the auxiliary yarn occurs in a more efficient manner without the risk of sagging or curling.

[0042] For one embodiment, the yarn buffer mechanism includes a yarn retaining member that is constructed and arranged to hold the auxiliary yarn of the yarn buffer in elastic tension as the auxiliary yarn of the yarn buffer grows or shrinks as the robotic arm moves the yarn manipulation tool.

[0043] The yarn holding member can be configured to hold the auxiliary yarn in elastic tension at a constant torque to eliminate curling and tangling of the yarn. During operation of the yarn manipulation tool via the robotic arm, the auxiliary yarn of the yarn buffer grows or shrinks, thereby holding the auxiliary yarn on the path outside the yarn manipulation tool in tension at a constant value.

[0044] For one embodiment, a control unit for the yarn buffer mechanism includes a stepper motor operatively connected to the yarn retaining member to maintain the yarn retaining member in a resiliently active working position as the auxiliary yarn of the yarn buffer grows or shrinks as the robotic arm moves the yarn manipulation tool.

[0045] The stepper motor is operatively connected to the yarn holding member so that the stepper motor operates in a low current mode to hold the yarn holding member in a resiliently active working position. In the resiliently active working position, the stepper motor allows the yarn holding member to obtain a retracted position when pulled by the movement of the robot arm, thereby causing the length portion of the accumulated yarn of the yarn buffer to shorten, and to resume an initial extended position when the robot arm moves closer to the yarn buffer mechanism, thereby causing the length portion of the accumulated yarn of the yarn buffer to grow.

[0046] Advantageously, at the initiation step of the coupling cycle, the stepper motor is operated in a high current mode so that the yarn holding member obtains a predetermined extended position, thereby forming a yarn buffer including a predetermined length portion of the auxiliary yarn. The predetermined length portion of the auxiliary yarn of the yarn buffer comes from the auxiliary yarn source. The stepper motor can be operated to move the yarn holding member to different fixed positions so as to be able to obtain the desired length portion of the auxiliary yarn from the auxiliary yarn source.

[0047] For one embodiment, the yarn holding member includes a yarn manipulation rod, which is operatively connected to a control unit of the yarn buffer mechanism and is arranged to pivot a rotation angle to form a yarn buffer when the control unit receives a signal from the processing and control device.

[0048] The yarn manipulation rod-shaped member can be a flexible rod-shaped member, and advantageously, the yarn manipulation rod-shaped member is arranged to accumulate potential energy in an active elastic working position to keep the auxiliary yarn of the yarn buffer tensioned at a predetermined value, and as the robotic arm moves the yarn manipulation tool to thread and connect the yarn, the auxiliary yarn of the yarn buffer grows or shortens.

[0049] Preferably, the yarn connecting system includes a yarn advancing device, which is arranged along the yarn delivery path inside the yarn manipulation tool, and the processing and control device is configured to: at the yarn initiation step of the connecting cycle, provide an enable signal to the yarn advancing device so that the yarn advancing device can advance the length portion of the auxiliary yarn of the yarn buffer to the yarn nozzle, thereby winding the free end of the auxiliary yarn of the yarn buffer onto the rotating spindle.

[0050] The yarn advancing device pulls the length of the auxiliary yarn of the yarn buffer and pushes the length to the yarn nozzle to wind the free end of the auxiliary yarn of the yarn buffer onto the rotating spindle tube.

[0051] According to one embodiment of the system, the yarn propulsion device includes a venturi and an air ejector assembly, which is arranged to suck air into the yarn inlet of the yarn manipulation tool when receiving an enable signal from the processing and control device. The venturi and air ejector assembly are installed on the manipulation tool, and preferably, the venturi and air ejector assembly are arranged so that the venturi is roughly aligned with the yarn nozzle. When enabled, the yarn propulsion device picks up the yarn from the yarn inlet and pushes the yarn toward the yarn outlet or the yarn nozzle of the yarn manipulation tool. The yarn propulsion device may or may not include the venturi. For example, they may not include the venturi and be constructed via a mechanical air-based device based on air.

[0052] For a preferred embodiment, the coupling system includes a liquid supply device, preferably, the liquid supply device is a liquid injection device, and the liquid supply device is arranged to: at the yarn initiation step of the coupling cycle, it is possible to wet the yarn contact area of ​​the rotating spindle tube used to contact the free end of the auxiliary yarn.

[0053] According to this preferred embodiment, the processing and control device is configured to provide an enable signal to the liquid supply device so that: when the free end of the auxiliary yarn is pushed into the yarn contact area of ​​the rotating spindle tube, the liquid spray is supplied to the yarn contact area of ​​the rotating spindle tube.

[0054] It has been found that when, at the start of the coupling cycle, a liquid spray is supplied to the spindle tube to wet the yarn contact area intended to be in contact with the free end of the auxiliary yarn, the success rate of the free end of the auxiliary yarn being wound onto the rotating spindle is significantly improved. In addition, the capture time is significantly shortened to an average time of three seconds, while the average time is nineteen seconds when no liquid spray is used.

[0055] For one embodiment, the yarn manipulation tool is attached to the robot arm in an articulated manner via an articulated joint, which is configured to allow the inclined base of the yarn manipulation tool to pivot to an angled position to absorb height differences in the working position of the movable support track of the ring spinning machine.

[0056] It is known that the movable support rail supporting the rotating spindle moves up and down during the spinning process. Therefore, the robot arm must track the movement of the movable support rail to perform the threading and coupling operations. For this purpose, a positioning sensor (e.g., a laser sensor) is fixed at one end of the ring spinning machine so that height position data can be provided to the controller of the robot arm at any time during the coupling cycle. However, the length of the movable support rail does not guarantee that the height position data provided by the positioning sensor is correct at the spinning station that needs maintenance. If the height position data is incorrect, the robot arm will not be able to correctly position the yarn manipulation tool to perform threading.

[0057] The claimed articulated joint allows the yarn manipulation tool to absorb height differences and obtain an optimal working angle to perform the yarn threading.

[0058] Preferably, the articulated joint comprises a resilient connection arranged to allow the inclined base of the yarn manipulation tool to pivot to an angled position when in contact with the movable support rail and to resume an initial rest position when out of contact with the movable support rail.

[0059] Advantageously, for embodiments having an articulated joint, the coupling system includes a tool angle sensor assembly operatively connected to a controller unit of the robotic arm to set the yarn manipulation tool at an optimal working angle position when the yarn manipulation tool contacts the movable support rail.

[0060] Preferably, the tool angle sensor assembly comprises at least two proximity sensors for detecting the presence of an inclined base of the yarn manipulation tool, and the controller unit is configured to check the status of the at least two proximity sensors and provide a setting signal to the processing and control device so that the processing and control device commands the movement of the robot arm to be synchronized with the movement of the movable support rail according to the calculated height offset value.

[0061] These proximity sensors can be arranged at the rear of the frame structure of the yarn manipulation tool to set the optimal working angle position of the yarn manipulation tool when the yarn manipulation tool contacts the movable support rail. The control unit of the robot arm sends a signal to the processing and control device of the system so that the movement of the robot arm can be synchronized with the up and down movement of the movable support rail.

[0062] Advantageously, the processing and control means are configured to:

[0063] - obtaining the actual working height position of the movable support rail at the spinning station requiring maintenance based on the angular position of the yarn manipulation tool provided by the controller unit of the robot arm,

[0064] - calculating a height offset value which is applied to the height position data of the movable support rail provided by a positioning sensor (e.g. a laser sensor fixed at one end of the ring spinning machine), and

[0065] - Based on the calculated height offset value, a signal is sent to a control unit of the robot arm in order to synchronize the movement of the robot arm with the movement of the movable support rail.

[0066] When the synchronization is completed, the robot arm starts to follow the movable support rail so that all the movements necessary to perform threading in the circulator 5 will be combined with the movements of the movable support rail 3 being tracked.

[0067] For a preferred embodiment, the yarn coupling system includes a yarn cutting device, which is arranged on the yarn delivery path inside the yarn manipulation tool to cut the auxiliary yarn inside the yarn path of the yarn manipulation tool when receiving a cutting signal from the processing and control device.

[0068] The yarn cutting device can be constructed by a small blade or cutter incorporated on the yarn manipulation tool so as to be able to cut the auxiliary yarn in the yarn path within the yarn manipulation tool so that the free end of the auxiliary yarn does not protrude beyond the yarn nozzle of the yarn manipulation tool after being cut. The blade or cutter can be driven by an electromagnet or a pneumatic actuator.

[0069] Preferably, the yarn coupling system comprises a yarn holder which is arranged on the same yarn transport path inside the yarn manipulation tool to hold the auxiliary yarn in place on the path inside the yarn manipulation tool, for example when the auxiliary yarn has been cut.

[0070] For one embodiment, the coupling system is prepared to perform a yarn self-threading procedure in the event of a yarn loss on a yarn delivery path inside a yarn manipulation tool. The yarn loss is detected by a sensor device configured to detect the presence and / or movement of the yarn inside the yarn manipulation tool. The sensor device is operatively connected to the processing and control device to inform the system of the status of the auxiliary yarn inside the tool. In order to be able to perform the yarn self-threading procedure, the yarn coupling system includes a yarn feeding device, which includes:

[0071] - the yarn outlet of the yarn buffer mechanism,

[0072] a yarn holder arranged to hold the free end of the auxiliary yarn in place outside the yarn outlet of the yarn buffer mechanism, and

[0073] - Air blowing means arranged to inject air into the yarn outlet of the yarn buffer mechanism.

[0074] The processing and control device is configured to perform an automatic self-threading operation comprising the following steps:

[0075] i. providing a signal to the drive device of the robot arm so that the robot arm positions the yarn inlet of the yarn manipulation tool to correspond to the yarn outlet of the yarn buffer mechanism,

[0076] ii. providing an activation signal to the air blowing device of the yarn feeding device to blow the free end of the auxiliary yarn to the outside of the yarn outlet of the yarn buffer mechanism and hold the auxiliary yarn of the yarn buffer in place on the outside of the yarn outlet, and

[0077] iii. providing an enabling signal to the yarn advancing device of the yarn manipulation tool so that said free end of the auxiliary yarn of the yarn buffer is sucked along the yarn delivery path inside the yarn manipulation tool.

[0078] Advantageously, the yarn feeding device also includes a yarn cutter operatively connected to the yarn outlet of the yarn buffer mechanism so as to be able to cut excess yarn outside the yarn outlet in the event of yarn loss, and preferably, the air blowing device includes a venturi tube and an air injector assembly, which is arranged to blow or inject air into the yarn outlet of the yarn buffer mechanism upon receiving a signal from the control device processing.

[0079] It is also advantageous that the yarn delivery path inside the yarn manipulation tool is configured to be sealed to maintain an optimal airflow generated by the yarn propulsion device of the yarn manipulation tool. It has been found that in the event of yarn loss, this helps the free end of the auxiliary yarn outside the yarn buffer mechanism to be effectively sucked into the yarn manipulation tool and thrown to the yarn nozzle of the tool.

[0080] For one embodiment, the bonding system includes an image capture device preferably disposed on the yarn manipulation tool, wherein the image capture device is operatively connected to an artificial vision system configured to inspect the bonding for obstructions (e.g., yarn segments knotted on a pig-rail) before the bonding cycle begins. For one embodiment, the image capture device (e.g., a camera) is disposed on the yarn manipulation tool.

[0081] Compared to known coupling systems for handling disconnected ends of yarn, the claimed coupling system is suitable for empty spindle tubes (after doffing) and spindle tubes filled with spun fibers (yarn packages) because the free end of the auxiliary yarn is always supplied to the spindle tube for winding. In addition, the claimed method and system have a higher reliability because, in the initiation phase, a predetermined length portion of the auxiliary yarn of the yarn buffer (i.e. a controlled yarn length portion) is pushed to the yarn nozzle to wind the free end of the auxiliary yarn of the yarn buffer onto the rotating spindle tube. In addition, the yarn is preferably pushed to a yarn contact area of ​​the spindle tube, which was previously or simultaneously wetted with a liquid, for example, by a liquid spray or atomized water. The yarn contact area can be an area of ​​the spindle tube where there is no yarn or an area of ​​the spindle tube where there is yarn.

[0082] As mentioned above, it has been found that by wetting the yarn contact area to be contacted by the free end of the auxiliary yarn in the initial step of the coupling cycle, the success rate of winding the free end of the auxiliary yarn onto the rotating spindle is significantly improved. In addition, the capture time is significantly reduced to an average of three seconds, while the average time is nineteen seconds when no liquid spray is used. The reduction in the time spent on grabbing the free end of the yarn is particularly significant when the contact area of ​​the spindle tube is free of yarn (after doffing).

[0083] The following table provides the results of the success rate and average capture time of grabbing the auxiliary yarn obtained from the yarn launch test with and without water spraying in the yarn contact area of ​​the rotating spindle tube.

[0084]

[0085] Although a liquid supply in combination with a yarn coupling system comprising a yarn manipulation tool and a yarn feeding device for feeding a length of auxiliary yarn to a yarn delivery path outside the yarn manipulation tool has been disclosed for wetting the yarn contact area of ​​a rotating spindle, the applicant reserves the right to claim as a separate invention the following yarn coupling system for threading and coupling the free end of an auxiliary yarn at a spinning station requiring maintenance of a ring spinning machine, the yarn coupling system comprising:

[0086] - a yarn feeding device for feeding the free end of the auxiliary yarn to the spindle tube of the rotating spindle, on which the free end is to be wound, the yarn feeding device comprising a yarn nozzle for feeding the free end of the auxiliary yarn to the spindle tube of the rotating spindle,

[0087] - a yarn holding device for holding the auxiliary yarn outside the yarn feed nozzle so as to form a threading portion of the auxiliary yarn when the free end of the auxiliary yarn is wound onto the spindle tube, and

[0088] - an automatic handling device for handling the yarn supply device and the yarn holding device,

[0089] The system also includes:

[0090] - liquid supply means arranged to wet the yarn contact area of ​​the rotating spindle intended for contact with the free end of the auxiliary yarn at the yarn initiation step of the joining cycle, and

[0091] - A processing and control device configured to provide an activation signal to the liquid supply device to supply a liquid spray onto the yarn contact area of ​​the rotating spindle tube before and / or while the free end of the auxiliary yarn is pushed onto said yarn contact area of ​​the rotating spindle.

[0092] Preferably, the liquid supply device comprises a liquid spray device. The liquid can be atomized or applied in any other way under the condition that the yarn contact area of ​​the rotating spindle is wet. The yarn contact area can be an area of ​​the rotating spindle tube with yarn or an area of ​​the rotating spindle without yarn.

[0093] For one embodiment, the automated handling means comprises a yarn manipulation tool attached to a computer controlled mechanical or robotic arm, and the liquid supply means and the yarn nozzle are both disposed on the yarn manipulation tool.

[0094] Advantageously, the yarn holding device is arranged on the yarn manipulation tool, and the processing and control device is configured to provide an enable signal to the drive device of the robot arm when the free end of the auxiliary yarn is wound onto the spindle and the rotation of the spindle stops, so that the yarn manipulation tool performs threading and connecting operations.

[0095] For one embodiment, the yarn coupling system includes a yarn buffer mechanism and a control unit for the yarn buffer mechanism, wherein the yarn buffer mechanism is used to form a yarn buffer for the auxiliary yarn between the yarn manipulation tool and the auxiliary yarn source along the yarn delivery path outside the yarn manipulation tool.

[0096] Advantageously, according to an embodiment of a system having a yarn buffer mechanism, the processing and control device is configured to: provide an enable signal to a yarn advancing device so that the yarn advancing device can push a length portion of the auxiliary yarn of the yarn buffer to the yarn nozzle, thereby allowing the free end of the auxiliary yarn of the yarn buffer to be wound onto the rotating spindle at the yarn initiation step of the coupling cycle.

[0097] In the present invention:

[0098] A robotic arm is to be understood as a robot arm or a computer-controlled robotic arm, preferably a computer-controlled arm having at least six degrees of freedom of movement.

[0099] The threading operation is understood to be the operation of creating or forming a threading portion of the auxiliary yarn outside the yarn nozzle of the yarn manipulation tool, and processing the threading portion at the flange of the ring of the ring spinning machine as it is threaded into the annulator of the ring spinning machine.

[0100] The coupling operation is understood to be an operation in which a yarn manipulation tool is positioned on the roving emerging from the front drafting roller of the drafting assembly of the ring spinning machine in order to couple the threading auxiliary yarn.

[0101] The bonding cycle of the claimed method and system is understood to include threading and bonding operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] The foregoing and other advantages and features will be more fully understood from the following detailed description of the embodiments contemplated herein which summarizes in an illustrative and non-limiting manner with reference to the accompanying drawings;

[0103] Specifically:

[0104] Figure 1 A perspective view of an embodiment of a yarn manipulation tool attached to a robot arm is shown (for clarity, only a portion of the robot arm is shown). The figure also shows a camera attached to the robot arm for capturing images to check if there is a connection obstruction, and a liquid spray nozzle attached to the frame structure of the yarn manipulation tool and vertically aligned with a yarn nozzle arranged at the yarn outlet of the yarn manipulation tool for feeding auxiliary yarn to the rotating spindle tube.

[0105] Figure 2 A schematic perspective rear view of a yarn manipulation tool attached to a robot arm and approaching an empty spinning tube is shown. The figure also shows a yarn feeding device, which is located between the yarn manipulation tool and an auxiliary yarn source (not shown), and a movable support track in which a plurality of spinning tubes are mounted, each belonging to a different spinning station of a ring spinning machine. Figure 2 An embodiment of a yarn feeding device is shown, which includes a yarn buffer mechanism that forms a yarn buffer of an auxiliary yarn along a yarn delivery path outside the yarn manipulation tool. The yarn buffer includes a first length portion "L0" of the auxiliary yarn that has been fed to the yarn path outside the yarn manipulation tool to be pushed toward the rotating spindle tube at the initiation step of the coupling cycle.

[0106] Figure 3A schematic stereoscopic view of a yarn manipulation tool attached to a robot arm is shown, wherein a yarn nozzle pushes a first length portion "L0" of the auxiliary yarn of a yarn buffer when the free end of the auxiliary yarn is pushed to the yarn contact area, and a liquid spray nozzle supplies liquid spray to wet the yarn contact area of ​​an empty rotating spindle.

[0107] Figure 4 Shown with Figure 2 A similar schematic perspective view in which the yarn buffer mechanism is forming a yarn buffer of the auxiliary yarn, the yarn buffer comprising a second length portion "L1" of the auxiliary yarn, which is fed to the yarn path outside the yarn manipulation tool after the free end of the auxiliary yarn is wound and the rotation of the spindle tube is stopped. The yarn manipulation tool is moved back and forth by the robot arm, which will cause the second length portion "L1" of the auxiliary yarn to increase or decrease, so as to allow the threading operation to be carried out without the yarn sagging and to prevent the formation of curls and twists on the yarn path outside the yarn manipulation tool.

[0108] Figure 5 is a perspective view of a yarn manipulation tool, showing a threading portion of an auxiliary yarn formed on the outside of a yarn nozzle by a holding element (e.g., a clamp) arranged on the yarn manipulation tool. The yarn manipulation tool needs to move precisely so that the yarn manipulation tool causes the holding element to hold or grip the auxiliary yarn outside the yarn nozzle to form the threading portion. When forming the threading portion, the threading portion must be threaded by a circulator mounted on a ring spindle, which is supported on a movable support track of a corresponding spindle tube.

[0109] Figure 6 yes Figure 1 Side view of a yarn manipulation tool in which the yarn manipulation tool is attached to a robot arm by an articulated joint, which is configured to allow the inclined base of the yarn manipulation tool to pivot to an angled position to absorb height differences in the working position of the movable support rail and obtain an optimal working angle before threading the yarn.

[0110] Figure 7a and Figure 7bA rear perspective view of a yarn manipulation tool is shown, the yarn manipulation tool approaching a movable support rail to just contact the movable support rail, thereby setting the yarn manipulation tool in an optimal working position by a tool angle sensor assembly when contacting the movable support rail. A controller unit (not shown) of the robot arm is configured to check the status of two proximity sensors, which are arranged to detect the presence of an inclined base of the yarn manipulation tool. The controller unit of the robot arm provides a setting signal to a processing and control device (not shown) of the system so that the processing and control device commands the movement of the robot arm to be synchronized with the movement of the movable support rail based on a calculated height offset value, which is applied to the height position data provided by a positioning sensor (e.g., a laser sensor that measures the height position of the movable support rail at one end of the ring spinning machine).

[0111] Figure 8 A perspective view of a yarn manipulation tool attached to a robot arm is shown, with the threading portion of the auxiliary yarn about to be threaded by the circulator. An air duct attached to the surface of the yarn manipulation tool pushes air to move the circulator over the flange of the ring spindle to facilitate threading.

[0112] Fig. 9 A schematic bottom view of a yarn manipulation tool is shown, showing internal components arranged on a yarn delivery path inside the yarn manipulation tool for delivering a length of auxiliary yarn from a yarn inlet to a yarn outlet, the yarn outlet being constructed by a yarn nozzle. Yarn advancing means, yarn cutting means, yarn retaining means and sensor means for detecting the presence and / or movement of a length of auxiliary yarn are arranged along the path.

[0113] Fig.10 An exploded schematic diagram of the yarn manipulation tool is shown from a bottom perspective.

[0114] Fig.11 yes Fig. 9 Schematic bottom view of a yarn manipulation tool showing a detailed partial cross section of a portion of the yarn path within the yarn manipulation tool, wherein a yarn cutter is arranged for cutting the auxiliary yarn. The figure shows a fragment of a length of the auxiliary yarn being blown out of the yarn nozzle after being cut by the yarn cutter inside the yarn manipulation tool. DETAILED DESCRIPTION

[0115] The following is a reference Figures 1 to 11 Description of the claimed invention, the figures illustrate exemplary embodiments of systems and methods that can be applied to a ring spinning machine including a row of spinning stations arranged adjacent to each other.

[0116] The claimed yarn coupling system and method are arranged to provide automatic service for any spinning station of a ring spinning machine that requires maintenance after a yarn break. As previously described, the claimed coupling system and method feeds the free end of the auxiliary yarn 1 to a rotating spindle having a rotating spindle tube 2 providing a winding surface on which the free end will be wound for the system to subsequently perform the threading and coupling operations.

[0117] The rotating spindles of the ring spinning machine are mounted and aligned on a movable support rail 3, which moves up and down during spinning. At each spinning station, a ring 4 is attached to the movable support rail 3, and a circulator 5 is movably mounted on the flange of the ring 4. Each rotating spindle is arranged coaxially in a vertical position relative to the ring 4, and a corresponding spindle tube 2 is placed on the rotating spindle to support the yarn wrap formed by spinning in a known manner, thereby forming a cop. During spinning, the circulator 5 and the yarn passed through the circulator run around the spindle tube 2 on the flange of the ring 4 for winding the yarn on the surface of the spindle tube 2. A balloon limiting ring (not shown), a yarn guide (not shown) and a drafting assembly (not shown) are arranged above each rotating spindle tube 2. The drafting assembly includes a rear drafting roller, a middle drafting roller and a front drafting roller, and the drafted roving is emitted from the rear drafting roller, the middle drafting roller and the front drafting roller.

[0118] The present invention provides a yarn joining system and method, wherein the threading and joining operations are handled by a yarn handling tool 6 attached to a robot arm 7 of an automatic service station, the automatic service station comprising a carrier arrangement (not shown) on which the robot arm 7 is mounted. The carrier can be displaced along the rows of spinning stations of a ring spinning machine.

[0119] For the exemplary embodiment, the camera 29 is arranged on the robot arm 7 and is operatively connected to the artificial vision system, which is configured to check whether there is an obstruction to the connection. If the captured image finds something that affects the connection, the processing and control device of the system will request operator intervention to restore normal working conditions so that the yarn connection system can provide automatic service.

[0120] The interior of the yarn manipulation tool 6 is arranged with a yarn delivery path for delivering the auxiliary yarn 1 from the yarn inlet 8 of the yarn manipulation tool 6 to the yarn outlet constructed by the yarn nozzle 9. The exterior of the yarn manipulation tool 6 is provided with a yarn delivery path for delivering the auxiliary yarn 1 from an auxiliary yarn source (not shown) to the yarn inlet 8 of the yarn manipulation tool 6. The yarn feeding device 10 is mounted on the same supporting arrangement structure and is configured to feed a length portion of the auxiliary yarn 1 to the yarn delivery path outside the yarn manipulation tool 6. This length portion of the auxiliary yarn 1 outside the yarn manipulation tool 6 has been found to act as a yarn buffer, which helps to improve the manipulation of the auxiliary yarn 1 outside the yarn manipulation tool 6.

[0121] According to a preferred embodiment of the system and method, the yarn feeding device 10 includes a yarn buffer mechanism 11, which forms a yarn buffer for the auxiliary yarn 1 along the yarn delivery path outside the yarn manipulation tool 6. The yarn buffer includes a first length portion "L0" of the auxiliary yarn 1, which has been fed to the yarn path outside the yarn manipulation tool 6 at the initiation step of the coupling cycle to be advanced to the rotating spindle tube 2 (see Figure 2 ).

[0122] In the disclosed embodiment, the yarn buffer mechanism 11 comprises a yarn holding member 12, which is constructed and arranged to hold the auxiliary yarn 1 of the yarn buffer in elastic tension. The yarn holding member 12 comprises a yarn holding rod, which is operatively connected to a control unit (not shown) of the yarn buffer mechanism 11 to pivot a rotation angle to form a yarn buffer when the control unit receives a signal from the processing and control means of the system.

[0123] for Figure 2 and Figure 4 In the illustrated embodiment, the control unit of the yarn buffer mechanism 11 comprises a stepper motor 13 operatively connected to the yarn holding rod for pivoting the yarn holding rod to different fixed positions, thereby enabling a desired length portion of the auxiliary yarn 1 to be obtained from the auxiliary yarn source.

[0124] At the initiation step of the bonding cycle, the yarn handling and control device of the system provides a signal to the control unit of the yarn buffer mechanism 11 to form a yarn buffer having a predetermined length portion (e.g., a first length portion "L0") of the auxiliary yarn from the auxiliary yarn source. The length portion of the auxiliary yarn 1 of the yarn buffer required for initiation may vary depending on factors such as the type of yarn to be bonded.

[0125] In order to advance a predetermined length portion of the auxiliary yarn 1 of the yarn buffer to the rotating spindle tube 2, the yarn connection system includes a yarn advancing device arranged on the yarn path inside the yarn manipulation tool 6. For the illustrated embodiment, the yarn advancing device includes a venturi tube and an air ejector assembly 14, which is arranged to suck air into the yarn inlet 8 of the yarn manipulation tool 6 upon receiving a signal from the processing and control device, thereby advancing the length portion of the auxiliary yarn 1 of the yarn buffer through the yarn nozzle 9.

[0126] Advantageously, the yarn joining system comprises liquid supply means configured to wet the yarn contact area of ​​the rotating spindle tube 2 intended for contact with the free end of the auxiliary yarn 1 at the initiation step of the joining cycle. The processing and control means of the system are configured to provide an enabling signal to the liquid supply means so that a liquid spray (e.g. atomized water) is supplied to the yarn contact area of ​​the rotating spindle tube 2 when the free end of the auxiliary yarn 1 is advanced to said yarn contact area.

[0127] The liquid supply device comprises a liquid spray nozzle 15, which is associated with a container of liquid (not shown) and two solenoid valves (not shown) to control the passage of liquid and air for atomizing a small amount of liquid in an air jet. In the embodiment shown, the liquid spray nozzle 15 is arranged on the yarn manipulation tool 6, vertically aligned with the yarn nozzle 9 of the yarn manipulation tool 6, but it does not necessarily have to be arranged on the yarn manipulation tool 6.

[0128] Figure 3 A schematic stereoscopic view of a yarn manipulation tool 6 attached to a robot arm 7 is shown, wherein the yarn nozzle 9 advances the first length portion "L0" of the auxiliary yarn 1 of the yarn buffer when the free end of the auxiliary yarn 1 is pushed to the yarn contact area, and the liquid spray nozzle 15 supplies liquid spray to wet the yarn contact area of ​​the empty rotating spindle tube 2.

[0129] As previously mentioned, it has been found that the success rate of winding the free end of the auxiliary yarn on the rotating spindle tube 2 is significantly improved (98% compared to 46%) when the liquid spray is supplied to the spindle tube 2 to wet the yarn contact area. In addition, the gripping time is significantly reduced to an average gripping time of three seconds when spraying with liquid spray, compared to an average time of nineteen seconds. Wetting eliminates electrostatic effects and increases the adhesion of the auxiliary yarn 1 to the surface of the rotating spindle tube 2.

[0130] After the free end of the auxiliary yarn is successfully wound on the surface of the rotating spindle tube 2, the rotation of the spindle is stopped, and the stepper motor 13 of the yarn buffer mechanism 11 actuates the yarn holding member 12 to the initial retracted position. Subsequently, the yarn feeding device 10 supplies the second length portion "L1" of the auxiliary yarn 1 to the yarn path outside the yarn manipulation tool 6. Since the end of the auxiliary yarn 1 is fixed to the rotating spindle tube 2, when the yarn holding rod-shaped member is actuated by the stepper motor 13 and pivoted to a new predetermined angular position, the length portion "L1" of the auxiliary yarn 1 is supplied from the auxiliary yarn source (see Figure 4 ).

[0131] The threading performed by moving the yarn manipulation tool 6 by the robot arm 7 causes the second length portion "L1" of the auxiliary yarn 1 to increase or decrease, so as to allow this operation to be performed without sagging and to keep the auxiliary yarn 1 outside the yarn manipulation tool 6 in tension and without curling. To this end, when the auxiliary yarn 1 of the yarn buffer increases or decreases as the robot arm 7 moves the yarn manipulation tool 6 back and forth, the stepper motor 13 operates in a low current mode to keep the yarn holding rod-shaped member in an elastically active working position. In the elastically active working position, the stepper motor 13 allows the yarn holding member 12 to obtain a partially retracted position when pulled by the movement of the robot arm 7, thereby shortening the second length portion "L1" of the auxiliary yarn 1 of the yarn buffer. When the robot arm 7 moves close to the yarn buffer mechanism 11, the yarn holding member 12 returns to the extended position, thereby increasing the second length portion "L1" of the auxiliary yarn 1 of the yarn buffer. The yarn brakes 17, 18 are arranged along the path outside the yarn manipulation tool 6. The inlet yarn brake 17 controls the auxiliary yarn 1 entering the yarn buffer from the yarn source, and the outlet yarn brake 18 controls the output of the auxiliary yarn 1 from the yarn buffer. The two brakes 17, 18 are operatively connected to the controller unit of the yarn buffer mechanism 11.

[0132] Figure 5 1 is a perspective view of a yarn manipulation tool, showing the threading portion of the auxiliary yarn 1 formed on the outer side of the yarn nozzle 9 by a holding element 16 (e.g., a clamp) arranged on the yarn manipulation tool 6. This threading portion must be threaded by a circulator 5 mounted on a ring spindle 4, which is supported on a movable support rail 3 of a corresponding spindle tube 2.

[0133] Before performing the yarn threading, the robot arm 7 drives the yarn manipulation tool 6 close to the movable support rail 3 so that the yarn manipulation tool 6 contacts the movable support rail 3 .

[0134] As mentioned above, it is well known that the movable support rail 3 supporting the rotating spindle tube 2 moves up and down during spinning. Therefore, the robot arm 7 must track the movement of the movable support rail 3 to perform threading and coupling. To this end, a positioning sensor 19 (for example, a laser sensor) is fixed to one end of the ring spinning machine so that height position data can be supplied to the controller of the robot arm 7 at any time during the coupling cycle. However, the length of the movable support rail 3 cannot guarantee that the height position data provided by the positioning sensor 19 at the spinning station that needs maintenance is correct. If the height position data is incorrect, the robot arm 7 cannot correctly position the yarn manipulation tool 6 to perform threading.

[0135] For an exemplary embodiment of the system claimed, the yarn manipulation tool 6 is attached to the robot arm 7 in an articulated manner by means of an elastic articulated joint 20, which is arranged to allow the tilting base 21 of the yarn manipulation tool 6 to pivot to an angled position when in contact with the movable support rail 3 and to return to an initial resting position when it stops contacting the movable support rail 3. An elastic member 30 arranged between the tilting base 21 and the frame 25 helps the tilting base 21 to return to the initial resting position. The articulated joint 21 allows the yarn manipulation tool 6 to absorb height differences when in contact with the movable support rail 3 and obtain an optimal working angle for performing threading (see Figure 6 , Figure 7a and Figure 7b ).

[0136] Advantageously, the coupling system also comprises a tool angle sensor assembly 22, which is operatively connected to the controller unit of the robot arm 7, so as to allow the yarn manipulation tool to be set in an optimal working angle position when the yarn manipulation tool is in contact with the movable support rail 3, and to provide a signal to the processing and control means of the system for causing said processing and control means to:

[0137] - based on the angular position of the yarn manipulation tool 6 provided by the controller unit of the robot arm 7, obtaining the actual working height position of the movable support rail 3,

[0138] - calculation of a height offset value applied to the height position data of the movable support rail 3 provided by a positioning sensor 19, for example a laser sensor fixed to one end of the ring spinning machine, and

[0139] Based on the calculated height offset value, a signal is sent to the controller unit of the robot arm 7 to synchronize the movement of the robot arm 7 with the up and down movement of the movable support rail 3 .

[0140] The tool angle sensor assembly 22 comprises at least two proximity sensors 23 , 24 for detecting the presence of the inclined base 21 of the yarn manipulation tool 6 . Fig.10 These proximity sensors 23, 24 are shown arranged on a rear part of a frame structure 25 of the yarn manipulation tool 6.

[0141] Figure 7a and Figure 7b A rear perspective view of a yarn manipulation tool 6 is shown, which approaches the movable support rail 3 to just contact the movable support rail 3, so that the yarn manipulation tool 6 is set in an optimal working position by the tool angle sensor assembly 22 when the yarn manipulation tool 6 contacts the movable support rail 3. The controller unit (not shown) of the robot arm 7 is configured to check the status of two proximity sensors 23, 24, which are arranged to detect the presence of the inclined base 20 of the yarn manipulation tool 6. The controller unit of the robot arm 7 provides a setting signal to the processing and control device (not shown) of the system so that the processing and control device commands the movement of the robot arm 7 to be synchronized with the movement of the movable support rail 3 according to the calculated height offset value, which is applied to the height position data provided by the positioning sensor 19 (for example, a laser sensor measuring the height position of the movable support rail 3 at one end of the ring spinning machine).

[0142] When synchronization is complete, the robot arm 7 starts to follow the movable support rail 3 so that all the movements necessary to perform threading in the circulator 5 will be combined with the movements of the tracked movable support rail 3. As mentioned before, threading is performed without rotation of the spindle tube 2 to obtain maximum precision.

[0143] Figure 8 A perspective view of the yarn manipulation tool 6 attached to the robot arm 7 is shown when the threading portion of the auxiliary yarn 1 is about to be threaded by the circulator 5. An air duct 31 is attached to the surface of the yarn manipulation tool 6 to propel air to move the circulator 5 on the flange of the ring 4.

[0144] When the circulator 5 is threaded, the robot arm 7 moves the yarn manipulation tool 6 upward and passes the yarn through the balloon limiting ring (not shown) and the yarn guide (not shown). The spindle brake (not shown) is released, and the yarn manipulation tool 6 is lifted until the yarn manipulation tool 6 brings the auxiliary yarn 1 to the front roller of the drafting assembly to perform the coupling of the auxiliary yarn 1 on the roving emitted from the front roller. Then, the cutter 26 incorporated in the yarn manipulation tool 6 cuts the auxiliary yarn 1 in the path inside the yarn manipulation tool 6 so that the free end of the auxiliary yarn 1 does not extend outside the yarn nozzle 9 after cutting. The yarn holder 27 is arranged on the same yarn delivery path inside the yarn manipulation tool 6 to fix the auxiliary yarn 1 in place after the auxiliary yarn 1 is cut. At this time, the coupling cycle is completed, and the robot arm 7 returns the yarn manipulation tool 6 to the initial position of the yarn manipulation tool 6 and moves to the next spinning station that needs to be coupled.

[0145] Fig. 9 , Fig.10 and Fig.11 Different views of the components of the yarn manipulation tool 6 are shown.

[0146] Fig. 9 is a schematic bottom view of a yarn manipulation tool 6, which includes a yarn delivery path inside the yarn manipulation tool 6 for delivering a length of auxiliary yarn 1 from a yarn inlet 8 to a yarn outlet, which is constructed by a yarn nozzle 9. Arranged along the path are: a venturi tube and air injector assembly 14 for sucking air into the yarn inlet 8, thereby advancing the length of auxiliary yarn 1 of the yarn buffer; a yarn cutter 26 driven by an electromagnet; a yarn holder 27 for fixing the auxiliary yarn inside the yarn manipulation tool 6 after the auxiliary yarn 1 has been cut; and a sensor device 28 for detecting the presence and / or movement of the length of auxiliary yarn 1. The sensor device 28 is mainly used for processing and control devices, so as to stop the connection in the event of loss of the auxiliary yarn 1 inside the yarn manipulation tool, or to initiate a self-threading process.

[0147] Fig.10 is another schematic bottom view of the inner parts of a yarn manipulation tool 6 showing a detailed section of a part of the yarn path inside the yarn manipulation tool, the yarn manipulation tool being provided with a yarn cutter 26 for cutting the auxiliary yarn 1 .

[0148] Fig.11A schematic exploded view of the yarn manipulation tool 6 is shown, which shows that: among the various components, a tool angle sensor assembly 22 and at least two proximity sensors 23, 24 are arranged on the rear part of the frame structure 25 for detecting the presence of the inclined base 21 of the yarn manipulation tool 6.

[0149] The claimed system has the advantage that it allows to perform an automatic yarn self-threading process in case of yarn loss on the yarn delivery path inside the yarn manipulation tool 6. In order to be able to perform this process, the yarn feeding device 10 also comprises;

[0150] - a yarn outlet (not shown) of the yarn buffer mechanism 11,

[0151] a yarn holder (not shown) which is arranged on the yarn feeding device 10 for holding the free end of the auxiliary yarn 1 in place outside the yarn outlet of the yarn buffer mechanism 11,

[0152] - an air blowing device (not shown) arranged to inject air into the yarn outlet of the yarn buffer mechanism 11, and

[0153] - a yarn cutter (not shown) operatively connected to the yarn outlet of the yarn buffer mechanism 11 so as to be able to cut off excess yarn outside the yarn outlet in case of yarn loss.

[0154] The processing and control device of the system is configured to perform an automatic self-threading operation including the following steps:

[0155] i. providing a signal to the drive device of the robot arm 7 so that the robot arm 7 positions the yarn inlet 8 of the yarn manipulation tool 6 to correspond to the yarn outlet of the yarn buffer mechanism 11,

[0156] ii. providing an enabling signal to the yarn cutter to cut the excess yarn outside the yarn outlet,

[0157] iii. providing an activation signal to the air blowing device of the yarn feeding device 10 to blow the free end of the auxiliary yarn 1 to the outside of the yarn outlet of the yarn buffer mechanism 11 and hold the auxiliary yarn 1 of the yarn buffer in place on the outside of the yarn outlet, and

[0158] iv. providing an enable signal to the yarn propulsion device 14 of the yarn manipulation tool 6 so that the free end of the auxiliary yarn 1 of the yarn buffer is sucked in along the yarn transmission path located inside the yarn manipulation tool 6.

[0159] The air blowing means comprises a venturi tube and an air injector assembly arranged to blow or inject air into the yarn outlet of the yarn buffer mechanism 11 upon receiving a signal from the processing and control means of the system.

[0160] In summary, the present invention provides a system and method for coupling the free end of an auxiliary yarn 1, which provides a higher reliability and precision of both the threading operation and the coupling operation compared to known coupling methods. In addition, the claimed method and system significantly improve the handling of the auxiliary yarn 1 by the following facts:

[0161] - prevent the auxiliary yarn outside the yarn manipulation tool 6 from curling and twisting,

[0162] - allows the preparation and supply of an accurately predetermined length of auxiliary yarn 1 to be advanced,

[0163] - improves the success rate of the auxiliary yarn 1 being captured by the rotating spindle tube 2 at the initiation step of the coupling cycle,

[0164] - reducing the average time during which the auxiliary yarn 1 is caught by the rotating spindle tube 2, and / or

[0165] - Allows an automatic self-threading process in the event of yarn loss in the yarn path inside the yarn manipulation tool 6.

[0166] Those skilled in the art may make changes and modifications to the described embodiments without departing from the scope of the invention as defined in the appended claims. For example, although a yarn coupling system and method have been disclosed in which a step of supplying liquid to wet the yarn contact area of ​​the rotating spindle tube is disclosed, which step is combined with a yarn manipulation tool and a yarn feeding device arranged along a path outside the yarn manipulation tool, different yarn coupling systems and methods may be required, which eliminate the use of the yarn manipulation tool and the robot arm, but are still provided with a liquid supply device arranged to wet the yarn contact area of ​​the rotating spindle tube. Similarly, although the yarn manipulation tool 6 has been disclosed as being attached to the robot arm 7, the yarn manipulation tool 6 can be attached to an automatic manipulation device other than the robot arm 7, provided that the automatic manipulation device allows the yarn nozzle and the yarn holding device to be manipulated for threading.

Claims

1. A yarn coupling system for threading and coupling an auxiliary yarn (1) at a spinning station requiring maintenance of a ring spinning machine, the yarn coupling system comprising: - a yarn manipulation tool (6) attached to a computer-controlled mechanical or robotic arm (7), - drive means for the robot arm (7), - a yarn delivery path inside the yarn manipulation tool (6), the yarn delivery path inside the yarn manipulation tool (6) being used to deliver the auxiliary yarn (1) from the yarn inlet (8) to the yarn outlet, - a yarn nozzle (9) which is located at the yarn outlet of the yarn manipulation tool (6), - a yarn holding device (16) arranged on the yarn manipulation tool (6) so as to be able to form a threading portion of the auxiliary yarn (1) on the outside of the yarn nozzle (9), and - a processing and control device, which is configured to: when the free end of the auxiliary yarn (1) is wound onto the rotating spindle tube (2) and the rotation of the rotating spindle tube (2) stops, the processing and control device provides an enabling signal to the drive device of the robot arm (7) so that the yarn manipulation tool (6) performs a threading operation and a coupling operation, Wherein, the system further comprises: - a yarn delivery path located outside the yarn manipulation tool (6), the yarn delivery path located outside the yarn manipulation tool (6) being used to deliver the auxiliary yarn (1) from an auxiliary yarn source to the yarn inlet (8) of the yarn manipulation tool (6), and - a yarn feeding device (10) arranged and configured to feed a length portion ("L0", "L1") of an auxiliary yarn (1) to a yarn delivery path located outside the yarn manipulation tool (6) during operation of the yarn manipulation tool (6) via the robot arm (7).

2. The yarn binding system according to claim 1, wherein: The yarn feeding device (10) comprises: - a yarn buffer mechanism (11) for forming a yarn buffer for the auxiliary yarn (1) between the yarn manipulation tool (6) and the auxiliary yarn source along a yarn delivery path outside the yarn manipulation tool (6), and - A control unit for the yarn buffer mechanism (11).

3. The yarn binding system according to claim 2, wherein: The yarn processing and control device is configured to: at the initiation step of the splicing cycle, provide a signal to the control unit of the yarn buffer mechanism (11) so that the yarn buffer mechanism (11) forms the yarn buffer including a predetermined length portion ("L0") of the auxiliary yarn (1).

4. The yarn binding system according to any one of claims 2 to 3, wherein: The yarn buffer mechanism (11) includes a yarn holding member (12), which is constructed and arranged to keep the auxiliary yarn (1) of the yarn buffer in elastic tension when the auxiliary yarn (1) of the yarn buffer grows or shrinks as the robot arm (1) moves the yarn manipulation tool (6).

5. The yarn binding system according to claim 3, wherein: The control unit for the yarn buffer mechanism (11) includes a stepper motor (13) which is operatively connected to the yarn retaining member (12) to maintain the yarn retaining member (12) in a resiliently movable working position as the auxiliary yarn (1) of the yarn buffer is lengthened or shortened as the robotic arm (1) moves the yarn manipulation tool (6).

6. The yarn binding system according to any one of claims 4 to 5, wherein: The yarn holding member (12) comprises a yarn manipulating rod operatively connected to the control unit and arranged to pivot by a rotation angle to form the yarn buffer when the control unit receives a signal from the processing and control device.

7. The yarn binding system according to any one of claims 2 to 6, -in, The yarn coupling system comprises a yarn propulsion device (14), which is arranged along a yarn delivery path inside the yarn manipulation tool (6); -Wherein, the processing and control device is configured to: at the yarn initiation step of the coupling cycle, provide an enable signal to the yarn advancing device (14) so ​​that the yarn advancing device (14) advances the length portion of the auxiliary yarn of the yarn buffer to the yarn nozzle (9), thereby winding the auxiliary yarn (1) of the yarn buffer onto the rotating spindle tube (2).

8. The yarn connecting system according to any one of claims 1 to 7, comprising a liquid supply device (15), wherein the liquid supply device (15) is arranged to wet the yarn contact area of ​​the rotating spindle tube (2) used to contact the free end of the auxiliary yarn (1) at the yarn initiation step of the connecting cycle.

9. The yarn binding system according to claim 8, wherein: The processing and control device is configured to provide an enable signal to the liquid supply device (15) to supply liquid spray to the yarn contact area of ​​the rotating spindle tube (2) when the free end of the auxiliary yarn (1) is pushed into the yarn contact area of ​​the rotating spindle tube (2).

10. The yarn binding system according to any one of claims 1 to 9, wherein: The yarn manipulation tool (6) is attached to the robot arm (7) in an articulated manner by means of an articulated joint (21), which is configured to allow the inclined base (20) of the yarn manipulation tool (6) to be pivoted to an angled position to absorb height differences in the working position of the movable support rail (3) of the ring spinning machine.

11. The yarn binding system according to claim 10, wherein: The articulated joint (21) comprises an elastic connection member, which is arranged to allow the inclined base (20) of the yarn manipulation tool (6) to pivot to an angled position when in contact with the movable support rail (3) and to resume an initial rest position when ceasing to be in contact with the movable support rail (3).

12. The yarn connecting system according to any one of claims 10 to 11, comprising a tool angle sensor assembly (22), wherein the tool angle sensor assembly (22) is operably connected to a controller unit of the robot arm (7), so that at the spinning station requiring maintenance, when the yarn manipulation tool (6) contacts the movable support rail (3), the yarn manipulation tool (6) is set at an optimal working angle position.

13. The yarn binding system according to claim 12, wherein: The tool angle sensor assembly (22) comprises at least two proximity sensors (23, 24) for detecting the presence of the inclined base (20) of the yarn manipulation tool (6), and wherein the controller unit is configured to check the status of the at least two proximity sensors (23, 24) and provide a setting signal to the processing and control device so that the processing and control device commands the movement of the robot arm (7) to be synchronized with the movement of the movable support rail (3) according to the calculated height offset value.

14. The yarn binding system according to any one of claims 12 or 13, wherein: The processing and control device is configured to: - obtaining the actual working height position of the movable support rail (3) at the spinning station requiring maintenance based on the angular position of the yarn manipulation tool (6) provided by the controller unit of the robot arm (7), - calculating a height offset value which is applied to the height position data of the movable support rail (3) provided by a positioning sensor (19), and - Based on the calculated height offset value, sending a signal to the controller unit of the robot arm (7) to synchronize the movement of the robot arm (7) with the movement of the movable support rail (3).

15. The yarn connecting system according to any one of claims 1 to 14, comprising a yarn cutting device (26), which is arranged on the yarn conveying path inside the yarn manipulation tool (6) for cutting the auxiliary yarn inside the yarn manipulation tool (6) when receiving a cutting signal from the processing and control device.

16. The yarn binding system according to any one of claims 2 to 15, wherein: The yarn feeding device (10) comprises: - a yarn outlet of the yarn buffer mechanism (11), a yarn holder arranged to hold the free end of the auxiliary yarn (1) in place outside the yarn outlet of the yarn buffer mechanism (11) in the event of yarn loss, and - an air blowing device arranged to inject air into the yarn outlet of the yarn buffer mechanism (11), - wherein, in the event of yarn loss on the yarn delivery path inside the yarn manipulation tool (6), the processing and control means are configured to perform an automatic self-threading operation comprising the following steps: i. providing a signal to the drive device of the robot arm (7) so that the robot arm (7) positions the yarn inlet (8) of the yarn manipulation tool (6) to correspond to the yarn outlet of the yarn buffer mechanism (11), ii. providing an activation signal to the air blowing device of the yarn feeding device (10) to blow the free end of the auxiliary yarn (1) to the outside of the yarn outlet of the yarn buffer mechanism (11), and to hold the auxiliary yarn (1) of the yarn buffer in place on the outside of the yarn outlet, and iii. providing an enabling signal to the yarn advancing device (14) of the yarn manipulation tool (6) so that the free end of the auxiliary yarn (1) of the yarn buffer is sucked along the yarn transfer path inside the yarn manipulation tool (6).

17. The yarn binding system according to claim 16, wherein: The yarn feeding device (10) further comprises a yarn cutter which is operatively connected to the yarn outlet of the yarn buffer mechanism (11) so as to be able to cut excess yarn outside the yarn outlet in case of yarn loss.

18. The yarn binding system according to any one of claims 1 to 17, comprising an image capture device (29), preferably arranged on the yarn manipulation tool (6), wherein The image capture device (29) is operatively connected to an artificial vision system configured to inspect the coupling for obstructions prior to the initiation of the coupling cycle.

19. A method for coupling an auxiliary yarn (1) at a spinning station requiring maintenance of a ring spinning machine, the method comprising the following steps; a) feeding a first length portion ("L0") of the auxiliary yarn (1) to a yarn delivery path external to a yarn manipulation tool (6) driven by a robot arm, b) bringing the yarn manipulation tool (6) close to the rotating spindle tube (2) requiring maintenance, c) advancing a first length portion ("L0") of the auxiliary yarn (1) to the yarn nozzle (9) of the yarn manipulation tool (6) so that the free end of the auxiliary yarn (1) is wound onto the rotating spindle tube (2), d) after the free end of the auxiliary yarn is wound onto the rotating spindle tube (2), the rotation of the rotating spindle is stopped, e) After step d), the second length portion ("L1") of the auxiliary yarn (1) is fed to the yarn delivery path outside the yarn manipulation tool (6), and the second length portion ("L1") of the auxiliary yarn (1) is lengthened or shortened when the robot arm (7) moves the yarn manipulation tool (6) for threading and connecting.

20. The method for coupling auxiliary yarns according to claim 19, wherein: - step a) comprises: forming a yarn buffer including a first length portion ("L0") of the auxiliary yarn (1) along the yarn delivery path outside the yarn manipulation tool (6), - step c) comprises: advancing a first length portion ("L0") of the auxiliary yarn (1) of the yarn buffer to the yarn nozzle (9) of the yarn manipulation tool (6) in order to wind the free end of the auxiliary yarn (1) of the yarn buffer onto the rotating spindle tube (2), and - Step e) comprises: i. forming a yarn buffer comprising a second length portion ("L1") of said auxiliary yarn (1), and ii. Maintaining the second length portion ("L1") of the auxiliary yarn (1) of the yarn buffer in elastic tension as the second length portion ("L1") of the auxiliary yarn grows or shrinks as the robotic arm (7) moves the yarn manipulation tool (6) for threading and connecting.

21. A method for coupling auxiliary yarns according to any one of claims 19 to 20, wherein: The method comprises, before or simultaneously with step c), the step of supplying a liquid spray to the yarn contact area of ​​the rotating spindle tube (2) intended for contact with the free end of the first length ("L0") of the auxiliary yarn (1).

Images