Splicing system and method for splicing auxiliary yarns at a spinning station of a ring spinning machine requiring repairs

Abstract

A yarn splicing system for threading and splicing an auxiliary yarn (1), comprising: a yarn handling tool (6) attached to a computer-controlled mechanical or robotic arm (7); a yarn nozzle (9) on a yarn outlet of the yarn handling tool (6); a yarn holding means (16) disposed on the yarn handling tool (6) capable of forming a threaded portion of the auxiliary yarn (1); and processing and control means configured to provide activation signals to a drive means of the robotic arm (7) for the yarn handling tool (6) to perform the threading and splicing operation, the splicing system further comprising a yarn feeding device (10) disposed and configured to feed lengths ("L0", "L1") of the auxiliary yarn (1) to a yarn transport path outside the yarn handling tool (6) during movement of the yarn handling tool (6) by the robotic arm (7).

Description

[Technical Field]

[0001] The present invention relates generally to a splicing system for splicing an auxiliary yarn in the event of a yarn breakage at a spinning station of a ring spinning machine. The present invention also relates to a method for automatically splicing an auxiliary yarn at a spinning station. [Background technology]

[0002] Splicing systems are known that automatically splice broken ends of yarns. When a yarn break occurs in a ring spinning machine, the broken end of the yarn is wound onto a bobbin after the break. In these systems, an automatic yarn handling device is used to detect the broken end of the yarn by means of a suction tube connected to a vacuum source. The suction tube is attached to an automatic maintenance station that is movably arranged along the row of spinning stations and has the option of stopping at selected spinning stations that require maintenance work.

[0003] In the conventional splicing system described above, in order to resume spinning after a yarn breakage, the yarn end is sucked into a vacuum suction tube, which positions the yarn end on the bobbin, and then threads the yarn end through the vacuum suction tube. The vacuum suction tube is used to position the yarn end on the bobbin, and then threads the yarn end through the vacuum suction tube. The vacuum suction tube is placed on the flange of the ring, and a traveler on the ring of the spinning machine is set to operate by compressed air, so that it is placed on the vacuum suction tube and threads the yarn end through the traveler. After the yarn is threaded, the same vacuum suction tube is used to position the yarn end for splicing onto the roving coming out of the roving delivery roller.

[0004] Splicing systems that deal with broken yarn ends have the disadvantage that it is difficult to detect a yarn break when it occurs after a bobbin change (doffing), when the spindle tube is still free of yarn. Similarly, it is difficult to detect if the broken end remains wound on a portion of the spindle tube located below the ring rail of the spinning machine. This situation occurs when two spinning stations require simultaneous maintenance work and the automatic maintenance station takes more time than is required to assist the second spinning station, resulting in a large portion of the spindle tube of the second spinning station being free of yarn above the ring rail.

[0005] To overcome the problems of splicing systems dealing with broken ends of yarns, known splicing systems have been developed to improve the splicing process by feeding the free end of an auxiliary yarn into a spindle tube of a rotating spindle onto which the free end is to be wound. Such known splicing systems can eliminate the step of detecting broken ends of the yarn.

[0006] Japanese Patent Application Laid-Open No. 3-199436 discloses the aforementioned known splicing system having an automatic maintenance station, which can be arranged in a spinning station for supplying a free end of an auxiliary yarn from an auxiliary yarn supply source to a rotating spindle having a spindle tube providing a winding surface around which the free end of the auxiliary yarn is to be wound. The free end of the auxiliary yarn is supplied to the spindle tube of the rotating spindle from a yarn feed nozzle that propels the free end of the auxiliary yarn with air. The system also includes finger elements for securing the auxiliary yarn outside the yarn feed nozzle to form a threading portion when the free end of the auxiliary yarn is wound around the spindle tube. For this purpose, automatic handling means are provided for handling both the yarn feed nozzle and the finger elements to perform the threading operation. Once threaded, the end of the auxiliary yarn is positioned by another finger element for splicing onto a roving yarn exiting a front roller of a draft assembly.

[0007] The yarn splicing system disclosed in JP 3-199436 A has several problems. One of the problems is that the winding operation of the free end of the auxiliary yarn onto the spindle tube fails, especially when there is no yarn on the spindle tube after doffing, due to insufficient adhesion of the free end of the auxiliary yarn to the surface of the spindle tube. Another problem is that the threading operation must be performed while the spindle tube continues to rotate in order to apply appropriate tension to the auxiliary yarn outside the yarn feed nozzle and prevent slack in the threading section. Nevertheless, it has been found that in practice, performing the threading operation by rotating the spindle tube is even more difficult and complicated because threading requires high precision in positioning the yarn.

[0008] Therefore, there is a need to provide an alternative to the prior art that fills the gaps found in the prior art by providing a splicing system and method for splicing an auxiliary yarn that overcomes the above-mentioned problems, thereby providing a system that has fast and reliable threading and splicing operations, even on spindle tubes that are empty of yarn, and improved reliability for winding the free end of the auxiliary yarn. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 3-199436 Summary of the Invention

[0010] To this end, the present invention relates in a first aspect to a splicing system for splicing an auxiliary yarn at a spinning station of a ring spinning machine that needs repair, the splicing system comprising: - a yarn handling tool attached to a computer-controlled mechanical or robotic arm; drive means for the robot arm; - a yarn transport path inside the yarn handling tool for transporting the auxiliary yarn from the yarn inlet to the yarn outlet; a yarn nozzle at the yarn outlet of the yarn handling tool; - thread holding means arranged on the thread handling tool so as to be able to form a threading portion of the auxiliary thread outside the thread nozzle; - processing and control means adapted to provide an activation signal to the drive means of the robot arm in order for the threading and splicing operations to be performed by the thread handling tool when the free end of the auxiliary thread is wound onto the spindle and the rotation of the spindle is stopped; Equipped with The thread splicing system is a yarn transport path outside the yarn handling tool for transporting the auxiliary yarn from an auxiliary yarn supply to a yarn inlet of the yarn handling tool; a yarn feeding device arranged to feed a length of auxiliary yarn into a yarn transport path external to the yarn handling tool during operation of the yarn handling tool by the robotic arm; Further provided are:

[0011] In accordance with the claimed features, the present invention provides a yarn splicing system in which both threading and thread following operations are handled by a yarn handling tool mounted on a robotic arm of an automated maintenance station, and a yarn feeding device is arranged and configured to feed a length of auxiliary yarn into a path outside the yarn handling tool during operation of the yarn handling tool by the robotic arm.

[0012] It has been found that auxiliary yarns on the outside of the yarn handling tool can slacken, twist and wind up on themselves during operation, causing yarn curl which can alter and interfere with threading and splicing.

[0013] In the claimed system, the yarn feeder supplies a length of auxiliary yarn to a path outside the yarn handling tool, which serves to improve the handleability of the auxiliary yarn outside the yarn handling tool by acting as a yarn buffer and preventing curls and twists from forming while the robotic arm or computer-controlled mechanical arm operates to perform threading and splicing.

[0014] According to a second aspect, the present invention relates to a method for splicing an auxiliary yarn in a spinning station of a ring spinning machine requiring repair, the method comprising: a) feeding a first length of auxiliary yarn into a yarn transport path outside a yarn handling tool driven by a robotic arm; b) bringing a yarn handling tool into contact with the rotating spindle tube of the rotating spindle requiring repair; c) propelling the first length of auxiliary yarn to a yarn outlet of the yarn handling tool such that a free end of the auxiliary yarn is wound onto a rotating spindle tube; d) stopping the rotation of the rotating spindle after the free end of the auxiliary thread is wound around the rotating spindle; e) after step d), while the robot arm is operating the yarn handling tool to perform threading and splicing, feeding the second length of auxiliary yarn to a yarn transport path outside the yarn handling tool to increase or decrease the second length of auxiliary yarn; Includes.

[0015] In contrast to known splicing methods, in the claimed method a first length of auxiliary yarn is fed into a yarn path outside the yarn handling tool to accurately prepare a length of yarn to be propelled and wound onto the spindle tube.

[0016] Once the free end of the auxiliary yarn is wound, the rotation of the rotating spindle is stopped and a second length of auxiliary yarn is fed along the yarn path outside the yarn handling tool. Back and forth movement of the yarn handling tool by the robotic arm increases or decreases this second length of auxiliary yarn, allowing threading and splicing operations to be performed without slack in the yarn. In this manner, the reliability and accuracy of both threading and splicing operations are significantly improved.

[0017] In one embodiment, the yarn feeding device of the claimed system is preferably configured to feed a length of auxiliary yarn under tension, and steps a) and e) of the claimed method are preferably performed by feeding a first length of auxiliary yarn under tension and a second length of auxiliary yarn under tension, respectively.

[0018] Advantageously, the yarn splicing system comprises a yarn buffer mechanism between the yarn handling tool and the auxiliary yarn supply source for forming a yarn buffer of the auxiliary yarn along the yarn transport path outside the yarn handling tool, and a control unit for the yarn buffer mechanism.

[0019] It has been found that the yarn buffer helps improve the handling of the auxiliary yarn outside of the yarn handling tool by preventing curls and twists from forming while the robotic arm or computer-controlled mechanical arm operates to perform the threading and splicing.

[0020] In a preferred embodiment, the yarn buffer mechanism is configured to form a yarn buffer for the tensioned auxiliary yarn in order to more efficiently defurl and twist the length of the auxiliary yarn along an outer path of the yarn handling tool.

[0021] In a preferred embodiment including a yarn buffer mechanism, there is provided a method of splicing an auxiliary yarn, comprising the steps of: - step a) includes forming a yarn buffer including a first length of auxiliary yarn along a yarn transport path outside the yarn handling tool; - step c) includes propelling a first length of auxiliary yarn in the yarn buffer to a yarn nozzle of the yarn handling tool so that a free end of the auxiliary yarn in the yarn buffer is wound onto the rotating spindle tube; step e) i. forming a yarn buffer including a second length of auxiliary yarn; ii. holding the second length of auxiliary yarn in the yarn buffer under elastic tension while increasing or decreasing the second length of auxiliary yarn in the yarn buffer when the robotic arm operates the yarn handling tool to thread and splice; A method for piecing auxiliary yarns is claimed, comprising:

[0022] Advantageously, the processing and control means is configured to provide a signal to the control unit of the thread buffer mechanism in order for the thread buffer mechanism to form a thread buffer containing the predetermined length of auxiliary thread during the feed step of the splicing cycle.

[0023] These features allow a length of auxiliary yarn to be fed along a path outside the yarn handling tool between the auxiliary yarn supply and the yarn inlet of the yarn handling tool. This length of auxiliary yarn is set to be advanced onto the rotating spindle during the feed step of the splicing cycle. Depending on the type of yarn, the length of yarn to be advanced may vary. Because the length of auxiliary yarn to be advanced is prepared by the yarn buffer mechanism, the auxiliary yarn is handled more efficiently without the risk of slack or curl.

[0024] In one embodiment, the thread buffer mechanism comprises a thread holding member constructed and arranged to hold the auxiliary thread in the thread buffer under elastic tension while the auxiliary thread in the thread buffer increases or decreases as the robotic arm operates the thread handling tool.

[0025] The yarn holding member may be configured to hold the auxiliary yarn under elastic tension with a constant torque to eliminate curls and tangles of the yarn. During operation of the yarn handling tool by the robotic arm, the auxiliary yarn in the yarn buffer increases or decreases under tension to keep the auxiliary yarn at a constant value along the outer path of the yarn handling tool.

[0026] In one embodiment, the control unit of the thread buffer mechanism comprises a stepper motor operatively connected to the thread holding member to maintain the thread holding member in an active elastic actuation position while the auxiliary thread in the thread buffer is increased or decreased when the robotic arm operates the thread handling tool.

[0027] The stepper motor is operatively connected to the thread holding member and is operated in a low current mode to maintain the thread holding member in an active elastic operating position in which the stepper motor allows the thread holding member to assume a retracted position when pulled by the movement of the robot arm, thereby reducing the stored thread length in the thread buffer, and to regain an initial extended position when the robot arm approaches the thread buffer mechanism, thereby increasing the stored thread length in the thread buffer.

[0028] Advantageously, the same stepper motor is operated in a high current mode in the let-off step of the splicing cycle in order to cause the thread holding member to assume a predetermined extended position to form a thread buffer containing a predetermined length of auxiliary thread, said predetermined length of auxiliary thread coming from an auxiliary thread supply, and the stepper motor may be activated to move the thread holding member to different fixed positions so as to be able to take the required length of auxiliary thread from the auxiliary thread supply.

[0029] In one embodiment, the thread holding member comprises a thread handling rod operatively connected to a control unit for the thread buffer function, said thread handling rod being configured to pivot through a rotational angle when the control unit receives a signal from the processing and control means to form the thread buffer.

[0030] The yarn handling rod may be a flexible rod, and advantageously the yarn handling rod is configured to store potential energy in an active elastic operating position to keep the auxiliary yarn in the yarn buffer tensioned at a predetermined value, while the auxiliary yarn in the yarn buffer increases or decreases as the robotic arm operates the yarn handling tool to perform threading and splicing.

[0031] Preferably, the splicing system comprises a yarn pushing means arranged along the yarn transport path inside the yarn handling tool, and the processing and control means is configured to provide an activation signal to the yarn pushing means during the yarn let-off step of the splicing cycle so that said yarn pushing means pushes a length of auxiliary yarn from the yarn buffer to the yarn nozzle and so that a free end of the auxiliary yarn from the yarn buffer is wound onto the rotating spindle tube.

[0032] The yarn pushing means pulls the length of auxiliary yarn in the yarn buffer and pushes the auxiliary yarn towards the yarn nozzle so that the free end of the auxiliary yarn is wound onto the rotating spindle tube.

[0033] According to one embodiment of the system, the yarn propulsion means comprises a Venturi and air injector assembly configured to draw air into the yarn inlet of the yarn handling tool upon receiving an activation signal from the processing and control means. The Venturi and air injector assembly is attached to the handling tool, preferably positioned so that the Venturi is substantially aligned with the yarn nozzle. When activated, the yarn propulsion means picks up the yarn from the yarn inlet and pushes it toward the yarn outlet or yarn nozzle of the yarn handling tool. The yarn propulsion means may or may not include a Venturi. For example, they may not include a Venturi and may be constituted by a mechanical air-based device.

[0034] In a preferred embodiment, the splicing system comprises liquid supply means, preferably liquid spray means, configured to be able to wet the yarn contact area of ​​the rotating spindle tube with which the free end of the auxiliary yarn is intended to come into contact during the yarn let-off step of the splicing cycle.

[0035] According to this preferred embodiment, the processing and control means is configured to provide an activation signal to the liquid supply means for supplying a liquid spray to the yarn contact area of ​​the rotating spindle tube while the free end of the auxiliary yarn is being propelled to the yarn contact area of ​​the rotating spindle tube.

[0036] It has been found that the success rate of winding the free end of the auxiliary yarn onto the rotating spindle is significantly higher when a liquid spray is supplied to the spindle tube to wet the yarn contact area intended to be contacted by the free end of the auxiliary yarn during the delivery step of the splicing cycle. Furthermore, the acquisition time is significantly reduced to an average of 3 seconds compared to an average time of 19 seconds when the use of the liquid spray is omitted.

[0037] In one embodiment, the yarn handling tool is articulated to the robot arm by an articulated joint configured to allow the tilting base of the yarn handling tool to pivot to an angular position to accommodate large differences in the working position of the movable support rail of the ring spinning machine.

[0038] It is well known that the movable support rail that supports the rotating spindle moves up and down during rotation. Therefore, the robot arm must track the movement of the movable support rail to perform the threading and splicing operations. For this purpose, a positioning sensor (e.g., a laser sensor) is fixed to one end of the ring spinning machine so that height position data can be provided to the robot arm's controller at any point in the splicing cycle. Nevertheless, 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 repair. If the height position data is incorrect, the robot arm will not be able to accurately position the yarn handling tool to perform threading.

[0039] The claimed articulated joint allows the thread handling tool to absorb large variations and assume the optimum working angle for performing threading.

[0040] Preferably, the articulated joint comprises a resilient connection configured to allow the tilting base of the yarn handling tool to pivot to an angular position when it contacts the movable support rail and to restore its initial rest position when it ceases contact with the movable support rail.

[0041] Advantageously, in embodiments having an articulated joint, the splicing system comprises a tool angle sensor assembly operatively connected to the control unit of the robot arm, which sets the yarn handling tool to an optimum working angle position upon contact with the movable support rail.

[0042] Preferably, the tool angle sensor assembly comprises at least two proximity sensors for detecting the presence of the tilting base of the yarn handling tool, and the control unit is configured to check the status of the at least two proximity sensors and to provide a set-up signal to the processing and control means in order to instruct it to synchronize the movement of the robot arm with the movement of the movable support rail in accordance with the calculated height offset value.

[0043] These proximity sensors may be located at the rear of the framework of the yarn handling tool in order to set the optimum working angular position of the yarn handling tool when it comes into contact with the movable support rail. The control unit of the robot arm sends signals to the processing and control means of the system so that synchronization of the robot arm movements with the up and down movement of the movable support rail can be performed.

[0044] Advantageously, the processing and control means comprises: - obtaining the actual working height position of the movable support rail at the spinning station requiring repair based on the angular position of the yarn handling tool provided by the control unit of the robot arm; - calculating a height offset value to be applied to height position data of the movable support rail provided by a positioning sensor (e.g., a laser sensor fixed to one end of a ring spinning machine); and - based on the calculated height offset value, sending a signal to a control unit of the robot arm to synchronize the movement of the robot arm with the movement of the movable support rail; It is composed.

[0045] Once synchronization is complete, the robot arm will begin to follow the movable support rail, so that all movements required to perform threading on the ring traveler will be merged with the tracking movements of the movable support rail.

[0046] In a preferred embodiment, the yarn splicing system comprises a yarn cutter means arranged in the yarn transport path inside the yarn handling tool for cutting the auxiliary yarn inside the yarn handling tool upon receiving a cut signal from the processing and control means.

[0047] The yarn cutter means is constituted by a small blade or cutter integrated in the yarn handling tool for cutting the auxiliary yarn in the yarn path inside the yarn handling tool so that after cutting the free end of the auxiliary yarn does not protrude outside the yarn nozzle of the yarn handling tool. The blade or cutter may be driven by an electromagnet or a pneumatic actuator.

[0048] Preferably, the yarn splicing system comprises a yarn holding means arranged on the same yarn transport path inside the yarn handling tool to hold the auxiliary yarn in place on the path inside the yarn handling tool, for example when the auxiliary yarn is cut.

[0049] In one embodiment, the splicing system is arranged to perform an automatic threading process of the thread in the event that the thread is lost along the thread transport path inside the thread handling tool. The loss of the thread is detected by sensor means configured to detect the presence and / or movement of the thread inside the thread handling tool. The sensor means is operatively connected to the processing and control means for informing the system about the status of the auxiliary thread inside the tool. To be able to perform the automatic threading process, the splicing system comprises: a yarn outlet of the yarn buffer mechanism; - thread holding means configured to hold the free end of the auxiliary thread in place outside the thread outlet of the thread buffer mechanism in the event of a thread loss; and a blowing means arranged to inject air into the yarn outlet of the yarn buffer mechanism.

[0050] The processing and control means i. providing a signal to a drive means of the robot arm to cause the robot arm to position a yarn inlet of the yarn handling tool relative to a yarn outlet of the yarn buffer mechanism; ii. providing an activation signal to a blowing means of the yarn feeding device to blow air onto a free end of the auxiliary yarn outside the yarn outlet of the yarn buffer mechanism while holding the auxiliary yarn of the yarn buffer in place outside the yarn outlet; iii. providing an actuation signal to a yarn propelling means of the yarn handling tool so that the free end of the auxiliary yarn of the yarn buffer is sucked along a yarn transport path inside the yarn handling tool; The apparatus is configured to perform an automatic self-threading operation including:

[0051] Advantageously, the yarn feeding device further comprises a yarn cutter operatively connected to the yarn outlet of the yarn buffer mechanism so as to cut off excess yarn outside the yarn outlet in case of yarn loss, and preferably the blowing means comprises a venturi tube and air injector assembly configured to blow or inject air into the yarn outlet of the yarn buffer mechanism upon receiving a signal from the processing and control means.

[0052] Also advantageously, the yarn transport path inside the yarn handling tool is configured airtight to maintain an optimal air flow generated by the yarn propulsion means of the yarn handling tool, which has been found to help, in the event of a yarn breakage, to efficiently suck the free end of the auxiliary yarn outside the yarn buffer mechanism inside the yarn handling tool and drop it into the yarn nozzle of the tool.

[0053] In one embodiment, the splicing system comprises an image capturing means preferably disposed on the yarn handling tool, the image capturing means being operatively connected to an artificial vision system configured to check for any obstructions to performing the splice (e.g., pieces of yarn tangled on the pig rail) before the splicing cycle begins. In one embodiment, the image capturing means (e.g., a camera) is disposed on the yarn handling tool.

[0054] In contrast to known splicing systems that deal with broken ends of the yarn, the claimed splicing system is suitable for use with either a spindle tube without a yarn (after doffing) or a spindle tube holding spun fibers (yarn package), since the free end of the auxiliary yarn is always supplied to the spindle tube for winding. Furthermore, the claimed method and system are highly reliable because, during the delivery phase, a predetermined length (i.e., a controlled yarn length) of the auxiliary yarn from the yarn buffer is propelled to the yarn nozzle so that the free end of the yarn buffer is wound onto the rotating spindle tube. Furthermore, the yarn is preferably propelled toward a yarn contact area of ​​the spindle tube that has been pre- or simultaneously wetted with a liquid, such as a liquid spray or atomized water. This yarn contact area may be a yarn-free area of ​​the spindle tube or a yarn-present area of ​​the spindle tube.

[0055] As previously mentioned, it has been found that the success rate of winding the free end of the auxiliary yarn onto the rotating spindle is significantly increased by wetting the yarn contact area intended to be contacted by the free end of the auxiliary yarn during the let-off step of the splicing cycle. Furthermore, the capture time is significantly reduced to an average of 3 seconds compared to an average time of 19 seconds when the use of a liquid spray is omitted. The reduction in time spent gripping the free end of the yarn is particularly significant when there is no yarn in the contact area of ​​the spindle tube (after doffing).

[0056] Below is a table showing the success rate and average capture time results for gripping the auxiliary yarn obtained from yarn let-off tests with and without water sprayed onto the yarn contact area of ​​the rotating spindle tube.

[0057] [Table 1]

[0058] While the supply of a liquid for wetting the yarn contact area of ​​a rotating spindle has been disclosed in combination with a splicing system including a yarn handling tool and a yarn feeder for feeding a length of auxiliary yarn into a yarn transport path external to the yarn handling tool, the applicant has disclosed a splicing system for threading and splicing a free end of an auxiliary yarn at a spinning station of a ring spinning machine requiring repair, comprising: - yarn supply means for supplying a free end of the auxiliary yarn to a spindle tube of a rotating spindle around which the free end is wound, the yarn supply means including a yarn nozzle for supplying the free end of the auxiliary yarn to the spindle tube of the rotating spindle; - a thread holding means for holding the auxiliary yarn outside the yarn feeding nozzle when the free end of the auxiliary yarn is wound around the spindle tube, thereby forming a threading portion for the auxiliary yarn; automatic handling means for handling the yarn supply means and the yarn holding means; Equipped with This thread splicing system is - liquid supply means adapted to wet the yarn contact area of ​​the rotating spindle with which the free end of the auxiliary yarn is intended to come into contact during the yarn let-off step of the splicing cycle; - processing and control means configured to provide an activation signal to the liquid supply means for supplying a liquid spray to the yarn contact area of ​​the rotating spindle tube before and / or while the free end of the auxiliary yarn is propelled to the yarn contact area of ​​the rotating spindle; The present invention reserves the right to claim as a separate invention a yarn splicing system further comprising:

[0059] Preferably, the liquid supply means comprises a liquid spray means. The liquid may be atomized or applied in other manners, provided that the yarn contact area of ​​the rotating spindle is wetted. The yarn contact area may be an area of ​​the rotating spindle tube with the yarn or an area of ​​the rotating spindle without the yarn.

[0060] In one embodiment, the automated handling means comprises a yarn handling tool attached to a computer-controlled mechanical or robotic arm, with both the liquid supply means and the yarn nozzle located on the yarn handling tool.

[0061] Advantageously, the thread holding means is arranged on the thread handling tool, and the processing and control means is configured to provide an activation signal to the drive means of the robot arm when the free end of the auxiliary thread is wound on the spindle and rotation of the spindle is stopped, in order for the thread handling tool to perform both threading and splicing operations.

[0062] In one embodiment, the yarn splicing system comprises a yarn buffer mechanism for forming a yarn buffer of the auxiliary yarn along the yarn transport path outside the yarn handling tool between the yarn handling tool and the auxiliary yarn supply source, and a control unit for the yarn buffer mechanism.

[0063] Advantageously, according to an embodiment of the system having a thread buffer mechanism, the processing and control means is configured to provide an activation signal to the thread pushing means so that the thread pushing means can push a length of auxiliary thread from the thread buffer towards the thread nozzle so that a free end of the auxiliary thread from the thread buffer is wound onto the rotating spindle in a thread let-off step of the splicing cycle.

[0064] In the present invention, A robotic arm is understood to refer to a robotic arm or a computer-controlled mechanical arm, preferably a computer-controlled arm having at least six degrees of freedom of movement.

[0065] The threading operation is to be understood as meaning the operation of making or forming a threading portion of the auxiliary yarn outside the yarn nozzle of the yarn handling tool and the operation of handling the threading portion at the flange of the ring of the ring spinning machine so that said threading portion is threaded into the ring traveler of the ring spinning machine.

[0066] A splicing operation is understood to mean the operation of positioning a yarn handling tool in order to splice a threaded auxiliary yarn onto a roving yarn exiting the front draft roller of the draft assembly of a ring spinning machine.

[0067] The splicing cycle of the claimed methods and systems should be understood to include both threading and splicing operations.

[0068] The foregoing and other advantages and features will be more fully understood from the following detailed description of the embodiments, taken in conjunction with the accompanying drawings, which should be considered in an illustrative and non-limiting manner. [Brief explanation of the drawings]

[0069] [Figure 1] 1 is a perspective view of one embodiment of a yarn handling tool mounted on a robotic arm (only a portion of the robotic arm is shown for clarity), which also shows a camera mounted on the robotic arm to capture images to check for any obstructions to performing the splice, and a liquid spray nozzle mounted on the frame structure of the yarn handling tool and aligned perpendicular to a yarn nozzle located at the yarn outlet of the yarn handling tool to feed an auxiliary yarn to the rotating spindle tube. [Figure 2]

[0023] Figure 2 is a schematic rear perspective view showing a yarn handling tool mounted on a robotic arm approaching a rotating spindle tube with no yarn. This view also shows a yarn feeding device interposed between the yarn handling tool and an auxiliary yarn supply (not shown), and a movable support rail on which are mounted multiple rotating spindle tubes, each belonging to a different spinning station of the ring spinning machine. This Figure 2 shows an embodiment of a yarn feeding device including a yarn buffer mechanism that forms a yarn buffer of auxiliary yarn along the yarn transport path outside the yarn handling tool. The yarn buffer contains a first length "L0" of auxiliary yarn that was fed into the yarn path outside the yarn handling tool for urging it toward the rotating spindle tube during the let-off step of the splicing cycle. [Figure 3] FIG. 1 is a schematic perspective view of a yarn handling tool mounted on a robotic arm, showing a yarn nozzle propelling a first length “L0” of auxiliary yarn through a yarn buffer, a liquid spray nozzle supplying a liquid spray to wet a yarn contact area of ​​a rotating spindle where no yarn is present, and a free end of the auxiliary yarn being propelled into said yarn contact area. [Figure 4] 3 is a schematic perspective view similar to that of FIG. 2 , showing the yarn buffer mechanism forming a yarn buffer of the auxiliary yarn including the auxiliary yarn of a second length “L1” fed into the yarn path outside the yarn handling tool after the free end of the auxiliary yarn has been wound and the rotation of the spindle tube has stopped. Back and forth movement of the yarn handling tool by the robotic arm adds or removes this second length “L1” of auxiliary yarn to allow threading operations to be performed without slackening the yarn and by preventing curls and twists from forming along the yarn path outside the yarn handling tool. [Figure 5] 1 is a perspective view of a yarn handling tool showing a threading portion of an auxiliary yarn formed outside the yarn nozzle by a holding element (e.g., a grip) disposed on the yarn handling tool. The yarn handling tool requires precise movement of the yarn handling tool so that the holding element holds or grips the auxiliary yarn outside the yarn nozzle to form the threading portion. Once formed, the threading portion must be threaded by a ring traveler attached to a ring supported on a movable support rail of a corresponding spindle tube. [Figure 6] FIG. 2 is a side view of the yarn handling tool of FIG. 1 attached to a robotic arm by an articulated joint configured to allow the tilting base of the yarn handling tool to pivot to an angular position to accommodate height differences in the working position of the movable support rail and to assume an optimal working angle before performing threading. [Figure 7a]1 is a rear perspective view showing the yarn handling tool approaching the movable support rail sufficiently to be set by the tool angle sensor assembly to an optimum operating position upon contact with the movable support rail. A control unit of the robot arm (not shown) is configured to check the status of two proximity sensors positioned to detect the presence of the tilting base of the yarn handling tool. The control unit of the robot arm provides setting signals to a processing and control means (not shown) of the system, which directs the synchronization of the movements of the robot arm and the movable support rail according to a calculated height offset value applied to height position data provided by a positioning sensor (e.g., a laser sensor measuring the height position of the movable support rail at one end of the ring spinning machine). [Figure 7b] FIG. 7b is a side view of the thread handling tool of FIG. 7a. [Figure 8] 1 is a perspective view of a thread handling tool attached to a robot arm while a threading portion of an auxiliary thread is about to be threaded by a ring traveler. An air conduction tube attached to the surface of the thread handling tool propels air to move the ring traveler over the flange of the ring to facilitate threading. [Figure 9] 1 is a schematic bottom view of a yarn handling tool showing internal components arranged on a yarn transport path inside the yarn handling tool for transporting said length of auxiliary yarn from a yarn inlet to a yarn outlet defined by a yarn nozzle, along which path are arranged yarn pushing means, yarn cutter means, yarn holding means, and sensor means for detecting the presence and / or movement of said length of auxiliary yarn. [Figure 10] FIG. 1 is a schematic exploded view showing the thread handling tool from the bottom. [Figure 11] 10 is a schematic bottom view of the yarn handling tool of Figure 9, showing a detailed partial cross section of a portion of the yarn path inside the yarn handling tool, where a yarn cutter is positioned to cut the auxiliary yarn, the view showing the length of auxiliary yarn being blown out of the yarn nozzle after being cut by the yarn cutter inside the yarn handling tool. DETAILED DESCRIPTION OF THE INVENTION

[0070] The following is a description of the claimed invention with reference to Figures 1 to 11, which depict exemplary embodiments of systems and methods applicable to a ring spinning machine with a single row of spinning stations arranged adjacent to one another.

[0071] The claimed splicing system and method is provided to provide automatic maintenance to any spinning station of a ring spinning machine that requires repair after a yarn break. As noted above, the claimed splicing system and method involves feeding the free end of an auxiliary yarn 1 to a rotating spindle having a rotating spindle tube 2 that provides a winding surface onto which the free end of the auxiliary yarn is to be wound, and the system then performs the threading and splicing operations.

[0072] The rotating spindles of a ring spinning machine are aligned and mounted on a movable support rail 3 that moves up and down during spinning. At each spinning station, a ring 4 is mounted on the movable support rail 3, and a ring traveler 5 is movably attached to the flange of the ring 4. Each rotating spindle is arranged coaxially and vertically relative to the ring 4, and each spindle tube 2 is disposed on the rotating spindle to support a yarn package formed by spinning in a well-known manner, forming a cop. During spinning, the ring traveler 5 and the yarn threaded therethrough move around the spindle tube 2 on the flange of the ring 4, and the yarn is wound around the surface of the spindle tube 2. Above each rotating spindle tube 2 are arranged a balloon-type contraction ring (not shown), a yarn guide (not shown), and a draft assembly (not shown) including a rear draft roller, an intermediate draft roller, and a front draft roller from which the roving to be drafted emerges.

[0073] The present invention provides a yarn splicing system and method in which both threading and splicing operations are handled by a yarn handling tool 6 mounted on a robotic arm 7 of an automated maintenance station which includes a carriage arrangement (not shown) to which the robotic arm 7 is attached. The carriage is displaceable along the row of spinning stations of the ring spinning machine.

[0074] In the illustrated embodiment, a camera 29 is located on the robotic arm 7 operatively connected to an artificial vision system configured to check whether there are any obstacles to performing the splice. If the captured images show that something is impairing the splice, the processing and control means of the system request operator intervention to restore normal operating conditions so that the splicing system can provide automatic maintenance.

[0075] Inside the yarn handling tool 6, a yarn transport path is arranged for transporting the auxiliary yarn 1 from a yarn inlet 8 via a yarn nozzle 9 to a yarn outlet of the yarn handling tool 6. Outside the yarn handling tool 6, there is a yarn transport path for transporting the auxiliary yarn 1 from an auxiliary yarn supply (not shown) to the yarn inlet 8 of the yarn handling tool 6. A yarn feeding device 10 is mounted on the same carriage device and is configured to feed a length of the auxiliary yarn 1 to the yarn transport path outside the yarn handling tool 6. It has been found that this length of auxiliary yarn 1 outside the yarn handling tool 6 acts as a yarn buffer which helps to improve handling of the auxiliary yarn 1 outside the yarn handling tool 6.

[0076] According to a preferred embodiment of the present system and method, the yarn feeding device 10 includes a yarn buffer mechanism 11 that forms a yarn buffer of the auxiliary yarn 1 along the yarn transport path outside the yarn handling tool 6. The yarn buffer contains a first length "L0" of the auxiliary yarn 1 that was fed into the yarn path outside the yarn handling tool 6 for urging it towards the rotating spindle tube 2 in the let-off step (see FIG. 2) of the splicing cycle.

[0077] In the disclosed embodiment, the thread buffer mechanism 11 includes a thread holding member 12 constructed and arranged to hold the auxiliary thread 1 of the thread buffer under elastic tension. The thread holding member 12 includes a thread holding rod operatively connected to a control unit (not shown) of the thread buffer mechanism 11, and pivots through a rotation angle when the control unit receives a signal from the processing and control means of the system for forming the thread buffer.

[0078] In the embodiment shown in Figures 2 and 4, the control unit of the thread buffer mechanism 11 includes a stepper motor 13 operatively connected to the thread holding rod for pivoting the thread holding rod at different fixed positions so that the required length of auxiliary thread 1 can be obtained from the auxiliary thread supply source.

[0079] In the let-off step of the yarn splicing cycle, the yarn processing and control means of the system sends a signal to the control unit of the yarn buffer mechanism 11 to form a yarn buffer with a predetermined length (e.g., a first length "L0") of auxiliary yarn coming from the auxiliary yarn supply source. The length of auxiliary yarn 1 required for let-off from the yarn buffer may vary depending on the type of yarn being spliced, etc.

[0080] The splicing system includes a yarn pushing means disposed in the yarn path inside the yarn handling tool 6 for pushing a predetermined length of auxiliary yarn 1 in the yarn buffer towards the rotating spindle tube 2. In the illustrated embodiment, the yarn pushing means comprises a Venturi tube and air injector assembly 14 configured to draw air into the yarn inlet 8 of the yarn handling tool 6 for pushing said length of auxiliary yarn 1 in the yarn buffer through the yarn nozzle 9 upon receiving a signal from the processing and control means.

[0081] Advantageously, the splicing system comprises liquid supply means configured to be able to wet the yarn contact area of ​​the rotating spindle tube 2 intended to be contacted by the free end of the auxiliary yarn 1 during the delivery step of the splicing cycle. The processing and control means of the system are configured to provide an activation signal to the liquid supply means to supply a liquid spray (e.g. atomized water) to the yarn contact area of ​​the rotating spindle tube 2 while the free end of the auxiliary yarn 1 is being propelled to the yarn contact area.

[0082] The liquid supply means comprises a liquid spray nozzle 15 associated with a container of liquid (not shown) and two solenoid valves (not shown) for controlling the passage of liquid and air to atomize small amounts of liquid in the jets of air. In the illustrated embodiment, the liquid spray nozzle 15 is arranged on the yarn handling tool 6 in vertical alignment with the yarn nozzle 9 of the yarn handling tool 6, but it does not necessarily have to be arranged on the yarn handling tool 6.

[0083] FIG. 3 is a schematic perspective view showing the yarn handling tool 6 attached to the robot arm 7 while the yarn nozzle 9 is propelling the auxiliary yarn 1 of the first length "L0" in the yarn buffer and the liquid spray nozzle 15 is supplying a liquid spray to wet the yarn contact area of ​​the rotating spindle tube 2 free of yarn, and the free end of the auxiliary yarn 1 is being propelled to said yarn contact area.

[0084] As mentioned above, it was found that when a liquid spray is supplied to the spindle tube 2 to wet the yarn contact area, the success rate of winding the free end of the auxiliary yarn onto the rotating spindle tube 2 is significantly increased (98% vs. 46%). Furthermore, the capture time is significantly reduced to an average time for gripping of 3 seconds compared to an average time of 19 seconds when the use of the liquid spray is omitted. Wetting eliminates electrostatic effects and increases the adhesion of the auxiliary yarn 1 to the surface of the rotating spindle tube 2.

[0085] After the free end of the auxiliary yarn is successfully wound around the surface of the rotating spindle tube 2, the rotation of the spindle is stopped and the stepping motor 13 of the yarn buffer mechanism 11 moves the yarn holding member 12 to the initial retracted position. Subsequently, the yarn feeding device 10 supplies the auxiliary yarn 1 of a second length "L1" to the yarn path outside the yarn handling tool 6. Since the end of the auxiliary yarn 1 is fixed to the rotating spindle tube 2, when the yarn holding rod is pivoted to a new predetermined angular position (see FIG. 4) operated by the stepping motor 13, the auxiliary yarn 1 of length "L1" is supplied from the auxiliary yarn supply source.

[0086] Movement of the yarn handling tool 6 by the robot arm 7 to perform threading increases or decreases the auxiliary yarn 1 in this second length "L1," allowing this operation to be performed without slack, while the auxiliary yarn 1 outside the yarn handling tool 6 remains tensioned and curl-free. To this end, the stepper motor 13 operates in a low current mode to maintain the yarn holding rod in an active elastic operating position while the auxiliary yarn 1 in the yarn buffer increases or decreases as the robot arm 7 moves the yarn handling tool 6 back and forth. In the active elastic operating position, the stepper motor 13 causes the yarn holding member 12 to assume a partially retracted position when pulled by the movement of the robot arm 7, thereby shortening the auxiliary yarn 1 in the second length "L1" in the yarn buffer. The yarn holding member 12 resumes its extended position when the robot arm 7 approaches the yarn buffer mechanism 11, thereby lengthening the auxiliary yarn 1 in the second length "L1" in the yarn buffer. Yarn brakes 17, 18 are provided in the path outside the yarn handling tool 6. The inlet yarn brake 17 controls the introduction of the auxiliary yarn 1 from the yarn source into the yarn buffer, and the output yarn brake 18 controls the discharge of the auxiliary yarn 1 from the yarn buffer. Both brakes 17, 18 are operatively connected to the control unit of the yarn buffer mechanism 11.

[0087] 5 is a perspective view of the yarn handling tool, showing the threading portion of the auxiliary yarn 1 formed outside the yarn nozzle 9 by a holding element 16 (e.g. a grip) arranged on the yarn handling tool 6. This threading portion has to be threaded by a ring traveler 5 attached to a ring 4 supported on a movable support rail 3 of the corresponding spindle tube 2.

[0088] Before threading, the robot arm 7 brings the thread handling tool 6 close to the movable support rail 3 and brings the thread handling tool 6 into contact with the movable support rail 3.

[0089] As mentioned above, it is well known that the movable support rail 3 supporting the rotating spindle tube 2 moves up and down during rotation. Therefore, the robot arm 7 must track the movement of the movable support rail 3 in order to perform threading and splicing. For this purpose, a positioning sensor 19 (e.g., a laser sensor) is fixed to one end of the ring spinning machine and can provide height position data to the controller of the robot arm 7 at any point in the splicing cycle. However, the length of the movable support rail 3 does not guarantee that the height position data provided by the positioning sensor 19 will be accurate at the spinning station requiring repair. If the height position data is inaccurate, the robot arm 7 will not be able to correctly position the yarn handling tool 6 to perform threading.

[0090] In the illustrated embodiment of the claimed system, the yarn handling tool 6 is articulated to the robot arm 7 by a resilient articulated joint 20 configured to allow a tilting base 21 of the yarn handling tool 6 to pivot to an angular position when it contacts the movable support rail 3, and to restore an initial rest position when it ceases to contact the movable support rail 3. A spring 30 interposed between the tilting base 21 and the frame 25 helps the tilting base 21 to restore its initial rest position. The articulated joint 21 absorbs height differences when the yarn handling tool 6 contacts the movable support rail 3, allowing it to assume an optimal working angle for performing threading (see Figures 6, 7a and 7b).

[0091] Advantageously, the splicing system further comprises a tool angle sensor assembly 22 operatively connected to the control unit of the robot arm 7, which, upon contact with the movable support rail 3, enables the yarn handling tool to be set to an optimum working angular position and provides a signal to the processing and control means of the system so that said processing and control means: - obtaining the actual working height position of the movable support rail 3 based on the angular position of the yarn handling tool 6 provided by the control unit of the robot arm 7; calculating a height offset value to be applied to the height position data of the movable support rail 3 provided by a positioning sensor 19 (for example a laser sensor fixed at one end of the ring spinning machine); - Based on the calculated height offset value, sending a signal to the control 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.

[0092] The tool angle sensor assembly 22 comprises at least two proximity sensors 23, 24 for detecting the presence of the tilting base 21 of the yarn handling tool 6. Figure 10 shows these proximity sensors 23, 24 located at the rear of the frame structure 25 of the yarn handling tool 6.

[0093] 7a and 7b are rear perspective views showing the yarn handling tool 6 close enough to the movable support rail 3 that the tool angle sensor assembly 22 sets the yarn handling tool 6 in an optimal operating position when it contacts the movable support rail 3. A control unit (not shown) for the robot arm 7 is configured to check the status of two proximity sensors 23, 24 configured to detect the presence of the tilting base 20 of the yarn handling tool 6. The control unit for the robot arm 7 provides a set-up signal to the system's processing and control means (not shown), which directs the synchronization of the movements of the robot arm 7 with the movements of the movable support rail 3 according to a calculated height offset value that is applied to height position data provided by a positioning sensor 19 (e.g. a laser sensor measuring the height position of the movable support rail 3 at one end of the ring spinning machine).

[0094] Once synchronization is complete, the robot arm 7 starts to follow the movable support rail 3, so that all movements required to perform threading on the ring traveler 5 are merged with the tracking movements of the movable support rail 3. As mentioned above, for maximum accuracy, threading is performed without rotating the spindle tube 2.

[0095] 8 is a perspective view showing the yarn handling tool 6 attached to the robot arm 7 when the threading portion of the auxiliary yarn 1 is about to be threaded by the ring traveler 5. An air conduction tube 31 is attached to the surface of the yarn handling tool 6 for injecting air to move the ring traveler 5 on the flange of the ring 4.

[0096] Once the ring traveler 5 is threaded, the robot arm 7 moves the yarn handling tool 6 upward, passing the yarn through a balloon-type contraction ring (not shown) and a yarn guide (not shown). The spindle brake (not shown) is released, and the yarn handling tool 6 is raised to carry the auxiliary yarn 1 to the front roller of the draft assembly and splice the auxiliary yarn 1 onto the roving yarn exiting the front roller. A cutter 26 integrated into the yarn handling tool 6 then cuts the auxiliary yarn 1 in its internal path so that the free end of the auxiliary yarn 1 does not protrude outside the yarn nozzle 9 upon cutting. A yarn holding means 27 is positioned in the same yarn transport path inside the yarn handling tool 6 to hold the auxiliary yarn 1 in place after cutting. At this point, the splicing cycle is completed, and the robot arm 7 returns the yarn handling tool 6 to its initial position and moves to the next spinning station requiring a splice.

[0097] 9, 10 and 11 show different views of the components of the thread handling tool 6.

[0098] 9 is a schematic bottom view showing the yarn handling tool 6, including a yarn transport path inside the yarn handling tool 6 for transporting a length of auxiliary yarn 1 from the yarn inlet 8 to the yarn outlet formed by the yarn nozzle 9. Along this path are arranged a Venturi tube and air injector assembly 14 for drawing air into the yarn inlet 8 to propel said length of auxiliary yarn 1 in the yarn buffer, a yarn cutter 26 driven by an electromagnet, yarn holding means 27 for holding the auxiliary yarn 1 inside the yarn handling tool 6 when it is cut, and sensor means 28 for detecting the presence and / or movement of said length of auxiliary yarn 1. The sensor means 28 is primarily used for the processing and control means to issue an instruction to stop splicing or to initiate the self-threading process if the auxiliary yarn 1 is lost inside the yarn handling tool.

[0099] FIG. 10 is another schematic bottom view of the internal components of the yarn handling tool 6, showing a detailed cross section of a portion of the yarn path inside the yarn handling tool with a yarn cutter 26 positioned to cut the auxiliary yarn 1.

[0100] FIG. 11 is a schematic exploded view showing the yarn handling tool 6, showing, among other components, a tool angle sensor assembly 22 having at least two proximity sensors 23, 24 located at the rear of a frame structure 25 for detecting the presence of the tilting base 21 of the yarn handling tool 6.

[0101] The claimed system has the advantage that it makes it possible to carry out an automatic self-threading process in case of a loss of yarn along the yarn transport path inside the yarn handling tool 6. To make this process possible, the yarn feeding device 10 comprises: - a yarn outlet (not shown) of the yarn buffer mechanism 11; - a yarn holding means (not shown) arranged in the yarn feeding device 10 so as to hold the free end of the auxiliary yarn 1 in place outside the yarn outlet of the yarn buffer mechanism 11; - a blowing means (not shown) configured to inject air into the yarn outlet of the yarn buffer mechanism 11; a thread cutter (not shown) operatively connected to the thread outlet of the thread buffer mechanism 11 so as to be able to cut off excess thread outside the thread outlet in case of loss of thread; Further provided are:

[0102] The processing and control means of the system i. providing a signal to the drive means of the robot arm 7 so that the robot arm 7 positions the yarn inlet 8 of the yarn handling tool 6 relative to the yarn outlet of the yarn buffer mechanism 11; ii. supplying an activation signal to the yarn cutter to cut off excess yarn outside the yarn outlet; iii. supplying an activation signal to the air blowing means of the yarn feeding device 10 to blow air onto the free end of the auxiliary yarn 1 outside the yarn outlet of the yarn buffer mechanism 11 while holding the auxiliary yarn 1 of the yarn buffer in a predetermined position outside the yarn outlet; iv. supplying an activation signal to the yarn propelling means of the yarn handling tool 6 so that the free end of the auxiliary yarn 1 in the yarn buffer is sucked along the yarn transport path inside the yarn handling tool 6; The needle is configured to perform an automatic self-threading operation including:

[0103] The blowing means comprises a venturi tube and air injector assembly configured to blow or inject air into the yarn outlet of the yarn buffer mechanism 11 upon receiving a signal from the system processing and control means.

[0104] The present invention, in summary, provides a system and method for splicing the free end of an auxiliary thread 1, which, in contrast to known splicing methods, provides high reliability and precision for both the threading and splicing operations. Furthermore, the claimed method and system: the fact that it prevents the formation of curls and twists of the auxiliary yarn outside the yarn handling tool 6; the fact that it makes it possible to prepare and supply the auxiliary thread 1 of a precise predetermined length to be propelled, - increasing the success rate of the auxiliary yarn 1 being captured by the rotating spindle tube 2 during the let-off step of the splicing cycle; the fact that it reduces the average time that the auxiliary thread 1 is captured on the rotating spindle tube 2, and / or the fact that it allows an automatic self-threading process in case of a lost thread in the thread path inside the thread handling tool 6; This significantly improves the handling of the auxiliary yarn 1.

[0105] Those skilled in the art can introduce changes and modifications to the described embodiments without departing from the scope of the invention, as defined in the appended claims. For example, while a yarn splicing system and method is disclosed in which the step of supplying liquid to wet the yarn contact area of ​​the rotating spindle tube is described in combination with the use of a yarn handling tool and a yarn feeder disposed along a path external to the yarn handling tool, a different yarn splicing system and method may be claimed that does not require the use of a yarn handling tool and a robotic arm, but still provides a liquid supply means configured to wet the yarn contact area of ​​the rotating spindle tube. Similarly, while a yarn handling tool 6 is disclosed that is attached to a robotic arm 7, the yarn handling tool 6 can be attached to an automated handling means other than the robotic arm 7, provided that the automated handling means is capable of manipulating the yarn nozzle and yarn holding means to perform threading.

Claims

1. A yarn splicing system for threading an auxiliary yarn (1) at a spinning station of a ring spinning machine that needs repair, comprising: - a yarn handling tool (6) attached to a computer-controlled mechanical or robotic arm (7); - drive means for said robot arm (7); - a yarn transport path inside said yarn handling tool (6) for transporting the auxiliary yarn (1) from the yarn inlet (8) to the yarn outlet; - a yarn nozzle (9) at the yarn outlet of the yarn handling tool (6); - thread holding means (16) arranged on said thread handling tool (6) so as to be able to form a threading portion of the auxiliary thread (1) outside said thread nozzle (9); - processing and control means adapted to provide an activation signal to the drive means of the robot arm (7) so that the threading and piecing operations are performed by the thread handling tool (6) when the free end of the auxiliary thread (1) is wound onto the rotating spindle tube (2) and the rotation of the rotating spindle tube (2) is stopped; Equipped with The yarn splicing system comprises: - a yarn transport path outside the yarn handling tool (6) for transporting an auxiliary yarn (1) from an auxiliary yarn source to the yarn inlet (8) of the yarn handling tool (6); a yarn feeding device (10) arranged and configured to feed a length ("L0", "L1") of auxiliary yarn (1) to the yarn transport path outside the yarn handling tool (6) during movement of the yarn handling tool (6) by the robot arm (7); The thread splicing system further comprises:

2. The yarn feeding device (10) a thread buffer mechanism (11) between the thread handling tool (6) and the auxiliary thread supply, forming a thread buffer for the auxiliary thread (1) along the thread transport path outside the thread handling tool (6); - a control unit for said thread buffer mechanism (11); The splicing system of claim 1 , comprising:

3. 3. The yarn splicing system according to claim 2, wherein the yarn processing and control means is configured to provide a signal to the control unit of the yarn buffer mechanism (11) so that the yarn buffer mechanism (11) forms the yarn buffer containing a predetermined length ("L0") of auxiliary yarn (1) during the let-off step of the yarn splicing cycle.

4. 3. The yarn splicing system according to claim 2, wherein the yarn buffer mechanism (11) comprises a yarn holding member (12) constructed and arranged to hold the auxiliary yarn (1) in the yarn buffer under elastic tension while the auxiliary yarn (1) in the thread buffer increases or decreases when the robot arm (1) operates the yarn handling tool (6).

5. 5. The yarn splicing system according to claim 4, wherein the control unit of the yarn buffer mechanism (11) comprises a stepping motor (13) operatively connected to the yarn holding member (12) to maintain the yarn holding member (12) in an active elastic operating position while the auxiliary yarn (1) in the yarn buffer increases or decreases when the robot arm (1) operates the yarn handling tool (6).

6. The thread holding member (12) comprises a thread handling rod operatively connected to the control unit; 5. The yarn splicing system of claim 4, wherein the yarn handling rod is configured to pivot through a rotation angle when the control unit receives the signal from the processing and control means to form the yarn buffer.

7. - said yarn splicing system comprises yarn driving means (14) arranged along said yarn transport path inside said yarn handling tool (6); 3. A yarn splicing system according to claim 2, wherein during a yarn letting-off step of the splicing cycle, the processing and control means is configured to provide an activation signal to the yarn pushing means (14) so ​​that the yarn pushing means (14) pushes the length of auxiliary yarn from the yarn buffer towards the yarn nozzle (9) so that the auxiliary yarn (1) from the yarn buffer is wound onto the rotating spindle tube (2).

8. 2. A yarn splicing system according to claim 1, comprising liquid supply means (15) configured to be able to wet a yarn contact area of ​​the rotating spindle tube (2) intended to be contacted by the free end of the auxiliary yarn (1) during the yarn let-off step of the splicing cycle.

9. 9. The yarn splicing system according to claim 8, wherein the processing and control means is configured to provide an activation signal to the liquid supply means (15) for supplying a liquid spray to the yarn contact area of ​​the rotating spindle tube (2) while the free end of the auxiliary yarn (1) is being propelled to the yarn contact area of ​​the rotating spindle tube (2).

10. said yarn handling tool (6) being articulated to said robot arm (7) by means of an articulated joint (21); 2. The yarn splicing system according to claim 1, wherein the articulated joint (21) is configured to allow the tilting base (20) of the yarn handling tool (6) to pivot to an angular position to accommodate large differences in the operating position of the movable support rail (3) of the ring spinning machine.

11. 11. The yarn splicing system according to claim 10, wherein the articulated joint (21) comprises a resilient connection configured to allow the tilting base (20) of the yarn handling tool (6) to pivot to an angular position when it contacts the movable support rail (3) and to restore an initial rest position when it stops contacting the movable support rail (3).

12. 11. The splicing system according to claim 10, further comprising a tool angle sensor assembly (22) operatively connected to a control unit of the robot arm (7) for setting the yarn handling tool (6) to an optimum working angular position when it contacts the movable support rail (3) at the spinning station requiring repair.

13. the tool angle sensor assembly (22) comprises at least two proximity sensors (23, 24) for detecting the presence of the tilting base (20) of the yarn handling tool (6); 13. The splicing system according to claim 12, wherein the control unit is configured to check the status of the at least two proximity sensors (23, 24) and to provide a setup signal to the processing and control means to instruct it to synchronize the movement of the robot arm (7) with the movement of the movable support rail (3) according to a calculated height offset value.

14. The processing and control means - to obtain the actual working height position of the movable support rail (3) at the spinning station requiring repair based on the angular position of the yarn handling tool (6) provided by the control unit of the robot arm (7), - to calculate a height offset value to be applied to the height position data of said movable support rail (3) provided by the positioning sensor (19); and - based on the calculated height offset value, sending a signal to the control unit of the robot arm (7) to synchronize the movement of the robot arm (7) with the movement of the movable support rail (3); The yarn splicing system according to claim 12,

15. 2. The yarn splicing system according to claim 1, further comprising a yarn cutter means (26) arranged in the yarn transport path inside the yarn handling tool (6) for cutting the auxiliary yarn inside the yarn handling tool (6) upon receiving a cut signal from the processing and control means.

16. The yarn feeding device (10) - a yarn outlet of said yarn buffer mechanism (11); - thread holding means adapted to hold the free end of the auxiliary thread (1) in place outside the thread outlet of the thread buffer mechanism (11) in case of thread loss; - air blowing means arranged to inject air into the yarn outlet of the yarn buffer mechanism (11); Equipped with - in case of a loss of yarn along the yarn transport path inside the yarn handling tool (6), said processing and control means i. providing a signal to the drive means of the robot arm (7) for causing the robot arm (7) to position the yarn inlet (8) of the yarn handling tool (6) relative to the yarn outlet of the yarn buffer mechanism (11); ii. providing an activation signal to the air blowing means of the yarn supplying device (10) to blow air onto the free end of the auxiliary yarn (1) outside the yarn outlet of the yarn buffer mechanism (11) while holding the auxiliary yarn (1) of the yarn buffer in a predetermined position outside the yarn outlet; iii. Providing an activation signal to the yarn urging means (14) of the yarn handling tool (6) so that the free end of the auxiliary yarn (1) of the yarn buffer is sucked along the yarn transport path inside the yarn handling tool (6); 3. The splicing system of claim 2 configured to perform an automatic self-threading operation including:

17. 17. The yarn splicing system according to claim 16, wherein the yarn supply device (10) further comprises a yarn cutter operatively connected to the yarn outlet of the yarn buffer mechanism (11) so as to cut off excess yarn outside the yarn outlet in case of yarn loss.

18. image capturing means (29) preferably arranged on said yarn handling tool (6), 2. The splicing system of claim 1, wherein the image capturing means (29) is operatively connected to an artificial vision system configured to check for any obstructions to splicing before the splicing cycle begins.

19. 1. A method for splicing an auxiliary yarn (1) in a spinning station of a ring spinning machine requiring repair, comprising: a) feeding a first length ("L0") of auxiliary yarn (1) into an outer yarn transport path of a yarn handling tool (6) driven by a robotic arm; b) bringing said yarn handling tool (6) close to the rotating spindle tube (2) requiring repair; c) propelling the first length ("L0") of the auxiliary yarn (1) into a yarn nozzle (9) of the yarn handling tool (6) so that a free end of the auxiliary yarn (1) is wound onto the rotating spindle tube (2); d) stopping the rotation of the rotating spindle after the free end of the auxiliary thread is wound around the rotating spindle tube (2); e) after step d), while the robot arm (7) operates the yarn handling tool (6) to perform threading and splicing, feeding a second length ("L1") of auxiliary yarn (1) to the yarn transport path outside the yarn handling tool (6) and increasing or decreasing the second length ("L1") of the auxiliary yarn (1); A method for piecing an auxiliary yarn (1), comprising:

20. - step a) comprises forming a yarn buffer comprising said first length ("L0") of said auxiliary yarn (1) along a yarn transport path outside said yarn handling tool (6), - step c) comprises propelling the first length ("L0") of the auxiliary yarn (1) in the yarn buffer to a yarn nozzle (9) of the yarn handling tool (6) so that the free end of the auxiliary yarn (1) in the yarn buffer is wound onto the rotating spindle tube (2); step e) is i. forming a yarn buffer containing said second length ("L1") of said auxiliary yarn (1); ii. holding the second length ("L1") of the auxiliary yarn (1) in the thread buffer under elastic tension while increasing or decreasing the second length ("L1") of the auxiliary yarn in the thread buffer when the robot arm (7) operates the yarn handling tool (6) to perform threading and splicing; 20. A method for piecing auxiliary yarns (1) according to claim 19, comprising:

21. 20. The method for splicing auxiliary yarns (1) according to claim 19, comprising, prior to or simultaneously with step c), the step of supplying a liquid spray to a yarn contact area of ​​the rotating spindle tube (2) intended to be contacted by the free end of the auxiliary yarn (1) of the first length ("L0").

Images