CN115110185A

CN115110185A - Yarn joining system and method for ring spinning machine and yarn processing tool

Info

Publication number: CN115110185A
Application number: CN202210290694.1A
Authority: CN
Inventors: A·塞拉特利亚
Original assignee: Pinter Caipo SAU
Current assignee: Pinter Caipo SAU
Priority date: 2021-03-23
Filing date: 2022-03-23
Publication date: 2022-09-27
Also published as: EP4063543A1

Abstract

A yarn splicing system and method for splicing an auxiliary yarn at a spinning station of a ring spinning machine, comprising: -a yarn supply device for supplying a free end (12a) of an auxiliary yarn (12); a yarn fastening device (11) for fastening an auxiliary yarn (12) outside the yarn feed nozzle (10) to form a threading section ("S") of the auxiliary yarn (12); and an automatic processing device (7) for processing the yarn supplying device and the yarn fastening device. The system is characterized in that the automatic processing device (7) comprises a yarn processing tool (8) with a yarn feed mouth (10) and in that the system comprises: an aspiration device (13) arranged to aspirate air into the yarn feed nozzle (10); and processing and control means configured to provide an activation signal to the suction means in order to suck air into the yarn feed mouth (10).

Description

Yarn joining system and method for ring spinning machine and yarn processing tool

Technical Field

The present invention generally relates to a yarn piecing system (yarn piecing system) for piecing auxiliary yarns when a yarn breakage occurs at a spinning station of a ring spinning machine. The invention also relates to a method for automatically piecing auxiliary yarns at a spinning station, and to a yarn processing tool for use in the claimed system.

Background

Known yarn splicing systems automatically splice the broken ends of the yarn. When a yarn breakage occurs on the ring spinning machine, the broken end of the yarn is wound on the bobbin after the breakage. In those systems, an automated yarn handling device is used to detect broken ends of the yarn through a suction tube connected to a vacuum source. The suction tube is mounted on an automatic service station, which is displaceably arranged along a row of spinning stations, optionally stopped at selected spinning stations requiring service operations.

In the known yarn splicing system described above, in order to restart spinning after yarn breakage, the yarn end is sucked into a vacuum tube through which the yarn end is positioned with respect to the bobbin, and then a threading operation (threading operation) is performed by creating a threading section of the yarn end. The threading section is located at a flange of a ring, and a traveler (traveller) on the ring of the spinning machine is moved by compressed air so that the traveler is put on the threading section of the yarn end and threads the yarn end into the traveler. Once threaded, the yarn ends are positioned by the same suction tube for splicing to the roving issuing from the roving delivery roller.

Yarn splicing systems that treat broken ends of yarn have the following disadvantages: when a yarn breakage occurs after bobbin replacement (doffing) (in the case where the bobbin is still empty of yarn), it is difficult to detect the broken end. Also, if the broken end is wound all the way around the bobbin section located below the ring rail of the spinning machine, it is difficult to detect the broken end. This occurs when two spinning stations need to be serviced simultaneously and the automatic service station takes more time than the time needed to assist the second spinning station so that most of the spindles of the second spinning station have no yarn above the ring rail.

In order to solve the drawbacks of the yarn splicing systems dealing with broken ends of the yarn, known splicing systems have been developed to improve the splicing process by supplying the free end of the auxiliary yarn to the spindle tube of the revolving yarn, which free end is to be wound onto the spindle tube of the revolving spindle. Those known yarn splicing systems can omit the step of detecting the broken end of the yarn.

JP03199436A discloses such a known yarn splicing system with an automatic service station positionable at the spinning station for supplying the free end of the auxiliary yarn from an auxiliary yarn source to a revolving spindle having a spindle tube providing a winding surface around which the free end is to be wound. The free end of the auxiliary yarn is supplied by a yarn feed nozzle which advances the free end of the auxiliary yarn together with air to the spindle tube of the revolving spindle. The system is also provided with a finger element for fastening the auxiliary yarn outside the yarn feed mouth, forming a threading section once the free end of the auxiliary yarn is wound onto the bobbin. To this end, automatic handling means are provided to handle the yarn feed nozzle and the finger elements to perform the threading operation. Once threaded, the yarn end of the auxiliary yarn is positioned by another finger element for splicing it to the roving issuing from the front roller of the drafting assembly.

The joint system disclosed in JP03199436A has several disadvantages. One of said drawbacks is the failure of the winding operation of the free end of the auxiliary thread with the bobbin, due to the poor adhesion of the free end of the auxiliary thread with the surface of the bobbin, particularly when the bobbin is empty of thread after doffing. Another disadvantage is that the threading operation is performed while the spindle tube is kept rotating, and proper tension is applied to the auxiliary yarn outside the yarn feeding nozzle and the threading part is prevented from sagging. However, in practice it has been found that threading by rotation of the spindle tube is even more difficult and complicated, since threading requires a high precision in positioning the yarn.

There is therefore a need to provide an alternative to the prior art, which overcomes the above-mentioned drawbacks by providing a yarn splicing system for splicing auxiliary yarns to cover the gaps found therein, and therefore a system having a fast and reliable threading and splicing operation, and an improved reliability of the winding operation of the free end of the auxiliary yarn, even with empty bobbins.

Disclosure of Invention

To this end, in a first aspect, the invention relates to a yarn splicing system for splicing an auxiliary yarn at a spinning station of a ring spinning machine, comprising:

-a yarn supply device for supplying a free end of an auxiliary yarn onto a spindle tube of a revolving spindle, said free end being to be wound on said spindle tube, said yarn supply device comprising a yarn feed nozzle for feeding the free end of the auxiliary yarn to the spindle tube of the revolving spindle,

-a yarn fastening device for fastening an auxiliary yarn outside the yarn feed mouth to form a threading section of the auxiliary yarn after the free end of the auxiliary yarn has been wound onto the spindle tube, and

-automatic handling means for handling the yarn supply means and the yarn fastening means.

In contrast to known yarn splicing systems, in the yarn splicing system according to the first aspect of the invention, the automatic processing device comprises a yarn processing tool in which at least a yarn feed nozzle is mounted, and the system comprises:

-suction means arranged to draw air into the yarn feed nozzle, an

-a processing and control device configured to provide an activation signal to said suction device to suck air into the yarn feed mouth as soon as the free end of the auxiliary yarn is wound onto the spindle and the rotation of the spindle tube stops.

Thanks to the claimed features, the invention provides a splicing system in which air is sucked into the yarn feed mouth itself, which is used to supply the free end of the auxiliary yarn. Thus, during threading and piecing, the auxiliary yarn outside the yarn feed nozzle can be held at an appropriate tension without the need to rotate the spindle tube and wind the auxiliary yarn from an auxiliary source. In this way, the reliability of the threading operation and the splicing operation is significantly improved.

Furthermore, in the claimed system, the yarn feeding mouth is mounted on a yarn processing tool adapted to process yarn fastening devices, such as clamping elements, involving the formation of a threading section outside the yarn feeding mouth. Thus, the accuracy of the yarn processing is greatly improved, since both the threading operation and the piecing operation can be performed using the same processing tool.

For one embodiment, the yarn supply of the yarn splicing system further comprises:

a blowing device arranged to inject or blow air into the yarn feeding nozzle, and

-a yarn holding device configured to hold an auxiliary yarn of a predetermined length (L0) in position outside the yarn feed mouth before the free end is wound onto the surface of the rotating bobbin at the start of the piecing cycle, and

-a processing and control device configured to provide an activation signal to said blowing device to blow the free end of said auxiliary yarn of predetermined length (L0) outside the yarn feeding mouth when the yarn processing tool approaches the revolving bobbin.

Due to the presence of said yarn holding device, a predetermined length (L0) of auxiliary yarn can be held in place outside the yarn feed mouth at the start of the piecing cycle. Preferably, the holding means is configured to hold a length of yarn in position by contact with the shifting board. By blowing air into the yarn feed nozzle, the free end of a predetermined length (L0) of auxiliary yarn outside the yarn feed nozzle can be positioned tangential to the surface of the revolving spindle tube while the yarn processing tool is close to the revolving spindle. In this way, the chance of the free end sticking to the surface of the revolving bobbin is increased.

Furthermore, in contrast to known yarn splicing systems that eject or advance the yarn toward the revolving spindle tube to wrap around it, the claimed system does not advance or eject an auxiliary yarn, but merely blows out a predetermined length of auxiliary yarn that remains in place outside the yarn feed nozzle. The predetermined length of auxiliary yarn may oscillate tangentially to the surface of the rotating spindle tube to promote adhesion of the free end of the yarn by oscillating a yarn handling tool attached to the automated handling device. Once the free end of the auxiliary yarn adheres to the surface of the revolving bobbin, the tension of the yarn running around the bobbin is made to be unable to hold by the lifting of the sliding plate.

According to one embodiment, the yarn fastening device of the yarn splicing system comprises at least one clamping element for fastening the auxiliary yarn outside the yarn feed mouth, and preferably the at least one clamping element is arranged on the yarn processing tool to allow the yarn processing tool to form a threading section of the auxiliary yarn.

By gripping element it is understood to mean an element for holding or gripping the yarn outside the yarn feed mouth. The clamping element may be configured as a protrusion or projection attached to the yarn processing tool, configured or adapted to hold or grip a portion of the yarn outside of the yarn feed nozzle.

Advantageously, both the yarn fastening device (e.g. the at least one clamping element) and the yarn feeding nozzle are integrally attached to an end of the frame structure of the yarn processing tool.

For one embodiment, the ends of the frame structure are configured as tolerance absorbing structures to bend or flex the ends to absorb operational tolerances of the yarn joint system. For example, the end frame structure comprises a flexible metal strip.

Thanks to the provision of such a flexible end frame structure, the claimed yarn splicing system prevents the automatic handling device from stopping automatically when the yarn feeding mouth or the clamping element accidentally collides with the loop rail. Furthermore, it has been found that such a flexible end frame structure constitutes a tolerance absorbing structure which helps to reduce the failure of the threading operation in case the process tool is not positioned in the correct position.

Preferably, the automatic handling device comprises a robot arm for handling the yarn handling tool. Advantageously, the mechanical arm has a movement with at least six degrees of freedom of movement to allow the yarn fastening device (e.g. at least one clamping element) to secure the auxiliary yarn outside the yarn feed mouth to form a threading section of the auxiliary yarn.

In the claimed system, the processing tool is attached to the robotic arm, and the processing and control device is configured to provide a motion signal to the robotic arm:

-fastening the auxiliary yarn outside the yarn feed mouth with a yarn fastening device (e.g. at least one clamping element) allowing an integral attachment to the processing tool to form a threading section, and

-positioning a threading section of yarn at the flange of the ring to thread the threading section into the ring traveler.

Thanks to these features, the threading operation and the piecing operation can be performed by using only one processing tool attached to the robot arm, wherein the yarn feeding nozzle and the yarn fastening device are attached, preferably integrally attached, to the processing tool mounted on the robot arm.

According to one embodiment of the system, the suction device comprises a first venturi tube and an air injector assembly arranged to suck air into the yarn feeding mouth upon receiving an activation signal from the processing and control device.

The first venturi tube and air jet assembly is mounted on the processing tool and is preferably arranged such that the venturi tube is substantially aligned with the yarn feed nozzle.

For a preferred embodiment, the blowing device comprises a second venturi tube and air injector assembly arranged to blow or inject air into the yarn feeding nozzle upon receiving an activation signal from the processing and control device.

The second venturi tube and air jet assembly is also mounted on the processing tool, preferably in substantial alignment with the first venturi tube and the yarn feed nozzle.

For one embodiment, the venturi of the first venturi and air jet assembly and/or the second venturi and air jet assembly is configured and arranged such that the auxiliary yarn passes along the venturi before being supplied through the yarn feeding nozzle.

Advantageously, the yarn holding device is arranged between the first venturi tube and air injector assembly and the second venturi tube and air injector assembly. In particular, they are arranged in a rear position with respect to the second venturi tube and ejector assembly and with respect to the yarn feeding mouth.

This arrangement has been found to be very effective for accurately controlling both the feeding and the treatment of the auxiliary yarn by means of the yarn feeding nozzle of the treatment tool.

Preferably, the yarn holding device comprises: a spring-loaded slide plate for holding a predetermined length (L0) of the auxiliary yarn in place outside the yarn feed nozzle by contact with the second plate; and a piston and cylinder assembly arranged to actuate at least one compression spring against the glide plate.

Once the free end of the auxiliary yarn adheres to the surface of the rotating bobbin, the tension of the wound yarn is not maintained by the lifting spring-loaded slide plate. Thus, a greater length of auxiliary yarn is fed through the yarn feed nozzle for winding around the spindle tube. The spring-loaded glide plate is configured to allow the yarn to glide without causing yarn breakage.

For one embodiment of the system, the processing and control means of the claimed system is configured to:

-providing a signal to actuate the piston and cylinder assembly of the yarn holding device to release a predetermined length (L0) of the auxiliary yarn outside the yarn feed nozzle after a predetermined time without the free end of the auxiliary yarn adhering to the spindle tube,

-providing a signal to the automatic processing device to position the yarn feed mouth of the processing tool backward and/or forward with respect to the auxiliary yarn, so that the auxiliary yarn of the second predetermined length is located outside the yarn feed mouth, and

-providing a signal to the piston and cylinder assembly of the yarn holding device to hold the second predetermined length of auxiliary yarn in place outside the yarn feeding mouth at the start of the piecing cycle.

Advantageously, according to the same embodiment, the processing and control means are also configured to provide an activation signal to said blowing means to blow the free end of said second predetermined length of auxiliary yarn outside the yarn feeding mouth while the yarn processing tool approaches the revolving spindle.

It has been found that auxiliary yarns of different lengths may be suitable to approach the revolving spindle at the start of the piecing cycle. Depending on the type of yarn to be adhered to the surface of the spindle tube and the coefficient of friction of the surface on which the yarn is to be wound, a longer or shorter predetermined length of auxiliary yarn is required. The claimed features allow to optimize the time taken and the quality of the winding operation.

A second aspect of the invention relates to a yarn processing tool suitable for use with the claimed yarn splicing system, comprising:

-a frame structure attachable to an automated processing unit,

-an end portion of the frame structure,

-a yarn feed mouth attached to an end of the frame structure for supplying a free end of an auxiliary yarn,

-fastening means attached to the end of the frame structure for fastening the auxiliary yarn outside the yarn feed mouth,

-suction means arranged to draw air into the yarn feed nozzle, and preferably,

-a blowing device arranged to inject air into the yarn feed nozzle, and

-a yarn holding device "R" configured to hold in position an auxiliary yarn of predetermined length L0 outside the yarn feeding mouth.

Again preferably, the yarn fastening device (e.g. the at least one clamping element) and the yarn feeding mouth are integrally attached to an end of the frame structure of the processing tool, and advantageously the end of the frame structure is a tolerance absorbing structure configured to bend or flex to absorb operational tolerances of the yarn joint system.

For one embodiment, the suction device comprises a first venturi tube and an air injector assembly arranged on the processing tool to suck air into the yarn feeding nozzle upon receiving an activation signal from the processing and control device of the yarn splicing system.

Advantageously, the blowing device comprises a second venturi tube and air injector assembly arranged on the processing tool to blow or inject air into the yarn feeding nozzle upon receiving an activation signal from the processing and control device of the yarn splicing system.

Advantageously again, the venturi tube in said first venturi tube and air injector assembly and/or said second venturi tube and air injector assembly is configured and arranged such that the auxiliary yarn passes along the venturi tube before being fed through the yarn feeding mouth.

For a preferred embodiment, the thread holding device is arranged on the processing tool between the suction device and the blowing device. In particular, between the first venturi tube and air injector assembly and the second venturi tube and air injector assembly.

Preferably, the yarn retention device "R" comprises: a spring-loaded slide plate for holding a predetermined length (L0) of the auxiliary yarn in place outside the yarn feed nozzle by contact with the second plate; and a piston and cylinder assembly arranged to actuate the at least one compression spring against the glide plate.

Advantageously, the processing tool further comprises an air duct arranged to propel air to the ring of the spinning machine to cause intentional movement of the ring traveler on the flange of the ring during the threading operation.

A third aspect of the invention relates to a method for piecing an auxiliary yarn at a spinning station of a ring spinning machine, comprising the steps of;

a) the free end of the auxiliary yarn is supplied through a yarn feed nozzle arranged on a yarn processing tool of the automatic processing device,

b) the free end of the auxiliary yarn is made to approach the spindle tube of the revolving spindle, the free end of the auxiliary yarn is made to wind on the spindle tube,

c) the rotation of the rotary yarn spindle tube is stopped,

d) after step c), drawing air into the yarn feed nozzle, and

e) positioning a yarn processing tool to perform a threading operation and a piecing operation while drawing air into a yarn feeding nozzle, wherein the threading operation includes the steps of: the auxiliary yarn is fixed to the outside of the yarn feeding nozzle to form a threading section "S" of the auxiliary yarn.

Thanks to the claimed features, the invention provides a method for piecing the free end of an auxiliary yarn, which allows, in contrast to known piecing methods, to perform threading and piecing operations under a suitable tension of the yarn, without sagging, and without the need to rotate the spindle tube. In this way, the reliability and accuracy of the threading operation and the splicing operation are significantly improved.

Furthermore, the claimed method significantly simplifies the piecing process, since the threading operation and the piecing operation can be performed with only one yarn handling tool, preferably one yarn handling tool attachable to a robotic arm. Advantageously, the robotic arm has a motion with at least six degrees of freedom of motion. Most known methods require more than one yarn handling tool to perform the threading and piecing operations. Therefore, there is a need in the prior art systems to control and synchronize several yarn processing tools.

Another advantage of the claimed method is that it is applicable both to empty bobbins (after doffing) and to bobbins containing spun fibres (yarn packages), since the free end of the auxiliary yarn is always supplied to the bobbin for winding.

As mentioned before, the yarn splicing system for treating the broken end of the yarn has the following drawbacks: when the bobbin has no yarn, it is difficult to detect a broken end when a yarn breakage occurs after doffing. Also, if the broken end is wound all the way around the bobbin section below the ring rail of the spinning machine, it is difficult to detect the broken end.

For one embodiment of the method, step a) comprises holding a predetermined length (L0) of the auxiliary yarn in position outside the yarn feed nozzle, and step b) comprises blowing air into the yarn feed nozzle to position the predetermined length (L0) of the auxiliary yarn tangent to the spindle tube to aid in winding.

In contrast to the known methods, the claimed method does not eject the free end of the auxiliary yarn onto the revolving spindle, but rather a predetermined length of the auxiliary yarn approaches the revolving spindle outside the yarn feed mouth. The auxiliary yarn of a predetermined length is held in place by a yarn holding device arranged on the yarn processing tool. The length of auxiliary yarn is positioned tangentially to the surface of the bobbin by blowing air into the yarn feed nozzle to assist winding.

Preferably, step b) comprises the steps of: the yarn treatment tool is moved in an oscillating manner while blowing air into the yarn feed nozzle so that the length of auxiliary yarn is positioned tangentially to the surface of the spindle tube at different tube heights.

It has been found that by this oscillating movement the chance of the free end of the auxiliary yarn winding onto the surface of the spindle tube is significantly increased.

For one embodiment, in step e), the step of fastening the auxiliary yarn outside the yarn feeding mouth to form a threading section of the auxiliary yarn comprises fastening a portion of the auxiliary yarn by a fastening device (e.g. at least one clamping element) integrally attached to the yarn processing tool.

Thus, according to a preferred embodiment of the claimed method, only one yarn handling tool is responsible for creating a threading section "S" of the auxiliary yarn outside the yarn feed nozzle and for handling the threading section at the flange of the ring for threading it into the ring traveler of the ring spinning machine. Precise movement of the yarn processing tool is required because it causes the clamping element to hold or grip the auxiliary yarn outside the yarn feed mouth. Preferably, a robot arm with a yarn processing tool attached thereto is used for handling the yarn processing tool.

Advantageously, the claimed method comprises the step of cutting the auxiliary yarn after the piecing operation of step e) to provide a cut free end of the auxiliary yarn, said cutting step comprising positioning the yarn processing tool at a predetermined distance from the cutting tool to obtain an auxiliary yarn of a predetermined length (L0) outside the yarn feed mouth.

Thus, after the auxiliary yarn is pieced with the roving from the drafting roller, the processing tool is positioned relative to the cutting tool to allow the cutting tool to cut the auxiliary yarn outside the yarn feed mouth at a position suitable for obtaining an auxiliary yarn of a predetermined length (L0). In this way, the system remains ready to start a new piecing cycle at a new spinning station where a yarn break is detected.

In the present invention:

the threading operation is understood to be the following operation: creating or forming a threading part "S" of the auxiliary yarn outside the yarn feeding nozzle, and processing the threading section "S" at a flange of a ring of the ring spinning machine to thread the threading section "S" into a ring traveler of the ring spinning machine.

The joint operation is understood to be the following: the yarn processing tool is positioned to thread the threaded auxiliary yarn end onto the roving from the front drafting roller of the drafting assembly of the ring spinning machine.

The splice cycle of the claimed process and system is understood to include both threading and splicing operations.

Drawings

The foregoing and other advantages and features will be more fully understood from the following detailed description of embodiments, taken together with the accompanying drawings, which must be considered in an illustrative and non-limiting manner, in which it is summarized;

in detail:

fig. 1 shows a perspective view of an embodiment of a yarn processing tool showing an auxiliary yarn of a predetermined length L0 held in place outside the yarn feeding nozzle, and a clamping element integrally attached to the frame structure of the processing tool and the yarn feeding nozzle.

Fig. 2 shows a perspective view of the yarn processing tool of fig. 1, wherein the free end of a predetermined length L0 of the auxiliary yarn is blown outside the yarn feeding mouth while being held in place by the yarn holding device.

Fig. 3 is a schematic bottom view of the yarn processing tool of fig. 1, showing the respective venturi tubes of the suction device and the blowing device. The yarn holding device is arranged between these venturi tubes. It can be seen that the auxiliary yarn passes along the venturi before reaching the yarn feed mouth. For the sake of clarity, the figure does not show an air injector arranged for injecting air into the venturi.

Fig. 4a is a schematic exploded view of the yarn processing tool of the embodiment of fig. 1. Fig. 4b shows another perspective view of the yarn processing tool of the embodiment of fig. 1.

Fig. 5 shows a perspective view of a robot arm with attached yarn handling tools for performing the yarn splicing system. For the sake of clarity, the figure does not show a carriage arrangement on which the robot arm is displaceably mounted along a row of spinning units of the ring spinning machine. The robot arm can stop at a specific spinning cell to perform a service operation.

Fig. 6 shows a perspective view of a yarn handling tool attached to a robotic arm and approaching an empty revolving bobbin, where a predetermined length (L0) of yarn is positioned tangentially to the surface of the bobbin to aid winding.

Fig. 7 shows a perspective view of a yarn handling tool attached to a robot arm and the robot arm making precise and specific movements to cause a gripping element to hold or grasp an auxiliary yarn outside the yarn feeding mouth to form a threading section of the auxiliary yarn outside the yarn feeding mouth. The arrows next to the yarn feed nozzle represent, in a diagrammatic manner, the air sucked into the yarn feed nozzle.

Fig. 8 is a perspective view of the yarn handling tool attached to the robotic arm showing the threading section "S" secured between the yarn feed nozzle and the clamping element. The arrows next to the yarn feed nozzle graphically represent the air sucked into the yarn feed nozzle.

Fig. 9 shows a perspective view of the yarn handling tool attached to the robotic arm, while the threading section "S" of the auxiliary yarn will be threaded through the ring traveler. An air conduit attached to the surface of the yarn handling tool pushes air to move the ring of wire over the flange of the ring. The threading operation is carried out without stopping the rotation of the yarn bobbin. The arrows next to the yarn feed nozzle graphically represent the air sucked into the yarn feed nozzle.

Fig. 10 shows a schematic perspective view of a yarn handling tool attached to a robotic arm and positioned for threading an auxiliary yarn into a balloon shrink ring. The arrows next to the yarn feed nozzle graphically represent the air sucked into the yarn feed nozzle.

Fig. 11 shows a schematic perspective view of a yarn handling tool attached to a robotic arm and positioned for placing an auxiliary yarn splice on a roving emanating from a front drafting roller. For clarity, the roving is not shown, only the front drafting rollers of the drafting assembly are represented. The arrows next to the yarn feed nozzle graphically represent the air sucked into the yarn feed nozzle.

Detailed Description

The claimed invention is described below with reference to fig. 1 to 11, which fig. 1 to 11 show exemplary embodiments of the invention suitable for a ring spinning machine comprising a row of spinning stations arranged next to each other and a common ring rail (not shown) which is mounted on the frame of the machine so as to be displaceable up and down.

At each spinning station, a ring 1 is attached to a ring rail, and a ring traveler 2 is movably mounted on a flange 3 of the ring 1. A revolving spindle (not shown) is arranged on the axial vertical axis of the ring spindle 1. The bobbin 4 is placed on a rotating spindle and a yarn package "P" is formed on the bobbin by spinning in a well-known manner to form a cop. During spinning, the ring traveler 2 and the yarn threaded therein run around the spindle tube 4 on the flange 3 of the ring 1 to wind the yarn on the surface of the spindle tube 4. Above the revolving spindle tube 4, an air bag shrink ring 5, a yarn guide (not shown) and a drafting assembly including a rear drafting roller, a middle drafting roller and a front drafting roller from which drafted roving is issued are provided. Figure 11 shows in a schematic way the drafting assembly with only the front drafting roller 6 of the drafting assembly.

Fig. 5 shows a robot arm 7, in which a yarn handling tool 8 can be attached to perform the yarn splicing system and method. The robot arm 7 is displaceably mounted along a row of spinning units (not shown) of the ring spinning machine. The claimed system comprises processing and control means configured to provide signals to the robotized arm 7 so that, when said processing and control means receive signals from the sensor element (which detects the breakage of the yarn at the corresponding spinning position), the robotized arm 7 is automatically moved along the row of spinning stations to a specific spinning position. For the exemplary embodiment shown in fig. 5, the robotic arm 7 has a motion with at least six degrees of freedom of motion to allow only one yarn processing tool 8 to create the threading section "S" of the auxiliary yarn 12 by itself.

As previously mentioned, the present invention relates to a yarn splicing system and method in which the splicing process is performed by supplying the free end 12a of the auxiliary yarn 12 to the spindle tube 4 of the revolving spindle. Thus, the claimed system and method does not deal with the splicing of the broken end of the yarn, but rather with the splicing of the free end 12a of the auxiliary yarn 12 to the revolving bobbin 4.

The yarn handling tool 8 attachable to the robot arm 7 itself constitutes a claimable aspect of the invention. In the embodiment shown in fig. 1-4 a, 4b, the yarn handling tool 8 comprises a frame structure 9 attachable to the robot arm 7, and a yarn feeding mouth 10 and a gripping element 11 attached to an end 9a of said frame structure 9. In the illustrated embodiment, the clamping element 11 and the yarn feed mouth 10 are integrally attached to the robot arm 8.

The yarn feeding mouth 10 is used to feed the free end 12a of the auxiliary yarn 12 to the spindle tube 4 of the revolving spindle, around which spindle tube 4 the free end 12a of the auxiliary yarn is to be wound. When the mechanical arm 7 performs a specific and precise movement to cause said gripping element 11 to grip or seize the auxiliary yarn 12 and form the threading section "S" of the auxiliary yarn 12, the gripping element 11 is used to fix the auxiliary yarn 12 outside the yarn feeding mouth 10.

For the illustrated embodiment, suction and blowing devices are also provided on the yarn processing tool 8 to allow air to be sucked and injected, respectively, into the yarn feed nozzle 12. A yarn holding device is also arranged on the yarn processing tool 8 between the suction device and the blowing device, which yarn holding device is configured to hold an auxiliary yarn 12 of a predetermined length L0 in position outside the yarn feeding nozzle 10.

According to a preferred embodiment, the suction means comprise a first venturi tube 13 and an air injector assembly arranged on the yarn processing tool 8 to suck air into the yarn feeding mouth 10 upon receiving an activation signal from the processing and control means of the claimed system. Likewise, the blowing device comprises a second venturi tube 14 and an air injector assembly arranged on the yarn processing tool 8 to blow air into the yarn feeding nozzle 10 upon receiving an activation signal from the processing and control device of the same system. As schematically represented in the bottom view of fig. 3, the

venturi tubes

13, 14 are mounted substantially in alignment with the yarn feed mouth 10 and they are configured and arranged so that the auxiliary yarn 12 passes along the

venturi tubes

13, 14 before being supplied through the yarn feed mouth 10.

Between the first venturi tube 13 and the air injector assembly and the second venturi tube 14 and the air injector assembly, a yarn holding device is mounted and configured to hold a predetermined length L0 of the auxiliary yarn 12 in position before the free end 12a is wound onto the surface of the revolving spindle tube 4.

For the exemplary embodiment shown in detail in the exploded view of fig. 4a, the yarn holding device "R" comprises a spring-loaded glide plate 15 to be held in place by contacting a predetermined length L0 of the auxiliary yarn 12 with the second plate 19. The yarn holding device further comprises a piston and cylinder assembly 16 arranged to actuate a plurality of compression springs 17 against the slide plate 15.

In contrast to the known systems and methods, the free end 12a of the auxiliary yarn is not ejected towards the revolving spindle tube 4, but is held by the yarn holding device "R" and positioned tangentially to the surface of the spindle tube 4 by blowing air into the yarn feeding mouth 10, as shown in fig. 2 and 6. Once the free end 12a of the auxiliary yarn 12 adheres to the surface of the revolving bobbin 4, the tension of the yarn running around the bobbin 4 is kept ineffective by lifting the spring-loaded slide plate 15. Accordingly, a greater length of the auxiliary yarn 12 is fed through the yarn feeding nozzle 10 to be wound on the bobbin 4. The stroke of the piston and cylinder assembly 16 is configured to actuate a plurality of compression springs 17 against the slide plate 15 so that the auxiliary yarn 12 slides without causing yarn breakage.

In the disclosed embodiment, the end 9a of the frame structure 9 of the yarn processing tool 8 is configured as a tolerance absorbing structure comprising a flexible metal strap 18 attached to two

plates

20a, 20b to bend or flex the end 9a of the frame structure 9 to absorb the operating tolerances of the yarn joint system. In this way, the mechanical arm 7 is prevented from stopping when the yarn feeding mouth 10 or the gripping element 11 accidentally collides with the ring rail of the ring spinning machine. Furthermore, the tolerance absorbing structure helps to reduce the failure of the threading operation in case the robotic arm 7 does not position the yarn handling tool 8 in the correct position corresponding to the movable ring rail.

The claimed auxiliary yarn splicing method is explained below with reference to the drawings.

Once a yarn break is detected at one of the spinning stations of the ring spinning machine, the mechanical arm 7 receives signals from the processing and control means of the system to shift along the row of spinning stations and to be positioned centrally in front of the spindle tube 4 of the spinning station where the yarn break.

In a first step, an auxiliary yarn of a predetermined length L0 is supplied to the yarn feeding mouth 10 and is held in place outside the yarn feeding mouth 10 by a spring-loaded slide plate 15, which spring-loaded slide plate 15 brings a portion of the auxiliary yarn 12 into contact with the second plate 19 of the yarn holding device "R".

Then, in a second step, air is injected into the second venturi tube 14 and the air injector assembly to blow the free end 12a of the auxiliary yarn 12 and position the auxiliary yarn 12 of length L0 in alignment with the yarn feeding nozzle 10 (see fig. 2).

In a third step, the robotic arm 7 approaches the yarn handling tool 8 to the revolving spindle tube 4, so that the auxiliary yarn 12 of a predetermined length L0 is positioned tangentially to the surface of the spindle tube 4 by blowing air into the yarn feeding mouth 10 (see fig. 6). In order to ensure that the free end 12a of the auxiliary yarn is wound correctly on the surface of the spindle tube 4, the yarn processing tool 8 is made to oscillate vertically, since the auxiliary yarn 12 of length L0 is positioned tangentially at different tube heights.

After a period of time when the free end 12a of the auxiliary yarn 12 is not wound onto the surface of the bobbin 4, the processing and control means provides a signal to actuate the piston and cylinder assembly 16 of the yarn holding device to release the auxiliary yarn 12 of a predetermined length L0 outside the yarn feeding nozzle 10. The robotic arm 7 is then actuated to position the yarn feed mouth 10 of the processing tool 8 either backwards or forwards with respect to the auxiliary yarn 12, so that the second predetermined length of auxiliary yarn is located outside the yarn feed mouth 10. A new signal is provided to actuate the piston and cylinder assembly 16 of the yarn holding device "R" to hold in place the second predetermined length of auxiliary yarn 12 outside the yarn feed nozzle 10 at this time.

It has been found that the length L0 of the auxiliary yarn 12 to be held outside the yarn feed nozzle 10 can vary depending mainly on the coefficient of friction of the surface onto which the yarn is to be wound. For example, if the surface of the bobbin 4 is empty of yarn, the length L0 of the auxiliary yarn 12 may need to be longer to assist in winding the yarn, whereas the shortest length L0 may be needed if the surface onto which the free end 12a is to be wound has a yarn package "P".

The winding of the free end 12a of the auxiliary yarn 12 triggers the stop of the rotation of the bobbin 4 and the activation of the suction device to suck the air inside the yarn feeding mouth 10. For the illustrated embodiment, the drawing of air is performed by injecting air into the first venturi tube 13 and the air injector assembly. However, other known suction means can be envisaged to suck air into the yarn feed nozzle 10.

Fig. 7 shows a perspective view of the yarn handling tool 8 attached to the robot arm 7, and the robot arm 7 performs a precise and specific movement to cause the gripping element 11 to hold or grasp the auxiliary yarn 12 outside the yarn feeding mouth 10, forming a threading section "S" (see fig. 8).

In the claimed system and method, air (see arrows) within the yarn feed nozzle 10 is sucked to hold the auxiliary yarn 12 at a suitable tension and the yarn treatment tool 8 is allowed to shift relative to the auxiliary yarn 12 to cause the gripping element 11 to hold or grasp the auxiliary yarn 12 outside the yarn feed nozzle 10.

In contrast to the known methods, the claimed method allows to perform threading and splicing operations with only one yarn handling tool 8 attachable to the robot arm 7. The processing and control means of the system are configured to provide a motion signal to the robotic arm 7 to position the threading section "S" at the flange 3 of the ring 1 for threading of the threading section "S" into the ring traveler 2 (see fig. 9).

As shown in fig. 9, an air duct 21 is arranged on the yarn processing tool 8 for pushing air (see arrows) to the ring 1 to cause an intentional movement of the ring traveler 2 on the flange 3 of the ring 1 during threading.

Once the auxiliary yarn penetrates the ring traveler 2, the robotic arm 7 displaces and positions the yarn handling tool 8 to thread the auxiliary yarn 12 into the balloon constricting ring 5 (see fig. 10). Then, the robot arm 7 positions the yarn processing tool 8 so that the auxiliary yarn 12 outside the yarn feeding nozzle 10 is pieced with the roving from the front draft roller 6 (see fig. 11). All these operations are carried out without rotation of the bobbin 4 to obtain maximum precision.

In the final step of the method, the robotic arm 7 positions the yarn processing tool 8 at a predetermined distance from the cutting tool (not shown) so that said cutting tool cuts the auxiliary yarn 12 outside the yarn feed mouth 10 at a position configured to obtain a new auxiliary yarn 12 of predetermined length L0. The system is then ready to start a new piecing cycle at a new spinning station where yarn breakage is detected.

As mentioned before, if the gripping element 11 or the yarn feed mouth 10 accidentally collides with the oscillating ring spindle rail during the process, the end 9a of the frame structure 9 of the yarn processing tool 8 may bend or flex to allow the parts to be repositioned, thus avoiding malfunction or stoppage of the robotic arm 7.

In summary, the present invention provides a system and a method for piecing the free end 12a of an auxiliary yarn 12, which provides a high reliability and accuracy of the threading operation and of the piecing operation compared to known piecing methods. Furthermore, the claimed method significantly simplifies the piecing process, since the threading operation and the piecing operation can be performed with only one yarn handling tool 8, preferably one yarn handling tool 8 attachable to the robot arm 7 with a movement of at least six degrees of freedom of movement.

For the non-illustrated embodiment, no robotic arm is used and the yarn fastening device is arranged on the second tool of the automatic processing device. In this case, the claimed yarn processing tool will comprise:

a frame structure 9 attachable to the automated processing unit,

-an end portion 9a of said frame structure 9,

a yarn feed mouth 10 attached to an end 9a of the frame structure 9 to supply a free end 12a of an auxiliary yarn 12,

-suction means 13 arranged to suck air into the yarn feed mouth 10, and preferably;

air blowing device 14 arranged to inject air into yarn feeding nozzle 10, and yarn holding device "R" configured to hold auxiliary yarn 12 of predetermined length "L0" in position outside yarn feeding nozzle 10.

In an embodiment not illustrated here, the yarn fastening device can be configured as a pincer or suction tube attached to the second tool to fasten the auxiliary yarn 12 outside the yarn feed mouth and to assist the yarn handling tool 8 in performing threading and piecing operations. .

Variations and modifications may be introduced in the described embodiments by those skilled in the art without departing from the scope of the invention, as defined in the appended claims. For example, although an embodiment has been disclosed in which the yarn fastening device is configured to be attached to the clamping element 11 of the yarn processing tool 8, another embodiment may be provided in which the yarn fastening device is configured as a forceps or a pipette arranged on the claimed yarn processing tool or a different tool of the automatic processing device.

Claims

1. A yarn splicing system for splicing an auxiliary yarn at a spinning station of a ring spinning machine, comprising:

-a yarn supply device for supplying a free end (12a) of an auxiliary yarn (12) to a spindle tube (4) of a revolving spindle, said free end (12a) being to be wound on said spindle tube (4), said yarn supply device comprising a yarn feed mouth (10) for feeding the free end (12a) of said auxiliary yarn (12) to the spindle tube (4) of said revolving spindle,

-a yarn fastening device (11) for fastening the auxiliary yarn (12) outside the yarn feed mouth (10) to form a threading section ("S") of the auxiliary yarn (12) when the free end (12a) of the auxiliary yarn (12) is wound on the bobbin (4), and

-automatic handling means (7) for handling the yarn supply means and the yarn fastening means (11),

characterized in that said automatic processing device (7) comprises a yarn processing tool (8), in which yarn processing tool (8) at least said yarn feeding mouth (10) is mounted, and in that said system comprises:

-suction means (13) arranged for sucking air into the yarn feed nozzle (10), and

-a processing and control device configured to provide an activation signal to said suction device to suck air into the yarn feeding mouth (10) as soon as the free end (12a) of the auxiliary yarn (12) is wound onto the bobbin (4) and the rotation of the bobbin (4) is stopped.

2. The yarn splicing system of claim 1, wherein the yarn supply device comprises:

-a blowing device (14) arranged for injecting air into the yarn feeding nozzle (10), and

-a yarn holding device ("R") configured to hold in position an auxiliary yarn (12) of a predetermined length (L0) outside the yarn feeding mouth (10), and

-wherein the processing and control device is configured to provide an activation signal to the blowing device (14) to blow the free end (12a) of the auxiliary yarn (12) of the predetermined length (L0) outside the yarn feeding nozzle (10) while the yarn processing tool (8) approaches the revolving bobbin (4) at the start of the piecing cycle.

3. Yarn splicing system according to any one of claims 1 or 2, wherein the yarn fastening device comprises at least one clamping element (11) for fastening the auxiliary yarn (12) outside the yarn feeding mouth (10), and wherein the clamping element (11) is arranged on the yarn processing tool (8) to allow the yarn processing tool (8) to form a threading section ("S") of the auxiliary yarn (12).

4. Yarn splicing system according to any of the claims 1 to 3, wherein both the yarn fastening device (11) and the yarn feeding nozzle (10) are integrally attached to an end portion (9a) of a frame structure (9) of the yarn processing tool (8).

5. Yarn joint system according to claim 4, wherein an end portion (9a) of said frame structure (9) is configured as a tolerance absorbing structure to bend or flex said end portion (9a) to absorb operational tolerances of said yarn joint system.

6. Yarn splicing system according to any of the claims 1 to 5, wherein the automatic handling means comprise a yarn handling tool (8) attached to a robotic arm (7).

7. Yarn splicing system according to claim 6, when dependent on any one of claims 4 or 5, wherein said mechanical arm (7) has at least six degrees of freedom of movement to allow the yarn fastening device to form a threading section ("S") of the auxiliary yarn (12).

8. Yarn splicing system according to any one of claims 1 to 7, wherein said suction means comprise a first venturi tube (13) and an air jet assembly, said first venturi tube (13) and air jet assembly being arranged to suck air into said yarn feeding mouth (10) upon receiving an activation signal from said processing and control means.

9. Yarn splicing system according to any one of claims 1 to 8, when dependent on claim 2, wherein said blowing means comprise a second venturi tube (14) and an air injector assembly, said second venturi tube (14) and air injector assembly being arranged to blow air into said yarn feeding nozzle (10) upon receipt of an activation signal from said processing and control means.

10. Yarn splicing system according to any one of claims 8 and 9, wherein the venturi tubes (13, 14) in the first and/or second venturi tube and air jet assembly are configured and arranged such that the auxiliary yarn (12) passes along the venturi tubes (13, 14) before being fed through the yarn feeding nozzle (10).

11. Yarn splicing system according to claims 9 and 10, when depending on claim 2, wherein said yarn retention device ("R") is arranged between the first dune tube (13) and the air jet assembly and the second venturi tube (14) and the air jet assembly.

12. The yarn splicing system according to any one of claims 2 to 11, wherein said yarn holding device ("R") comprises:

-a spring-loaded slide plate (15) which holds in place a predetermined length (L0) of the auxiliary yarn (12) outside the yarn feed nozzle (10) by contact with the second plate (19), and

-a piston and cylinder assembly (16) arranged to actuate at least one compression spring (17) against the glide plate (15).

13. The yarn splicing system of claim 12, wherein the processing and control device is configured to:

-a piston and cylinder assembly (16) providing a signal to actuate said yarn holding device ("R"), releasing a predetermined length (L0) of auxiliary yarn (12) outside the yarn feeding mouth (10) after a predetermined time without the free end (12a) of the auxiliary yarn (12) adhering to the bobbin (4),

-providing a signal to activate the automatic processing device (7) to position the yarn feed mouth (10) of the processing tool (8) backwards and/or forwards with respect to the auxiliary yarn (12) so that the auxiliary yarn (12) of a second predetermined length is located outside the yarn feed mouth (10), and

-providing a signal to a piston and cylinder assembly (16) of said yarn holding device ("R") to hold a second predetermined length of auxiliary yarn (12) in position outside the yarn feeding nozzle (10) at the start of a piecing cycle.

14. A yarn processing tool (8) for use with a yarn splicing system according to any one of the claims 1 to 13, comprising:

-a frame structure (9) attachable to an automated processing unit (7),

-an end (9a) of the frame structure (9),

-a yarn feeding mouth (10) attached to an end (9a) of the frame structure (9) for supplying a free end (12a) of an auxiliary yarn (12),

-fastening means (11) attached to an end (9a) of the frame structure (9) for fastening an auxiliary yarn (12) outside the yarn feeding mouth (10),

-suction means (13) arranged to suck air into the yarn feed nozzle (10), and preferably,

-a blowing device (14) arranged to inject air into the yarn feeding nozzle (10), and

-a yarn holding device ("R") configured to hold in position an auxiliary yarn (12) of a predetermined length (L0) outside the yarn feeding mouth (10).

15. Yarn processing tool according to claim 14, wherein the yarn fastening device (11) and the yarn feeding mouth (10) are each integrally attached to an end (9a) of the frame structure (9), and the frame structure (9) is attached to the robot arm (7).

16. Yarn processing tool (8) according to any of the claims 14 to 15, wherein an end portion (9a) of the frame structure (9) is a tolerance absorbing structure configured to bend or flex to absorb operational tolerances of a yarn joint system.

17. Yarn processing tool (8) according to any of the claims 14 to 16, wherein a yarn retention device ("R") is arranged between the suction device (13) and the blowing device (14).

18. A method for piecing an auxiliary yarn at a spinning station of a ring spinning machine, comprising the steps of:

a) the free end (12a) of the auxiliary yarn (12) is supplied through a yarn feed nozzle (10) arranged on a yarn processing tool (8) of the automatic processing device (7),

b) bringing the free end (12a) of the auxiliary yarn close to the spindle tube (4) of the revolving spindle so that the free end (12a) of the auxiliary yarn (12) is wound on the spindle tube (4),

c) stopping the rotation of the rotary yarn spindle tube (4),

d) after step c), drawing air into the yarn feed nozzle (10), and

e) positioning a yarn handling tool (8) to perform a threading operation and a piecing operation while drawing air into a yarn feeding nozzle (10), wherein the threading operation comprises the steps of: the auxiliary thread (12) is fixed outside the thread feed nozzle (10) in order to form a threading section ("S") of the auxiliary thread (12).

19. The method of piecing an auxiliary yarn according to claim 18, wherein:

-step a) comprises holding in position an auxiliary yarn (12) of predetermined length (L0) outside the yarn feed mouth (10), and

-step b) comprises blowing air into the yarn feeding mouth (10) to position an auxiliary yarn (12) of predetermined length (L0) tangential to the bobbin (4) to assist winding.

20. The method of piecing an auxiliary yarn according to claim 19, comprising the steps of: the yarn processing tool (8) is moved in an oscillating manner while air is blown into the yarn feed nozzle (10).

21. Method of piecing an auxiliary yarn according to one of the claims 18 to 20, wherein the step of fastening the auxiliary yarn (12) outside the yarn feed mouth (10) to form a threading section ("S") comprises fastening the auxiliary yarn (12) by means of at least one clamping element (11) integrally attached to the yarn processing tool (8).