Patent Description:
In textile spinning mills, ring spinning machines are very crucial machines. The said ring spinning machines produce the resultant form of cotton in a spinning line, so called yarn. During ring spinning, yarn breakage occurs frequently which is a major setback. Yarn breakage has to be continuously monitored and broken yarn has to be pieced then and there by manual labour. The yarn breakage occurs due to various parameters of yarn and machine and it is unavoidable. In long spinning frame sites, manual labour continuously monitors yarn breakages and performs manual piecing of broken yarns round the clock walking along the aisle of the ring frames. This has to be done for a machine frame normally consisting of more than <NUM> spindles and about <NUM> metres long. Then, yarn spinning sequence has to be restarted then and there after piecing in order to avoid wastage of yarn.

To overcome above problems, automatic piecing units are developed. The automatic piecing unit is in the form of a movable vehicle with wheels/rails. The said piecing vehicle stops at respective spindle positions which require piecing attention. The piecing unit in general moves longitudinally along the machine frame aisles. Before initiating piecing operation, the piecing vehicle stops in front of the spindle position of the ring spinning machine. Then the broken yarn end which is available on the spinning cop has to be found and detached from the cop and lifted above to enable piecing operation. The said detaching of yarn from the spinning cop automatically is a major challenge for the textile spinning industry in general.

In the known piecing arrangements as shown in <FIG>, the automatic piecing unit (<NUM>) moves longitudinally along the aisle of the ring spinning machine. The ring spinning machine is capable of winding yarn onto a bobbin mounted on the spinning spindle, so called cop (<NUM>). When yarn breakage occurs in the spinning sequence, the broken yarn becomes tangled on the spinning cop (<NUM>). To enable yarn piecing, the tangled yarn end has to be detached from the cop (<NUM>). For broken yarn picking from the cop, auto piecing units are provided with yarn picking suction arrangements. The cylindrical suction nozzle (<NUM>) with horn type mouth extends from the piecing unit and is positioned usually at a predetermined distance above the top of the spinning cop (<NUM>). The distance maintained in known arrangements is approximately <NUM> upwards from the top of the spinning cop (<NUM>). In this type of arrangement, broken yarn end from the bottom of the chase length of the cop (<NUM>) cannot be picked. Even if the broken yarn is present somewhere at the top portion of the chase length, the height difference of the suction mouth (<NUM>) from the cop (<NUM>) does not provide the required suction to effectively pick the broken yarn from the cop (<NUM>). Thus, the existing arrangement is not reliable in picking the broken yarn end from the cop.

<CIT> teaches loosening a thread end on a cop winding with the aid of a blowing nozzle, sucking the thread end into a suction bell arranged coaxially to the axis of the spindle, moving the suction bell into a transfer position causing a predetermined thread position or - if the thread end is not found - throwing an auxiliary thread onto the bobbin winding or an empty sleeve by a starter and moving the starter with the auxiliary thread into a transfer position causing the predetermined thread position.

<CIT> teaches a system for piecing of yarn breakage in a ring spinning machine. The system comprises yarn holding means for holding a yarn and/or a loose end of a yarn of a spindle of a ring spinning machine, traveller positioning means for positioning of a traveller of a spindle, first yarn threading means for threading a held yarn and/or a loose end of a yarn into a positioned traveller of a spindle, second yarn threading means for threading a held yarn and/or a loose end of a yarn into guide elements of a ring spinning machine and yarn piecing means for piecing together a held yarn and/or a loose end of a yarn with a drafted material.

<CIT> teaches an automatic apparatus for joining a sliver delivered from a draft means of a spinning unit with the free end of a broken yarn unwound from a spool upon which a spinning yarn is broken, the improvement comprising in combination: means for unwinding the free end of broken yarn from said spool, means for threading said unwound yarn into a traveller positioned upon a ring of said spinning unit, means for joining said free end of broken yarn unwound from said spool with a sliver delivered from said draft means related to said spinning unit, said unwinding means comprising an air jet nozzle directed toward the chase of said spool and mounted on a lifting plate capable of following the up and down motion of the ring rail of said spinning machine, said joining means having a suction nozzle for receiving the free end of said broken yarn carried by an upward air stream from said air jet nozzle and moveable contact means for contacting the upper portion of said broken yarn as it extends between said suction nozzle and said spool with said sliver delivered from said draft unit and cutter means mounted on said contact means for severing said yarn from said suction nozzle simultaneously with a completion of a forward motion of said contact means for contacting said upper end portion of unwound yarn received by said suction nozzle with said sliver.

<CIT> teaches a method for restarting the feed or yarn from a drafting device through a package building device to a yarn package supported at a spinning station of a textile machine, the restarting of the feed of yarn being performed to restart the winding of a package following a break in the yarn being fed to the package, the break in the yarn resulting in an end of unwound yarn which has been drafted through the drafting device and a trailing end of yarn which has already been wound on the package, the method comprising delivering one length of auxiliary yarn to the package with the end of the one length of auxiliary yarn being freely disposed on the package independent from the trailing end of the already wound yarn, disposing the one length of auxiliary yarn relative to the unwound yarn end for piecing therewith such that the one length of auxiliary yarn thereafter draws the unwound yarn pieced therewith onto the package as the one length of auxiliary yarn is wound on the package, detecting the failure of the one length of auxiliary yarn to successfully piece with the unwound yarn end after a predetermined time period, removing the one length of auxiliary yarn completely from the package in response to the detection of the failure of the one length of auxiliary yarn to piece with the unwound yarn end and delivering another length of auxiliary yarn to the package in response to detection of the failure of the one length of auxiliary yarn to piece with the unwound yarn end, the delivering of the another length of auxiliary yarn to the package being coordinated with the completion of the removal of the one length of auxiliary yarn from the package.

<CIT> teaches a device for detaching and winding off the exposed yarn end from a body of wound-up yarn on a bobbin by means of compressed air, comprising a holder for a bobbin, a duct system for compressed air comprising an inlet duct, at least three outlet nozzles arranged concentrically around and directed towards the axis of said bobbin when mounted on said holder, and intermediate duct means connecting said inlet duct of said nozzles, a driving device for effecting relative to-and-fro movement in the direction of the bobbin, between said holder and said ductsystem, said nozzles being directed to detach and wind off the exposed yarn end from said bobbin, and a reception tube mounted to receive said yarn end when detached from said bobbin, said reception tube having an open end directed towards said nozzles.

There exists a need to develop an improved broken yarn picking from the cop which reliably picks the yarn without fail, to which the present invention provides a solution.

These objectives are provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This objective is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

An important object of the invention aims at providing a solution for the shortcomings of the automatic piecing unit.

Another object of the invention is to provide an arrangement for picking broken yarn end from the spinning cop to enable automatic piecing in ring spinning machines.

Yet another object of the present invention is to provide an arrangement for broken yarn end picking anywhere in the chase length of the cop in ring spinning machines.

Further object of the present invention is to provide an arrangement for detaching broken yarn end from the spinning cop of the ring spinning machines.

It is yet another object of the present invention to provide a method for picking broken yarn end from the cop in ring spinning machines.

According to an aspect of the invention, the yarn picking arrangement for an automatic yarn piecing unit in ring spinning machines comprises a suction jet assembly comprising a hose having a first end and a second end. The first end is connected to a suction air source, and the second end has a circumferential housing. A driving means coupled to the suction jet assembly is capable of moving the suction jet assembly vertically up and down such that the circumferential housing is capable of surrounding the cop at the outer portion at the top of the cop. The suction air source generates a suction pull which pulls the broken yarn end present anywhere in the chase length from bottom to top of the cop into the circumferential housing.

According to another aspect of the invention, a method for picking a yarn by a yarn picking arrangement comprises the steps of moving a suction jet assembly from a drafting zone to a cop zone such that a circumferential housing of the suction jet assembly surrounds a cop at the outer portion at the top of the cop. In the next step, tangled broken yarn end is picked by a suction pull into the housing, wherein the broken yarn end is picked on the cop anywhere in the chase length from bottom to top. In the further step, the suction jet assembly is moved from the cop zone to the drafting zone to enable automatic piecing operation in the ring spinning machine.

Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

For a more detailed understanding of this invention, reference is made to the accompanying drawings in which:.

The <NUM> over <NUM> drafting arrangement is shown herein in figures only for illustrative purpose. The drafting arrangement also includes <NUM> over <NUM> drafting and compact spinning drafting arrangement, etc..

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.

Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, and features.

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents.

An automatic piecing unit is provided for textile ring spinning machines. The automatic piecing unit moves longitudinally along the aisle of the ring spinning machine. The ring spinning machine is capable of winding yarn onto a bobbin mounted to a spinning spindle, so called cop. When yarn breakage occurs in the spinning sequence, the broken yarn end is tangled on the spinning cop. To enable yarn piecing, the tangled yarn end has to be picked from the cop. Thus, the automatic piecing unit assists in yarn piecing operation during yarn breakage incidents in ring spinning machines. The proper picking of the broken yarn end from the spinning cop is necessary for the successful piecing of the broken yarn ends. To enable the picking of the broken yarn end, the present invention is provided with a yarn picking arrangement in the automatic piecing unit.

<FIG> shows a side view of the yarn picking arrangement in the piecing unit, according to an embodiment of the present invention. Accordingly, a yarn picking arrangement (<NUM>) for an automatic yarn piecing unit (<NUM>) to detach the broken yarn end (<NUM>) from a spinning cop (<NUM>) to enable automatic piecing operation in a textile ring spinning machine (<NUM>) comprises a suction jet assembly comprising a hose (<NUM>) having a first end and a second end. The first end of the hose (<NUM>) is connected to a suction air source (not shown in figure), and the second end has a circumferential housing (<NUM>). Further a driving means (<NUM>) is coupled with the suction jet assembly for moving the suction jet assembly vertically up and down. The driving means (<NUM>) can be a pneumatic driving unit, or a hydraulic driving unit having piston and cylinder arrangement with actuators. The drive means can also comprise of screw rod, cylinder and all types of actuating means.

Further, the arrangement (<NUM>) includes a control apparatus functionally connected with the driving means (<NUM>) comprising a control unit coupled with a plurality of sensors and stoppers for precisely controlling the movement of the suction jet assembly so as to move the circumferential housing (<NUM>) vertically up and down such that the circumferential housing (<NUM>) is capable to stop anywhere around the cop (<NUM>) at the outer portion from top to bottom. The suction air source generates a suction pull which pulls the broken yarn end (<NUM>) anywhere in the chase length from bottom to top of the cop (<NUM>) into the housing (<NUM>) to enable automatic piecing operation in the textile ring spinning machine (<NUM>).

In the process of yarn picking, the suction jet assembly of the yarn picking arrangement (<NUM>) is moved from the drafting zone (<NUM>) to the cop zone (<NUM>) such that the circumferential housing (<NUM>) of the suction jet assembly surrounds a cop (<NUM>). The internal diameter of the hose (<NUM>) and/or the housing (<NUM>) of the suction jet assembly is such that it is substantially greater than the external diameter of the cop (<NUM>). The corresponding <FIG> shows a side view of the yarn picking arrangement of the piecing unit at the cop zone (<NUM>) surrounding the cop (<NUM>) for picking the broken yarn end from the cop, according to an embodiment of the present invention.

In the next step, suction air source generates a suction pull which pulls the broken yarn end (<NUM>) anywhere in the chase length from bottom to top of the cop (<NUM>) into the circumferential housing (<NUM>). In the further step, suction jet assembly is moved from the cop zone (<NUM>) to the drafting zone (<NUM>) to enable automatic piecing operation in the textile ring spinning machine (<NUM>). <FIG> shows a side view of the yarn picking arrangement of the piecing unit at the drafting zone after successful picking of the broken yarn end from the cop and for subsequent piecing operation according to an embodiment of the present invention.

According to the invention the suction jet assembly comprising the circumferential housing (<NUM>) surrounds the cop (<NUM>) at the outer portion while moving vertically from top to bottom. During which the suction jet assembly reaches a position adjacent to the balloon control ring (<NUM>) travelling around <NUM> downwards. The moving suction jet assembly covers substantially at least <NUM> of the cop (<NUM>) height from the top and surrounds the cop (<NUM>) before reaching a position adjacent to the balloon control ring (<NUM>). The inner diameter of the suction jet assembly is designed such that it is capable of surrounding the cop (<NUM>) for picking the broken yarn end (<NUM>) effectively. The movable suction jet assembly picks the tangled broken yarn end (<NUM>) from the cop (<NUM>) successfully anywhere in the chase length even at the bottom of the chase length. The distance between the balloon control ring (<NUM>) and the suction jet assembly while yarn picking is around <NUM> only for the bottom most ring rail position compared to that of the known arrangement which is around <NUM>.

According to an embodiment of the present invention, before yarn picking, the movable suction jet assembly mounted in the piecing unit can be moved forward through suitable drive means. Subsequently, the downward movement of the suction jet assembly for surrounding the cop is effected by pneumatic or hydraulic drive means mounted in the auto piecing unit.

Claim 1:
A ring spinning machine (<NUM>) comprising at least one spinning station with a spinning cop (<NUM>) in a cop zone (<NUM>), a drafting zone (<NUM>) above the spinning cop (<NUM>), a balloon control ring (<NUM>) situated in between the drafting zone (<NUM>) and the cop zone (<NUM>), and an automatic yarn piecing apparatus (<NUM>) with a yarn picking arrangement (<NUM>) to detach a broken yarn end (<NUM>) from the spinning cop (<NUM>) to enable an automatic piecing operation in the ring spinning machine (<NUM>), the yarn picking (<NUM>) arrangement comprising:
a suction jet assembly comprising a hose (<NUM>) having a first end and a second end, the first end connected to a suction air source, and the second end having a circumferential housing (<NUM>) and
a driving means (<NUM>) coupled to the suction jet assembly for moving the suction jet assembly vertically downwards
from the drafting zone (<NUM>) to the cop zone (<NUM>), such that the circumferential housing (<NUM>) of the suction jet assembly surrounds the cop (<NUM>) at the outer portion at the top of the cop (<NUM>), and for moving around <NUM> vertically downwards from the top of the cop (<NUM>) towards a position adjacent to the balloon control ring (<NUM>), said suction jet assembly thereby covering at least <NUM> of the cop height from the top of the cop (<NUM>),
the suction air source generating a suction pull which pulls the broken yarn end (<NUM>) present anywhere in the chase length from bottom to top of the cop (<NUM>) into the circumferential housing (<NUM>).