DESC:FIELD OF THE INVENTION
The present invention relates to a positioning device for an automatic piecing unit for piecing broken yarn ends in textile ring spinning machines. More particularly, the invention relates to an improved distance sensing and positioning device for the automatic piecing unit in textile ring spinning machines and method thereof.

BACKGROUND OF THE INVENTION
Textile ring spinning machines are the resultant yarn producing machines in textile spinning mill industry. Globally, the textile spinning mill industry is facing a long pending problem, which is frequent yarn breakage in textile ring spinning machines. The yarn breakage is a major problem that needs regular attention from the workers. The yarn breakage nowadays remains a major disadvantage in textile ring spinning machines which has forced huge number of workers to continuously monitor the textile ring spinning machines at both the sides throughout the length of the machine frame, which is normally more than 1600 spindles and more than 75 meters long. The broken yarn is required to be pieced manually by the workers and the yarn spinning sequence must be restarted then and there after yarn breakage in order to avoid wastage of yarn. Nowadays, due to the scarcity of skilled manual workers in spinning mill industry there is an urgent need for automation in spinning mills. Even though limited number of workforces is available, the physical ability and health of the workers gets affected due to continuous walking along the long ring spinning frames to manually piece the broken yarn ends throughout the day, as the spinning mills are operating round the clock unless there is any maintenance or power shutdown.
As an improvement towards the conventional method of manual piecing, automatic piecing units are being developed. The automatic piecing devices involves a robot or worker in a piecing vehicle or piecing device which has in-built drive units and sensing units. Such automatic piecing devices are advanced towards the textile ring spinning machine for piecing operation and returned after completing the piecing operation. There exists a need for reliable positioning of automatic piecing unit in front of the spindle station, before initiating the piecing operation.
In the automatic piecing unit according to German patent publication DE4229285, a longitudinal positioning rail is provided along the textile ring spinning machine. Said positioning rail is provided with two or more holes as identification marks in each individual spinning position. The said holes are detected by two inductive sensors provided in the automatic piecing unit when travelling to and fro in front of textile ring spinning machine. Based on the output signal modulations of the inductive sensors, number of spindles is calculated, and the automatic piecing unit is positioned in front of spinning station having the yarn breaks.
In another known arrangement according to European patent publication EP0388937, a positioning device for automatic piecing unit is provided with one or more inductive or capacitive sensors for positioning the automatic piecing unit. The said arrangement also employs an additional rail with plurality of pair of holes as identification marks. Said pair of holes in the rail is aligned with the individual spinning positions of the textile ring spinning machine. The pair of sensors mounted in the automatic piecing unit detects a pair of holes provided in the rail, by detecting the change in the permeability or the dielectric constants in the detection range of the sensors. The number of spindles to be travelled is calculated before positioning piecing units with respect to the spinning station having end breaks.

The problem associated with above said arrangements is that one or more additional positioning rail is needed to be placed before the textile ring spinning machine before installing the automatic piecing unit. In addition, said rail is to be provided with a plurality of holes, which serves as identification marks in each spinning position. Nowadays, textile ring spinning machines are manufactured with more than 2000 spindles, due to which length of the machine extends even more than 75 meters. This additional need of the positioning rail for the corresponding higher length textile ring spinning machines, results in major increase in manufacturing and operating costs associated with the automatic piecing arrangement for textile ring spinning machines. Also, precise positioning in front of the broken yarn spindle is not always achieved, when positioning based on counting the number of spindles. The improper positioning will lead to failure of piecing sequence even after multiple attempts, resulting in lower efficiency of the automatic piecing unit. Thus, reduced efficiency of automatic piecing unit affects overall production efficiency of the textile ring spinning machines in the spinning mills.
To overcome the above-mentioned disadvantages, the present invention provides an improved positioning device for automatic piecing unit of textile ring spinning machines.

OBJECTS OF THE INVENTION
The main object of the present invention is to provide an improved automatic piecing unit for textile ring spinning machines.

Another object of the present invention is to provide a novel and improved positioning arrangement for automatic piecing unit of the textile ring spinning machines.
Yet another object of the present invention is to provide an improved positioning arrangement for the automatic piecing unit in the textile ring spinning machine without the need for additional positioning rails.

SUMMARY OF THE INVENTION
In one aspect the present invention provides a positioning device for a piecing unit in a textile ring spinning machine having a yarn breakage detecting sensor mounted for each spindle position. The positioning device includes a sensing unit and reflector to detect the position of the piecing unit. The positioning device further includes a control unit, configured to determine the distance to be travelled by the piecing unit and align the piecing unit with the spindle position containing the broken yarn for initiating a yarn piecing operation.
According to the present invention, the control unit is configured to travel to the nearest spindle when breakage of yarn occurs at two spindles simultaneously.According to the present invention, the sensing unit is mounted at a headstock end or an endstock end of the textile ring spinning machine or directly on the floor or on the track of the piecing unit.
According to the present invention, the sensing unit is mounted at a headstock end (gear end) or an endstock end (off end) of the textile ring spinning machine through bracket means.
According to the present invention, the reflector is a surface of the textile ring spinning machine or a surface of the piecing unit or a reflective surface mounted on the textile ring spinning machine or the piecing unit.
According to the present invention, the sensing unit is a laser sensor, an optical sensor, an ultrasonic sensor, a radar sensor, a vision-based sensor, or an electromagnetic sensor.
According to the present invention, the sensing unit comprises an emitter and a receiver.
According to an embodiment of the present invention, the sensing unit is mounted at the headstock end or the endstock end of the textile ring spinning machine and the reflector is on the piecing unit.
According to an embodiment of the present invention, the sensing unit is mounted on the piecing unit and the reflector is at the headstock end or endstock end of the textile ring spinning machine.
According to an embodiment of the present invention, two sensing units are positioned in two ends of the textile ring spinning machine, and reflectors are provided for each sensing unit of the textile ring spinning machine.
In another aspect the present invention provides a method for positioning a piecing unit in a textile ring spinning machine having a yarn breakage detecting sensor mounted for each spindle position. The method includes a step of sending, by the sensor mounted on the spindle, a signal to the control unit when a yarn breaks;. The method also includes a step of detecting, by a sensing unit and a reflector , a position of the piecing unit. The method further includes a step of determining, by a control unit, the distance to be travelled by the piecing unit. The method further includes a step of aligning, by the control unit, the piecing unit with the spindle position having the broken yarn for a yarn piecing operation.
According to the present invention, the step of aligning of the piecing unit includes aligning the piecing unit with the nearest spindle when yarn breakage occurs at multiple spindles.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 illustrates a side view of a textile ring spinning machine, according to the present disclosure;
Figure 2 illustrates a parking position of an automatic piecing unit in the textile ring spinning machine, according to the present disclosure;
Figure 3 illustrates a side view of a sensing unit of a positioning device, according to the present disclosure; and
Figure 4 illustrates a logic diagram for a control unit of the positioning device, according to the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawings.
Embodiments are provided to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth relating to specific components to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
References in the present disclosure to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in an embodiment” or “in an implementation” in various places in the specification are not necessarily all referring to the same embodiment or implementation.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises,” “comprising,” “consists,” “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated elements, modules, units and/or components, but do not forbid the presence or addition of one or more other elements, components, and/or groups thereof.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
FIGS 1, 2, and 3 illustrate a textile ring spinning machine (1), according to the present disclosure. The textile ring spinning machine (1) has a yarn breakage detection sensor mounted for each single spindle position. The textile ring spinning machine (1) is provided with a piecing unit (2). The piecing unit (2) is automatic.
The piecing unit (2) assists in yarn piecing operation during yarn breakage in the textile ring spinning machines (1). In a piecing operation a broken yarn having spindle is braked, broken yarn end from a cop (3) is lifted upstream by air blowing means (not shown). The said lifted yarn end is held inside a suction tube (not shown) of the piecing unit (2) positioned above the cop (3). The yarn end held by the said suction tube is to be threaded/inserted inside the ring traveler (not shown) before piecing said yarn end with the delivering yarn from a drafting zone (4). The piecing unit (2) needs to be aligned with the spindle which has the broken yarn before the piecing operation begins. The present invention provides a positioning device (100) to ensure proper alignment of the piecing unit (2) with the spindle having the broken yarn.
The positioning device (100) includes a sensing unit (6). The sensing unit (6) is a laser sensor fixedly mounted at a headstock end (gear end) or an endstock end (off end) of the textile ring spinning machine (1). It should be noted that the sensing unit (6) can be disposed on either ends of the textile ring spinning machine (1) without limiting the scope of what is disclosed. It should be noted that the sensing unit (6) may be mounted at the headstock end or the endstock end of the textile ring spinning machine (1) or directly on the floor or on a track (9) of the piecing unit (2) without limiting the scope of what is disclosed. According to the disclosed embodiment, the sensing unit (6) is a laser sensor. It should be noted that the sensing unit (6) may be an optical sensor, an ultrasonic sensor, a radar sensor, a vision-based sensors, or an electromagnetic sensor without limiting the scope of what is disclosed.
The positioning device (100) further includes a control unit (5). The control unit (5) is configured to determine the distance to be travelled by the piecing unit (2) and align the piecing unit (2) with the spindle position containing the broken yarn for initiating a yarn piecing operation.
The sensing unit (6) has an emitter and a receiver. The emitter of the sensing unit (6) is configured to emit a laser beam towards the piecing unit (2). A reflector on the piecing unit (2) reflects said emitted laser beam towards the receiver of the sensing unit (6). Therefore, the reflector is always mounted opposite to the sensing unit (6). It should be noted that the reflector may be a surface of the piecing unit (2) or a surface of the textile ring spinning machine (1) or a reflective surface mounted on the piecing unit (2) or the textile ring spinning machine (2) without limiting the scope of what is disclosed. The sensing unit (6) determines the distance between the sensing unit (6) and the automatic piecing unit (2) by at least one of technique of time of flight, multiple frequency phase shift, interferometry, light attenuation by atmospheric absorption, triangulation.
In one embodiment of the present invention the sensing unit (6) is mounted at the headstock end or the endstock end while the reflector is on the piecing unit (2). In another embodiment the sensing unit (6) is mounted on the piecing unit (2) while the reflector is at the headstock end or the endstock end. The sensing unit (6) is mounted with bracket means (7). It should be noted that the sensing unit (6) may be mounted using any other mounting method (200) without limiting the scope of what is disclosed.
In another embodiment, the textile ring spinning machine (1) is provided with at least two sensing units (6) (not shown) each positioned in two ends of the track (9) / textile ring spinning machine (1) such as one sensing means at the headstock and another sensing means at the endstock. The piecing unit (2) is accordingly provided with two reflectors (not shown) in both sides, each for respective sensing units (6) or the piecing unit (2) structure itself acts as a reflecting element. The piecing unit (2) is positioned in front of broken yarn spindle based on the detected distance value received from two sensing units (6). The detected distance between the sensing unit (6) and the automatic piecing unit (2) is displayed in a display unit (not shown) provided in the sensing unit (6). The said distance can also be displayed in both the display of the piecing unit (2) and/or the textile ring spinning machine (1).
As illustrated in FIG. 4, the control unit (5) controls the speed of a drive motor (8) of the piecing unit (2) based on the detected distance between the sensing unit (6) and reflector. The control unit (5) is configured to increase the speed of driving motor (8), if the distance to be travelled by automatic piecing unit (2) to reach the broken yarn spindle position is higher than the predetermined distance. The control unit (5) also decreases the travelling speed of the piecing unit (2) by reducing the speed of the driving motor (8) of the piecing unit (2), if the distance to be travelled by the piecing unit (2) to the reach the broken yarn spindle position is lesser than a predetermined distance. The said predetermined distance can be manually set by the operator in the display of piecing unit (2) or in the display of the textile ring spinning machine (1).
In one embodiment the textile ring spinning machine (1) with piecing unit (2) is provided with at least one parking sensor (not shown). The said parking sensor is mounted in at least one end proximal to the track (9) of the piecing unit (2) or textile ring spinning machine (1) structure. The said end can be a headstock or an endstock of the textile ring spinning machine (1). The said parking sensor ensures the parking position of the automatic piecing unit (2) at the headstock or the endstock side of the textile ring spinning machine (1).
In one embodiment the automatic piecing unit (2) is provided with at least one light emitting device such as LED lights on the outer cover. The said LED can emit different colour lights such as green, orange, and red corresponding to the various movements of automatic piecing unit (2). For example, the green colour of the LED light indicates the travelling movement. The orange colour indicates the automatic piecing unit (2) engaged in piecing action in the broken yarn spindle. The red colour indicates the interference of objects in between the rays of sensing unit (6) and the automatic piecing unit (2). The automatic piecing unit (2) is provided with at least one stopper element (not shown) on the track (9) at the headstock end (gear end) or the endstock end (off end) of the textile ring spinning machine (1) through connecting means. The said stopper element prevents the derailing of the automatic piecing unit from the ends of the track.
In another embodiment, when yarn breakage occurs at multiple spindles the control unit (5) is configured to move the piecing unit (2) to the spindle nearest to the piecing unit (2) to carry out the yarn piecing operation.
The positioning of the piecing unit (2) is carried out by a method (200). The method (200) includes a step of sending, by the sensor mounted on the spindle, a signal to the control unit (5) when the yarn breaks. The method (200) also includes a step of detecting, by the sensing unit (6) and reflector a position of the piecing unit (2). The method (200) further includes a step of determining, by the control unit (5), the distance to be travelled by the piecing unit (2). The method (200) further includes a step of aligning, by the control unit (5), the piecing unit (2) with the spindle position having the broken yarn for the yarn piecing operation.
The step of aligning the piecing unit (2) of the method (200) also includes aligning the piecing unit (2) with the nearest spindle when yarn breakage occurs at multiple spindles. The alignment of the piecing unit (2) with the nearest spindle provides an increase in efficiency of the piecing unit (2).
The sensing unit (6) of the present invention can be mounted in existing textile ring spinning machines (1) already operating in the textile spinning mills. The piecing unit (2) is always positioned precisely in front of the broken yarn spindle based on the distance measurements received from the sensing unit (6), before initiating the piecing sequence. The present invention also has the advantage of eliminating the need for a separate sensing rail throughout the length of the textile ring spinning machine (1), thus a considerable manufacturing and operating cost is reduced when implementing the present invention.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
Any discussion of devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
,CLAIMS:
1. A positioning device (100) for a piecing unit (2) in a textile ring spinning machine (1) having a yarn breakage detecting sensor mounted for each spindle position, the positioning device (100) comprising:
a sensing unit (6) and a reflector to detect the position of the piecing unit (2); and
a control unit (5), configured to determine the distance to be travelled by the piecing unit (2) and align the piecing unit (2) with the spindle position containing the broken yarn for initiating a yarn piecing operation.
2. The positioning device (100) as claimed in claim 1, wherein the control unit (5) is configured to move the piecing unit (2) to the spindle nearest to the piecing unit (2) when a yarn breakage occurs at multiple spindles.
3. The positioning device (100) as claimed in claim 1, wherein the sensing unit (6) comprises an emitter and a receiver.
4. The positioning device (100) as claimed in claim 1, wherein the reflector is a surface of the textile ring spinning machine or a surface of the piecing unit or a reflective surface mounted on the textile ring spinning machine or the piecing unit.
5. The positioning device (100) as claimed in the claims 3 to 4, wherein the sensing unit (6) is mounted at a headstock end or an endstock end of the ring spinning machine or directly on the floor or on the track (9) of the piecing unit (2).
6. The positioning device (100) as claimed in any of the claims 1 to 5, wherein the sensing unit (6) is mounted at the headstock end (gear end) or the endstock end (off end) of the ring spinning machine through bracket means (7).
7. The positioning device (100) as claimed in any of the claims 1 to 6, wherein the sensing unit (6) is a laser sensor, an optical sensor, an ultrasonic sensor, a radar sensor, a vision-based sensor, or an electromagnetic sensor.
8. The positioning device (100) as claimed in claim 1, wherein the sensing unit (6) is mounted at the headstock end or the endstock end of the ring spinning machine and the reflector is on the piecing unit (2).
9. The positioning device (100) as claimed in claim 1, wherein the sensing unit (6) is mounted on the piecing unit (2) and the reflector is at the headstock end or endstock end of the ring spinning machine.
10. The positioning device (100) as claimed in claim 1, wherein two sensing units (6) are positioned in two ends of the ring spinning machine, and the reflectors are provided for each sensing unit (6) of the ring spinning machine.
11. A method (200) for positioning a piecing unit (2) in a textile ring spinning machine (1) having a yarn breakage detecting sensor mounted for each spindle position, the method (200) comprising steps of:
sending, by the sensor mounted on the spindle, a signal to the control unit (5) when a yarn breaks;
detecting, by a sensing unit (6) and a reflector a position of the piecing unit (2);
determining, by a control unit (5), the distance to be travelled by the piecing unit (2); and
aligning, by the control unit (5), the piecing unit (2) with the spindle position having the broken yarn for a yarn piecing operation.

12. The method (200) as claimed in claim 11, wherein the step of aligning of the piecing unit (2) incudes aligning the piecing unit (2) with the nearest spindle when yarn breakage occurs at multiple spindles.