DESC:FIELD OF THE INVENTION

The present invention relates to textile ring spinning machines. Particularly, the invention relates to yarn suction arrangement for an automatic yarn piecing unit in ring spinning machines. More particularly, the invention relates to broken yarn picking arrangement to detach the broken yarn end from the spinning cop to enable automatic piecing operation in textile ring spinning machines.

BACKGROUND OF THE INVENTION

Ring spinning machines are the final yarn producing machines in textile spinning mills, which are very crucial machines. The said ring spinning machines produces the resultant form of cotton in spinning line, so called yarn. Yarn breakage occurs frequently in ring spinning machines which is a major setback spinning industry is facing worldwide. Yarn breakage has to be continuously monitored and broken yarn has to be pieced then and there by the workers. The yarn breakage occurs due to various parameters of yarn and machine and it is unavoidable. In long spinning frame sites, human labours continuously monitor yarn breakages and perform manual piecing of broken yarns round the clock walking along the pathways of the ring frames. This has to be done for a machine frame normally consisting of more than 1600 spindles and about 75 metres long. After successful piecing of broken yarn, yarn spinning sequence has to be restarted then and there for every broken yarn spindles, in order to avoid wastage of yarn.

To overcome above problems, automatic piecing units are being developed. The automatic piecing unit is in the form of a movable vehicle with guiding means. The said piecing vehicle stops at respective broken yarn spindle position which requires piecing attention. The piecing unit in general moves longitudinally over the machine frame aisles. Before initiating piecing operation, the piecing vehicle stops in front of the spindle position of ring spinning machine. Then the broken yarn end which is available in 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 spinning cop automatically is a very difficult task in general.

Extensive trials are being done for past several years to successfully implement automatic piecing units in textile spinning machines. But till date, automatic piecing units were not implemented due to the difficulties involved. In the existing piecing arrangements which were on trials, 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 spinning spindle, so called cop. When yarn breakage occurs in the spinning sequence, the broken yarn thread becomes entangled in the spinning cop. To enable yarn piecing, the entangled yarn end has to be detached from the cop. For picking the broken yarn end from the cop, automatic piecing units are normally provided with suction arrangements. The cylindrical suction nozzle with mouth / opening extends from the piecing unit and is positioned usually at a predetermined distance above the top of the spinning cop to suck the yarn end from the cop. For providing the required suction, normally suction motors are used. The existing suction motors are large in size and expensive. Also, suction motor occupies considerable space in automatic piecing unit due to its size. This results in increased mass of the automatic piecing unit in addition to increased cost.

There exists a need to develop an improved broken yarn picking from the cop which compromises both space and cost of the automatic piecing unit, to which the present invention provides a solution. The present invention provides an improved arrangement for picking the broken yarn end from the spinning cop to enable automatic piecing in 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 mechanism for improved yarn picking which saves space and reduces cost in the automatic piecing unit of the textile ring spinning machines.

Another object of the present invention is to provide a broken yarn picking arrangement from the spinning cop with improved suction arrangement in the automatic piecing unit of the textile ring spinning machines.

SUMMARY OF THE INVENTION
This summary is provided to introduce aspects related to systems and methods for forecasting volume data, and the aspects are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

In one non-limiting embodiment, an automatic piecing unit for yarn piecing operation during yarn breakage incidents in ring spinning machines is disclosed. Proper picking / detaching of the broken yarn end is necessary for the successful piecing of the broken yarn ends. To enable the same, the automatic piecing unit (1) is provided with a suction assembly comprising a suction pipe (2) having a suction opening / mouth (3). The suction assembly is capable of moving from top to bottom to displace at a predetermined distance at the top of a cop (4). The suction assembly also comprises a venturi jet (5) instead of large suction motors, for picking the yarn end from the cop (4). The venturi jet (5) is designed in such a way that it receives compressed air and blows the air inside the suction pipe (2) in the direction opposite to the cop (4), i.e. blows air upstream of the cop (4). The venturi jet (5) has a plurality of inlets in a tapered manner blowing air inside the venturi jet (5), thereby creating suction inside the suction pipe (2) in upward direction to lift the broken yarn end from the cop (4). Thus, the compressed air leaving the venturi jet (5) at the outlet creates suction force in upward direction which in turn picks the yarn end from the cop (4).

In an embodiment, the automatic piecing unit (1) comprises two venturi jets i.e. a first venturi jet (5a) and a second venturi jet (5b) having multiple flow control, instead of a suction motor. In addition to the venturi jet (5), plurality of air jets are provided around the bottom of the cop (4) to assist in lifting the broken yarn end (not shown).

In another non-limiting embodiment, a method for automatic piecing of broken yarns in a ring spinning machine is disclosed. The method may comprise sucking a broken yarn end from a cop (4) using a suction assembly. The suction assembly may comprise a suction pipe (2) having a suction mouth (3) present at an end facing the cop (4). The suction pipe (2) may be positioned at a predetermined height over the cop (4). At least a venturi jet (5a) may be affixed with the suction pipe (2), and the venture jet (5a) may receive compressed air from a pressure supply port. A movement of the compressed air through a constricted section of the said venturi jet (5a) may create vacuum in the suction mouth (3) to suck the broken yarn end from the cop (4) into the suction pipe (2).

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.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Fig. 1 shows a schematic side view of a suction assembly of an automatic piecing unit, according to an embodiment of the present invention.

Fig. 2 shows a perspective view of a venturi jet arrangement of an automatic piecing unit, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings in which like numerals represent like elements throughout the several figures, and in which example embodiments are shown. Embodiments of the claims may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The examples set forth herein are non- limiting examples and are merely examples among other possible examples.

Referring to Fig. 1 showing a schematic side view of a suction assembly of an automatic piecing unit (1), operation of the automatic piecing unit (1) is explained. The automatic piecing unit (1) moves longitudinally along the aisle of a ring spinning machine. The ring spinning machine is capable of winding yarn onto a bobbin mounted to spinning spindle, so called cop (4). When yarn breakage occurs in the spinning sequence, a broken yarn thread gets entangled in the spinning cop (4). To enable yarn piecing, the broken or entangled yarn end has to be detached from the cop (4). A suction assembly of the automatic piecing unit (1) provides the required suction to pick the broken yarn end from the cop (4). The suction assembly comprises a suction pipe (2) that may be cylindrical in shape, and may having a suction mouth / opening (3). The suction pipe (2) is displaced at a predetermined height at the top of the cop (4) so as to suck the broken yarn end from the cop (4).

As shown in Fig. 1, the suction assembly is provided with a venturi jet instead of suction motor, for picking the broken yarn end from the cop (4). Preferably, two venturi jets i.e. a first venturi jet (5a) and a second venturi jet (5b) may be used to suck the broken yarn end from the cop (4). As an embodiment, multiple venturi jets can also be used. The first venturi jet (5a) is fixed adjacent to the suction pipe (2). The second venturi jet (5b) is fixed away from the suction mouth (3) at the farther end of the suction assembly as shown in Fig. 1. Compressed air from a pressure supply port or the ring spinning machine suction unit or spinning mill suction unit or any source may be passed inside the first venturi jet (5a) and the second venturi jet (5b) sequentially. When the compressed air flows into the venturi jet (5a), a constricted section of the first venturi jet (5a) increases the flow velocity of the compressed air. Due to this process, a vacuum is created in the suction mouth (3), which causes suction in the upward direction due to the Venturi effect, to lift the broken yarn end from cop (4).

In an aspect of the present invention, working sequence of the suction assembly is as described hereinafter. The compressed air is passed inside the first venturi jet (5a) through the inlet provided in the first venturi jet (5a). The compressed air leaves the venturi jet (5a) at an outlet towards the inner side of the suction pipe (2), thereby creating a suction effect or vacuum in the upward direction inside the suction mouth (3). The varying diameter profile of venturi inner pipe from one end to another creates the desired suction effect in upward direction. Due to the suction effect or vacuum, the broken yarn end from the cop (4) is picked and sucked inside the suction mouth (3) into the suction assembly. The sucked broken yarn end may be then delivered for piecing operation.

In another embodiment, the second venturi jet (5b) may be placed at the farther end of the suction assembly. A sensor (not shown) may be placed inside the suction pipe (2) near the second venturi jet (5b) to detect the sucked broken yarn end. The sensor position may provide an output upon detecting the broken yarn end in the suction pipe (2). Based on such output, the second venturi jet (5b) may be provided with compressed air. Simultaneously, supply of the compressed air to the first venturi jet (5a) may be cut off. Consequently, the broken yarn end is held inside the suction pipe (2) in a controlled manner without unwinding from the cop (4). The above sequence is continued whenever required.

Fig. 2 illustrates a perspective view of venturi jet (5). The compressed air is passed inside the venturi jet (5) from an inlet. The venturi jet (5) has tapered inner profile that purges the compressed air at an outlet of the venturi jet (5) at an upward direction of the cop (4) inside the suction pipe (2). This creates suction at the mouth (3) and the broken yarn end is picked upwards from the cop (4).

In another embodiment of the present invention, multiple / plurality of venturi jets can also be used. The venturi jet usage may not be limited to one or two. In one scenario, a suction pressure due to the compressed air flow is varied at any sequence with a single or multiple flow controls. Timing of providing multiple flow controls may be varied in any sequence according to picking requirement of the broken yarn end. As a result, the suction pressure may desirably be maintained for efficient yarn picking and piecing.

As an example embodiment, a suction pressure for the first venturi jet (5a) is maintained in a suitable operating range, preferably 50 mbar to 70 mbar, until the broken yarn end is picked/sucked from the cop (4) and detected by the sensor positioned adjacent to second venturi jet (5b). Then, the second venturi jet (5b) is provided with compressed air. Simultaneously, the compressed air supply to first venturi jet (5a) is cut off. A suction pressure for the second venturi jet (5b) is maintained in a suitable operating range, preferably the range of 30 mbar to 50 mbar, until the sucked broken yarn end is delivered for piecing.

In addition to the venturi jet (5), a plurality of air jets may be provided around the bottom of the cop (4) to assist in lifting the broken yarn end (not shown).

In another non-limiting embodiment, a method for automatic piecing of broken yarns in a ring spinning machine is disclosed. The method may comprise sucking a broken yarn end from a cop (4) using a suction assembly. The suction assembly may comprise a suction pipe (2) having a suction mouth (3) present at an end facing the cop (4). The suction pipe (2) may be positioned at a predetermined height over the cop (4). At least a venturi jet (5a) may be affixed with the suction pipe (2), and the venture jet (5a) may receive compressed air from a pressure supply port. A movement of the compressed air through a constricted section of the said venturi jet (5a) may create vacuum in the suction mouth (3) to suck the broken yarn end from the cop (4) into the suction pipe (2).

Thus, the above described automatic piecing unit and a method for automatic piecing of broken yarns in a ring spinning machine provides a reliable solution for picking the broken yarn end from the cop without completely unwinding the cop (4) in a cost effective manner. Space is also considerably reduced in the automatic piecing unit (1) by eliminating use of heavy suction motor.

In view of the present disclosure which describes the present invention, all changes, modifications and variations within the meaning and range of equivalency are considered within the scope and spirit of the invention, as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, means, methods and steps described in the specification.

As one will readily appreciate from the disclosure, processes, machines, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, means, methods, or steps.
,CLAIMS:We Claim:
1. An automatic piecing unit (1) for piecing broken yarns in a ring spinning machine, the automatic piecing unit (1) comprising:
a suction assembly for sucking a broken yarn end from a cop (4), wherein the suction assembly includes:
a suction pipe (2) having a suction mouth (3) present at an end facing the cop (4), said suction pipe (2) is positioned at a predetermined height over the cop (4), to suck the broken yarn end from the cop (4); and
a first venturi jet (5a) affixed with the suction pipe (2), to receive compressed air from a pressure supply port, wherein movement of the compressed air through a constricted section of the firstventuri jet (5a) creates vacuum in the suction mouth (3) to suck the broken yarn end from the cop (4) into the suction pipe (2).

2. The automatic piecing unit (1) as claimed in claim 1, wherein velocity of the compressed air increases upon passing through the constricted section of the said first venturi jet (5a) that results into the vacuum in the suction mouth (3).

3. The automatic piecing unit (1) as claimed in claim 1, wherein suction pressure for the first venturi jet (5a) is maintained in a suitable operating range, preferably 50 mbar to 70 mbar, until the broken yarn end is picked.

4. The automatic piecing unit (1) as claimed in claim 1, further comprising a second venturi jet (5b) connected at an end of the suction pipe (2) present distant from the cop (4).

5. The automatic piecing unit (1) as claimed in claim 4, wherein compressed air is provided for operation of the second venturi jet (5b) based on an output of a sensor positioned within the suction pipe (2), and wherein the sensor provides the output upon detecting presence of the broken yarn end in the suction pipe (2).

6. The automatic piecing unit (1) as claimed in claim 5, wherein supply of the compressed air to the first venturi jet (5a) is cut-off when the second venturi jet (5b) operates.

7. The automatic piecing unit (1) as claimed in claim 4, wherein suction pressure for the second venturi jet (5b) is maintained in a suitable operating range, preferably 30 mbar to 50 mbar, until the picked broken yarn is delivered for piecing.

8. The automatic piecing unit (1) as claimed in claim 1 and 4, wherein said first venturi jet (5a) and said second venturi jet (5b) have multiple flow controls.

9. The automatic piecing unit (1) as claimed in claim 8, wherein the suction pressure for the first venturi jet (5a) and the second venturi jet (5b) due to the compressed air flow is varied through a flow control.

10. The automatic piecing unit (1) as claimed in claim 8, wherein timing of providing the multiple flow controls is varied according to picking requirement of the broken yarn end.

11. The automatic piecing unit (1) as claimed in claim 1, further comprising at least one air jet at bottom of the cop (4) to assist suction of the broken yarn end into the suction pipe (2).

12. A method for automatic piecing of broken yarns in a ring spinning machine, the method comprising:
sucking a broken yarn end from a cop (4) using a suction assembly with a suction pipe (2) having a suction mouth (3) present at an end facing the cop (4), positioned at a predetermined height over the cop (4), and at least a first venturi jet (5a) affixed with the suction pipe (2), which receives compressed air from a pressure supply port, wherein movement of the compressed air through a constricted section of the said first venturi jet (5a) creates vacuum in the suction mouth (3) to suck the broken yarn end from the cop (4) into the suction pipe (2).

13. The method for automatic piecing as claimed in claim 12, wherein velocity of the compressed air increases upon passing through the constricted section of the said first venturi jet (5a) that results into the vacuum in the suction mouth (3).

14. The method for automatic piecing as claimed in claim 12, wherein suction pressure for the first venturi jet (5a) is maintained in a suitable operating range, preferably 50 mbar to 70 mbar, until the broken yarn end is picked.

15. The method for automatic piecing as claimed in claim 12, wherein a second venturi jet (5b) connected at an end of the suction pipe (2) present distant from the cop (4) is provided with compressed air for operation of said second venturi jet (5b) based on an output of a sensor positioned within the suction pipe (2), and wherein the sensor provides the output upon detecting presence of the broken yarn end in the suction pipe (2).

16. The method for automatic piecing as claimed in claim 15, wherein supply of the compressed air to the first venturi jet (5a) is cut-off when the second venturi jet (5b) operates.

17. The method for automatic piecing as claimed in claim 15, wherein suction pressure for the second venturi jet (5b) is maintained in a suitable operating range, preferably 30 mbar to 50 mbar, until the picked broken yarn is delivered for piecing.

18. The method for automatic piecing as claimed in claim 12 and 15, wherein said first venturi jet (5a) and said second venturi jet (5b) have multiple flow controls.

19. The method for automatic piecing as claimed in claim 18, wherein the suction pressure for the first venturi jet (5a) and the second venturi jet (5b) due to the compressed air flow is varied through a flow control.

20. The method for automatic piecing as claimed in claim 18, wherein timing of providing the multiple flow controls is varied according to picking requirement of the broken yarn end.

21. The method for automatic piecing as claimed in claim 12, wherein at least one air jet is provided at bottom of the cop (4) to assist suction of the broken yarn end into the suction pipe (2).