FIELD OF INVENTION

The present invention relates to an improved piecing mechanism in an air spinning machine. This invention particularly relates to the joining of the spun yarn to the drafted fibre during starting and restarting the machine after yarn breakage.

BACKGROUND OF THE INVENTION

The process for preparing a piecing mechanism is very critical in the quality and productivity aspect of textile air spinning machine. For carrying out the piecing mechanism, several concepts and devices have already been developed.

The air jet spinning arrangement comprises a drafting zone, involves main drafting zone of pair of apron rollers and delivery rollers and an air spinning device where such yarn is formed by twisting the fibres by utilizing whirling air flow. When the spinning process is interrupted due to breakage of yarn, the piecing process is done by inserting winding side yarn (lead yarn) from spinning nozzle outlet to the spinning device and also the sliver end is guided to the spinning device and these two ends are spliced by spinning process during restarting of the machine and by such way piecing is done. In known piecing mechanism, both sliver and winding end are placed in a suction tube away from the spinning device during stationary state. This increases the success rate of yarn piecing and improves the yarn pieced part without requiring adjustment of the pulling time of lead yarn and supply time of sliver to the spinning device. However, this piecing mechanism adversely affects the quality of the yarn resulting in more thick places during splicing since both yarn and sliver are fed simultaneously to the spinning device. Such kind of device is disclosed in United States patent number 5813209 filed by Murata machinery Ltd.

Yet in another method of piecing mechanism, the winding end yarn is guided up to the delivery roller by lifting the top roller and a suction tube is placed to hold the same. Then the sliver end is prepared by stopping the delivery rollers and apron rollers one after another and the apron rollers are slightly moved backward so as to pull the sliver end into the aprons. Therefore, the negative pressure in the suction tube does not affect the sliver end. While piecing, the top rollers are closed and the sliver end is allowed to be spliced along with the winding end right from the delivery roller. But this process is more complicated since lifting of the top rollers during spinning and placing a suction tube in between delivery rollers and apron rollers will impose more practical difficulties. Further, the loaded fibre in the apron moved reversely leads to the higher fibre crimpiness and shows the negative effect in the spun yarn quality. This method of piecing is described in United States patent number 7464530 (United States patent application no. 2008066442) filed by Rieter AG Maschinenfabrik.

OBJECTS OF THE INVENTION

The object of the present invention is to eliminate the complicated process in piecing mechanism so as to provide a simple and an improved piecing method in an air spinning machine.

Another object of the present invention is to provide a spinning nozzle, which controls the suction for piecing at both the sliver input end and yarn winding end quite simply in an air spinning machine.
Yet another object of the present invention is to improve the reliability of piecing and quality of the pieced part of the yarn in an air spinning machine.

Yet another object of the present invention is to improve the success rate of piecing and to produce yarn having stable quality.

SUMMARY OF THE INVENTION

The drafted sliver end is found at the top of the spinning nozzle and wound yarn is collected from the bottom of the nozzle after the breakage of spun yarn occurred. A calculated length of winding end yarn is placed in the outlet of spinning nozzle so that it will be sucked into the whirling zone of air spinning nozzle. For controlling the suction at winding yarn input side, a plunger is provided at the sliver input side. The magnitude of suction at winding yarn side is high and suction at sliver input side is low when the plunger is closed or partially open. This plunger will divert the suction, which is required at sliver input side in the normal spinning operation, to winding yarn input side during piecing operation. Such an arrangement will eliminate the complicated components of the device such as auxiliary nozzles, suction tube etc. Further, the sliver is supplied to the nozzle through sliver input side, so that sliver is whirled together with the end part of supplied winding end yarn. Thus the yarn piecing operation is carried out by improving the reliability of piecing and quality of the pieced part of the yarn in an air spinning machine.

According to the first aspect of the present invention, there is provided an improved piecing mechanism in an air spinning machine having a drafting device for supplying sliver in a spinning nozzle for piecing with wound yarn and means for withdrawing a calculated length of wound yarn and placing the yarn in the outlet of the spinning nozzle so that the yarn is sucked into the whirling zone of the spinning nozzle wherein at least a plunger is provided in the nozzle for controlling the suction of the wound yarn.
According to another aspect of the present invention, there is provided an improved piecing mechanism in an air spinning machine having a drafting device for supplying sliver in a spinning nozzle for piecing with wound yarn and means for withdrawing a calculated length of wound yarn and placing the yarn in the outlet of the spinning nozzle so that the yarn is sucked into the whirling zone of the spinning nozzle wherein a plunger is provided at the sliver input side of the nozzle for controlling the suction of the wound yarn.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 illustrates the insertion of calculated length of wound yarn (1) into the whirling zone (6) of the spinning nozzle (4).

Figure 2 illustrates the piecing action of drafted sliver end (7) and wound yarn (1) at the whirling zone (6) of the spinning nozzle (4).

Figure 3 illustrates the position of the plunger (5) and the direction of the increased sucking air (10) for the entry of winding yarn end (1) inside the spinning nozzle (4) before the piecing operation.

Figure 4 illustrates the normal spinning operation of air spinning machine.

Figure 5 illustrates the condition after breakage of spun yarn

Figure 6 illustrates the condition when air supply to the nozzle is stopped Figure 7 illustrates the condition when the plunger is closed and compressed air is supplied and suction at winding yarn end side is high and suction at sliver end is low.

Figure 8 illustrates the condition when wound yarn is taken from the package and placed in front of winding yarn input side Figure 9 illustrates the condition when wound yarn is carried along the air and placed in the spinning zone of the spinning nozzle

Figure 10 illustrates the condition when the plunger is open and suction at winding yarn end is low and suction at sliver end is high

Figure 11 illustrates the condition when the drafting system is restarted and fibres areplaced at sliver input side

Figure 12 illustrates the condition when the sliver is sucked into the spinning zone of the spinning nozzle
Figure 13 illustrates the condition when the winding mechanism is restarted.

DETAILED DESCRIPTION OF THE INVENTION

Figure-1 shows the calculated length of wound yarn (1) being sucked into the spinning nozzle by placing it in the winding yarn input side (2) (outlet of spinning nozzle) through compressed air (3) produced inside the air spinning nozzle (4). A plunger (5) is placed at sliver input side (8) of the nozzle (4) as shown in figure, which controls the suction at winding yarn input side (2). During piecing wound yarn is picked from yarn package and placed at the winding yarn input side (2). Due to partial or full closure of plunger (5) provision, there will be high flow of air at the winding yarn side (2) , which will carry the calculated length of yarn into the whirling zone (6) of spinning nozzle (4). The selection of the yarn length is very important, so that it should be sufficient for end part of the wound yarn (1) to be placed in the whirling zone (6) of air spinning nozzle (4). The length of the wound yarn (1) will be such that the piecing end will be in the middle of the whirling zone (6) as shown in figure-1, which will be of calculated length, for example around 22 mm. The piecing operation is feasible with the winding yarn when the inserted length is in the range of not less than 20% or not more than 50% of calculated length of yam. Therefore, while increasing the winding yarn length to be inserted, the quality of piecing is deteriorated and by increasing beyond 50%of calculated length of yarn, the wound yarn (1) will disturb the air flow pattern and the piecing operation is not possible.

Then, by decreasing the inserted length of the wound yarn below 20%of calculated length of yarn, it is not sufficient to pull the drafted fibers into the whirling zone (6) and hence the piecing operation is not possible. Thus the yarn piecing operation is done by improving the reliability of piecing and quality of the pieced part of the yarn in an air spinning machine when very specific length of wound yarn (1) is supplied to the whirling zone (6).

During normal operation of the machine suction is low at the winding yarn input side (2) and suction is high at sliver input side (8). The plunger (5) will be open.

Figure-2 shows the sliver (7)is being supplied to the spinning nozzle (4), through the sliver input side (8) towards the whirling zone (6), so that it gets whirled together with the end part of the supplied calculated length of wound yarn (1) at the whirling zone (6). The piecing of broken yarn according to present invention is carried out by providing plunger (5) in the spinning nozzle (4) which controls the suction for piecing, both at the the sliver (7) input end (8) and winding yarn input side (2) , quite simply in an air spinning machine.

Figure-3 shows the partially closed position of the plunger (5) and the direction of the increased suction of air (10) for the entry of wound yarn (1) inside the spinning nozzle (4) before the piecing operation.
For providing the improved suction of the wound yarn (1), the suction that is used for pulling the drafted sliver (7) in a normal spinning operation is diverted by means of plunger (5), which is placed at the sliver input side (8). The plunger will partially or fully close the sliver input side (8), which results in increased suction (10) at winding yarn input side (2) for drawing the required length of wound yarn (1). After the wound yarn is placed inside the whirling zone (6), the plunger (5) will be partially or fully open to allow the drafted sliver (7) inside the nozzle (4), thereby facilitating improved piecing process. The amount of closing distance in the sliver input side (8) by the plunger (5) during piecing is determined by different counts & raw material used for the spinning process. This mechanism eliminates other extra components such as auxiliary nozzle, suction tube, etc. for the piecing purpose. Thus the present invention eliminates the complicated process in the existing piecing mechanism so as to provide a simple and an improved
method of piecing in an air spinning machine.

WORKING OF THE INVENTION:

Step 1: During normal spinning operation, suction (2) towards whirling zone (6) at the winding yarn side (2) is low. Suction at sliver input side (8) towards whirling zone (6) is high. Compressed air (3) towards whirling zone (6) is ON. The plunger (5) is at open state. This arrangement is shown in figure 4

Step 2: The yarn gets cut for some reasons. No yarn is being spun in the nozzle (4). The supplied sliver (7) is eliminated as waste. The suction (2 & 8), compressed air (3) and plunger position (5) remains same as in step 1. This arrangement is shown in figure 5

Step 3: The air supply (3) to the nozzle (4) is cut off and the nozzle (4) is cleaned. Now no sliver or yarn is present in the nozzle (4). Suction (2 & 8) is nil. The plunger (5) is at open state. This arrangement is shown in figure 6

Step 4: The plunger (5) is closed and the compressed air (3) is ON. The magnitude of suction (2) at winding yarn side(2) is increased and the magnitude of suction at sliver input side(8) is decreased when compared to that of spinning condition. No sliver or yarn is present in the nozzle (4). This arrangement is shown in figure 7

Step 5: The suction at winding yarn input side(2) is high. The suction at sliver input side(8) is low or nil depending upon whether the plunger (5) is fully closed or partially closed. The air (3) is ON. The wound yarn end is picked from the package and placed in front of winding yarn input side (2). The high flow of air at this end carries the yarn end along its flowing direction. Only calculated amount of 22 mm yarn is allowed inside the nozzle (4). The arrangement is shown in figure 8

Step 6: The wound yarn end is carried to the whirling zone (6) of the nozzle (4). The yarn end is continuously revolved together with the air in whirling zone (6). This arrangement is shown in figure 9

Step 7: The plunger (5) is open. This makes the magnitude of suction at winding yarn side(2) get reduced and the magnitude of suction at sliver input side(8) get increased.

The compressed air (3) is still ON. The yarn end continuously revolves in the whirling zone (6) of spinning nozzle (4). This arrangement is shown in figure 10

Step 8: Now the drafting system is switched ON. The supplying sliver (7) is placed at the sliver input side (8). The sliver is yet to enter the nozzle (4) and the wound yarn is still revolving in the whirling zone (6). This arrangement is shown in figure 11

Step 9: The sliver gets sucked into the nozzle (4) due to high suction (8) at sliver input side. The sliver is joined to the wound yarn which is already revolving in the whirling zone (6). This arrangement is shown in figure 12

Step 10: The winding mechanism is switched ON. This will pull the yarn from the nozzle (4) and continuous spinning process is started. The suction at winding yarn input side(2) remains low. The suction at sliver input side (8) remains high. The plunger (5) is open and the compressed air (3) remains ON. This arrangement is shown in figure 13

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Hence any modification of the disclosed embodiment incorporating the sprit and substance of the invention should be construed within the scope of the invention.

We claim:

1) An improved piecing mechanism in an air spinning machine having a drafting system for supplying sliver (7) in a spinning nozzle (4) for piecing with wound yarn (1) and means for withdrawing a calculated length of wound yarn (1) and placing the yam (1) in the outlet (2) of the spinning nozzle (4) so that the yarn (1) is sucked into the whirling zone (6) of the spinning nozzle (4) wherein at least a plunger (5) is provided in the nozzle (4) for controlling the suction of the wound yarn (1).

2) An improved piecing mechanism in an air spinning machine as claimed in claim 1, wherein a plunger (5) is provided at the sliver input side (8) of the nozzle (4) for controlling the suction of the wound yarn (1).

3) An improved piecing mechanism in an air spinning machine as claimed in claim 1, wherein a calculated length of 22 mm of wound yarn (1) is inserted into the nozzle (4) at the winding yarn input end (2).

4) An improved piecing mechanism in an air spinning machine as claimed in claim 3, wherein length of yarn in the range of not less than 20% and not more than 50% of the calculated length of yarn is supplied to the whirling zone (6) of spinning nozzle (4).

5) An improved piecing mechanism in an air spinning machine as claimed in claim 1, wherein suction at the winding yam input side (2) is increased by partial or full closure of plunger (5).

6) An improved piecing mechanism in an air spinning machine as claimed in claim 1, wherein sliver (7) is supplied from the drafting system to the whirling zone (6) of spinning nozzle (4) for entangling with wound yarn (1) when plunger (5) is partially or fully open for piecing.

7) An improved piecing mechanism in an air spinning machine substantially herein described with reference to the accompanying drawings.