DESC:TITLE:

An under winding clamping device and process of clamping the yarn thereof.

FIELD OF INVENTION:

The present invention relates to a clamping device for ring spinning machine, more particularly a clamping device arrangement of axially displaceable clamping elements for clamping the yarn. The invention also relates to the process of clamping the yarn using the clamping device.

BACKGROUND OF THE INVENTION:

Conventional ring spinning machine have plurality of spindles (approx. 1200) or even more that rotate at a very high speed and winds the yarn produced by ring spinning on the bobbin mounted on the spindle. When the winding on the bobbin is completed it is necessary to exchange the bobbins with the empty bobbins to continue production. This process of exchanging the bobbins is called doffing and is done automatically by means of a mechanism called doffer.

During the doffing process when the full bobbin has to be replaced with an empty bobbin, just before the spindle stops rotating, the yarn being delivered to the bobbin is clamped on the spindle by means of a clamping device. When the bobbin is removed, the yarn breaks between the bobbin and the clamping device. The end of the yarn clamped in the clamping device (A) facilitates successful winding of initial turns on the empty bobbins when the spindle starts to rotate again.

The disadvantage of the conventional or other clamping device is that sometimes the yarn is not clamped or there is a slippage of yarn and then the winding of yarn on the new bobbin will not restart automatically, resulting in loss of production and time, until the operator reconnects yarn manually to the spindle.

Further in the conventional or other clamping devices, when the yarn slippage occurs while starting up of new bobbins, the spindle may run without yarn till the operator attends and reconnects the yarn manually. During this period the loss of yarn production on that particular spindle, and the loss of cotton roving delivered as the same will be carried into waste box by suction system. Thus resulting in lot of wastage during the production of the yarns.

Since the yarn produced by the ring spinning machine is very thin, it is necessary to have accurate contact of clamping surfaces. Generally the clamping device comprises of stationary or fixed parts and moving parts and the limitation of manufacturing processes makes it difficult to achieve the proper contact of the clamping surfaces.

OBJECTIVE OF THE INVENTION:

1. It is an objective of the present invention to provide a clamping device in such a way that an accurate and substantially continuous operation of the clamping device is ensured.

2. It is another objective of the present invention to provide a clamping device comprising of axially displaceable clamping elements to improve the reliability of clamping the yarns.

3. It is yet another objective of the present invention to provide a clamping device comprising of balls that are positioned on the radial tracks of the axially displaceable clamping elements.

4. It is yet another objective of the present invention to provide a method of assembly of a clamping device in such a way that an accurate and substantially continuous operation of the clamping device is ensured.

5. It is yet another objective of the present invention to facilitate the cleaning of the clamping device required in case accumulation of yarns occurs.

6. It is yet another objective of the present invention to provide a clamping device that is cost-effective and easy to install.

7. It is yet another objective of the present invention to provide a clamping device that can accurately clamp the yarn.

8. It is yet another object of the present invention to provide a process of clamping the yarn using a clamping device.

9. It is yet another objective of the present invention to provide a clamping device that opens up at high speeds to receive the yarn, and closes at lower speeds to clamp the yarn.

SUMMARY OF THE INVENTION:

The present invention relates to a clamping device for ring-spinning machine to improve the reliability of clamping the yarn during the doffing cycle. The clamping device is arranged in a manner so that it has movable clamping elements on opposite direction and are supported by means of springs, in such a manner that both the clamping elements have flexibility to align and axially displace with respect to the other. The said clamping element comprises of balls that are positioned on the radial track such that when the spindle approaches the opening speed, the centrifugal force of the balls exceeds the force due to spring, allowing the balls to move radially outwards, thus the clamping elements separates. And when the spindle speed reduces below the closing speed of clamping device the balls are moved radially inwards due to the spring force. Thus due to the self-alignment of the clamping elements by springs and the centrifugal force of the balls, the reliability of clamping is improved.

One aspect of the present invention relates to a clamping device for doffing in a ring spinning machine comprising, an inner piece (1), a cutter (3) fixed on top of the inner piece (1), upper clamping element (8) axially slidable on the inner piece and, said upper clamping element (8) is pressed towards the lower clamping element (6) by first spring (5), said first spring (5) is located between the cutter (3) and the upper clamping element (8), lower clamping element (6) axially slidable on the inner piece and is pressed towards the upper clamping element (8) by second spring (7), said second spring (7) is located between the lower clamping element (6) and spring cup (4), balls (9) positioned on the radial track of the clamping elements (8,6), Characterized in that the clamping elements (8,6) are movable in opposite directions to one another, wherein atleast one loading springs (5,7) and at least one load relieving balls (9) acts in opposite direction to the direction of the spring force, whereby the load-relieving balls is movable under centrifugal force when the spindle is rotating.

In another aspect of the present invention relates to a process of clamping an yarn in a ring spinning machine comprising, clamping elements (8,6) that are axially movable in opposite directions to one another, loading springs (5,7) for closing the clamping element by means of a loading force, load relieving balls (9) that are positioned on the radial tracks for generating a relieving force that acts in opposite direction to the direction of the spring force, whereby the load-relieving balls moves in the radial tracks of the clamping device under centrifugal force when the spindle is rotating and whereby the clamping elements can be opened by means of load relieving force.

In yet another aspect of the present disclosure a clamping device for doffing in a ring spinning machine is disclosed. The clamping device may comprise an inner piece (1). The inner piece (1) may further comprise a cutter (3) fixed on the inner piece (1). The clamping arrangement may further comprise at least two clamping element (8, 9). The at least two clamping element (8, 9) may be configured to slide axially in direction opposite to each other on the inner piece (1). Further at least two loading springs (5, 7), may be positioned in the cutter (3) and a spring cup (4), and may be configured to press the at least two clamping elements towards each other by way of spring force. The clamping arrangement may further comprise a plurality of balls (9) positioned on a radial track embedded on the at least two clamping element (8, 9), characterized wherein at least one load relieving balls from the plurality of balls (9) act in opposite direction to the direction of the spring force of at least one loading spring (5, 7) the load-relieving balls moves under centrifugal force creating a clamping gap (11).

DETAILED DESCRIPTION OF THE INVENTION:

The detailed description is described with reference to the accompanying figures.

Fig. 1 shows the section view of the arrangement of the clamping device (A), that is when the clamping gap (11) is in the open position.

Fig. 2 shows the section view of the arrangement of the clamping device (A), that is when the clamping gap is in the closed position.

DETAILED DESCRIPTION OF THE INVENTION:

Fig. 1 shows the section view of the arrangement of the clamping device (A), that is when the clamping gap (11) is in the open position.

The clamping device has inner piece (1) on which the cutter (3) is fixed at the top. The upper clamping element (8) can slide axially on the inner piece (1), and is pressed towards the lower clamping element (6) by the first spring (5) located between the cutter (3) and the upper clamping element (8). The lower clamping element (6) can also slide axially on the inner piece (1), and is pressed towards the upper clamping element (8) by second spring (7) located between the lower clamping element (6) and the spring cup (4).

Both the clamping elements (8, 6) respectively have radial tracks for the balls (9). The arrangement of the tracks are such that when the spindle speed increases the balls (9) tends to move radially outwards in the tracks due to centrifugal forces. That is when the spindle approaches the opening speed of clamping device the centrifugal force of the balls exceeds the force due to springs (5, 7) respectively, allowing the balls (9) to move radially outwards thus creating a clamping gap (11).Thus due to the geometry of the tracks, the clamping elements (8, 6) are separated creating a clamping gap (11) as the balls (9) slides outwards. The clamping gap (11) thus created is in a ready position to clamp the yarn being delivered to the bobbin.

Fig. 2 shows the section view of the arrangement of the clamping device (A), that is when the clamping gap is in the closed position.

The clamping device has inner piece (1) on which the cutter (3) is fixed at the top. The upper clamping element (8) can slide axially on the inner piece (1), and is pressed towards the lower clamping element (6) by the first spring (5) located between the cutter (3) and the upper clamping element (8). The lower clamping element (6) can also slide axially on the inner piece (1), and is pressed towards the upper clamping element (8) by second spring (7) located between the lower clamping element (6) and the spring cup (4).

Both the clamping members (8, 6) respectively have radial tracks for the balls (9). The arrangement of the tracks are such that when the spindle speed decreases below certain level, the balls (9) tends to move radially inwards in the tracks due to force of springs (5,7) respectively. Thus due to the geometry of the tracks, when the spindle speed reduces below the closing speed of the clamping device, the centrifugal forces reduces and the balls (9) are moved radially inwards due to the spring force. That is when the force due to the springs (5, 7) exceeds the centrifugal force of the balls, allowing the ball (9) to move radially inwards. Such that the clamping gap (11) is closed as the balls (9) slides inwards. The clamping gap (11) thus closed enables the clamping device (A) to clamp the yarn being delivered to bobbin. That is during the doffing cycle, when the winding on the bobbin is done and just before the spindle stops, the yarn is delivered by the machine into the clamping gap (11) between clamping elements (8,6).

The clamping elements (8,6) are arranged such that they are movable in opposite directions to one another, wherein atleast one loading springs (5,7) and at least one load relieving balls (9) acts in opposite direction to the direction of the spring force, whereby the load-relieving balls is movable under centrifugal force when the spindle is rotating.

The process of clamping an yarn in a ring spinning machine comprises of axially movable clamping elements (8,6) in opposite direction to one another, loading springs (5,7) for closing the clamping element by means of a loading force, load relieving balls (9) that are positioned on the radial track for generating a relieving force that acts in opposite direction to the direction of the spring force, whereby the load-relieving balls moves in the radial tracks of the clamping device under centrifugal force when the spindle is rotating and whereby the clamping elements can be opened by means of load relieving force.

The present invention works on the principle that when the spindle speed increases beyond certain level, the balls (9) tends to move radially outwards in the tracks due to centrifugal forces of the balls. When the spindle speed approaches the opening speed of the clamping device, the centrifugal force of the balls exceeds the force due to spring (5,7), allowing the balls (9) to move radially outwards. Due to the geometry of the tracks, the clamping elements (8, 6) are separated as the balls (9) slides outwards. And when the spindle speed reduces below the closing speed of the clamping device the balls (9) are moved radially inwards due to the spring force (5, 7).

Further in the present invention during the doffing cycle, when the winding on the bobbin is done and just before the spindle stops, the yarn is delivered by the machine into the clamping gap (11) between clamping elements (8,6). When the spindle stops the full bobbins are exchanged with the empty bobbins, during the exchange of bobbins, the yarn is broken in the region between the bobbin and the clamping device (A). And after the empty bobbins are mounted the spindle rotation starts, the yarn clamped in the clamping device (A) facilitates successful winding of initial turns, on the empty bobbin. When the speed of the spindle increases, the clamping elements (8, 6) gets separated and the clamped yarn end is released, which moves out of the clamping device (A) due to centrifugal force.

Further the spring cup (4) is supported by the helical compression spring (10) resting on the base ring (2). The compression spring (10) facilitates further downward movement of the lower clamping element (6) manually for cleaning, required if there is any yarn accumulation.

In the conventional ring spinning machine the residual yarn accumulated in the device and obstructs the clear or complete travel of the clamping members and due to this effective clamping force reduces. Thus the tendency of yarn slippage due to inadequate clamping increases with the increase in accumulation of the yarn in the device. This generates the necessity to periodically clean the residual yarn accumulation which consumes lot of time.

Hence the problem addressed by the present invention is to increase the reliability of operation and to save time required for cleaning the clamping device. Therefore it is necessary to develop a method for assembling a clamping device (A) such that no yarn accumulation occurs as disclosed by the present invention.

Since in the present invention the clamping device (A) is rotating the yarn is moved out with centrifugal forces. The resistance to the yarn movement is minimal with flat annular contact clamping elements. However it is difficult to achieve adequate clamping forces on the complete annular contact of clamping elements considering the requirements of manufacturing tolerances and tolerances required for moving parts. To resolve this problem the object of the present invention is to propose a method of assembling a clamping device (A) wherein both the clamping elements (8,6) are suspended on springs (5,7) so that the clamping elements (8,6) can align such that they can ensure complete contact of each other.

Further the spring elements (5,7) is arranged such that equally distribution of load is applied at multiple points on the clamping elements (6, 8).

Further the clamping device also comprises a helical compression spring (10) that rests on a base ring (2) of the claiming device.

The technical and commercial advantages of the present invention are to increase production efficiency in mills by reduction in production losses, such as wastage of yarns. This can be achieved by the assembly of the clamping device (A) as proposed in the present invention.

Further Ring frame has large number of spindles approx. 1200 or more. For cleaning the residual yarn the machine has to stop and can be restarted only after cleaning of all devices is completed which needs a long time. This in-turn reduces the productive time of the machine. Saving of this time will help in increasing the production efficiency of the machine. This can be achieved by the assembly of the clamping device (A) as proposed in the present invention.

Although the invention has been disclosed in the context of certain aspects and embodiments, it will be understood by those skilled in the art that the present invention extends beyond the specific embodiments to alternative embodiments and/or uses of the invention and obvious implementations and equivalents thereof. Thus, it is intended that the scope of the present invention disclosed herein should not be limited by the disclosed aspects and embodiments above.

,CLAIMS:WE CLAIM:

1. A clamping device for doffing in a ring spinning or twisting machine comprising:
an inner piece (1);
a cutter (3) fixed on top of the inner piece (1);
an upper clamping element (8) configured to slide axially on the inner piece (1);
a lower clamping element (6) configured to slide axially on the inner piece (1);
a first spring (5) located between the cutter (3) and the upper clamping element (8), wherein the first spring (5) is configured to press the upper clamming element (8) towards the lower clamping element (6);
a second spring (7) located between the lower clamping element (6) and a spring cup (4), wherein the second spring (7) is configured to press the lower clamping element (6) towards the upper clamping element (8); and
a plurality of balls (9) positioned on a radial tracks of the upper clamping element (8) and the lower clamping element, characterized wherein the upper clamping element (8) and the lower clamping element (6) are both configured to move in opposite directions to one another, and further at least one load relieving balls from the plurality of balls (9) act in opposite direction to the direction of the spring force of at least one loading spring from the first spring (5) or second spring (7), the load-relieving balls move under centrifugal force creating a clamping gap (11).

2. The clamping device as claimed in claim 1, wherein the spring cup (4) is supported by means of helical compression spring (10).

3. The clamping device as claimed in claim 1, wherein the helical compression spring (10) rest on a base ring (2) of the claiming device.

4. The clamping device as claimed in claim 1, wherein the helical compression spring (10) facilitates downward movement of the lower clamping element (6) for cleaning.

5. A process of clamping an yarn in a ring spinning machine comprising:
atleast two clamping elements (8,6) axially movable in opposite directions to one another for clamping the yarn;
loading springs (5,7) for closing the clamping element by means of a loading force;
load relieving balls (9) that are positioned on the radial tracks for generating a relieving force that acts in opposite direction to the direction of the spring force;
whereby the load-relieving balls moves in the radial tracks of the clamping device under centrifugal force when the spindle is rotating and whereby the clamping elements can be opened by means of load relieving force creating a clamping gap; and
wherein when the spindle speed reduces below the closing speed of clamping device the load-relieving balls radially move inward due to the spring force generated by the loading spring thus closing the clamping gap.

6. The process of clamping the yarn as claimed in claim 5, wherein as the spindle speed increases beyond certain level the centrifugal force of the balls (9) exceeds the force due to springs (5, 7) allowing the balls (9) to move radially outwards thus creating a clamping gap (11).

7. The process of clamping the yarn as claimed in claim 5, wherein as the spindle speed decreases below certain level the spring force of the springs (5,7) exceeds the centrifugal force of the balls (9) allowing the balls (9) to move radially inwards thus closing a clamping gap (11).

8. A clamping device for doffing in a ring spinning machine comprising:
an inner piece (1);
a cutter (3) fixed on top of the inner piece (1);
at least two clamping element (8, 9) configured to slide axially in direction opposite to each other on the inner piece (1);
at least two loading springs (5, 7), positioned in the cutter (3) and a spring cup (4), are configured to press the at least two clamping elements towards each other by way of spring force; and
a plurality of balls (9) positioned on a radial tracks embedded on the at least two clamping element (8, 9), characterized wherein at least one load relieving balls from the plurality of balls (9) act in opposite direction to the direction of the spring force of at least one loading spring (5,7) the load-relieving balls moves under centrifugal force creating a clamping gap (11).

9. The clamping device as claimed in claim 8, wherein the spring cup (4) is supported by means of helical compression spring (10).

10. The clamping device as claimed in claim 8, wherein the helical compression spring (10) rest on a base ring (2) of the claiming device.