AN APPARATUS FOR RELEASABLE GRIPPING DEVICE IN A TEXTILE RING SPINNING OR TWISTING MACHINE
FIELD OF THE INVENTION
The present invention relates to a device for releasable gripping in a textile ring spinning or twisting machine equipped with auto doffer and ,in particular, to a griping device in a textile ring spinning or twisting machine equipped with auto doffer which is adapted to make effective utilization of compressed air used in the gripping mechanism in relation to its installation with respect to a gripper rail. Importantly, the gripping device of the invention would avoid the problems of unwanted release of compressed air in the event of dismounting of the gripping device from the gripper frame. Also, the gripping device is adapted further with inflatable movable member and interchangeable fixed member cooperatively facilitating the gripping in such textile ring spinning or twisting machines and the like.
BACKGROUND ART
The usage of ring spinning machines for the production of yarn is known. In a typical arrangement, a textile spinning or doubling machine includes a spindle rail on which are mounted a plurality of spindles uniformly spaced along the longitudinal extent of the textile machine on at least one side thereof. The conical tubes on which the yarn is wound are fitted to the spindles and driven by suitable drive means. The spindles individually support tubes during the building of yarn thereon in a yarn package building operation during which full yarn packages are built on the tubes.
In one conventional arrangement for supplying empty tubes to the spindles and for transporting full yarn packages from the spindles, a belt assembly is provided which includes an endless belt extending parallel to the row of spindles at spacing. The endless belt is provided with two series of vertical posts, each post for individually supporting a tube inserted thereon, with the spacing between the vertical posts of each series being at the same uniform spacing as the spacing between the spindles. The endless belt transports a plurality of empty tubes in upright dispositions to a transfer location below the row of spindles in preparation for transferring full yarn packages from the spindles to the vertical posts of one series of vertical posts and for transferring the empty tubes supported on the other series of vertical posts on the endless belt to the spindles.

German patent DE 12 92 563 discloses one known device, commonly referred to as an ' auto-doffer, for effecting transfer of the empty tubes and full yarn packages between the endless belt and the spindles of a textile machine. The auto-doffer is vertically movable to raise and lower the respective pluralities of empty tubes or full yarn packages supported thereby and, additionally, the auto-doffer is laterally movable in a direction -transverse to the row of spindles so that the supported tubes or packages can be moved laterally outwardly for doffing.
The usage of ring spinning machines for the production of yarn is known in the prior art. Normally the ring spinning machine comprises a spindle rail to carry predetermined number of spindles arranged at predetermined pitch arranged on both side of the machine. The conical tubes on which the yarn is wound are fitted to the spindles and driven by suitable drive means. Ring rails arranged coaxial to the spindle rail and carries spinning ring and traveler assembly of same number and pitch as that of spindle. The ring rails further provided with means for travel up and down in a direction traverse to the spindle axis for the built up of yarn on to the conical tubes attached to the revolving spindles.
Roving bobbins of equal number as that of the spindles are arranged in a creel member attached to the ring spinning machine for the introduction of roving into the drafting arrangement through suitable guide means and drafted. The conical tubes being attached to the spindles and driven by the spindle drive system and the drafted fibre emerging from the drafting rollers which are driven by the drafting arrangement drive system is incorporated with twist by means of the ring and ring traveler assembly and the yarn is produced. The yarn produced in this manner is subsequently wound on the conical tubes and the cop built up takes place. Soon after the conical tubes are filled with predetermined length of yarn, the spindles are stopped and the cop is replaced with empty conical tubes and the machine is subsequently re started.
The presently known ring spinning machines are constructed with spindles in the order of more than 1200. Replacing of the cop with empty conical tubes normally known as doffing and manual doffing of such large number of spindles requires more man power and time consuming. Modern Ring Spinning machines employ auto for the above purpose. The doffer normally comprises a tube loader, peg tray carrying a plurality of pegs, intermediate peg tray and a gripper rail attached to the doffer beam. Conical tubes

are loaded into the pegs arranged in the peg tray by the tube loader and displaced along the row of spindles so that each conical tube is positioned in front of respective spindle. Soon after the cop built up is completed, conical tubes present in the pegs are exchanged with the full bobbins otherwise known as cops by the doffer. During doffing, the conical tubes / the cops are releasably grasped by the gripper.
Grippers provided with rubber membrane arranged co axial to the spindle axis and inflated inwardly to releasably grip the conical tubes / the cops are known in the art. In this type due to the inward inflation of the rubber membrane in the cylinder the rubber gets a number of folds during its expansion and after a number of cycles the rubber membrane gets tear at the folds. This necessitates the costly replacement of the rubber membrane. And the one more disadvantage in this type is, also if the gripper is demounted from the gripper rail during the operation due to reasons like misalignment, the air supply is not stopped to the gripper and hence there is air leakage which affects the air pressure in the entire auto doffer system.
The other known type grippers comprises a moveable member and an inter changeable fixed member. US Patent 5203155 discloses among others things a pusher element displaceable towards and away from the abutment element, and means including an actuator for pushing the pusher element towards the abutment element for clamping the respective tube between the pusher element which is being moveable and the abutment element. The actuator being biased by spring pressure means which pushes the actuator to its home when the gripper is dismounted from the gripper rail. This eliminates the air leakage.
Therefore, there exists a need for a gripper device which can overcome the above mentioned problems in the auto doffer system of a spinning machine.
OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to provide for a gripping device with clamping elements which is directed to take care of one or more of the afore discussed problems of the conventional systems/gripping apparatus presently used in the art.

Another object ot the present invention is directed to a gripping device with clamping elements adapted with enhanced clamping surfaces directed to provide more contact area with the tube for effective gripping.
A further object of the present invention is directed to provide a releasable gripping device in a textile ring spinning or twisting machine which would be cost effective and avoid complex operative units such as any actuators required for pushing the pusher element.
A further object of the present invention is directed to provide a gripping device which would be user friendly, cost effective and importantly also provide for effective utilization of compressed air for gripping function by a cooperative mounting and dismounting arrangement of the gripping device from the gripper frame.
A further object of the present invention is directed to provide a gripping device which would involve a simple and effective gripping mechanism involving an inflatable movable member and an interchangeable fixed member.
Another object of the present invention is directed to provide a gripping device for a textile ring spinning or twisting machine equipped with auto doffer which would involve simple operative units and eliminate the needs for any additional components for actuating movable gripping elements.
Another object of the present invention is directed to a gripping device which would be advantages both in terms of effective gripping function and also user friendly by way of simplicity and cost effective gripper provision for textile ring spinning or twisting machines.
SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided a gripping
device in a textile ring spinning or twisting machine equipped with auto doffer
comprising:
a gripper holder adapted for mounting with respect to a gripper rail and thereby establish
an operative communication with an air duct provided in the gripper rail;
a gripper body adapted for fitting with respect to said gripper holder;

an intiatable clamping element and a stationary clamping element cooperatively adapted to grip an empty conical tube/cops and hold in clamping fashion during doffing operation and release of the empty conical tube /cops at appropriate time;
a non-return valve means adapted to open compressed air communication through said air duct in the gripper rail such that upon mounting of the gripper holder on the gripper rail the said valve means assumes a normally open state whereby if compressed air is passed through said air duct the same reaches the inflatable clamping element for inflating the said inflatable element and along with said stationary clamping element provided for a cooperative gripping function and on dismounting and/ or in misaligned disposition of the gripper body on the gripper holder the said valve is adapted to close the said compressed air communication through said air duct.
In the above gripping device of the invention the said gripper holder, gripper body , a inflatable clamping element and a stationary clamping element together comprise a gripper assembly.
Importantly, the said gripper holder is adapted to be mounted on the gripper rail preferably by fastener means and is obtained of plastic material preferably selected from nylon, ABC by injection moulding process.
In accordance with an aspect of the invention , the gripping device comprises a stem/protrusion for operating a non return valve and a nut for fastening the gripper holder on the gripper rail which are embedded in the gripper holder preferably as an integral piece such that the gripper holder can be mounted on the gripper rail with a single screw. Preferably, the non return valve is fitted in a stem provided in the gripper holder.
In the above gripping device the compressed air enters the gripper rail through a hole and reaches the inflatable clamping element through the non return valve .
For such purpose ,when the gripper body is fitted on the gripper holder, a protrusion provided in the gripper body is adapted to press the non return valve and there by the non return valve reaches the normally opened state and under such disposition of the valve when ever compressed air is passed to the gripper rail, the same reaches the inflatable clamping element and in the event of dismounting of the gripper assembly due

to reasons like misalignment the non return valve, since the protrusion is no more pressing the non return valve the same gets closed and prevents the flow of the compressed air to the atmosphere, even though the compressed air is supplied to the gripper rail.
The gripper body is preferably obtained of plastic material comprising nylon, ABC and preferably manufactured by injection moulding process.
Advantageously, in the gripping device the gripper body is provided with an aperture to receive the empty conical tube / cops with the tube entering side aperture obtained of in the shape of an inverted funnel to facilitate aligning of the conical tube / cops to the center of the gripper body .
The gripper body is further provided with a passage opening to receive the inflatable clamping element and the said inflatable clamping element preferably constructed in box shape with six sides and provided with opening at one side to receive the compressed air which is being supplied for inflating it such that all the four sides of inflatable clamping element are arrested and the inflatable clamping element can expand only in the side opposite to that of the opening provided for air entry which facilitates the gripping of the conical tube / cops, the said inflatable clamping element being further provided with a flange like protrusions at its opening side, adapted to get seated in the corresponding recess provided in the gripper body. The aforesaid protrusions also serve as air tight seal between the gripper body and the gripper holder .
Importantly, the stationary clamping element is adapted to be fitted to the gripper body in the side opposite to that of the inflatable clamping element with said stationary clamping element comprising a separate component or an integral part of the gripper body.
In accordance with another aspect of the invention, the inflatable clamping element and the stationary clamping element are selectively shaped, located and spaced such that when the moveable clamping element is inflated, the conical tube / cops are firmly gripped in between them, the gripping face of the stationary clamping element and the moveable clamping element are provided with clamping surfaces of curved shape for the effective holding of the conical tube /cops.

The curvature of the clamping surfaces are adapted according to the geometry of the conical tube being handled by the textile ring spinning or twisting machine.
The gripper body is further provided with plurality of flexible lugs to facilitate snap fitting with the gripper holder.
It is thus possible by way of the above disclosed gripping device for a textile ring spinning or twisting machine equipped with auto doffer to provide for effective functioning of the gripping device during the time of doffing. For effective use of the gripping device the gripper rail to which the device is mounted is positioned at predetermined place such that the inflatable clamping element and the stationery clamping element are at the proximity of the gripping portion of the conical tube/cops. The compressed air supply is coordinated and initiated such that only when required and after effective disposition of the gripping device the compressed air supply inflates the inflatable clamping element with the conical tube/cops gripped in between the inflatable clamping element and the fixed clamping element. Subsequently the gripper rail carrying the plurality of conical tube/cops is moved to the next predetermined position. In such new position of the gripper rail the compressed air supply is stopped and the conical tube/cops are dropped on to the peg/spindle as the case may be.
Advantageously, as would be apparent from the features of the gripping device of the invention, the same provides for clamping elements with enhanced clamping surfaces which provide more contact area with the tube for effective gripping in a textile ring spinning or twisting machine. The gripping device is simple to obtain and does not require any actuator for pushing the pusher element.
Importantly, the gripping device of the invention serves for effective gripping involving use of compressed air and more importantly incorporates mechanism to eliminate to release of the compressed air in the event of the dismounting of the gripping device from the gripper rail. The selective provision of the non return valve provides to arrest the wastage of compressed air in the event of dismounting of the gripper from the gripper rail.
The fixed member of the clamping element can comprise of interchangeable fixed member adapted to cooperate with the inflatable movable member for the cooperative clamping action.

The details of the invention, its objects and advantages are explained hereunder in greater detail in relation to non limiting exemplary illustrations of the gripping device in a textile ring spinning or twisting machine equipped with auto doffer in accordance of the present invention as per the following accompanying figures :
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES:
Figure 1 illustrates the three dimensional view of the gripping device assembly according to the present invention ; and
Figure2 illustrates the sectional view of the gripping device assembly mounted on the gripper rail according to the present invention.
DETAILED DESCRIPTION OF THE ACCOMPANYING FIGURES:
As would be apparent from the disclosure herein before this invention provides a gripping device for changing the empty conical tube / cops during the doffing cycle of the ring spinning or twisting machine which comprises a plurality of gripper assembly mounted on the gripper holder, the gripper being provided with a stationary clamping element and a inflatable clamping element, the gripper assembly being fitted by snap fit with the gripper holder ,the gripper holder being mounted on the gripper rail and provided with a means for stopping the air supply in the event the gripper assembly is dismounted from the gripper holder for reasons such as misalignment of the gripper assembly and the empty conical tube / cops.
Reference is now invited to accompanying Figures 1 and 2 which illustrate an embodiment of the gripper device in accordance with the present invention. As shown in the said figures, the gripping device basically comprises a gripper assembly (1) comprising a gripper holder (2) , gripper body(3), an inflatable clamping element (4) and a stationary clamping element (5 ) .The inflatable clamping element (4) and the stationary clamping element (5 ) are adapted to cooperatively grip the empty conical tube / cops (18) between themselves and hold them in a clamping fashion during the subsequent doffing operation and release the empty conical tube / cops at the appropriate time. The gripper holder (2) being mounted on the gripper rail (7) by fastener means. The gripper holder (2) may be conveniently manufactured using plastic material such as nylon, ABC by injection moulding process. A stem (8) for operating a non return valve (6) and a nut (9) for fastening the gripper holder (2 ) on the gripper rail (7) may be

embedded in the gripper holder (2)during the molding process itself, and they may be made as an integral piece such that the gripper holder(2) can be conveniently mounted on the gripper rail (7) with a single screw. The non return valve (6) being like that one used in the pneumatic tubes used in the automotive tyre and being fitted in the stem (8) provided in the gripper holder (2).
The gripper holder (2) on mounting with the gripper rail (7) establishes flow communication with the air duct (17) provided in the gripper rail (7). The compressed air entering the gripper rail (7) through the hole (10) can reach the inflatable clamping element (4) through the non returned valve (6). When the gripper body(3) is fitted on the gripper holder (2), a protrusion (11) provided in the gripper body (3) press the non return valve(6) and there by the non return valve(6) reaches the normally opened state. By this when ever compressed air is passed to the gripper rail, the same reaches the inflatable clamping element (4). In the event of dismounting of the gripper assembly due to reasons like misalignment the protrusion (11) is no more pressing the non return valve (6) and the same get closed and prevents the flow of the compressed air to the atmosphere, even though the compressed air is supplied to the gripper rail.
The gripper body (3) may be made of plastic material such as nylon, ABC and preferably manufactured by injection moulding process. The gripper body (3) being provided with an aperture (13) to receive the empty conical tube / cops. The tube entering side the aperture (13) is constructed in the shape of an inverted funnel to facilitate aligning of the conical tube / cops to the center of the gripper body (3). The gripper body (3) is provided with a passage opening (14) to receive the inflatable clamping element (4). The inflatable clamping element (4) being constructed in box shape with six sides and provided with opening at one side to receive the compressed air which is being supplied for inflating it. Since all the four sides of inflatable clamping element (4) are arrested, the inflatable clamping element (4) can expand only in the side opposite to that of the opening provided for air entry which facilitates the gripping of the conical tube / cops. The inflatable clamping element(4) being further provided with a flange like protrusions (15 ) at its opening side, which get seated in the corresponding recess provided in the gripper body(3).
The protrusions also serves as air tight seal between the gripper (3) body and the gripper holder (2).The stationary clamping element (5) is fitted to the gripper body(3)

in the side opposite to that of the inflatable clamping element(4). The stationary clamping element (5) may be a separate component or it may be the integral part of the gripper (3) body. The inflatable clamping element (4) and the stationary clamping element (5) are shaped, located and spaced such that when the moveable clamping element (4) is inflated, the conical tube / cops being (18) firmly gripped in between them. The gripping face of the stationary clamping element (5) and the moveable clamping element (4) are provided with clamping surfaces of curved shape for the effective holding of the conical tube /cops. The curvature of the clamping surfaces being adopted according to the geometry of the conical tube being handled by the textile ring spinning or twisting machine. The gripper body (3) further being provided with a plurality of flexible lugs (16) to facilitate snap fitting with the gripper holder (2). The plurality of flexible lugs (16) being arranged in a plane perpendicular to the axis of the aperture (13) . This facilitates the dismounting of the griper body (3) from the griper holder(2) in the event of misalignment of the cop/conical tube.
It is thus possible by way of the above gripping device to favour effective functioning of gripping device during the time of doffing. The gripper rail is positioned at the pre determined location such that the inflatable clamping element and the stationary clamping element are at the proximity of the gripping portion of the conical tube/cops. The compressed air supply is initiated and the compressed air inflates the inflatable clamping element and the conical tube/cops being gripped in between the inflatable clamping element and the fixed clamping element. Subsequently, the gripper rail carrying the plurality of conical tube/cops is moved to the next pre determined position. In the new position of the gripper rail the compressed air supply is stopped and the conical tube/cops are dropped on to the peg/spindle as the case may be.
The above invention and ,in particular, the gripping device advantageously provides for the required enhanced clamping surfaces directed to provide more contact area with the tube for effective and reliable gripping. Also, the releasable gripping device in a textile ring spinning or twisting machine is cost effective and avoids complex operative units such as any actuators usually required for pushing the pusher element of such gripper units. The gripping device of the invention would thus be user friendly, cost effective and importantly provide the required efficient and reliable gripping function for textile ring spinning or twisting machines and the like.

WE CLAIM:
1. A gripping device in a textile ring spinning or twisting machine equipped with
auto doffer comprising:
a gripper holder adapted for mounting with respect to a gripper rail and thereby establish an operative communication with an air duct provided in the gripper rail;
a gripper body adapted for fitting with respect to said gripper holder;
an inflatable clamping element and a stationary clamping element cooperatively adapted to grip an empty conical tube/cops and hold in clamping fashion during doffing operation and release of the empty conical tube /cops at appropriate time;
means provided to allow the compressed air in to the inflatable clamping element only when the gripper body is mounted in the gripper holder and to disallow the compressed air in to the inflatable clamping element when the gripper body is dismounted and / or in misalignment with the gripper holder.
2. A gripping device as claimed in claim 1 wherein said gripper holder, gripper body , a inflatable clamping element and a stationary clamping element comprises a gripper assembly.
3. A gripping device as claimed in anyone of claims 1 or 2 wherein said gripper holder is mounted on the gripper rail preferably by fastener means and is obtained of polymer material preferably selected from nylon, ABC by injection moulding process.
4. A gripping device as claimed in anyone of claims 1 to 3 comprising a stem/protrusion for operating a non return valve and a nut for fastening the gripper holder on the gripper rail are embedded in the gripper holder preferably as an integral piece such that the gripper holder can be mounted on the gripper rail with a single screw.
5. A gripping device as claimed in anyone of claims 1 to 4 wherein the non return valve is fitted in a stem provided in the gripper holder.

6. A gripping device as claimed in anyone of claims 1 to 5 wherein the compressed air enters the gripper rail through a hole and reaches the inflatable clamping element through the non returne valve .
7. A gripping device as claimed in anyone of claims 1 to 6 wherein w hen the gripper body is fitted on the gripper holder, a protrusion provided in the gripper body is adapted to press the non return valve and there by the non return valve reaches the normally opened state and under such disposition of the valve when ever compressed air is passed to the gripper rail, the same reaches the inflatable clamping element and in the event of dismounting of the gripper assembly due to reasons like misalignment the non return valve, since the protrusion is no more pressing the non return valve the same gets closed and prevents the flow of the compressed air to the atmosphere, even though the compressed air is supplied to the gripper rail.
8. A gripping device as claimed in anyone of claims 1 to 7 wherein the gripper body is obtained from polymer material such as nylon, ABC and preferably manufactured by injection moulding process.
9. A gripping device as claimed in anyone of claims 1 to 8 wherein the gripper body is provided with an aperture to receive the empty conical tube / cops with the tube entering side aperture obtained in the shape of an inverted funnel to facilitate aligning of the conical tube/cops to the center of the gripper body .
10. A gripping device as claimed in anyone of claims 1 to 9 wherein the gripper
body is provided with a passage opening to receive the inflatable clamping
element the said inflatable clamping element preferably constructed in box
shape with six sides and provided with opening at one side to receive the
compressed air which is being supplied for inflating it such that all the four sides
of inflatable clamping element are arrested and the inflatable clamping element
can expand only in the side opposite to that of the opening provided for air entry
which facilitates the gripping of the conical tube / cops, the said inflatable
clamping element being further provided with a flange like protrusions at its
opening side, adapted to get seated in the corresponding recess provided in the
gripper body.

11. A gripping device as claimed in anyone of claims 1 to 10 wherein the said
protrusions also serve as air tight seal between the gripper body and the gripper
holder.
12. A gripping device as claimed in anyone of claims 1 to 11 wherein the stationary
clamping element is adapted to be fitted to the gripper body in the side
opposite to that of the inflatable clamping element , said stationary clamping
element comprising a separate component or an integral part of the gripper
body.
13. A gripping device as claimed in anyone of claims 1 to 12 wherein the inflatable
clamping element and the stationary clamping element are selectively shaped,
located and spaced such that when the moveable clamping element is inflated,
the conical tube / cops are firmly gripped in between them, the gripping face of
the stationary clamping element and the moveable clamping element are provided
with clamping surfaces of curved shape for the effective holding of the conical
tube /cops.
14. A gripping device as claimed in anyone of claims 1 to 13 wherein the curvature
of the clamping surfaces are adapted according to the geometry of the conical
tube being handled by the textile ring spinning or twisting machine.
15. A gripping device as claimed in anyone of claims 1 to 14 wherein the gripper
body is further provided with plurality of flexible lugs to facilitate snap fitting
with the gripper holder, the plurality of flexible lugs facilitate the dismounting of
the gripper body from the griper holder in the event of misalignment of the cop /
conical tube with the griper body.
16. A gripping device in a textile ring spinning or twisting machine equipped with
auto doffer substantially as herein described and illustrated with reference to the
accompanying figures.
Dated this 23rd day of January 2007