FIELD OF THE INVENTION
The present invention relates to an auto doffer for use in textile spinning machines. Particularly, the invention is concerned to an auto doffer with actuating means for transferring full and empty bobbins in a textile machine such as ring spinning or twisting machine and the like employing linear actuators.
BACKGROUND AND THE PRIOR ART
Generally, the doffers are provided with gripper beams with plurality of grippers for selectively gripping and releasing an individual conical tube/the cop as the case may be, The grippers are mounted on the gripper holder attached to the gripper beam. The gripper beam is attached to a scissor type member. The individual grippers being uniformly spaced from one another at the same spacing as the spindle spacing and means are provided for vertically and laterally moving che gripper beam relative to the textile machine. The laterally moving means being operable to move the gripper beam laterally toward and away from the row of spindles during gripping engagement of the conical tube / cop by the individual gripper. The vertically moving means being operable to raise and lower the gripper beam during the gripping engagement of the conical tube / cop by the individual gripper. The means for moving the gripper beam laterally toward and away from the row of spindles is

normally associated with * swing in ( and 'swing out' mechanism, which is complicated and imposes restriction in the reduction of the cycle time required for doffing.
In a typical arrangement, a textile spinning or twisting machine includes a plurality of spindles uniformly spaced along the longitudinal extent of the textile machine on at least one side thereof. The spindles individually support conical tubes during the building cf yarn thereon in a yarn package building operation during which full yarn packages are built on the conical tubes. Soon after the built up of predetermined length of yarn, the cops are exchanged with empty conical, tubes. To this effect a plurality of empty conical tubes are arranged along a row of spindles so that each empty conical tube is positioned in front of the respective spindle before the start of the doffing cycle. Subsequently the full bobbin other wise known as cops on the spindle are exchanged with the conical tubes by the auto doffer attached to the textile spinning or twisting machine.
US 3793818 discloses an apparatus for doffing full cops mounted on spindles of a textile machine such as draw-twisters for synthetic fibers onto an intermittently circuiatable conveyer mechanism of the zigzag pegs arrangement type and for donning of bare bobbins mounted on the conveyer mechanism onto the spindles by carrying them by pneumatically actuated resilient gripper assemblies which are moved along the prescribed routes by combination of vertical pantagraph motion of a lifting mechanism with horizontal pantagraph motion of a

horizontal displacer mechanism. The above arrangement is having number of levers and supporting brackets and also the drive movement is complicated.
US5125224 discloses an apparatus for transferring empty tubes and full yarn packages built on tubes between a support means and a plurality of spindles of a textile machine. The movement of gripper is by way of a conventional swing in and swing out mechanism.
US4899530 discloses bobbin doffing and donning apparatus there from by which a plurality of full bobbins, e.g. a tube, having a yarn package wound thereon, are removed from their respective spinning, twisting or doubling spindles and replaced by empty bobbins (tubes) on which in the next cycle of operation of the machine the yarns are then wound to form the next lot of packages. The vertical movement of the gripper is done by timing belt drive driven by a motor which but this operation is not accurate and precise.
US4145868 discloses a mobile type auto-doffer, for doffing a plurality of full bobbins from a row of spindles mounted on a spinning machine or a twisting frame and the like, for mounting full bobbins onto a row of pegs disposed between a spindle rail of the machine and a surface of the floor of the spinning plant, for dismounting the same number of fresh bobbins mounted on that row of pegs, and for donning fresh bobbins onto the row of spindles, wherein conveyance of full bobbins after being doffed and conveyance of fresh bobbins to be donned

can be both carried out simultaneously. Gripper beam performs rotational motion.
The doffing operations as described by the prior art referred hereinabove, however, do not disclose a fast, time effective, high precision and accurate doffing cycle.
Thus there is a need for an auto doffer for transferring full and empty bobbins in a textile machine such as ring spinning or twisting machine and the like which could bring about reduction in the doffing cycle time and high precision in the doffing operation.
The inventors have found that the doffing cycle time can be reduced by actuating means for lateral and vertical movements of the gripper means and arranging the doffing cycle such that the effective loading and unloading of the cops alone are done during the stoppage of machine and the connected operations are done before and after the cycle.
OBJECTS OF THE INVENTION
Accordingly, one object of the present invention is to provide auto doffer for textile spinning machine with reduction in the doffing cycle time.

Another object of the present invention is to provide high precision linear actuation for moving the gr ipper assembly.
Yet another object of the present invention is to provide defined movements with controlled limits.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided an auto doffer for textile spinning machine, said doffer comprising:
horizontal support beam (1) oprerably connected to link
means to provide up and down motion to the said
horizontal support beam , said horizontal support beam
being operative!;/ connected to gripper beam (5) , said
gripper beam comprising holder means on which plurality
of gripper means are mounted so as to selectively grip
and release an individual conical tube/cop;
characterized in that the said gripper beam is swingably connected to said horizontal support beam so as to facilitate accurate and high precision transferring of full and empty bobbins in a reduced doffing cycle time.
DETAILED DESCRIPTION OF THE INVENTION
The auto doffing system of the present invention comprises a gripper rail/gripper beam which is connected

to the horizontal support beam by means of plurality of links to facilitate the lateral movement of the gripper beam. The vertical up and down motion or travel of the gripper beam is controlled by a plurality of scissor linkage on which the said horizontal support beam is fitted.
Horizontal movement of the gripper beam is controlled by a drive arrangement through the links. The drive arrangement may be for example linear actuator, pneumatic cylinder and the like. A plurality of grippers being mounted on the gripper holder for selectively gripping and releasing an individual conical tube/ the cop. The moving element of linear actuators described hereinabove may be a ball screw, belt driven by dedicated drive attached to it, which may be stepper motor. But this drive and the type of the moving element of the drive arrangement does not restrict the scope of the present invention.
The grippers are actuated by pneumatic arrangement the. actuation of which is controlled by the control system of the machine.
In order to convey the empty conical tubes from the tube loader attached to the machine as well as to convey the cops unloaded from the spindles to the cop collecting zone a conveyor means is arranged. In the present-invention an endless conveyor for example belt made of synthetic material such as polyurethane on which plurality of pegs are arranged is used. However, the

material of the belt does not restrict the scope of the present invention and any other belt may be used.
The conveyor is driven by suitable known drive means which is controlled by the control system of the ring spinning and twisting machine in a programmed controlled manner.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 schematically illustrates an isometric view of the auto doffer of the present invention.
Figures 2 schematically illustrates the scissor linkage used in the auto doffer of the present invention.
Figures 3 schematically illustrates the drive arrangement used in the auto doffer of the present invention to provide the horizontal movement to the gripper beam.
Figures A schematically illustrates the peg conveyor used in the auto doffer of the present invention.
Figures 5 to 9 schematically illustrate the step of operation of the auto doffer of the present invention.
DETAILED DESCRIPTION OF THE ACCOMPANYING FIGURES
In figure 1 horizontal support beam (1) arranged to the entire working length of the machine shown attached to a

plurality of link means (2) (also shown in figure 2). The said link means comprises scissor linkage is extendable for raising the gripper beam (5) and collapsible for lowering the gripper beam (5). The scissor linkage (2) has a pair of arms, namely first arm (2a) (also shown in figure 2) and second arm (2b) (also shown in figure 2). While the upper end of the first arm (2a) is pivotally connected to the horizontal support beam (1) its lower end is pivotally connected to the guide bracket (2c) (also shown in figure 2) which is rigidly fitted to the pusher (3). The upper end of the second arm (2b) is pivotally connected to slider (2d) (also shown in figure 2) provided to slidably support the horizontal support beam (1). The lower end of the second arm (2b) is pivotally connected to the bracket (4) (also shown in figure 2) fitted on the machine frame. The said bracket
(4) further provided wi. th a passage opening for the
passage of the pusher (3) through it. The pusher (3) is
drivingly connected to a drive arrangement and driven by
any one of the known arrangement such that pusher (3) is
pushed/ pulled to facilitate lifting or lowering of the
horizontal support beam (1). In this manner the gripper
beam (5) (also shown in figure 3) attached to the
horizontal support beam (1) is lifted or lowered as per
the requirement.
In order to provide the lateral movement the gripper beam
(5) is swingably connected to the horizontal support beam
(1). In the drive zones the drive arrangements are
directly mounted on the horizontal support beam (1) and comprises bell crank (6) to swingably connect the gripper

beam (5) and the horizontal support beam (1). The bell crank (6) is provided with a first arm (6a) (also shown in figure 3) and a second arm (6b) (also shown in figure 3) arranged with an appropriate angle in between them is pivotally mounted on the horizontal support beam (1). The first arm (6a! is rigidly connected to the gripper beam (5) and the second arm (6b) is pivotally connected to the moving member (7a) (also shown in figure 3) of the drive arrangement (7) (also shown in figure 3) which may be for example a linear actuator driven by the dedicated motor (7b) (also shown in figure 3) attached to it. The linear actuators (7) through the bell crank (6) provide the required lateral movement to the gripper beam (5). The arrangement according to this invention facilitates that for the purpose of loading of the conical tube (9) / unloading of the cops (10) it is enough to radially displace the gripper beam for a distance half of the centre distance between the spindles (11). This facilitates reduction in the doffing time.
In the non-driving zones a plurality of supporting arms (14) are provided to swingably connected the gripper beam (5) and the horizontal support beam (1) . One end of the
supporting arm (14) is rigidly connected to the gripper
beam (5) and the other end is pivotally connected to the
horizontal support beam (1).
Plurality of grippers are mounted on gripper holder fitted on the gripper beam (5).

Empty conical tubes (9) are conveyed from the tube loader attached to the machine and the cops (10) (also shown in figure 4) unloaded from the spindles (11) are conveyed to the cop collecting zone by a conveyor means (12). Pegs (12a) are arranged on the conveyor means (12) in a pre determined centre distance in between them.
In the present invention during the cop built up i.e. when the spindles are in operation the tube loader attached to machine loads the empty conical tubes on alternate pegs (12a) attached to the conveyor means (12) and the conveyor means (12) is displaced such that equal number of conical tubes are present on the conveyor means (12) below the plurality of the spindles (11) arranged on the spindle rail before the start of the doffing cycle. Each step of the doffing cycle is now illustrated with reference to figures 5 to 9.
HOME
During the cop built up taking place, the horizontal horizontal support beam (1) is at the bottom position, which is the home position. In this position the grippers (8) (also shown in figures 1 and 3) are just above the top edges of the conical tubes (9) (also shown in figure 4) loaded in the pegs (12a) (also shown in figure 4) arranged on a conveyor means (12) (also shown in figure 4) -

STEP 1 (with reference to figure 5)
At a predetermined time, which is just before the completion of the cop built up, the horizontal support beam (1} moves up and stays in the top waiting position before stopping of the spindle with cops for tne doffing.
STEP 2 {with reference to figure 5)
After stopping of the spindle for doffing, the gripper beam (5) attached to the horizontal support beam (1) swings in the horizontal plane such that the plurality of the grippers (8) mounted on the gripper beam (5) are coaxial to spindle (11) with cops (10).
STEP 3 (with reference to figure 5)
The horizontal support beam (1) along with the gripper beam (5) moves down on to the top of the cops (10). Then the grippers (8) are actuated by the control system of the machine for gripping the cops (10).
STEP 4 (with reference to figure 6)
The horizontal support beam (1) along the gripper beam (5) with the grippers (8) grasping the cops (10) move to the top waiting position.

STEP 5 (with reference to figure 6)
The gripper beam (5) swings to a intermediate position in the horizontal plane such that the plurality of the cops (10) grasped by the grippers (8) are coaxial to the pegs (12a) arranged in between conical tubes (9) mounted on the pegs (12a) which are fitted on the conveyor means (12) .
STEP 6 (with reference to figure 6)
The horizontal support beam (1) with the gripper beam (5) along with the cops (10) grasped by the grippers (8) moves down to a pre determined position and releases the cops (10) on to the pegs (12a) which are fitted on the conveyor means (12).
STEP 7 (with reference to figure 7)
Then the conveyor means (12) carrying the conical tubes (9) and the cops (10) loaded on alternate pegs (12a) is moved to half the pitch of the spindle.
STEP 8 (with reference to figure 8)
The horizontal support beam (1) with the gripper beam (5) moves down and the grippers (8) are activated to grasp the conical tubes (9) resting on the pegs (12a) attached to the conveyor means (12).

STEP 9 {with reference to figure 8)
The horizontal support beam (1) along with the gripper beam (5) with the grippers (8) grasping the conical tubes (9) moves to the top position.
STEP 10 (with reference to figure 8)
The gripper beam (5) swings in the horizontal plane such that the plurality of the conical tubes (9) grasped by grippers (8) mounted on the gripper beam (5) are coaxial to spindle (11).
STEP 11 (with reference to figures 8 and 9)
The horizontal support beam (1) along with the gripper beam (5) moves down and place the conical tubes (91 on the spindles (H) ■
STEP 12 (with reference to figure 9)
The horizontal support beam (1) along with the gripper beam (5) moves up to the top waiting position.
STEP 13 (with reference to figure 9)
The gripper beam (5) swings in the horizontal plane such that the plurality of the grippers (8) mounted on the gripper beam (5) are coaxial to the alternate pegs (12a ) mounted on the conveyor means (12).

STEP 14 (with reference to figure 9)
The spindles (11) are restarted. While the cop built up is already in progress the gripper beam (5) along with horizontal support beam (1) comes down to the home position.
Then the conveyor means (12) carrying the plurality of cops (10) is driven by the drive system of the machine and when the conveyor means assumes it direction changing position at the unloading end, the cops (10) are dropped by gravity in to a collecting member which is arranged at the unloading end of the machine.
Subsequently while the cop built up is in progress, the conical tubes (9) are loaded on alternate pegs (12a) arranged on the conveyor means (12) by any one of the known tube loading arrangement (not shown and described) which is normally arranged on the side opposite to that of the unloading end of the machine.
Advantages :
1. Simplified mechanism with accuracy of control of positions.
2. Defined movements with controlled limits and each system is dedicated for a particular function.
3. Saving in doffing cycle time.

4. Delivery of finished cops without damage.
The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its spirit. The invention is not limited to the details cited above. The components herein described may be replaced by its technical equivalence and yet the invention can be performed. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.

WE CLAIM
1. An auto doffer tor textile spitininq machine, said dotfar comprising:
horizontal support beam (1} operably connected to link means to provide up and down motion to the said horizontal beam , said horizontal beam being operatively connected to gripper beam (5) , said gripper beam comprising holder means on which plurality of gripper means are mounted so as to selectively grip and release an individual conical tube/cop;
characterized in that the said gripper beam is swingably connected to said horizontal support beam so as to facilitate accurate and high precision transferring of full and empty bobbins in a reduced doffing cycle time.
2. An auto doffer for textile spinning machine as
claimed in claim 1 wherein horizontal support beam
further comprises at least one drive arrangement,
3, Auto doffer for textile spinning machine as claimed
in claims 1 and 2, wherein the drive arrangement
comprises at least one bell crank (6) pivotaily
mounted on horizontal support beam (1) such that
horizontal movement can be provided to gripper beam
(5) .

4. Auto doffer for textile spinning machine as claimed in claims 1 to 3, wherein bell crank (6) comprises first arm (6a) ana second arm (6b) arranged with an appropriate angle in between them.
5. Auto doffer for textile spinning machine as claimed in claims 1 to 4, wherein the first arm (6a) being rigidly connected to the grippe r beam (5) and the second arm (6b) being pivotally connected to the moving member (7a) of the drive arrangement [1) so as to provide desired later movement of gripper beam (5} .
6. Auto doffer for textile spinning machine as claimed in claim 1, wherein the link means comprises scissor linkage (2) adapted for raising and lowering of the gripper beam (5).
7. Auto doffer for textile spinning machine as claimed in claim 6, wherein the scissor linkage (2) comprises pair of arms comprising first arm and second arm.
8. Auto doffer for textile spinning machine as claimed in claims 6 and 7, wherein the second arm (2b) comprises an upper end having slider (2d) adapted for slidably support the horizontal support beam (1} .

9. Auto doffer for textile spinning machine as substantially herein described and illustrated with reference to accompanying figures,