FIELD OF THE INVENTION
The present invention generally relates to textile machines. Particularly, the invention relates to an automatic yarn piecing arrangement for textile ring spinning machines. More particularly, the invention deals with an improved positioning device for the automatic piecing unit of textile ring spinning machines.
BACKGROUND OF THE INVENTION
In textile spinning mills, yarn breakage in ring spinning machines is a frequent problem that requires continuous attention of the labours / work force. The yarn breakage nowadays remains an unavoidable problem in ring spinning machines which has forced huge number of workers / manual labours to continuously monitor the ring spinning machines at both the sides throughout the length of the machine frame, which is normally more than 1600 spindles. The broken yarns have to be pieced manually and the yarn spinning sequence has to be restarted then and there after yarn breakage, in order to avoid wastage of yarn. The stamina and health of the workers also gets affected due to day long walking along the long spinning frames to manually piece the broken yarn ends.
Automatic piecing units are developed as an improvement towards the conventional method of manual piecing. The automatic piecing units involves a robot or worker in a piecing vehicle or piecing unit which has in-built drive units, sensing units, suction units, gripping units, support units which are normally required for automatic piecing units. Such automatic piecing units are required to be positioned precisely in front of the ring spinning machine frame spindles through support units. The piecing unit moving longitudinally has a tower arrangement with piecing arms in a support unit. Before initiating

piecing operation, the piecing unit has to be positioned accurately in front of the spinning position.
In known type of auto piecing units, it is common to position the piecing unit with a V-notch when the unit is moved forward at the spindle base position extending towards the spindle bolster (as shown in Figure 1). This type of single V-notch forces the whole platform carrying the piecing unit to match with the position of the spindle. Moreover, this type single V-notch design does not correct a misalignment to the spindle row. The platform tends to have a horizontal angular displacement (shown as a and p in Figure 1) so that when the piecing unit reaches forward, it misses the positions.
In order to overcome the above shortcomings, the forthcoming invention disclosure provides an improved positioning device for the automatic piecing unit of textile ring spinning machines.
OBJECTS OF THE INVENTION
The main object of the present invention is to provide an improved piecing unit for textile ring spinning machines.
Another object of the present invention is to provide an improved positioning device for piecing unit of the textile ring spinning machines.
It is yet another object of the present invention to provide an improved positioning device for automatic piecing unit of the ring spinning machines which ensures precise piecing operation.
SUMMARY OF THE INVENTION

According to the invention, the textile ring spinning machine is provided with an improved automatic piecing unit. The automatic piecing unit assists in yarn piecing operation during yarn breakage incidents in ring spinning machines. The accuracy and efficiency of yarn piecing operation depends on the positioning of the piecing head in front of the spinning machine precisely. In the existing arrangements, when the piecing unit advances towards the spinning position, there is no proper mechanism to ensure the piecing head is precisely positioned to. detect the broken yarn ends and to piece the yarn ends perfectly.
To achieve proper piecing, the present invention provides an improved automatic yarn piecing unit with at least two V-notch profiles facing the spinning positions of the ring spinning machine. The inner contour of said V-notches locates with at least two spindle bolsters adjacent to the spinning position which requires automatic piecing unit assistance. This precise positioning arrangement enables there is no shake or misalignment at the piecing head during automatic piecing operation.
According to the present invention, the piecing unit is provided with a positioning device to position the platform of said piecing unit that serve several positions of a textile machine and moves along a textile machine and has a mechanical final positioning system characterized in that at least two position finders that are connected to said platform are moved towards fixed position elements.
According to an embodiment of the present invention, said position finders are fork elements having V shaped cut outs that position on the spindle base / bolster.

According to another embodiment of the present invention, at the start and end of the track a position element is added that simulates a spindle.
According to yet another embodiment of the present invention, the platform can move in two axis when moving forward.
According to yet another embodiment of the present invention, the forward movement of the platform is done by two linear actuators.
According to an embodiment of the present invention, the textile machine is a ring spinning machine.
According to the present invention, a method for positioning a platform of a piecing unit that serve several positions of a textile machine and moves along a textile machine, said method comprising, moving the platform towards the textile machine, positioning at least two position finders of the piecing unit with fixed position elements of the textile machine.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawing, illustrating by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 illustrates the positioning device of piecing unit according to the known art.

Figure 2 illustrates the improved positioning device of piecing unit according to an embodiment of the present invention.
Figure 3 illustrates the perspective view of the positioning device of automatic piecing unit according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
As already described in background part of the invention, figure 1 shows existing positioning device. The spindle beam (1) with plurality of spindles (2) are depicted in top schematic view. The platform (4) of the automatic piecing unit is moved forward and positioned with the base position / bolster of the spindle (2) by a V-notch / V-type fork (3). In this arrangement, disadvantageously, the platform (4) shifts at an angle horizontally with respect to the spindle axis. The said angular displacement is depicted as a and p. The piecing unit wheels (5) are depicted schematically.
The present invention as shown in figure 2 and figure 3, is provided with at least two substantially V-type forks (3) that positions the platform (4) of the automatic piecing unit precisely. As the platform (4) is moved towards the spinning machine, the two V-forks (3) locates with at least two spindle bases / bolsters (2). The forward movement of the platform (4) is done by two linear actuators (6). The linear actuators (6) may include pneumatic cylinders, electric cylinders, and the like. The tower (7) arrangement having piecing head moves forward along with the platform (4) for piecing operation. There is no possible deviation with respect to the spindle row and the piecing unit exactly positions and reaches its destination.

The bottom surface of the platform (4) is provided with stopper pin elements that will lock with V shaped cut outs provided in another fixed member provided below the platform (4), while returning to home position after piecing operation (not shown). This will ensure the tower (7) is at home position after automatic piecing operation.
The yarn break signal from textile machine is provided to a control unit. The control unit assists in the movement of the piecing unit to the specified location. The platform (4) movement towards the textile machine for locating with the spindle bolster (2) is controlled by the control unit. After successful piecing, the platform (4) with tower (7) moves back to home position with the aid of control unit (not shown).
As an alternate embodiment, the V-shaped parts can be provided in the spindle base / bolster and a pin like member is provided in the moving platform of the piecing unit for positioning.
Advantageously, the location technique according to the present invention ensures the piecing head is precisely positioned in front of the spinning machine at the piecing zone. This precise positioning arrangement enables there is no shake or misalignment at the piecing head during automatic piecing operation. The precise positioning arrangement is not usually available in the conventional piecing units. Hence the automatic piecing operation is not successful in conventional piecing arrangements.
Advantageously, at the start and end of the track, a position element is added that simulates a spindle. The platform can move in 2 axis when moving forward.

Thus, the above described automatic piecing unit for ring spinning machine frame provides an accurate and precise positioning of the piecing heads. Advantageously, the positioning arrangement according to the present invention results in improved and accurate piecing of the broken yarn ends by the automatic piecing unit in ring spinning machines.
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.

We claim:
1. A positioning device to position the platform of a piecing unit that serve several positions of a textile machine and moves along a textile machine and has a mechanical final positioning system characterized in that at least two position finders (3) that are connected to said platform (4) are moved towards fixed position elements (2).
2. The positioning device as claimed in claim 1 characterized in that, said position finders (3) are fork elements having V shaped cut outs that position on the spindle base / bolster (2).
3. The positioning device as claimed in claim 1 characterized in that, at the start and end of the track a position element is added that simulates a spindle.
4. The positioning device as claimed in claim 1 characterized in that, the platform can move in two axis when moving forward.
5. The positioning device as claimed in claim 1 characterized in that, the forward movement of the platform (4) is done by two linear actuators.
6. The positioning device as claimed in claim 1 characterized in that, the textile machine is a ring spinning machine.
7. Method for positioning a platform of a piecing unit that serve several positions of a textile machine and moves along a textile machine, said method comprising, moving the platform (4) towards the textile machine,

positioning at least two position finders (3) of the piecing unit with fixed position elements (2) of the textile machine.
8. The method as claimed in claim 7 characterized in that, said position finders (3) are fork elements having V shaped cut outs that position on the spindle base / bolster (2).
9. The method as claimed in claim 7 characterized in that, said textile machine is a ring spinning machine.

The present invention deals with an improved positioning device for a piecing unit of a textile machine. The platform of the piecing unit is provided with at least two positioning forks that matches with the fixed position elements of the textile machine. The piecing unit is automatic type which pieces the broken yarn ends. The textile machine is preferably ring spinning machine.