Field of Invention:
The invention relates to an automatic yarn winding turret type device that can
reliably and precisely position a spindle for winding after the bobbin changeover.
Background of Invention5 :
The automatic turret type winder is used for winding of continuously arriving
tapes, threads, or bands onto a bobbin. In general, on the turret type winder, a pair
of bobbin holders—also known as spindles—are mounted on the opposite ends of
a rotatable turret mounted on suitable machine frame. Each spindle is alternately
10 displaced from the normal winding position to the doffing position by every half
rotation of the turret. The turret keeps on rotating in the same direction at required
time intervals. Each spindle needs precisely controlled rotation around its own
axis, so may be driven independently by an electric motor through a suitable
mechanism such as a belt and pulley arrangement or with an independent direct
15 driving electrical motor system. Conventionally, the encoders or other suitable
devices are mounted on the motor for monitoring the motor revolutions, and the
signal is communicated to an electronic controller with the help of a suitable
cable. The controller further sends the electrical signals to the inverter/drive of the
active motor which determines the power to be given for the motor driving the
20 spindle.
The conventional winders of the above type are disclosed in the US Patent Nos.
5228630, 4765552 and European Patent 861800A2.
3
Automatic turret type winders were introduced for providing bobbins of
polyolefin flat/fibrillated yarns and to improve efficiency, reduce wastages.
Automatic changeover process replaces spindle carrying yarn bobbin with the
spindle carrying an empty bobbin5 .
In these conventional automatic winders, the turret is rotated by using a clutch and
a pulley in synchronicity. Turret rotation is performed by releasing clutch and
transferring the driving force to the pulley for rotation. After the turret rotation,
10 correct positioning of empty bobbin is done by drifting bobbin in reverse direction
towards the CAM box pressure roller. Ideally, spindle is positioned such that
pressure roller should exert pressure uniformly on spindle present for winding.
Reverse movement of turret carrying spindle is controlled according to the pre-set
time and speed parameters in the control system. Practically, in conventional
15 systems, turret movement is not uniform, and therefore not as smooth as required,
due to change in mechanical condition. Machines of the type being discussed here
are generally not operated under entirely dust-free environment. Therefore, as
time progresses, accumulation of foreign particles on the mechanical components
of the machinery increases even after taking abundant precaution to clean and
20 maintain the machine. Accumulation of particulate matter provides hindrance to
smooth motion of moving elements over a period of time. In other words, the
system's resistance to smooth movement of components increases due to general
wear and tear and accumulation of particulate matter.
4
For instance, a turret could become jammed due to accumulation of dust particles
or may become tightened or loosened than required during maintenance cycle,
leading to a turret rotation that is either faster or slower than desired or jerky.
These mechanical glitches often result in improper spindle positioning relative to
the pressure roller. Improper positioning causes a gap between the spindle bobbi5 n
which is ready to be wound and the pressure roller, which in turn produces uneven
winding tension and therefore non-uniform package density.
Second, the stated problem in conventional winding system develops when the
10 turret motion pushes the pressure roller extra in reverse direction. Similar to prior
stated problem, this condition also produces variation in winding tension and
formation of groves or undulations on the bobbin surface.
Therefore, there is a need to provide a method to position spindle precisely in
15 turret type automatic winder automatic method, especially a method to identify
correct stationing position of turret spindle after reverse movement post doffing.
There is also a need to provide a system that reduces possibility of turret
positioning itself at an intermediate location, thereby leaving a gap between the
20 spindle and the pressure roller, or positioning itself past its desired location,
thereby exerting extra pressure on the roller.
5
Objects of the invention:
Accordingly, it is an object of the present invention to provide a method to
position spindle precisely in turret type automatic winder, especially method to
identify correct stationing position of Turret spindle after reverse movement post
doffing5 .
Another object of the present invention is to provide a system that reduces
possibility of Turret positioning itself at an intermediate location, thereby leaving
a gap between the spindle and the pressure roller, or positioning itself past its
10 desired location, thereby exerting extra pressure on the roller.
List of parts:
Turret (1)
Spindle (2A)
15 Spindle (2B)
Tape (3)
CAM box (4)
Pressure Roller (5)
Tape Guide (6)
20 First and second bobbins (7, 7A)
Tensioning Bow (8)
Winding position line (9)
Close-by positional line (9')
25 Summary Of Invention
The invention relates to an automatic turret type yarn winding device. The
automatic bobbin changeover process involves winding of yarn on a bobbin,
followed by rotation of the turret to bring an empty bobbin into the winding
position. Pressure rollers are provided to ensure consistent and accurate winding.
6
The accurate relative positioning of the bobbins and pressure rollers is important.
Wear and tear and particulate dust may cause malfunctioning of winder systems
which may affect accuracy of turret rotations and relative positioning of the
bobbins and pressure rollers, especially when the turret rotation during bobbin
changeover stage is done in a single rotation. The invention provides a device an5 d
a method to position spindle precisely in turret type automatic winder, especially
to identify correct stationing position of turret spindle after reverse movement
post doffing. It involves, during the bobbin changeover process, the step of
rotating the turret in at least two discrete rotational movements carried out at
10 controlled speeds, whereby the empty bobbin assumes its accurate winding
position.
Brief description of figures:
The objects and advantages of the invention may be understood by making
15 reference to the following description, taken with the accompanying drawings:
Figure 1 shows a schematic of a turret with two spindles;
Figure 1A shows a perspective view of a turret with two bobbins
Figure 2 shows a schematic where the pre-set package size is reached;
Figure 3 shows a schematic of the transitional movement of the turret during the
20 bobbin changeover process;
Figure 4 shows a schematic representing bobbin locations at the end of first
rotational movement
7
Figure 5 shows a schematic of positioning of the turret and the bobbin at the final
intended winding position
Detailed Description of the invention:
The present invention discloses a method for precisely positioning the turret after
the bobbin changeover5 .
Figure 1 shows the present invention in an operational state. It shows a turret (1)
at the start of a winding operation. It has empty first and second bobbins (7, 7A)
mounted on two spindles (2A and 2B) with their centres respectively termed as
10 points A and A', which fall on what is termed as a winding-position-line (9) or a
bobbin positional axis/line, and where one of the two spindles (2A) is in a
winding position to start winding. The position of the winding positioning line
(9), which is an imaginary axis, is a position that is suitable for winding of yarn
and will be known to a person skilled in the art. When the turret (1) is in this
15 position, centres (A and A') of both bobbins (7, 7A) (presently empty) fall on the
winding positional line (9) and one of the empty winding bobbins (7 or 7A) which
is mounted on the spindles (2A or 2B) optimally touches the pressure roller (5). In
this position, the pressure exerted by the first bobbin (7) which is in the winding
position and the pressure roller (5) on each other is the optimal pressure for a
20 given yarn (3), something a person skilled in the art would readily know.
In the description that follows, the terms spindles and bobbins are used
interchangeably.
8
The tape (3) is delivered for winding after cutting and conditioning from tape line
machine (not shown in figures) from direction ‘a’ (indicated as an arrow in Figure
1) and after passing through a dancing arm (not shown in figures) which regulates
tape tension. The tape line speed of discharging tapes (3) varies from 100 to 5 1000
meters per minute; the linear density of the tape material varies from 100 to 30000
denier.
Tape winding starts on the presently empty first bobbin (7) after a CAM box (4)
10 bows down by an angle ‘θ’ (measured from the vertical) in the direction ‘b’
(indicated by a counterclock-wise arrow in Figure 1). The magnitude of the angle
is dependent on the turret geometry/design and would be known to a person
skilled in the art. As the tape (3) winding progresses, the first bobbin (7) package
diameter grows to a predetermined value. At this stage, a bobbin changeover is
15 expected whereupon the common controller for the winder head instructs the
motor of turret driving system (not shown in figures) to rotate for the bobbin
changeover, such that the now empty second bobbin (7A) assumes the winding
position.
20 Figure 2 shows a position of the CAM box (4) where the preset first bobbin (7)
diameter after winding of yarn has been achieved. As a part of the bobbin
changeover process, the CAM box now rotates in a clockwise direction (i.e. a
direction opposite to b) and the pressure roller (5) retracts from the wound first
9
bobbin (7). A device that carries out the aforementioned rotation of the CAM box
(4) may be an electromechanical, or a pneumatic or hydraulic system. Following
the retractive rotation of the CAM box, the turret (1) begins to rotate in a direction
indicated by arrow 'c' in Figure 3, which shows the turret in a state of transitional
movement5 .
At the end of the transitional movement, according to the invention, the turret
reaches a position such that the now empty second bobbin (7A) which is mounted
on the spindle (2B) reaches a position close to the winding position (Figure 4). At
10 the actual winding position, the centre (A') of the second bobbin (7A) should
precisely be at the position previously occupied by the centre (A) of the nowfilled
first bobbin (7) at the start of its winding. However, according to the present
invention, at the end of the transitional movement, the line joining the bobbin
centres (A-A') achieved at the end of the transitional movement is not
15 coincidental with the final position for winding represented by the winding
positional line (9); actual position of the line joining centres of both bobbins (AA')
at the end of the transitional movement is deliberately drifted by an angle ‘ϕ’
(see Figure 4), termed as the displacement angle, with respect to required winding
positional line (9). In one aspect of the invention, the displacement angle (ϕ) may
20 be up to 45o. The actual positional line joining the centres (A, A') of two bobbins
(7, 7A) at the end of first rotational movement is termed as a close-by positional
line (9'). If, as is the conventional manner, after winding of the operational first
bobbin (7) is complete, turret (1) at the end of its transitional movement is rotated
10
from its original winding position to its final position (so that the empty second
bobbin (7A) is in a winding position) in a single continuous movement (as
indicated by rotational direction arrow 'c'), then there is a strong possibility that
the spindle needing to be wound would stop before or after the pressure roller
location – but not at the precise desired location5 .
The present invention therefore proposes that the final position of the second
bobbin (7A) is arrived at as a result of at least two discrete rotational movements.
In the case where there are only two discrete rotational movements, the total
10 rotational movement comprises a first and a second rotational movement. At the
end of the transitional movement also termed as first rotational movement
(indicated by arrow c in Figure 3) for the purpose of this description, the empty
second bobbin (7A) is intentionally stopped at the close-by position (9'). At the
final intended winding position (9), the pressure roller leans on the empty second
15 bobbin (7A) and exerts a gentle pressure on it before the winding can begin. The
rotational speed of the first rotational movement depends on various parameters
such as the yarn type and denier, line speed, winder designs in general, and would
be known to a person skilled in the art.
20 The first rotational movement is followed by a second rotational movement
(indicated by direction d in Figure 4) in the direction required for the second
bobbin (7A) to attain the final intended position, which takes place at a speed
slower than the first rotational speed. As the second rotational movement
11
continues and the second bobbin (7A) approaches its final winding position, and
at some point touches the pressure roller (5) which may have already reached its
predetermine location or in process of reaching it. At this point in time, the
current in the turret motor starts to rise. The second rotational movement is
stopped when the current in the motor reaches a predetermined value, indicatin5 g
that the pressure roller (5) and the second bobbin (7A) are in the required final
relative positions where the winding can begin. In some winding systems, the
winding of the second bobbin (7A) may have already started before the pressure
roller (5) and the second bobbin (7A) assume their required final relative
10 positions.
As one aspect of the invention, the rotational speed (measured in RPM) of the
second rotational movement may be up to 25% of the first rotational speed. This
is done because controlling the movement at slow speeds to attain accurate final
15 positioning of the second bobbin (7A) is far more feasible or achievable than
trying to do so at high speed carried out in a single rotational movement. It is
preferable, but not necessary, that the position of the second bobbin (7A) at the
end of the first rotational movement is past the intended final position such that
the directions c and d may be opposite to each other.
20
In another embodiment, the position achieved by the second bobbin (7A) at the
end of the first rotational movement is before its final intended position. In this
situation, the second rotational movement takes places in the same direction as the
12
first rotational movement, i.e. the directions c and d may be same (i.e. both may
be clockwise).
The final winding position of the second bobbin (7A) (see Figure 5), is such that
the second bobbin (7A) touches the pressure roller (5) at a position where ta5 pe
tension does not vary much during winding process. In the preferred embodiment,
the second bobbin (7A) reaches required position by rotating slightly in reverse
direction ‘d’ (see Figure 4). Typically, this reverse motion (d) is controlled by set
parameters, however, sometimes due to the problems related to the mechanical
10 adjustment of the parts facilitating the motion, the spindle does not reach the
correct position. There is therefore a need to provide a procedure that will identify
the exact position of the spindle.
The present invention synchronizes software logic and hardware such that when
15 the second bobbin (7A) touches pressure roller (5), the current of motor driving
the turret driving system increases; when driving motor current reaches above a
pre-determined value, turret driving system sends a command to the motor of the
turret drive system to stop and lock reached optimum position of the second
bobbin (7A).
20 The invention can be also implemented by mounting strain gauge sensor on
pressure roller supporting arms, such that, as pressure applied by the second
bobbin (7A) on pressure roller (5) increases above set pressure limit the control
logic of turret driving system stops and locks the final turret position.
13
Secondly, present invention invokes a method which can work precisely under
low maintenance conditions.
It is apparent that the present invention has the following embodiments.
1. A method to position spindle precisely in turret type automatic winder, said
winder incorporating a rotatable turret (1) driven by a motor, said moto5 r
being controlled by a turret driving system, on which turret (1) at least a first
and a second bobbins (7, 7A) are mounted on respective spindles (2A, 2B) in
a diametrically opposite position along a winding-positional-line (9), and
wherein the first bobbin (7) is positioned in a position of winding a tape on it
10 whereby, at the start of the tape winding process, said first bobbin (7) touches
a pressure roller (5) provided on said winder, characterized in that said
method comprises the step of, upon said first bobbin (7) reaching its
predetermined package size, rotating the turret (1) in at least two discrete
rotational movements carried out at controlled speeds, preferably two discrete
15 rotational movements, wherein a first rotational movement is carried out at a
controlled first rotational speed up to a point where the centres (A, A') of said
bobbins (7, 7A) fall on a close-by positional line (9'), whereby said close-by
positional line (9') and said winding positional line (9) are at a finite
displacement angle (ϕ) with each other, followed by rotating said turret in a
20 required direction at a controlled second rotational speed to carry out a
second rotational movement, up to a point where said second bobbin (7A)
touches said pressure roller (5), followed by triggering a stop-and-lock action
to stop the rotation of said turret (1).
14
2. A method as disclosed in embodiment 1, characterized in that said second
controlled speed is less than or equal to first controlled speed.
3. A method as disclosed in any of embodiments 1 to 2, characterized in said
stop-and-lock action comprises the steps of
- increasing the current in said motor up to the predetermined value of sai5 d
motor
- sending a command to said motor through said turret driving system, to
stop the second rotational movement of said turret (1) upon attainment of
said predetermined value of current and then lock said turret (1) at the
10 position reached at the end of said second rotational movement.
4. A method as disclosed in any of embodiments 1 to 2, characterized in that
characterized in said stop-and-lock action comprises the steps of
- increasing the threshold value of strain sensing device inbuilt with
pressure roller
15 - sending a command to said motor through said turret driving system, to
stop the second rotational movement of said turret (1) upon attainment of
said predetermined value of strain and then lock said turret (1) at the
position reached at the end of said second rotational movement.
5. A method as disclosed in any of embodiments 1 to 4, characterized in that
20 said first movement is carried out so that said centre (A') of said second
bobbin (7A) crosses over said winding-positional-line (9).
15
6. A method as disclosed in embodiment 5, characterized in that the direction of
rotation of said second rotational movement is opposite to the direction of
rotation of said first rotational movement.
7. A method as disclosed in embodiment 6, characterized in that the direction of
rotation of said second rotational movement is same as the direction o5 f
rotation of said first rotational movement.
8. An apparatus to position spindle precisely in turret type automatic winder,
said winder incorporating a rotatable turret driven by a motor, said motor
being controlled by a driving system, on which turret at least a first and a
10 second bobbins (7, 7A) are mounted on respective spindles (2A and 2B) in a
diametrically opposite position along a winding-positional-line (9), and
wherein the first bobbin (7) is positioned in a position of winding a tape on it
whereby, at the start of the tape winding process, said first bobbin (7) touches
a pressure roller (5) provided on said winder, characterized in that said
15 apparatus is capable of, upon said first bobbin (7) reaching its predetermined
package size, rotating the turret (1) in at least two discrete rotational
movements carried out at controlled speeds, preferably two discrete rotational
movements, wherein a first rotational movement is carried out at a controlled
first rotational speed up to a point where the centres (A, A') of said bobbins
20 (7, 7A) fall on a close-by positional line (9'), whereby said close-by positional
line (9') and said winding positional line (9) are at a finite displacement angle
(ϕ) with each other, followed by rotating said turret in a required direction at
a second controlled speed to carry out a second rotational movement, up to a
16
point where said second bobbin (7A) touches said pressure roller (5),
followed by triggering a device to enable stop-and-lock action to stop the
rotation of said turret (1).
9. An apparatus as disclosed in embodiment 8, characterized in that said second
controlled speed less than or equal to first controlled spee5 d.
10. An apparatus as disclosed in any of embodiments 8 to 9, characterized in that
said device for enabling said stop-and-lock action increases the current in
said motor up to the predetermined value of said motor.
11. An apparatus as disclosed in any of embodiments 8 to 10, characterized in
10 that said device for enabling said stop-and-lock action increases the
predetermined threshold value of said strain sensing device inbuilt with said
pressure roller.
12. An apparatus as disclosed in any of embodiments 8 to 11, characterized in
that said first movement is carried out so that said centre (A') of said second
15 bobbin (7A) crosses over said winding-positional-line (9).
13. An apparatus as disclosed in any of embodiments 8 to 12, characterized in
that the direction of rotation of said second rotational movement is opposite
to the direction of rotation of said first rotational movement.
14. An apparatus as disclosed in embodiment 8 to 11, characterized in that the
20 direction of rotation of said second rotational movement is same as the
direction of rotation of said first rotational movement.
15. An apparatus disclosed in any of embodiments 8 to 14, characterized in that
said device is capable of increasing the current in said motor up to the rated
value of said motor, followed by the step of sending a command to said
17
motor through said driving system, to stop the rotation of said turret (1) and
lock said turret (1) in that position where it stops at the end of second
rotational movement.
16. An apparatus as disclosed in any of embodiments 8 to 14, characterized in
that said device comprises a strain gauge sensor mounted on pressure rolle5 r
supporting arms, such that, as pressure applied by spindle on pressure roller
(5) increases above set pressure limit the control logic of turret, said driving
system stops and locks the final turret position.
10 While the above description contains much specificity, these should not be
construed as limitation in the scope of the invention, but rather as an
exemplification of the preferred embodiments thereof. It must be realized that
modifications and variations are possible based on the disclosure given above
without departing from the spirit and scope of the invention. Accordingly, the
15 scope of the invention should be determined not by the embodiments illustrated,
but by the appended claims and their legal equivalents.

We claim:
1. A method to position spindle precisely in turret type automatic winder, said
winder incorporating a rotatable turret (1) driven by a motor, said motor
being controlled by a turret driving system, on which turret (1) at least a first
and a second bobbins (7, 7A) are mounted on respective spindles (2A, 2B) i5 n
a diametrically opposite position along a winding-positional-line (9), and
wherein the first bobbin (7) is positioned in a position of winding a tape on it
whereby, at the start of the tape winding process, said first bobbin (7) touches
a pressure roller (5) provided on said winder, characterized in that said
10 method comprises the step of, upon said first bobbin (7) reaching its
predetermined package size, rotating the turret (1) in at least two discrete
rotational movements carried out at controlled speeds, preferably two discrete
rotational movements, wherein a first rotational movement is carried out at a
controlled first rotational speed up to a point where the centres (A, A') of said
15 bobbins (7, 7A) fall on a close-by positional line (9'), whereby said close-by
positional line (9') and said winding positional line (9) are at a finite
displacement angle (ϕ) with each other, followed by rotating said turret in a
required direction at a controlled second rotational speed to carry out a
second rotational movement, up to a point where said second bobbin (7A)
20 touches said pressure roller (5), followed by triggering a stop-and-lock action
to stop the rotation of said turret (1).
2. A method as claimed in claim 1, characterized in that said second controlled
speed is less than or equal to first controlled speed.
3. A method as claimed in any of claims 1 to 2, characterized in said stop-and25
lock action comprises the steps of
- increasing the current in said motor up to the predetermined value of said
motor
19
- sending a command to said motor through said turret driving system, to stop
the second rotational movement of said turret (1) upon attainment of said
predetermined value of current and then lock said turret (1) at the position
reached at the end of said second rotational movement.
4. A method as claimed in any of claims 1 to 2, characterized in tha5 t
characterized in said stop-and-lock action comprises the steps of
- increasing the threshold value of strain sensing device inbuilt with
pressure roller
- sending a command to said motor through said turret driving system, to
10 stop the second rotational movement of said turret (1) upon attainment of
said predetermined value of strain and then lock said turret (1) at the
position reached at the end of said second rotational movement.
5. A method as claimed in any of claims 1 to 4, characterized in that said first
movement is carried out so that said centre (A') of said second bobbin (7A)
15 crosses over said winding-positional-line (9).
6. A method as claimed in claim 5, characterized in that the direction of rotation
of said second rotational movement is opposite to the direction of rotation of
said first rotational movement.
7. A method as claimed in claim 6, characterized in that the direction of rotation
20 of said second rotational movement is same as the direction of rotation of
said first rotational movement.
8. An apparatus to position spindle precisely in turret type automatic winder,
said winder incorporating a rotatable turret driven by a motor, said motor
being controlled by a driving system, on which turret at least a first and a
25 second bobbins (7, 7A) are mounted on respective spindles (2A and 2B) in a
diametrically opposite position along a winding-positional-line (9), and
wherein the first bobbin (7) is positioned in a position of winding a tape on it
20
whereby, at the start of the tape winding process, said first bobbin (7) touches
a pressure roller (5) provided on said winder, characterized in that said
apparatus is capable of, upon said first bobbin (7) reaching its predetermined
package size, rotating the turret (1) in at least two discrete rotational
movements carried out at controlled speeds, preferably two discrete rotationa5 l
movements, wherein a first rotational movement is carried out at a controlled
first rotational speed up to a point where the centres (A, A') of said bobbins
(7, 7A) fall on a close-by positional line (9'), whereby said close-by positional
line (9') and said winding positional line (9) are at a finite displacement angle
10 (ϕ) with each other, followed by rotating said turret in a required direction at
a second controlled speed to carry out a second rotational movement, up to a
point where said second bobbin (7A) touches said pressure roller (5),
followed by triggering a device to enable stop-and-lock action to stop the
rotation of said turret (1).
15 9. An apparatus as claimed in claim 8, characterized in that said second
controlled speed less than or equal to first controlled speed.
10. An apparatus as claimed in any of claims 8 to 9, characterized in that said
device for enabling said stop-and-lock action increases the current in said
motor up to the predetermined value of said motor.
20 11. An apparatus as claimed in any of claims 8 to 10, characterized in that said
device for enabling said stop-and-lock action increases the predetermined
threshold value of said strain sensing device inbuilt with said pressure roller.
12. An apparatus as claimed in any of claims 8 to 11, characterized in that said
first movement is carried out so that said centre (A') of said second bobbin
25 (7A) crosses over said winding-positional-line (9).
21
13. An apparatus as claimed in any of claims 8 to 12, characterized in that the
direction of rotation of said second rotational movement is opposite to the
direction of rotation of said first rotational movement.
14. An apparatus as claimed in any of claims 8 to 11, characterized in that the
direction of rotation of said second rotational movement is same as th5 e
direction of rotation of said first rotational movement.
15. An apparatus as claimed in any of claims 8 to 14, characterized in that said
device is capable of increasing the current in said motor up to the rated value
of said motor, followed by the step of sending a command to said motor
10 through said driving system, to stop the rotation of said turret (1) and lock
said turret (1) in that position where it stops at the end of second rotational
movement.
16. An apparatus as claimed in any of claims 8 to 14, characterized in that said
device comprises a strain gauge sensor mounted on pressure roller supporting
15 arms, such that, as pressure applied by spindle on pressure roller (5) increases
above set pressure limit the control logic of turret, said driving system stops
and locks the final turret position.