Title of Invention	METHOD AND DEVICE FOR OPERATING A WORKSTATION OF A TEXTILE MACHINE PRODUCING CROSS WOUND BOBBINS
Abstract	Method for operating a workstation of a textile machine producing cross-wound bobbins, comprising a creel for holding a relatable wind-on bobbin, a thread traversing mechanism, which is driven by a single motor, and a sensor element which can be calibrated and supplies a measured value that is proportional to the position of the thread guide, characterized in that a proper operating mode of the sensor element (19) is ensured in that an adjustment takes place between measured values supplied by the sensor element (19) and defined positions of the heard guide (13), at predeterminable time intervals and/or in relation to events.

Title of Invention

METHOD AND DEVICE FOR OPERATING A WORKSTATION OF A TEXTILE MACHINE PRODUCING CROSS WOUND BOBBINS

Abstract

Method for operating a workstation of a textile machine producing cross-wound bobbins, comprising a creel for holding a relatable wind-on bobbin, a thread traversing mechanism, which is driven by a single motor, and a sensor element which can be calibrated and supplies a measured value that is proportional to the position of the thread guide, characterized in that a proper operating mode of the sensor element (19) is ensured in that an adjustment takes place between measured values supplied by the sensor element (19) and defined positions of the heard guide (13), at predeterminable time intervals and/or in relation to events.

Full Text	FORM 2 THE PATENT ACT 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10, and rule 13) TITLE OF INVENTION METHOD AND DEVICE FOR OPERATING A WORKSTATION OF A TEXTILE MACHINE PRODUCING CROSS WOUND BOBBINS APPLICANT(S) a) Name : SAURER GMBH & CO., KG b) Nationality : GERMAN Company c) Address : LANDGRAFENSTRASSE 45, D-41069,MONCHENGLADBACH, GERMANY PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed : - PATENTS ACT 1977 VERIFICATION OF TRANSLATION Certificate of Priority Document on the filing of a Patent Application. File No. 10 2005 001 094.6 I, ASTRID TERRY, Translator of 11 Bounds Oaks Way, Tunbridge Wells, Kent, TN4 0UB, confirm that I am familiar with the English and German languages, and that to the best of my knowledge and belief the accompanying document which has been prepared by me, is a true translation of the authentic text of the Certificate of Priority Document on the filing of the Patent Application File No. 10 2005 001 094.6 dated 8th January 2005. Signed this 24th day of 2005 Description The invention relates to a method for operating a workstation of a textile machine producing cross-wound bobbins according to the preamble of claim 1 and a device for carrying out the method according to claim 5. In order to produce a textile bobbin, it is necessary, as known, on the one hand, to make the relevant textile bobbin rotate and, on the other hand, to traverse the thread which is winding onto the bobbin along the bobbin axis. By means of relatively fast traversing of the thread, a so-called cross-winding can thus be produced. Cross-wound bobbins of this type are not only distinguished by a relatively stable bobbin body, but also by good unwinding behaviour. With regard to the winding of cross-wound bobbins of this type a distinction is made between the winding type "random winding" and the winding type "precision winding" or "step precision winding". In particular, in conjunction with the winding type "random winding", so-called thread guide drums are often used in this case, which do not only traverse the thread which is winding on, but simultaneously also form a peripheral drive for the cross-wound bobbin. However, thread guide drums of this type cannot be used to produce a precision or step precision winding, as, in the production of these winding types, the drive of the cross-wound bobbin and the drive of the thread 2 traversing mechanism have to be separated. This means that in the production of a cross-wound bobbin of the winding type precision or step precision winding, the cross-wound bobbin is driven by a separate bobbin drive and the thread which is winding on is placed by an additional, separately driven thread traversing mechanism. Mechanisms, in which the thread guide, which is displaceable parallel to the rotational axis of the cross-wound bobbin, is connected to a reciprocating single drive via a traction means, or mechanisms, which operate with a so-called finger thread guide or wiper, in other words, thread guides, which have a finger-like thread placing lever, which can be pivoted over a certain angle range about an axis arranged substantially perpendicularly to the cross-wound bobbin axis, for example, have proven to be very suitable for fast thread cross-winding with accurate positioning. DE 100 21 963 Al describes a workstation of a textile machine producing cross-wound bobbins, in which a sleeve rotatably held in a creel can be rotated by a drive roller, which has a separate drive. The workstation also has a traversing thread guide, which can be fixed to a continuous belt and can be guided back and forth by a single drive which can be controlled in a defined manner, within a traversing stroke, which can be changed with respect to its length. The single drive of the traversing thread guide is coupled in this case to an angle transmitter, which detects the rotor position of the electric motor and transmits it to a controller. 3 DE 100 21 963 Al, however, contains no more detailed indications about the precise construction and the mode of functioning of the angle transmitter used. A workstation for a textile machine producing cross-wound bobbins is also known from DE 198 58 548 Al, in which the bobbin drive and the thread traversing mechanism have separate drives. The thread traversing mechanism is configured in this case as a finger thread guide, which is acted upon by an electromagnetic drive. The electromagnetic drive of the thread guide drive is thus controlled by a microprocessor, which controls the current strength and the current direction according to a predeterminable programme as a function of the angle and time in such a way that over the traversing width, the respectively desired placing angle of the thread is produced or in that the traversing width or the traversing end points can be adjusted in a targeted manner. To detect the instantaneous angle, an infrared light barrier is used in this case, which scans markings arranged coaxially to the axis of oscillation. Optical sensor mechanisms of this type are, however, not completely without problems owing to the air, which, as is known, is often substantially charged with dust and fluff in spinning works and winding departments. In other words, optical sensor mechanisms of this type require a relatively high outlay for cleaning to remain as far as possible free of disruption. DE 103 54 587 published subsequently describes a workstation of a textile machine producing cross-wound bobbins, which has a creel for holding a 4 rotatable wind-on bobbin and a finger thread guide for traversing a supplied thread. The electric motor single drive of the finger thread guide is equipped, in this case, with an angle sensor, which is connected to a workstation computer and has a pivotally mounted permanent magnet and a stationary Hall IC element. An angle sensor of this type in this case has a plurality of advantages. The relatively economical similar Hall IC element, which is influenced by the magnetic flux of a pivotally mounted permanent magnet, for example generates voltage values, which are proportional to the angle position of the permanent magnets and therefore to the angle position of the finger thread guide and can easily be processed by the workstation computer. These voltage signals emitted while traversing the thread placing lever of the thread guide also have a virtually linear course in the range covered by the finger thread guide between about -40° and +40°. As angle sensors of this type work contactlessly and therefore free of wear, they are furthermore distinguished by a long service life. It is also positive that angle sensors of this type only have a relatively small moment of inertia and therefore can be used reliably at high traversing speeds. It is disadvantageous, however, with these angle sensors, which are tried and tested per se, that fault influences appear in the course of time due to the principle. These fault influences due to the principle have to include, for example, the temperature drift or the ageing process of the permanent magnets. 5 Proceeding from the above-mentioned prior art, the invention is based on the object of developing a method or a device, which allows proper operation of a workstation of a textile machine producing cross-wound bobbins over a relatively long time period. In particular, it is to be ensured thereby, that the measured values of the angle sensor of the thread guide remain very precise over the entire service life of the mechanism. This object is achieved according to the invention by a method, as described in claim 1 and a device according to claim 5. Advantageous configurations of the method according to the invention or the pertaining device are the subject of the sub- claims . The method according to the invention reliably prevents fault influences due to the principle, such as, for example, the temperature drift or the ageing process of the permanent magnets being able to falsify the measured values of the angle sensor over time in a gradual and therefore unnoticed manner. In other words, owing to a periodic and/or event-related adjustment of the measured values supplied by a sensor element, with defined positions of the thread guide, fault influences are reliably recognised and, for example, correspondingly taken into account by the workstation computer. 6 As shown in claim 2, the thread guide is initially moved successively into two determined, defined positions to determine corresponding measured values of the sensor element. In these defined positions, a measured value is then generated in each case by the sensor element. The determined measured values are compared in the workstation computer and/or processed to calculate a characteristic correction curve of the sensor element. The characteristic correction curve calculated by the workstation computer in this case characterises the measured value course of the electric voltage, which the sensor element generates at this instant, when the thread guide traverses between its reversal points. As shown in claim 3, during the winding process, the workstation computer allocates according to the characteristic correction curve the associated position of the thread guide to each voltage generated by the sensor element, and this is then used to control the thread guide. In an advantageous configuration, the characteristic correction curve determined, as shown in claim 4, is used at least until the next adjustment. In other words, at the next adjustment, the characteristic correction curve is recalculated with the aid of the then existing measured values by means of the workstation computer and, if the calculation produces this, is replaced by a new characteristic correction curve. 7 According to claim 5, the device for carrying out the method according to the invention, in an advantageous embodiment, has a thread traversing mechanism acted upon by a single drive, an angle sensor equipped with a Hall IC element and a workstation computer. The angle sensor in this case supplies a respective measured value proportional to the position of a thread guide. Moreover, means are provided, which allow a positioning of the thread guide in defined positions. This means that precisely defined positions are available, in which an adjustment of the measured values supplied by the angle sensor can be made with known thread guide positions. As described in claim 6, the workstation computer is configured in this case such that it immediately links each electric voltage generated by the Hall IC element of the angle sensor with an associated position of the thread guide. In this manner, the workstation computer is in a position to optimally control the thread guide, in particular with regard to the reversal points thereof. In an advantageous embodiment, the thread guide, as described in claim 7, is configured as a finger thread guide, the thread placing lever of which can be positioned by disposing it on two stops, in each case in defined angle positions. In these so-called adjustment positions, in each case, a measured value generated by the Hall IC element of the angle sensor is detected and used in the workstation computer to calculate a characteristic correction curve of the angle sensor. This characteristic correction curve calculated by 8 the workstation computer characterises the instantaneous course of the electric voltage generated by the angle sensor at this instant during the traversing of the thread placing lever. This means that, by means of the workstation computer, when determining the respective angle of position of the thread placing lever, fault influences, which are produced from the construction principle of the angle sensor, for example on the basis of a certain ageing of the permanent magnet, are taken into account. As described in claim 8, in a preferred embodiment, the range which can be covered by the angle sensor during calibration thereof is between +40° and -40°. This means that this region is slightly larger than the operating region of the finger thread guide, the thread placing lever of which covers a range between +37.5° and -37.5° during the winding operation. A generous dimensioning of this type of the range which can be covered by calibration ensures that the installation tolerances occurring, for example during assembly of the thread guide drive can be reliably adjusted. The positioning of defined stops at +39° and -39° also easily allows an adjustment of the measured values supplied by the angle sensor with known angle positions of the thread placing lever of the thread guide. In other words, when the thread placing lever is disposed on these stops, it is ensured that the measured values generated by the angle sensor always relate to the same angle position and differences in these measured values are to be attributed to fault influences of the angle sensor due to the principle, which are taken into account by the workstation computer in calculating a characteristic correction curve. 9 In a further advantageous configuration it is provided that the angle sensor has a resolution of 0.024° (claim 9). Such a high resolution of the angle sensor allows a precise approach of the thread reversal points during thread traversing and therefore a homogeneous bobbin structure. The invention will be described in more detail hereinafter with the aid of an embodiment shown in the drawings. In the drawings: Fig. 1 schematically shows a workstation of a textile machine producing cross-wound bobbins, comprising a bobbin drive and a separate thread guide driven by a single motor, the drive of which is equipped with an angle sensor, Fig. 2 shows the angle sensor in cross-section, arranged on the shaft of the thread guide drive, Fig. 3 shows the angle sensor, according to Section III-III of Fig- 2, Fig. 4 shows the finger thread guide in the viewing direction of the arrow X, during an adjustment of the angle sensor, 10 Fig. 5 shows an angle position/initial voltage graph during an adjustment of the angle sensor. Fig. 1 shows a schematic side view of the workstation 2 of a textile machine producing cross-wound bobbins, in the present case a so-called automatic cross-winding machine 1. At the workstations 2 of automatic cross-winding machines 1 of this type, as known and therefore not described in more detail, the spinning cops 3 produced on a ring spinning machine are rewound to form large-volume cross-wound bobbins 5. The cross- wound bobbins 5, after their completion, are passed for example by means of an automatically operating service unit (not shown) to a machine-length cross-wound bobbin transporting mechanism 7 and transported to a bobbin loading station or the like arranged on the machine side. Automatic cross-winding machines 1 of this type generally also have a bobbin and tube transporting system 6, in which, the spinning cops 3 or empty tubes circulate on transporting plates 11. Of the bobbin and tube transporting system 6, only the cop supply section 24, the memory section 25, which can be driven reciprocally, one of the transverse transporting sections 26 leading to the winding heads 2 and the tube return section 27 are shown in Fig. 1. The individual workstations 2 also have, as known and therefore only indicated, various mechanisms, which ensure proper operation of workstations of this type. One of these mechanisms is, for example, the winding device 4. The winding device 4 has a creel 8 movably mounted, about a pivot axis 12. According to the present embodiment, the cross- 11 wound bobbin 5, during the winding process, lies with its surface on a drive drum 9 and is entrained by frictional engagement by this drive drum 9, which is acted upon by a single motor. The corresponding drive has the reference numeral 33. To traverse the thread 16 during the winding process, a thread traversing mechanism 10 is provided. A thread traversing mechanism 10 of this type indicated only schematically in Fig. 1 has, for example, a thread guide 13, with a finger-like thread placing lever 45. The thread placing lever 45 traverses, acted upon by an electromechanical drive 14, the thread 16, between the two end faces of the cross-wound bobbin 5. The drive 14 of the thread guide 13 is fixed in this case, for example, by a bracket (not shown), on the winding head housing 34 of the relevant workstation 2. Moreover, both the drive 14 of the thread guide 13 and the drive 33 of the drive drum 9 are connected to the workstation computer 28 via control lines 15 and 35. As can be seen, for example, from Fig- 2, the drive 14 has a motor shaft 17, on which the thread placing lever 45 configured in a finger-like manner is arranged in a manner secured against rotation. On the side of the motor shaft 17 opposite the thread guide 13, an angle sensor 19 is mounted so as to be protected under a removable cover cap 18; the construction of said angle sensor will be described hereinafter. As shown in Fig. 2, a plastics material moulded part 31 is fixed on the housing 39 of the drive 14, on the side opposing the thread placing lever 45 12 and has both a fastening hole 36 for a sensor carrier 23 and a bearing pin 37 for a printed circuit board 38 equipped with an electronic circuit 32. The electronic circuit 32 may in this case, contain, for example, a memory chip and an electronic control mechanism. A Hall IC element 29 is fixed on the sensor carrier 23 in a stationary manner and communicates with a permanent magnet 20, which is connected so as to be secured against rotation to the motor shaft 17 of the drive 14 via a support ring 21 and a screw bolt 22. Fig. 3 shows a rear view of the drive 14, in other words a view of the angle sensor 19 according to Section III-III of Fig. 2. As shown, the permanent magnet 20 is configured as a two-pole radially magnetisable annular magnet, the poles North, South of which are arranged orthogonally in the shown central position of the thread guide 13, in other words in the angle position 0°, with respect to the stationarily arranged Hall IC element 29. In other words, when the thread guide 13 adopts an angle position 0°, the poles North, South of the magnet ring 20 are aligned at right angles to the Hall IC element. Fig. 4 shows a view of the thread traversing mechanism 10 according to the viewing direction of the arrow X of Fig. 1 during an adjustment of the angle sensor 19. As shown, stops are let into the front plate 44 of the thread guide drive 14 in holes arranged in a defined manner and in each case define a predefined, exact angle position of the thread placing lever 45. The stops 40, 41 are in this case preferably positioned such that the thread placing lever 45 disposed during the adjustment at the stop 40 precisely has an angle 13 position of - 39°, while the angle position of the thread placing lever 45 at the stop 41 is precisely +39°. The electric voltage V initiated by the Hall IC element 29 during the disposing of the thread placing lever 45 on the stop 40 or 41 is processed in the electronic circuit 32 of the angle sensor 19 and passed on via a data and control line 15 to the workstation computer 28, which calculates therefrom if necessary, a characteristic correction curve, with the aid of which, each measured value can be allocated to a specific angle position of the thread placing lever 45. Characteristic curves 42, 43 are shown in Fig. 5 with the aid of a coordinate system and indicate the electric voltage course which is generated by the programmable Hall IC element 29 and is dependent on the angle positions of the thread placing lever 45 and therefore on the angle positions of the permanent magnet 20. The range in angle degrees, which can be covered in this case by the thread placing lever 45 during a thread traversing operation is shown on the abscissa of the coordinate system, while the ordinate of the coordinate system shows the voltage in volts generated by the Hall IC element 29; in other words the voltage V which the Hall IC element 29 generates from the magnetic flux of the permanent magnets 20, the angle position thereof and an apparatus constant. 43 in this case characterises a characteristic curve for the voltage course of the angle sensor 19, as was produced after calibration of the angle sensor 19 at the beginning of its use. In the embodiment, according to the characteristic curve 43 at an angle position of the thread placing lever 45 of - 39°, there is a voltage, for example, )f 0.71 V at the angle sensor 19. At an angle position of the thread placing 14 lever 45 of +39°, the corresponding voltage at the angle sensor 19 is 4.83 V. As indicated by the characteristic curve 43, the voltage course in the traversing range between -39° and +39° covered by the thread placing lever 45 is very substantially linear. In the central position 0° of the thread placing lever 45, a voltage of, for example 2.76 volts, is consequently produced at the angle sensor 19. The characteristic curve 42 shows the voltage course determined during a later adjustment of the angle sensor 19. In the embodiment, the electric voltage generated by the angle sensor 19 during this adjustment at an angle position of the thread placing lever 45 of -39° is 0.56 V. At an angle position of the thread placing lever 45 of +39°, 4.47 V are generated. As the characteristic curve 42 also has a very substantially linear course, this produces, for the central position 0° of the thread placing lever 45 at the angle sensor 19, a voltage of, for example 2.48 volts. A resolution 0.024° can be produced, for example, with the present angle sensor 19. Before starting up the thread guide drive 14 in the workstation 2, the angle sensor 19 firstly has to be calibrated. During this calibration of the angle sensor 19 on the fully assembled drive 14, various methods can be used, which are described in relative detail in DE 103 54 587, published subsequently. 15 In the case of one of these calibration methods, the magnetic characteristic curve of the permanent magnet 20 of the angle sensor 19, for example, is measured with the aid of defined angle positions of the thread placing lever 45 of the thread guide 13. In other words/ the thread placing lever 45 is positioned successively in defined angle positions by means of a simple mechanical device, for example, two stops 40, 41 and thus in each case detects the electric voltage generated because of the magnetic flux of the permanent magnet 20 in the Hall IC element 29. The workstation computer 28 of the relevant winding head 2 then calculates a first characteristic curve for the angle sensor 19 with the aid of the known positions of the thread placing lever 45 and the detected measured values of the angle sensor. This first characteristic curve is characterised in the coordinate system of Fig. 5 with the reference numeral 45. As indicated in Fig. 5, a specific angle position of the thread placing lever 45 and a corresponding measured value of the angle transmitter 19 are allocated to each point of the characteristic curve 45. With a central position of the thread placing lever 45, in other words with an angle position of 0°, the associated measured value of the angle sensor is, for example 2.76 V. The adjustment method according to the invention proceeds as follows: As the characteristic curve of the angle sensor 19 changes in the course of time due to the principle, for example owing to ageing of the permanent magnets 20 of the angle sensor 19 or owing to temperature drift or the like, a measured value of, for example 2.76 V only corresponds for a specific time 16 exactly to an angle position of 0° of the thread placing lever 45. In order to be able to ensure exact measured values of the angle sensor 19 even over a relatively long period of time, the angle sensor 19 is therefore adjusted from time to time. In this second calibration method, the magnetic characteristic curve of the permanent magnet 20 is remeasured. This may take place in an external calibrating device or in the workstation. The determined correction values are then stored either in the workstation computer 28 of the winding head or in an additional memory chip (not shown) of the electronic circuit 32 of the angle sensor 19. In other words, the thread placing lever 45 is again moved, successively, to the defined stops 40, 41 and, in these angle positions, detects the measured values generated by the angle sensor 19. From these detected measured values, the workstation computer 28 then calculates a characteristic correction curve 42, as shown in Fig. 5. The characteristic correction curve 42 has a linear course. Furthermore, a specific angle position of the thread placing lever 45 and an associated measured value of the angle sensor 19 in volts are allocated to each point of the characteristic correction curve 45. In the characteristic correction curve 42 shown in Fig. 5 as an embodiment, a measured value of, for example 0.56 V, corresponds to an angle position of the thread placing lever 45 of -39°. In the central position 0° of the thread placing lever 45 there is a measured value of 2.48 V at the angle sensor 19, 17 while the measured value of the angle sensor 19 at an angle position of +39° of the thread placing lever 45 is, for example 4.47 V. The characteristic correction curve 42 of the angle sensor 19 remains decisive until the next adjustment and is then optionally replaced by a new characteristic correction curve, which is also determined by a corresponding adjustment. 18 Claim: Method for operating a workstation of a textile machine producing cross-wound bobbins, comprising a creel for holding a rotatable wind-on bobbin, a thread traversing mechanism, which is driven by a single motor, and a sensor element which can be calibrated and supplies a measured value that is proportional to the position of the thread guide, characterised in that a proper operating mode of the sensor element (19) is ensured in that an adjustment takes place between measured values supplied by the sensor element (19) and defined positions of the thread guide (13), at predeterminable time intervals and/or in relation to events. Method according to claim 1, characterised in that to determine the measured values of the sensor element (19) during a winding interruption, the thread guide (13) is moved successively into determined, defined positions, in that in these positions, a respective measured value of the sensor element (19) is detected and in that the detected measured values are processed in the workstation computer (28) to calculate a characteristic correction curve (43) of the sensor element (19). Method according to claim 2, characterised in that during the winding process, the workstation computer (28, according to the characteristic correction curve (43), allocates the associated position of the thread 19 guide (13) to a voltage (V) generated by the sensor element (19) , which position is then used to control the thread guide (13). 4. Method according to claim 3, characterised in that the characteristic correction curve (43) determined is then used until the next adjustment of the sensor element (19). 5. Device for carrying out the method according to claim 1, characterised in that the single drive of the thread traversing mechanism has a calibrated angle sensor which is equipped with a Hall IC element and is connected to a workstation computer, and supplies a measured value proportional to the position of the thread guide and in that provided in the region of the thread traversing mechanism (10) are means (40,41), which allow a positioning of the thread guide (13) in defined, reproducible positions. 6. Device according to claim 5, characterised in that the workstation computer (28) is configured such that it links each voltage (V) generated by the Hall 1G element (29) of the angle sensor (19) with an associated position of the thread guide (13). 7. Device according to claim 5, characterised in that the thread traversing device (10) is configured as a finger thread guide, the thread placing lever (45) of which can be positioned in defined angle positions by disposing on stops (40,41). 20 8. Device according to claim 7, characterised in that the angle range which can be covered by the angle sensor (19) by calibration is between +40° and -40°, in that the working range of the thread placing lever (45) is between +37.5° and - 37.5° and in that the stops (40, 41), on which the thread placing lever (45) is positioned for adjustment, are arranged in each case at +39° and at -39°. 9. Device according to claim 5, characterised in that the angle sensor (19) has a resolution of 0.024°. Dated this 5th day of November, 2005 21

Full Text

FORM 2
THE PATENT ACT 1970 (39 of 1970)
&
The Patents Rules, 2003 COMPLETE SPECIFICATION
(See Section 10, and rule 13)
TITLE OF INVENTION
METHOD AND DEVICE FOR OPERATING A WORKSTATION OF A TEXTILE
MACHINE PRODUCING CROSS WOUND BOBBINS
APPLICANT(S)

a) Name : SAURER GMBH & CO., KG
b) Nationality : GERMAN Company
c) Address : LANDGRAFENSTRASSE 45, D-41069,MONCHENGLADBACH, GERMANY
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

PATENTS ACT 1977
VERIFICATION OF TRANSLATION
Certificate of Priority Document on the filing of a Patent Application. File No. 10 2005 001 094.6
I, ASTRID TERRY, Translator of 11 Bounds Oaks Way, Tunbridge Wells, Kent, TN4 0UB, confirm that I am familiar with the English and German languages, and that to the best of my knowledge and belief the accompanying document which has been prepared by me, is a true translation of the authentic text of the Certificate of Priority Document on the filing of the Patent Application File No. 10 2005 001 094.6 dated 8th January 2005.
Signed this 24th day of 2005

Description
The invention relates to a method for operating a workstation of a textile machine producing cross-wound bobbins according to the preamble of claim 1 and a device for carrying out the method according to claim 5.
In order to produce a textile bobbin, it is necessary, as known, on the one hand, to make the relevant textile bobbin rotate and, on the other hand, to traverse the thread which is winding onto the bobbin along the bobbin axis. By means of relatively fast traversing of the thread, a so-called cross-winding can thus be produced. Cross-wound bobbins of this type are not only distinguished by a relatively stable bobbin body, but also by good unwinding behaviour. With regard to the winding of cross-wound bobbins of this type a distinction is made between the winding type "random winding" and the winding type "precision winding" or "step precision winding".
In particular, in conjunction with the winding type "random winding", so-called thread guide drums are often used in this case, which do not only traverse the thread which is winding on, but simultaneously also form a peripheral drive for the cross-wound bobbin.
However, thread guide drums of this type cannot be used to produce a precision or step precision winding, as, in the production of these winding types, the drive of the cross-wound bobbin and the drive of the thread
2

traversing mechanism have to be separated. This means that in the production of a cross-wound bobbin of the winding type precision or step precision winding, the cross-wound bobbin is driven by a separate bobbin drive and the thread which is winding on is placed by an additional, separately driven thread traversing mechanism.
Mechanisms, in which the thread guide, which is displaceable parallel to the rotational axis of the cross-wound bobbin, is connected to a reciprocating single drive via a traction means, or mechanisms, which operate with a so-called finger thread guide or wiper, in other words, thread guides, which have a finger-like thread placing lever, which can be pivoted over a certain angle range about an axis arranged substantially perpendicularly to the cross-wound bobbin axis, for example, have proven to be very suitable for fast thread cross-winding with accurate positioning.
DE 100 21 963 Al describes a workstation of a textile machine producing cross-wound bobbins, in which a sleeve rotatably held in a creel can be rotated by a drive roller, which has a separate drive. The workstation also has a traversing thread guide, which can be fixed to a continuous belt and can be guided back and forth by a single drive which can be controlled in a defined manner, within a traversing stroke, which can be changed with respect to its length. The single drive of the traversing thread guide is coupled in this case to an angle transmitter, which detects the rotor position of the electric motor and transmits it to a controller.
3

DE 100 21 963 Al, however, contains no more detailed indications about the precise construction and the mode of functioning of the angle transmitter used.
A workstation for a textile machine producing cross-wound bobbins is also known from DE 198 58 548 Al, in which the bobbin drive and the thread traversing mechanism have separate drives. The thread traversing mechanism is configured in this case as a finger thread guide, which is acted upon by an electromagnetic drive. The electromagnetic drive of the thread guide drive is thus controlled by a microprocessor, which controls the current strength and the current direction according to a predeterminable programme as a function of the angle and time in such a way that over the traversing width, the respectively desired placing angle of the thread is produced or in that the traversing width or the traversing end points can be adjusted in a targeted manner. To detect the instantaneous angle, an infrared light barrier is used in this case, which scans markings arranged coaxially to the axis of oscillation. Optical sensor mechanisms of this type are, however, not completely without problems owing to the air, which, as is known, is often substantially charged with dust and fluff in spinning works and winding departments. In other words, optical sensor mechanisms of this type require a relatively high outlay for cleaning to remain as far as possible free of disruption.
DE 103 54 587 published subsequently describes a workstation of a textile machine producing cross-wound bobbins, which has a creel for holding a
4

rotatable wind-on bobbin and a finger thread guide for traversing a supplied thread. The electric motor single drive of the finger thread guide is equipped, in this case, with an angle sensor, which is connected to a workstation computer and has a pivotally mounted permanent magnet and a stationary Hall IC element. An angle sensor of this type in this case has a plurality of advantages. The relatively economical similar Hall IC element, which is influenced by the magnetic flux of a pivotally mounted permanent magnet, for example generates voltage values, which are proportional to the angle position of the permanent magnets and therefore to the angle position of the finger thread guide and can easily be processed by the workstation computer. These voltage signals emitted while traversing the thread placing lever of the thread guide also have a virtually linear course in the range covered by the finger thread guide between about -40° and +40°. As angle sensors of this type work contactlessly and therefore free of wear, they are furthermore distinguished by a long service life. It is also positive that angle sensors of this type only have a relatively small moment of inertia and therefore can be used reliably at high traversing speeds.
It is disadvantageous, however, with these angle sensors, which are tried and tested per se, that fault influences appear in the course of time due to the principle. These fault influences due to the principle have to include, for example, the temperature drift or the ageing process of the permanent magnets.
5

Proceeding from the above-mentioned prior art, the invention is based on the object of developing a method or a device, which allows proper operation of a workstation of a textile machine producing cross-wound bobbins over a relatively long time period. In particular, it is to be ensured thereby, that the measured values of the angle sensor of the thread guide remain very precise over the entire service life of the mechanism.
This object is achieved according to the invention by a method, as described in claim 1 and a device according to claim 5.
Advantageous configurations of the method according to the invention or the pertaining device are the subject of the sub- claims .
The method according to the invention reliably prevents fault influences due to the principle, such as, for example, the temperature drift or the ageing process of the permanent magnets being able to falsify the measured values of the angle sensor over time in a gradual and therefore unnoticed manner. In other words, owing to a periodic and/or event-related adjustment of the measured values supplied by a sensor element, with defined positions of the thread guide, fault influences are reliably recognised and, for example, correspondingly taken into account by the workstation computer.
6

As shown in claim 2, the thread guide is initially moved successively into two determined, defined positions to determine corresponding measured values of the sensor element.
In these defined positions, a measured value is then generated in each case by the sensor element. The determined measured values are compared in the workstation computer and/or processed to calculate a characteristic correction curve of the sensor element. The characteristic correction curve calculated by the workstation computer in this case characterises the measured value course of the electric voltage, which the sensor element generates at this instant, when the thread guide traverses between its reversal points.
As shown in claim 3, during the winding process, the workstation computer allocates according to the characteristic correction curve the associated position of the thread guide to each voltage generated by the sensor element, and this is then used to control the thread guide.
In an advantageous configuration, the characteristic correction curve determined, as shown in claim 4, is used at least until the next adjustment. In other words, at the next adjustment, the characteristic correction curve is recalculated with the aid of the then existing measured values by means of the workstation computer and, if the calculation produces this, is replaced by a new characteristic correction curve.
7

According to claim 5, the device for carrying out the method according to the invention, in an advantageous embodiment, has a thread traversing mechanism acted upon by a single drive, an angle sensor equipped with a Hall IC element and a workstation computer. The angle sensor in this case supplies a respective measured value proportional to the position of a thread guide. Moreover, means are provided, which allow a positioning of the thread guide in defined positions. This means that precisely defined positions are available, in which an adjustment of the measured values supplied by the angle sensor can be made with known thread guide positions.
As described in claim 6, the workstation computer is configured in this case such that it immediately links each electric voltage generated by the Hall IC element of the angle sensor with an associated position of the thread guide. In this manner, the workstation computer is in a position to optimally control the thread guide, in particular with regard to the reversal points thereof.
In an advantageous embodiment, the thread guide, as described in claim 7, is configured as a finger thread guide, the thread placing lever of which can be positioned by disposing it on two stops, in each case in defined angle positions. In these so-called adjustment positions, in each case, a measured value generated by the Hall IC element of the angle sensor is detected and used in the workstation computer to calculate a characteristic correction curve of the angle sensor. This characteristic correction curve calculated by
8

the workstation computer characterises the instantaneous course of the electric voltage generated by the angle sensor at this instant during the traversing of the thread placing lever. This means that, by means of the workstation computer, when determining the respective angle of position of the thread placing lever, fault influences, which are produced from the construction principle of the angle sensor, for example on the basis of a certain ageing of the permanent magnet, are taken into account.
As described in claim 8, in a preferred embodiment, the range which can be covered by the angle sensor during calibration thereof is between +40° and -40°. This means that this region is slightly larger than the operating region of the finger thread guide, the thread placing lever of which covers a range between +37.5° and -37.5° during the winding operation. A generous dimensioning of this type of the range which can be covered by calibration ensures that the installation tolerances occurring, for example during assembly of the thread guide drive can be reliably adjusted. The positioning of defined stops at +39° and -39° also easily allows an adjustment of the measured values supplied by the angle sensor with known angle positions of the thread placing lever of the thread guide. In other words, when the thread placing lever is disposed on these stops, it is ensured that the measured values generated by the angle sensor always relate to the same angle position and differences in these measured values are to be attributed to fault influences of the angle sensor due to the principle, which are taken into account by the workstation computer in calculating a characteristic correction curve.
9

In a further advantageous configuration it is provided that the angle sensor has a resolution of 0.024° (claim 9). Such a high resolution of the angle sensor allows a precise approach of the thread reversal points during thread traversing and therefore a homogeneous bobbin structure.
The invention will be described in more detail hereinafter with the aid of an embodiment shown in the drawings.
In the drawings:
Fig. 1 schematically shows a workstation of a textile machine producing cross-wound bobbins, comprising a bobbin drive and a separate thread guide driven by a single motor, the drive of which is equipped with an angle sensor,
Fig. 2 shows the angle sensor in cross-section, arranged on the shaft of the thread guide drive,
Fig. 3 shows the angle sensor, according to Section III-III of Fig- 2,
Fig. 4 shows the finger thread guide in the viewing direction of the arrow X, during an adjustment of the angle sensor,
10

Fig. 5 shows an angle position/initial voltage graph during an adjustment of the angle sensor.
Fig. 1 shows a schematic side view of the workstation 2 of a textile machine producing cross-wound bobbins, in the present case a so-called automatic cross-winding machine 1. At the workstations 2 of automatic cross-winding machines 1 of this type, as known and therefore not described in more detail, the spinning cops 3 produced on a ring spinning machine are rewound to form large-volume cross-wound bobbins 5. The cross- wound bobbins 5, after their completion, are passed for example by means of an automatically operating service unit (not shown) to a machine-length cross-wound bobbin transporting mechanism 7 and transported to a bobbin loading station or the like arranged on the machine side. Automatic cross-winding machines 1 of this type generally also have a bobbin and tube transporting system 6, in which, the spinning cops 3 or empty tubes circulate on transporting plates 11. Of the bobbin and tube transporting system 6, only the cop supply section 24, the memory section 25, which can be driven reciprocally, one of the transverse transporting sections 26 leading to the winding heads 2 and the tube return section 27 are shown in Fig. 1.
The individual workstations 2 also have, as known and therefore only indicated, various mechanisms, which ensure proper operation of workstations of this type. One of these mechanisms is, for example, the winding device 4. The winding device 4 has a creel 8 movably mounted, about a pivot axis 12. According to the present embodiment, the cross-
11
wound bobbin 5, during the winding process, lies with its surface on a drive drum 9 and is entrained by frictional engagement by this drive drum 9, which is acted upon by a single motor. The corresponding drive has the reference numeral 33.
To traverse the thread 16 during the winding process, a thread traversing mechanism 10 is provided. A thread traversing mechanism 10 of this type indicated only schematically in Fig. 1 has, for example, a thread guide 13, with a finger-like thread placing lever 45. The thread placing lever 45 traverses, acted upon by an electromechanical drive 14, the thread 16, between the two end faces of the cross-wound bobbin 5. The drive 14 of the thread guide 13 is fixed in this case, for example, by a bracket (not shown), on the winding head housing 34 of the relevant workstation 2. Moreover, both the drive 14 of the thread guide 13 and the drive 33 of the drive drum 9 are connected to the workstation computer 28 via control lines 15 and 35.
As can be seen, for example, from Fig- 2, the drive 14 has a motor shaft 17, on which the thread placing lever 45 configured in a finger-like manner is arranged in a manner secured against rotation. On the side of the motor shaft 17 opposite the thread guide 13, an angle sensor 19 is mounted so as to be protected under a removable cover cap 18; the construction of said angle sensor will be described hereinafter.
As shown in Fig. 2, a plastics material moulded part 31 is fixed on the housing 39 of the drive 14, on the side opposing the thread placing lever 45
12

and has both a fastening hole 36 for a sensor carrier 23 and a bearing pin 37 for a printed circuit board 38 equipped with an electronic circuit 32. The electronic circuit 32 may in this case, contain, for example, a memory chip and an electronic control mechanism. A Hall IC element 29 is fixed on the sensor carrier 23 in a stationary manner and communicates with a permanent magnet 20, which is connected so as to be secured against rotation to the motor shaft 17 of the drive 14 via a support ring 21 and a screw bolt 22.
Fig. 3 shows a rear view of the drive 14, in other words a view of the angle sensor 19 according to Section III-III of Fig. 2. As shown, the permanent magnet 20 is configured as a two-pole radially magnetisable annular magnet, the poles North, South of which are arranged orthogonally in the shown central position of the thread guide 13, in other words in the angle position 0°, with respect to the stationarily arranged Hall IC element 29. In other words, when the thread guide 13 adopts an angle position 0°, the poles North, South of the magnet ring 20 are aligned at right angles to the Hall IC element.
Fig. 4 shows a view of the thread traversing mechanism 10 according to the viewing direction of the arrow X of Fig. 1 during an adjustment of the angle sensor 19. As shown, stops are let into the front plate 44 of the thread guide drive 14 in holes arranged in a defined manner and in each case define a predefined, exact angle position of the thread placing lever 45. The stops 40, 41 are in this case preferably positioned such that the thread placing lever 45 disposed during the adjustment at the stop 40 precisely has an angle
13

position of - 39°, while the angle position of the thread placing lever 45 at the stop 41 is precisely +39°. The electric voltage V initiated by the Hall IC element 29 during the disposing of the thread placing lever 45 on the stop 40 or 41 is processed in the electronic circuit 32 of the angle sensor 19 and passed on via a data and control line 15 to the workstation computer 28, which calculates therefrom if necessary, a characteristic correction curve, with the aid of which, each measured value can be allocated to a specific angle position of the thread placing lever 45.
Characteristic curves 42, 43 are shown in Fig. 5 with the aid of a coordinate system and indicate the electric voltage course which is generated by the programmable Hall IC element 29 and is dependent on the angle positions of the thread placing lever 45 and therefore on the angle positions of the permanent magnet 20. The range in angle degrees, which can be covered in this case by the thread placing lever 45 during a thread traversing operation is shown on the abscissa of the coordinate system, while the ordinate of the coordinate system shows the voltage in volts generated by the Hall IC element 29; in other words the voltage V which the Hall IC element 29 generates from the magnetic flux of the permanent magnets 20, the angle position thereof and an apparatus constant. 43 in this case characterises a characteristic curve for the voltage course of the angle sensor 19, as was produced after calibration of the angle sensor 19 at the beginning of its use. In the embodiment, according to the characteristic curve 43 at an angle position of the thread placing lever 45 of - 39°, there is a voltage, for example, )f 0.71 V at the angle sensor 19. At an angle position of the thread placing
14

lever 45 of +39°, the corresponding voltage at the angle sensor 19 is 4.83 V. As indicated by the characteristic curve 43, the voltage course in the traversing range between -39° and +39° covered by the thread placing lever 45 is very substantially linear.
In the central position 0° of the thread placing lever 45, a voltage of, for example 2.76 volts, is consequently produced at the angle sensor 19.
The characteristic curve 42 shows the voltage course determined during a later adjustment of the angle sensor 19. In the embodiment, the electric voltage generated by the angle sensor 19 during this adjustment at an angle position of the thread placing lever 45 of -39° is 0.56 V. At an angle position of the thread placing lever 45 of +39°, 4.47 V are generated. As the characteristic curve 42 also has a very substantially linear course, this produces, for the central position 0° of the thread placing lever 45 at the angle sensor 19, a voltage of, for example 2.48 volts.
A resolution 0.024° can be produced, for example, with the present angle sensor 19. Before starting up the thread guide drive 14 in the workstation 2, the angle sensor 19 firstly has to be calibrated. During this calibration of the angle sensor 19 on the fully assembled drive 14, various methods can be used, which are described in relative detail in DE 103 54 587, published subsequently.
15

In the case of one of these calibration methods, the magnetic characteristic curve of the permanent magnet 20 of the angle sensor 19, for example, is measured with the aid of defined angle positions of the thread placing lever 45 of the thread guide 13. In other words/ the thread placing lever 45 is positioned successively in defined angle positions by means of a simple mechanical device, for example, two stops 40, 41 and thus in each case detects the electric voltage generated because of the magnetic flux of the permanent magnet 20 in the Hall IC element 29. The workstation computer 28 of the relevant winding head 2 then calculates a first characteristic curve for the angle sensor 19 with the aid of the known positions of the thread placing lever 45 and the detected measured values of the angle sensor. This first characteristic curve is characterised in the coordinate system of Fig. 5 with the reference numeral 45. As indicated in Fig. 5, a specific angle position of the thread placing lever 45 and a corresponding measured value of the angle transmitter 19 are allocated to each point of the characteristic curve 45. With a central position of the thread placing lever 45, in other words with an angle position of 0°, the associated measured value of the angle sensor is, for example 2.76 V.
The adjustment method according to the invention proceeds as follows: As the characteristic curve of the angle sensor 19 changes in the course of time due to the principle, for example owing to ageing of the permanent magnets 20 of the angle sensor 19 or owing to temperature drift or the like, a measured value of, for example 2.76 V only corresponds for a specific time
16

exactly to an angle position of 0° of the thread placing lever 45. In order to be able to ensure exact measured values of the angle sensor 19 even over a relatively long period of time, the angle sensor 19 is therefore adjusted from time to time.
In this second calibration method, the magnetic characteristic curve of the permanent magnet 20 is remeasured. This may take place in an external calibrating device or in the workstation. The determined correction values are then stored either in the workstation computer 28 of the winding head or in an additional memory chip (not shown) of the electronic circuit 32 of the angle sensor 19.
In other words, the thread placing lever 45 is again moved, successively, to the defined stops 40, 41 and, in these angle positions, detects the measured values generated by the angle sensor 19. From these detected measured values, the workstation computer 28 then calculates a characteristic correction curve 42, as shown in Fig. 5. The characteristic correction curve 42 has a linear course. Furthermore, a specific angle position of the thread placing lever 45 and an associated measured value of the angle sensor 19 in volts are allocated to each point of the characteristic correction curve 45. In the characteristic correction curve 42 shown in Fig. 5 as an embodiment, a measured value of, for example 0.56 V, corresponds to an angle position of the thread placing lever 45 of -39°. In the central position 0° of the thread placing lever 45 there is a measured value of 2.48 V at the angle sensor 19,
17

while the measured value of the angle sensor 19 at an angle position of +39° of the thread placing lever 45 is, for example 4.47 V.
The characteristic correction curve 42 of the angle sensor 19 remains decisive until the next adjustment and is then optionally replaced by a new characteristic correction curve, which is also determined by a corresponding adjustment.
18

Claim:
Method for operating a workstation of a textile machine producing cross-wound bobbins, comprising a creel for holding a rotatable wind-on bobbin, a thread traversing mechanism, which is driven by a single motor, and a sensor element which can be calibrated and supplies a measured value that is proportional to the position of the thread guide, characterised in that a proper operating mode of the sensor element (19) is ensured in that an adjustment takes place between measured values supplied by the sensor element (19) and defined positions of the thread guide (13), at predeterminable time intervals and/or in relation to events.
Method according to claim 1, characterised in that to determine the measured values of the sensor element (19) during a winding interruption, the thread guide (13) is moved successively into determined, defined positions, in that in these positions, a respective measured value of the sensor element (19) is detected and in that the detected measured values are processed in the workstation computer (28) to calculate a characteristic correction curve (43) of the sensor element (19).
Method according to claim 2, characterised in that during the winding process, the workstation computer (28, according to the characteristic correction curve (43), allocates the associated position of the thread
19

guide (13) to a voltage (V) generated by the sensor element (19) , which position is then used to control the thread guide (13).
4. Method according to claim 3, characterised in that the characteristic correction curve (43) determined is then used until the next adjustment of the sensor element (19).
5. Device for carrying out the method according to claim 1, characterised in that the single drive of the thread traversing mechanism has a calibrated angle sensor which is equipped with a Hall IC element and is connected to a workstation computer, and supplies a measured value proportional to the position of the thread guide and in that provided in the region of the thread traversing mechanism (10) are means (40,41), which allow a positioning of the thread guide (13) in defined, reproducible positions.
6. Device according to claim 5, characterised in that the workstation computer (28) is configured such that it links each voltage (V) generated by the Hall 1G element (29) of the angle sensor (19) with an associated position of the thread guide (13).
7. Device according to claim 5, characterised in that the thread traversing
device (10) is configured as a finger thread guide, the thread placing
lever (45) of which can be positioned in defined angle positions by
disposing on stops (40,41).
20

8. Device according to claim 7, characterised in that the angle range
which can be covered by the angle sensor (19) by calibration is
between +40° and -40°, in that the working range of the thread
placing lever (45) is between +37.5° and - 37.5° and in that the stops
(40, 41), on which the thread placing lever (45) is positioned for
adjustment, are arranged in each case at +39° and at -39°.
9. Device according to claim 5, characterised in that the angle sensor (19)
has a resolution of 0.024°.
Dated this 5th day of November, 2005

21

METHOD AND DEVICE FOR OPERATING A WORKSTATION OF A TEXTILE MACHINE PRODUCING CROSS WOUND BOBBINS

Documents:

Inventors:

PCT Conventions: