EP0182389B1 - Winding spindle drive - Google Patents

Description

The present invention relates to a machine for winding filament material in bobbin packages. The filament material can be a synthetic plastic material, such as e.g. Polyester, polyamide or polypropylene. The filament material can be monofilament or multifilament, both types being referred to below as "thread".

It is common practice today to assemble thread bobbin packs on a rotatable bobbin mandrel, with the drive being carried out via a drive friction roller which touches the scope of the bobbin pack - cf. e.g. U.S. Patent 3,907,217. The package speed is a measure of the speed with which thread is taken up in the package and which is of crucial importance for the spinning process, since it determines the spinning conditions in the area of the spinneret, which in turn determine the properties of the thread. At speeds over 5000 m / min. however, the slip in the contact zone between the drive friction roller and the bobbin pack becomes unacceptably large. Many proposals have therefore already been made for a direct drive of the bobbin mandrel during the winding process, and some of these proposals also maintain the friction roller drive on the surface of the bobbin pack, cf. e.g. U.S. Patents 4,146,376 and 4,069,985, GB Patents 944 552 and 995 185 and Japanese Patent Application Publication 51/49026.

US Patent 4,069,985 in particular deals with the regulation of the winding mandrel speed. A feedback signal is obtained from the friction roller and compared with a setpoint in order to enable the control of the mandrel speed. The feedback signal mentioned represents the power consumed by the friction roller. However, the power consumed by the friction roller is composed of various variables which are important for the winding process. US Pat. No. 4,069,985 does not deal with the question of whether (and if so how) the various "components" of the friction roller performance can be taken into account individually.

The present invention relates to a winding machine for winding thread onto a package with a mandrel on which the package is built up during the winding process and with means for driving the mandrel for rotation about a spool axis extending along the same. Usually, the thread turns of the bobbin pack are formed on a bobbin tube, which is detachably attached to the bobbin mandrel. In this description, the term "coil package" includes the coil sleeve if one is used. The winder further comprises a rubbing roller for contacting the package around its periphery during a winding process, and means for driving the roller to rotate about a roller axis extending therealong.

A winder according to the invention is characterized by

Regulating means for regulating the speed of rotation of the bobbin mandrel when the friction roller is in contact with a thread bobbin pack placed on the bobbin mandrel, by reference to a feedback signal corresponding to the speed of rotation of the friction roller, in such a way that the peripheral speed of the package and therefore the rotational speed of the friction roller remain constant during the pack build-up will and

Control means for controlling the speed setting of the friction roller, the circumferential force exerted between the friction roller and the bobbin pack can be adjusted by changing this speed setting with respect to a speed imposed on the friction roller by the said regulating means.

The invention further provides a method for winding threads into a bobbin package, wherein both a bobbin mandrel for receiving a bobbin package and a rubbing roller for contacting the periphery of the bobbin package are driven.

The method is characterized in that the rotational speed of the friction roller is determined by the rotational speed of the pack, that the rotational speed of the bobbin mandrel is regulated on the basis of a feedback signal corresponding to the rotational speed of the friction roller, and that the peripheral force exerted on the pack by the friction roller is determined by the rotational speed setting of the friction roller drive is adjustable.

The regulating means are preferably adjustable in such a way that such a circumferential force can be selectively adjusted. For example, if the distributor roller is driven by an asynchronous drive motor, this motor can be regulated in such a way that it delivers a regulated drive torque (with certain restrictions depending on the motor design used), regardless of the speed of the distributor roller, which is separated separately by means of feedback with inclusion the contact between the distributor roller and the bobbin pack is regulated when the regulating means are set for normal winding operation.

The feedback signal from the friction roller for regulating the drive means for the coil mandrel is preferably a signal that corresponds to the peripheral speed of the roller. Since the diameter of the roller remains constant over the entire winding process, the rotational speed of the roller corresponds to its peripheral speed multiplied by a constant factor. The signal can be taken from a tachometer generator assigned to the friction roller. Since the drive for the bobbin pack is derived both from the drive means for the bobbin mandrel and from the drive means for the friction roller, the slip between the roller and the Coil pack are canceled so that the feedback signal, which corresponds to the peripheral speed of the friction roller, corresponds at the same time to the peripheral speed of the coil package.

The winding machine can include a substantially conventional traverse device for reciprocating the thread along the axis of the bobbin mandrel to enable the package to be built up. The machine can also be equipped with a conventional threading device, which allows the thread to be placed on a rotating spool at the start of the process. The bobbin mandrel can be constructed in a generally customary manner and can be provided with thread catching means which catch a thread placed thereon and separate it from the retracting means.

• Fig 1. ein schematischer Aufriss einer Maschine die zur verwendung dieser Erfindung geeignet ist,
• Fig. 2 eine schematische Seitenansicht der gleichen Maschine, deren Elemente jedoch in einer verschiedenen Lage relativ zueinander gezeigt sind,
• Fig. 3 ein Schema zur Erklärung der Beziehung zwischen der Spulenpackung und der Reibwalze während der Anfangsphase des Aufwindevorganges,
• Fig. 4 ist ein Schaltschema zur Erklärung eines Reguliersystems gemäss dieser Erfindung,
• Fig. 5 ist ein Schaltschema zur Erklärung dieses Reguliersystems in einer anderen Konfiguration,
• Fig. 6 ein Schema zur Erklärung der Schaltung gemäss Fig. 4,
• Fig. 7 ein Schema zur Erklärung der Schaltung gemäss Fig. 5,
• Fig. 8 ist eine schematische Vorderansicht einer weiteren Maschine, die zur Verwendung dieser Erfindung geeignet ist.

In the following, embodiments of the present invention are described in more detail by way of examples with reference to the drawings. Show it:

• 1 is a schematic elevation of a machine suitable for use with this invention;
• 2 is a schematic side view of the same machine, but the elements of which are shown in a different position relative to one another,
• 3 is a diagram for explaining the relationship between the bobbin pack and the friction roller during the initial phase of the winding process;
• 4 is a circuit diagram for explaining a regulating system according to this invention,
• 5 is a circuit diagram for explaining this control system in another configuration,
• 6 shows a diagram for explaining the circuit according to FIG. 4,
• 7 is a diagram for explaining the circuit of FIG. 5,
• Figure 8 is a schematic front view of another machine suitable for use with this invention.

The machine shown in Figures 1 and 2 is a high-speed winding machine for synthetic filaments. To facilitate the description and the graphic representation, the machine is only described with reference to a single thread run. However, as is known in the art, the machine can also be adapted for the simultaneous treatment of several threads. Figure 1 shows the machine during a winding process, while Figure 2 shows the parked machine.

The machine comprises a frame and housing part ("frame") 10 on and in which the other parts are mounted. A side wall of the housing is omitted in Fig. 2 to make the inside of the housing visible. A spool mandrel 12 is mounted on a carriage 14 so that it projects in front of the front of the machine. The spool mandrel 12 is mounted on the carriage 14 in such a way that it can rotate about its longitudinal mandrel axis 16, the rotation being driven by an electric motor 18 which is also mounted on the carriage 14. The motor 18 is designed as an asynchronous motor.

The carriage is movably mounted on guides 15 on the frame 10 and follows the expansion and retraction of movement means which are actuated by means of a fluid, such as e.g. a piston and cylinder unit (not shown). The carriage thus moves the mandrel 12 towards and away from a friction roller 20. The latter is attached to the frame 10 so that it can rotate about its longitudinal axis 22, the roller axis 22 being fixed relative to the frame 10. The roller 20 is driven by an electric asynchronous motor 24 for rotation, which is fixed to the frame and drives the roller via a drive shaft 23. In another embodiment, which is shown schematically in FIGS. 4 and 5, the roller 20 can be designed as an external rotor motor with a stator fixedly attached to the frame, the rotor surrounding the stator. Motors of this type are known in winding machines.

When the spool mandrel 12 moves towards and away from the roller 20, the axis 16 moves along the movement path 26 according to FIG. 1. At one end of the movement path 26, which is furthest away from the roller 20, the spool mandrel is located in a rest position (also shown in Fig. 2). In this rest position, a sleeve clamping device (not shown) of conventional design can be incorporated into the spool mandrel construction 12, for clamping / releasing a bobbin tube 28, on which bobbin tube thread turns 30 are formed and during the bobbin winding process are built up into a package.

As shown in FIG. 1, the winding machine corresponds to the "print friction" type, in which the thread 32 runs over part of the circumference of the friction roller 20 before it passes from the roller into the thread turns 30. Before the spool mandrel 12 reaches the upper end of the movement path 26, the operator guides the thread 32 around the roller 20. When the spool mandrel has reached the upper end of the movement path 26 and rotates at the desired speed, the operator places the thread on the spool mandrel 12 where the thread is captured by a conventional thread catching and separating mechanism 34 (FIG. 2) and placed on the bobbin tube 28, whereupon thread turns begin to form on the bobbin tube. During the construction of the thread windings 30, the thread is moved back and forth along the bobbin mandrel axis 16 by means of a conventional traversing mechanism 36 (FIG. 1), which is provided in front of the friction roller 20. Although not shown in the drawings, the machine may also be equipped with a conventional threading device for automatically threading the thread onto the spool mandrel 12, as shown, for example, in US Patent 4,136,834. Conventional devices can also be provided to create reserve turns on the bobbin tube 28 before the winding of the main thread turns begins, these reserve turns serving to enable the connection of one package to another during the further processing of the thread.

Immediately after completion of the pulling-in process, the bobbin mandrel 12 remains in its position at the end of the movement path 26 closest to the friction roller 20. This state is shown in solid lines in FIG. 3 and shows that there is still a distance S between the circumference of the thread turns 30, which are already built on the coil sleeve 28 and the circumference of the friction roller 20 remains. The radial thickness of the thread turns created at this stage is exaggerated in Figure 3 for clarity. The distance S is determined by the position of a stop 40 (FIG. 2) against which the carriage 14 bears at the end of the guide 15. Because of the distance S, a piece of thread L extends freely between the rubbing roller 20 and the thread turns 30 applied during this phase of the winding process. At this time, the friction roller 20 is driven by the motor 24 so that the peripheral speed of the roller is the same as the thread running speed required for the production of the thread.

The rotating spool mandrel 12 remains at the upper end position of its path of movement 26 without moving, as shown in FIG. 3, until the spool pack has built up sufficiently and bridges the distance S, so that the spool pack comes into contact with the circumference of the friction roller 20 (as shown in Figure 3 with dashed lines). From this phase onwards, the further coil pack construction is accompanied by a backward movement of the coil mandrel along its path of movement 26 against its rest position shown in FIG. This movement takes place under the influence of the carriage moving means in such a way that a controlled contact pressure is maintained between the surface of the coil package and the surface of the roller, as is known in the prior art.

A control system for regulating the wind-up speed during a normal wind-up process is shown in FIG. 4, while FIG. 5 shows the system in the start-up phase. The setting for the initial phase is maintained from the moment in which the thread is placed on the spool to the moment in which the thread turns 30 and the rubbing roller 20 are in contact. Then the regulating system is switched to the setting for normal wind-up operation, as shown in FIG. 4. This setting is maintained until the thread turns have reached the desired diameter, at which point the winding process is stopped, either by responding to automatic thread length measuring means which measure the length of the wound thread, e.g. by comparing the coil package diameter, or by responding to manual actuation of a stop button. The carriage 14 then quickly moves the spool mandrel 12 to the rest position, where the rotation of the spool mandrel is brought to a standstill and the clamping means are released, so that the full spool package can be removed and replaced by an empty spool sleeve. The winding cycle can then be repeated.

First, the normal winding state of the regulating system will now be described with reference to the circuit shown in solid lines in FIG. In this state, the contact between the thread turns 30 and the rubbing roller 20 is made, so that drive forces can be transmitted between them. As is apparent from the following description, a driving force can either be transmitted from the friction roller to the bobbin pack, or vice versa. For the time being it is assumed that the friction roller transmits a driving force to the package.

The regulating system comprises a tachometer generator 42, which is coupled to the rotor or the drive shaft 23 (FIG. 2) of the roller 20, a tachometer generator 44, which is coupled to the drive shaft of the spool mandrel 13, an inverter 46 for feeding of the friction roller motor 24, an inverter 48 for feeding the mandrel motor 18, a regulator 50 for regulating the output of the inverter 46, a regulator 52 for regulating the output of the inverter 48, a setting device 54 for setting the output of the inverter 46, a setting device for setting a setting value for the regulator 52, an auxiliary setting device 58 and a timer 60 for a purpose to be described later.

In the state of the circuit shown in FIG. 4, the regulator 52 receives the output of its setting device 56 and also the output of the tachometer generator 42. The regulator 52 compares the inputs coming from the setting device 56 and from the generator 42 and provides an output signal to the inverter 48, which depends on this comparison. The inverter 48 provides appropriate input to the motor 18 to regulate the rotational speed of the latter. Assuming that there is no slippage in the contact zone between the thread layers 30 and the roller 20, the tangential speed of the thread windings in the contact zone is the same as the tangential speed of the roller 20. Since the diameter of the roller is constant during the entire winding process remains, this speed is given directly by the output signal of the tachometer generator 42. The regulator 52 intervenes via the inverter 48 in order to keep the output signal of the generator 42 constant at a desired value set on the setting device 56, ie the regulator 52 maintains the rotational speed of the Rubbing roller 20 constant over this part of the winding process, above which the switching state of the circuit shown in FIG. 4 applies. As the diameter of the bobbin pack continues to increase during the winding process, a gradual reduction in the speed of rotation of the motor 18 and the mandrel 12 through the winding process is required. In this circuit state, the tacho generator 44, the device 58 and the timer 60 do not yet play a role in the control process.

The motor 24 meanwhile receives an input from its own inverter 46. This input is determined directly by the adjusting device 54, which for this purpose is directly connected to the inverter 46, bypassing the regulator 50. The influence of the adjustment of the setting of the device 54 can be seen from the diagram of FIG. 6, which is only shown for explanation and does not necessarily represent the preferred arrangement which will be described in the following. The curve shown in solid lines in FIG. 6 represents the typical output speed N (ordinate) versus the output torque M (abscissa) for the motor 24. The setting device 54 determines the synchronous speed at which the characteristic intersects the vertical axis. In the "no load" state, ie if the motor 24 were driven by the inverter 46, as shown in FIG. 4, but without contact between the roller 20 and the coil pack, the motor 24 would drive the roller at the speed N _A and that Drive output torque M _A. Given the load conditions, ie with contact between the roller 20 and the coil package, it is assumed that the speed of the motor 24 is N _B ; the output torque then becomes M _B. The speed N _B corresponds to the speed which is determined by the feedback loop via the tacho generator 42, regulator 52, inverter 48, motor 18 and the package of coils which is being built up on the mandrel 12.

The drive torque M _B - M _A acts on the reel pack from the roller and depends on the adjusting device 54. Thus, if the adjusting device 54 is adjusted to increase the synchronous speed of the motor 24, the motor characteristic is shifted upward, for example to the dashed curve in FIG. 6. The drive torque M _A "without load" remains the same, but assuming it If there is no change in the required rotational speed N _B , the drive torque of the motor increases under load to the value M, 31, so that the motor 24 transmits an additional tangential force to the circumference of the coil pack. The electrical slip in the motor changes accordingly.

It should be noted that the adjustment device 54 can be designed such that any required tangential force can be exerted on the circumference of the coil package within certain physical limits. These limits result in part from the conditions in the contact zone where, for example, a very large circumferential force exerted by the roller on the package of coils simply leads to slippage between these elements, thereby failing to achieve the purpose of the feedback loop. The limits also result from the design of the motor 24, which is chosen for a particular machine. The permissible electrical slip in a given motor depends on the motor design and limits the drive torque range that can be achieved with this motor. Within the given limits, the setting of the device 54 can be adjusted according to practical requirements. The adjustment device 54 can be adjusted so that the motor 24 does not transmit any tangential force to the coil package. The adjuster 54 could also be adjusted so that the roller 20 brakes the package of coils or transmits a tangential or circumferential force that changes in a predetermined manner during the normal winding process.

In the following, reference is made to the circuit diagram shown in FIG. 5. The control system is in this setting from the beginning of a winding cycle (ie from the moment in which the bobbin mandrel leaves its rest position) over the entire phase, during which there is a distance S (FIG. 3) between the thread turns 30 and the roller Contact between the thread turns 30 and the roller takes place. The step of changing the setting according to FIG. 5 to that according to FIG. 4 will be described in more detail later. 5, the inverter 46 receives its drive input from the regulator 50, and the setting device does not perform any control function. The output signal of the tachometer generator 42 now goes to the regulator 50, which also receives a setting input from the setting device 56. The roller 20 is therefore driven by the motor 24 according to the speed set on the adjusting device 56.

The speed of rotation of the motor 18 can of course not be regulated in accordance with the output signal from the generator 42 since there is no contact between the coil package and the roller 20. The regulator 52 therefore receives a signal from the tachometer generator 44, which measures the rotational speed of the motor 18 directly. The setting signal for the regulator 52 is not derived directly from the setting device 56; the reasons for this are explained below using the diagram in FIG. 7. In this diagram, the tangential speed at the circumference of the coil pack (vertical axis) and the coil pack diameter d (horizontal axis) are related. The vertical axis is set at the coil diameter d, which essentially corresponds to the outside diameter of the coil sleeve 28. A vertical line appears in the diagram at the Spu lenpack diameter D, at which the contact between the coil package and the roller circumference of the roller 20 occurs. The circumferential speed of the roller 20, which is set on the adjusting device 56 and regulated by means of the tachometer generator 42, is indicated by the horizontal line SR.

The following consideration applies to the circumferential speed of the coil pack during the coil build-up from diameter d to D. The design could be chosen so that this speed follows the line SP 1, which can be achieved if a suitable constant setting value from the setting device 56 to the regulator 52 is given. If this design is chosen, the peripheral speeds of the package and the roller are the same when they touch each other (intersection of lines SP 1 and SR at package diameter D). However, the circumferential speed of the coil pack at diameter d is below the value SR by an amount X, which depends on the difference D-d and the angular speed to be set for motor 18 in order to reach the circumferential speed SR at coil pack diameter D. The speed SR of the distribution roller should be equal to the linear thread running speed. Accordingly, the lower peripheral speed of the package at diameter d is associated with a drop in the thread tension in the thread piece of length L between the friction roller 20 and the thread turns 30 (FIG. 3). If this drop in thread tension is too great, poor thread turns result in this initial area of the package. This in turn leads to difficulties in pulling the thread off the package during further processing.

According to another variant, the peripheral speed could be guided in such a way that it follows line SP 2, likewise by inputting a constant setting value to the control circuit of the motor 18 during this start-up phase. In this case, the peripheral speed of the package would already correspond to the thread travel speed at the package diameter d . The circumferential speed of the package would, however, exceed the thread travel speed by an amount Y with the package diameter D. If the amount Y is too large, the system is hit at the moment the thread turns are touched by the roller 20. In addition to possible thread damage, there are vibrations in one or both feedback loops as shown in FIGS. 4 and 5 as a result of the change in the output signal of the generator 42 due to the impact, together with the switching of the system to the setting for the normal winding process according to FIG. 4 cause rocking in the control loops and can even lead to their instability.

A preferred interpretation of the characteristic of the peripheral speed is shown with the dashed line SP 3. The bobbin winding speed at the bobbin package diameter d is somewhat higher than the thread running speed, however, it decreases and when the bobbin package diameter D is reached it becomes essentially the same size as the thread running speed and the peripheral speed of the roller 20. The somewhat higher tension in the free thread piece of length L, which in Fig. 3, which is caused by the relatively high peripheral speed of the coil package with the coil package diameter d, results in a good package structure in this start-up phase. Adjusting the peripheral speed of the package at the coil diameter D avoids the occurrence of an impact and the above-mentioned difficulties.

However, the characteristic 3 cannot be achieved by specifying a constant setting value at the regulator 52; this value must be changed continuously over the phase during which the coil package diameter grows from d to D, and the auxiliary adjuster 58 is used for this purpose. The device 58 responds to a timer 60 which is started upon receipt of a signal at the input 62 and counts "downwards". This start signal is delivered at the time at which the thread begins to wind onto the bobbin tube 28, i.e. at the bobbin package diameter d, and it can e.g. come from the thread pulling system that the transfer of the thread signals from the system to the spool. The timer 60 is set so that it counts down at a predetermined speed over a period of time which corresponds to the time required for the coil package construction from the diameter d to the diameter D; this period of time must be determined depending on the operating conditions, including the thread speed, the initial distance between the package and the roll 20, the thread count (titer) and the package length (stroke). The timer 60 outputs an output signal to the setting device 58 which contains stored data which represent a sequence of setting values for the regulator 52. The device 58 outputs successive values of the sequence depending on the count signals received from the timer 60.

The setting values provided to the regulator 52 regulate the speed of rotation of the motor 18, which speed gradually decreases as the package diameter increases. The final setting value of the sequence stored in the device 58 must bring about a rotational speed of the motor 18, which results in a circumferential speed of the coil package when the coil diameter D is reached, which is equal to or, if possible, equal to SR; this value is therefore related to the value output by the setting device 56, which can be coupled to device 58, as shown in FIG. 5. The Vorrich-. device 58 may include a range of data, only a portion of which is required under given conditions, the range of the selected data sequence depending on the setting entered on device 56.

The data stored in the device 58 should also allow different initial diameters "d" to be taken into account, since the coil sleeve and coil mandrel diameters can differ depending on the respective boundary conditions. The starting point in the sequence should therefore also be adjustable independently of the regulator 56 and the timer 60.

Note, however, that the characteristics recorded in FIG. 7 represent "idealized" operations. Since there is no feedback from the scope of the coil package, it must be assumed that the coil package really builds up in the expected manner during this start-up phase - direct control only affects the rotational speed of the motor 18. Accordingly, the startup phase is preferably kept short, i.e. the distance S is kept small so that the feedback loop is effective as soon as possible from the circumference of the coil package.

It should also be noted that it is not necessary to follow the idealized form of the characteristic SP 3 (Fig. 7). It is important that the peripheral speed of the bobbin pack is sufficiently matched to the peripheral speed of the roller 20 so that a shock as described above and its effects are avoided. The degree of adaptation therefore depends on the impact effects that are tolerable for the system. In the best case, the peripheral speeds of the package and the roller are exactly the same when the contact occurs. Furthermore, it is important that the circumferential speed at the diameter d is high enough so that a bad package build due to a voltage drop in the free thread length L can be avoided. The speed required for this depends on many factors and can be determined empirically in practical cases. For example, a circumferential speed of the package that is lower than the thread running speed may be permissible under certain circumstances, and the characteristic SP 4 shown in broken lines may be permissible in this case. In any case, the speed adjustment during the start-up phase can also be carried out discontinuously, i.e. not continuously, as shown in the diagram.

It should be noted in particular that the peripheral speed of the distribution roller is kept constant (on the required thread running speed) from the beginning to the end of the entire winding process, ie in both settings of the control system according to FIGS. 4 and 5. This presupposes that the Motor 24 must run at the same speed both under load (FIG. 4) and “without load” (FIG. 5), as was discussed above with reference to the illustration in FIG. 6, ie N _A = N _μ . The motor design must allow adequate settings, ie adequate supply from inverter 46. In terms of electrical properties, the motor must be able to be operated over a sufficiently large range of electrical slip in order to be able to cover the intended load and non-load cases.

It is of course desirable not only to avoid "speed beats" at the time the bobbin pack comes into contact with the friction roller, but also "drive beats" at the time the regulating circuit is switched from the start-up setting to one of the normal wind-up operation. At the time of switching, the contact between the bobbin pack and the roller is made. After this contact occurs, the output of the inverter 46 changes to keep the output of the tachometer generator 42 constant (constant speed of the roller 20), despite the change in operating conditions caused by the contact between the package and the roller. The setting device 54 must be set up so that the output of the inverter 46 is kept constant at the value it had before the switchover. This usually has to be determined empirically and the setting of device 54 is chosen accordingly.

The device 54 can be designed to add only a predetermined correction factor to a setting input on the setting device. This design is shown schematically with the dashed connecting line in Fig. 4. On the other hand, it is not critical that the adjuster 56 be coupled to the device 58, as shown in FIG. 5. The two devices can be set independently. The timer 60 is preferably adjustable so that different counting speeds and different counting times can be set. The device 58 can be programmable to enable adaptations of the changeable sequence depending on various operating factors.

The control system can be designed such that it is automatically changed over to the setting for the start-up phase as soon as the spool mandrel 12 arrives in its rest position, for example in response to a signal from a position sensor 62 (FIG. 2). The control system is then in the start phase setting while the spool is moving along its path of travel 26 and while the motor 18 is accelerating to its "approach" speed before the thread is put on. The circuits shown can be coupled to conventional start-up circuits (not shown) which cause the regulator 52 to motor 18 to the required "start-up" speed brings speed, ie the speed selected for the package diameter d. The control system remains in the setting for the start-up phase (circuit state according to FIG. 5) for the entire period during which the coil mandrel axis is stationary at the upper end of the movement path 26 (FIG. 1). The dwelling of the coil mandrel in this position is registered by a second position sensor 64, which is installed in the stop 40, against which the carriage 14 (FIG. 2) bears. The sensor 64 detects the movement of the bobbin mandrel axis 16 away from the friction roller 20, which occurs as a result of the bobbin pack structure after the bobbin pack and the roller come into contact. Switching means (not shown) are provided which switch the regulating circuit from the setting according to FIG. 5 to that according to FIG. 4 as soon as the position sensor 64 detects the beginning of this movement away. The sensor 64 is, for example, an electrical switch that responds to very small movements of the carriage 14 in the return direction and actuates a relay, which in turn effects the switching of the switching state. This inevitably creates a small delay between the contact between the coil pack and the roller and the switching of the switching state of the regulating circuit. This delay is preferably kept as short as possible.

The initial distance S (FIG. 3) is preferably kept as small as possible, the risk of contact between the coil pack and the roller due to actuation of the cylinder means 17 actuated by means of pressurized fluid being avoided. A distance of 1 mm is usually sufficient in practical operation; the distance shown in Fig. 3 is shown exaggerated for clarity. The spool mandrel axis 16 is preferably held at the end of its path of movement 26 while the spool pack builds up over this initial distance S.

The present invention is not restricted to a feedback signal generated by means of a tachometer generator. Other systems with a feedback signal are known which represent the peripheral speed of a roller contacting a driven package. However, a tachometer generator is a convenient and economical means of generating the required signal.

In describing the timer 60 and the device 58, it was assumed that the timer was a digital counter and that the values stored in the device 58 were in the form of a sequence of discrete setting values. The device can be adapted to function as an analog device, e.g. by gradually adjusting a potentiometer, the output voltage of which represents the input value for the regulator 52. The start signal for the timer, which reaches input 62 (FIG. 5), is best taken from the thread pulling system. Such systems usually include one or more thread guides, which are set up in such a way that they carry out a predeterminable movement around the circumference of the spool in order to place the thread on the spool. The movement force for this movement can be controlled manually or automatically. In both cases, the start signal can be generated automatically during a predetermined phase of the movement sequence of the thread guide, for example when such a movement is completed.

The system according to the invention has been described for a "print-friction" winding machine. It can also be used on winding machines in which the thread comes directly onto the package, i.e. without, or without substantial wrap angle of the thread on the distribution roller. In this case, the speed of the friction roller has no direct influence on the thread running speed as in the "print friction" winding. However, the requirements for speed adjustment to avoid the creation of instabilities in the control system remain.

The system has also been described for winding machines which have only one spool 12 and in which the winding process is temporarily stopped while the spool returns to its rest position, full bobbin packs are removed and new bobbin sleeves are fitted. The present invention is not limited to application to machines of this type. Machines with multiple mandrels which are brought into a winding position one after the other and which allow winding to be wound up essentially without waste are already known, and the present invention is also applicable to such machines. In particular, the present invention can be applied to the winding machine described in European Patent Application No. 0073930 (filed on Aug. 04, 1982).

The system according to the invention has been described in connection with a machine in which the relative movement between the spool mandrel and the friction roller is achieved by moving the spool mandrel relative to a friction roller fixed with respect to the machine. In Fig. 8, a winding machine is shown in a highly schematic representation, in which the friction roller is moved relative to a fixed spool. The reference numerals of Fig. 8 correspond as far as possible to those used in Fig. 1. The roller 20A and a traversing device 36A are mounted on a carriage 62 which can be moved vertically up and down on a spool mandrel 12A. The axis 16A of the latter is fixed with respect to the frame 10A. A stop (not shown) corresponding to the stop 40 of FIG. 2 holds the carriage 62 in such a position that there is a distance between the roller 20A and one on the spool of 12A plugged coil sleeve remains free. No differences are required in the electrical circuit diagram, so that no further explanation is necessary.

The regulating elements 42 to and 62, which are shown in FIGS. 4 and 5, have been treated as a whole as "regulating means", which can be switched in response to a switch that occurs when contact occurs between the package and the friction roller, whereby control elements 42, 46, 48, 52 and at most 56 can be used together for both regulation settings. However, it is clear that there are no elements that are used in both settings. Separate units can be provided and the system could be switched from one unit to the other when switching. In this case, these two units are nevertheless to be regarded as part of the "regulatory means", the "switching" then encompassing switching from one unit to another.

In the description and in the claims the term regulation of the "rotational speed" of an element or the "peripheral speed" of an element is used. It should be noted that such regulation can be accomplished by referring to sizes that are directly related to the size to be regulated and by responding to parameters that are causally related to the size to be regulated. The description and the claims are therefore not to be interpreted as being limited to tapping directly on the size to be regulated, or as being limited to regulation through direct action on the element to be influenced.

Claims (3)

1. A winding machine for winding thread into a package comprising:

at least one chuck (12, 12A) for supporting a thread package (30),

means (18) for driving the chuck (12, 12A) into rotation about the longitudinal chuck axis (16),

a friction roll (20, 20A) for contacting the circumference of the thread package (30), and

means (24) for driving the roll (20, 20A) into rotation about the longitudinal roll axis (22), characterised by

control means (42, 52, 48) for controlling the speed of rotation of the chuck (12, 12A) when the friction roll (20, 20A) is in contact with a thread package (30) fitted on the chuck (12, 12A) by reference to a feedback signal corresponding to the speed of the friction roll (20, 20A) in such manner that the circumferential speed of the package (30) and hence the speed of rotation of the friction roll (20, 20A) is kept constant during the package build-up, and

setting means (56, 54, 46) for setting the speed of the friction roll (20, 20A), change of this speed setting in relation to a speed transmitted to the friction roll (20, 20A) by the said control means (42, 52, 48) enabling the circumferential force exerted between the friction roll (20, 20A) and the thread package (30) to be adjusted.

2. A machine according to claim 1, characterised in that another setting means (56, 60, 58, 52, 48) is provided which, during a startup phase when the friction roll (20, 20A) is not in contact with the thread package (30), so acts on the drive (18) for the chuck (12, 12A) that the speed of rotation of the chuck (12, 12A) is varied in a predetermined manner.

3. A method of winding thread into a package, both a chuck for receiving a thread package and a friction roll for contacting the circumference of the thread package being driven, characterised in that the speed of the friction roll (20, 20A) is determined by the speed of the package (30), in that the speed of rotation of the chuck (12, 12A) is regulated by reference to a feedback signal corresponding to the speed of rotation of the friction roll (20, 20A) and in that the circumferential force exerted by the friction roll on the package is adjustable by the speed setting of the friction roll drive.

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