EP0393330B1 - Method for running a spinning machine and spinning machine for carrying out this method - Google Patents

Description

The invention relates to a method for operating a spinning machine which produces cops with a coil winding wound on spool sleeves attached to driven spindles, in which a ring bench is driven to move up and down with a superimposed, step-by-step stroke movement, and in which the spindles Speeds are driven, which are lower at the beginning of the winding process and towards the end of the winding process than in a central area, and a spinning machine for performing the method.

In practice, the aim is to run a spinning machine, in particular a ring spinning machine, as fast as possible. The limits of the speed are usually set by the frequency of the thread breaks occurring. In the initial area of the winding process, which begins in the area of the lower end of the bobbin tubes, thread breaks occur more frequently than in the central area, so that lower speeds have to be worked in this initial area in order to increase the number of thread breaks within an acceptable range hold. Likewise, thread breaks occur more frequently towards the end of the winding process, so that lower spindle speeds must also be used in this area. In this way, the highest production speed can be achieved with a reasonable number of thread breaks.

The invention has for its object to provide a method and a device of the type mentioned, in which a perfect cop construction and a high degree of filling of the cops is obtained even at the optimized production speed.

This object is achieved in that the lifting movement of the ring bench is carried out with shortened steps in the central region of the winding process during the increased spindle speeds, in such a way that a constriction is avoided in the central region of the coil winding.

The invention is based on the knowledge that, because of the increased spindle speeds in the central area of the winding process, increased thread tensions occur, which lead to constriction of the cops in this central area. This constriction creates a bobbin shape which, with the same thread length, has a smaller volume than a corresponding bobbin without constriction. The resulting free space can now be filled up according to the invention by additional winding, so that a maximum degree of filling of the cops and thus maximum wound thread length is given. In order to achieve this, the change in the lifting movement of the ring bench slows down the upstream connection of the ring bench in this area, so that this area, which would otherwise have a constriction, is filled with thread.

In many cases it will suffice if the shortening of the steps of the lifting movement and the subsequent enlargement are each carried out in at least one stage. The larger the number the steps, the better a high degree of filling can be achieved.

In a further embodiment of the invention, a spinning machine is provided, in which the ring bench is provided with a drive which contains means for changing the size of the steps of the lifting movement of the ring bench during the operation of the spinning machine, the means being one of the steps of the lifting movement at high Control device shortening spindle speeds is connected, which can control these steps in such a way that a constriction in the central region of the bobbin winding can be avoided.

Fig. 1

zeigt eine schematische Darstellung eines Antriebes zum Antreiben einer Ringbank zur Auf- und Abbewegungen mit einer überlagerten, schrittweise ausgeführten Hubbewegung,

Fig. 2

ein Blockschaltbild einer Steuerung des Antriebs der Fig. 2,

Fig. 3

ein Diagramm zur Erläuterung des Verlaufs der Spindeldrehzahlen über den Hubvorgang und des zugeordneten Verlaufs der Größe der Schritte der Hubbewegung der Ringbank und

Fig. 4

eine Darstellung eines durch das erfindungsgemäße Verfahren erzeugten Kops.

Further features and advantages of the invention result from the following description of the embodiment shown in the drawing.

Fig. 1

shows a schematic representation of a drive for driving a ring bench for up and down movements with a superimposed, step-by-step lifting movement,

Fig. 2

2 shows a block diagram of a control of the drive of FIG. 2,

Fig. 3

a diagram for explaining the course of the spindle speeds over the lifting process and the associated course of the size of the steps of the lifting movement of the ring bench and

Fig. 4

a representation of a cop generated by the inventive method.

In Fig. 1, the ring banks (10, 11) of a right and a left machine side of a ring spinning machine are shown. The ring banks (10, 11) are arranged on vertical spindles (14, 15) with spindle nuts (12, 13). The spindles (14, 15) are non-rotatably connected to helical gears (16) and those to helical gears (17) are engaged, which are arranged on shafts (19, 20) running horizontally in the longitudinal direction of the machine, ie parallel to the ring banks (10, 11).

The shafts (19, 20) are driven by a drive motor (21) via a switchable gear transmission (22) which contains two clutches (23, 24) which determine the respective direction of rotation and thus an upward or downward movement of the ring banks (10, 11 ) determine. With this drive the ring banks (10, 11) can thus be driven to move up or down.

The movement of the ring banks (10, 11) is detected in such a way that a path-dependent signal is given. For this purpose, a high-resolution incremental encoder (26) is provided, which is driven by the shaft (20) by means of a pair of gearwheels (25). The incremental encoder (26) emits a large number of pulses during a movement through a certain angle of rotation. In addition, a further incremental encoder (27) is provided as a displacement encoder, which is only shown in dashed lines in the drawing, since its function can in principle also be taken over by the incremental encoder (26). The incremental encoder (27) is designed such that it indicates the absolute height position of the ring banks (10, 11) compared to a starting position serving as a reference variable, for example the height position of the ring banks (10, 11), which assume the lowest position at the start of the winding process .

The drive of the ring banks (10, 11) is controlled by means of a control device (30) shown schematically in Fig. 2 so that there is a bobbin winding in which the wound thread is wound in a plurality of overlapping conical layers. To achieve this movement, the control device (30) switches the drive in such a way that an up and down movement of the ring rail is carried out, which is superimposed on a gradual lifting movement. This happens in the way that the pulses emitted by the incremental encoder (26) are counted during movement by a first counter (28), a (+) counter, which is set to a preselected number of counting pulses. As soon as the preselected number of pulses in the counter (28) is reached during the upward movement, the latter sends a signal to a processor (31) while at the same time the counter content of the counter (28) is deleted. The processor (31) via an actuator (32) opens the clutch (23), which was switched on for the movement. At the same time, the processor (31) causes the previously opened clutch (24) to close via an actuator (33), so that the ring banks (10, 11) are then switched over to the downward movement. The pulses emitted by the incremental encoder (26) during the movement are counted by a second counter (29), a (-) counter, which is set to a preselected number of pulses. When this preselected number of pulses is reached, the counter (29) sends a signal to the processor (31) while at the same time its counter content is deleted. The processor (31) then causes the actuators (32, 33) to switch the clutches (23, 24) in such a way that the ring banks (10, 11) are then driven to move up again.

A spinning program is stored in the processor (31), for example via an input unit (not shown). This spinning program, which is selected and set in accordance with the fiber material to be processed, the yarn to be spun and other parameters, determines the number of pulses preselected with the counters (28, 29) at which the changeover signal is triggered. These pulse numbers are determined in such a way that the pulse number of the upward movement is greater than the pulse number of the downward movement, so that the ring banks (10, 11) are gradually shifted in height.

The pulses emitted by the incremental encoder (26) are fed to a further counter (34) which counts both the impulses during the upward movement and those during the downward movement. This Counter (34) is connected to a memory (35) which retains its contents even when the ring spinning machine is switched off or in the event of a power failure. The memory (35) is connected to the processor (31) which, before resuming the winding process after a standstill, queries the already counted number of pulses from the memory (35). On the basis of this number of impulses, it is possible to determine exactly the point in the spinning program at which the operation was interrupted. The spinning program can then be continued at this point when resuming.

In order to spin at the highest possible working speeds with an acceptable number of thread breaks, it is provided that the spindles are operated over the entire working range (A) of the winding process (FIG. 3) at speeds specified according to a spinning program. The spindles, not shown, are driven by tangential belts, which are preferably divided into several fields distributed over the length of the ring spinning machine, each of which has its own drive motor. In another embodiment, the individual spindles are driven by individual motors. In all cases, however, it is provided that all spindles always have the same speed, which is achieved, for example, via a frequency control when several drive motors are provided. The course of the speed (n) of the spindles is shown in Figure 3 over time (t). It is envisaged that the speed (s) of the spindles gradually increases at the beginning of the winding process and in the middle area also remain essentially at constant high speed values. In the end area of the winding process (A), the speed (n) of the spindles is then reduced again, whereby it can still remain at a value which is higher than the initial speed. The curve of the spindle speed is shown with the curve (36).

Would it be provided that the ring banks (10, 11) would be connected upstream with constant large steps of the lifting movement from the difference between the pulse numbers set on the counters (28 and 29), a cop (37) would result (FIG. 4), which had the constriction shown in dashed lines in its central region. Due to the increased rotational speed (s) of the spindles during this winding process, higher thread tensions also arise during winding, so that this shape would result. In order to avoid this constriction of the bobbin (37) wound on a bobbin tube (38) and to maintain the shape of the bobbin (37) shown in solid lines, the thread length that could be wound on the bobbin (37) would not be reached Constriction caused by the increased thread tension is compensated for by the fact that the lifting steps are reduced in the central area of the winding process (A), so that the lifting movement is slowed down. This is done by preselecting the number of pulses to be counted by the counters (28, 29). The difference between the preselected pulse numbers to be counted is reduced, so that the individual layers of the coil winding connect closer together in the axial direction and form a coil (37) corresponding to the shape shown in FIG. 4.

As shown in FIG. 3 with the dashed line (41), this shortening of the length of the lifting steps can take place in one step in such a way that, for example, the incremental encoder (27), which is designed as an absolute encoder, with a predetermined stroke in the height position (39 ) a corresponding signal is sent to the processor (31), which then causes the counters (28, 29) to be adjusted in the sense of a reduced difference in the number of pulses to be counted. In a corresponding manner, a corresponding signal can then be given by the incremental encoder (27) at a height position (40), by means of which the difference between the number of pulses to be counted by the counters (28, 29) is reset to the previous value. As shown by the dotted line (42), it is of course also possible to adjust this stroke step by changing the difference in the number of pulses to be counted a variety of steps. It is thus possible to very closely approximate the ideal course shown by the solid line (43).

Instead of changing the size of the steps of the lifting movement as a function of the height of the ring banks (10, 11), a corresponding time control can also be carried out via a timing element of the control device (30), since a certain time period also has a specific position in the work area (A ) is assigned to the winding process. It is also possible to detect the spindle speed (n) by means of a speed sensor and send a corresponding signal to the control device (30), i.e. to give the processor (31), which then changes the size of the steps of the lifting movement of the ring banks (10, 11) accordingly in the speed curve of the spindles. Since, in practice, the course of the speed (s) of the spindles represented by the curve (36) is also changed step by step, the steps of the lifting movement of the ring banks (10, 11) are also gradually reduced or increased. This is also done again by adjusting the number of pulses to be counted by the counters (28, 29).

The present invention has been explained on the basis of a spinning machine, in which ring banks (10, 11) are provided which guide runners in rings, which each determine the point at which the thread runs onto the cops (37). In the same way, the invention can of course also be realized in so-called bell spinning machines, in which the ring rail and the runners are replaced by bells which, in accordance with the ring rail, perform an up and down movement with a superimposed lifting movement and the thread on the lower edge thereof the cops runs.

Claims (8)

1. Method for running a spinning machine producing cops with a cop winding wound about empty tubes mounted on driven spindles, where a ring rail is operated to perform a reciprocating up and down movement and a superimposed lift movement to be performed in steps, and where the spindles are driven at speeds which are lower at the beginning and at the end of the winding process than during its central span, characterized in that during the central span of the winding process, where the spindle speeds are higher, the lift movement of the ring rail is performed in smaller steps so as to prevent any contraction in the middle portion of the cop winding.
2. Method according to claim 1, characterized in that the reduction in value of the steps of the lift movement and the subsequent increase thereof are carried out in at least one step.
3. Method according to claim 1 or 2, characterized in that changing the amount of the steps of the lift movement is effected simultaneously with, but in opposite direction to, the change of the spindle speed.
4. Spinning machine for producing cops with a cop winding wound about empty tubes mounted on driven spindles, having a ring rail that is operated to move up and down and to perform a superimposed lift movement to be performed in steps, and having drive means operating the spindles and provided with a speed control which ensures lower speeds at the beginning and at the end of the winding process than during its central span, characterized in that the ring rail (10, 11) is provided with a drive comprising means (23, 24) for changing the amount of the steps of the lift movement of the ring rail (10, 11) during operation of the spinning machine, and in that said means (23, 24) are connected to a control means (30) which reduces the amount of the steps of the lift movement at high spindle speeds (n) and which is adapted to control said steps in such a way that any contraction in the central area of the cop winding can be avoided.
5. Spinning machine according to claim 4, characterized in that the control means (30) is connected to a position encoder (26, 27) associated with the ring rail (10, 11) for detecting the latter's vertical position.
6. Spinning machine according to claim 4 or 5, characterized in that the control means (30) comprises adjustable counters (28, 29) whose counting pulse difference provides a measure for the wandering motion of the ring rails (10, 11).
7. Spinning machine according to any of claims 4 to 6, characterized in that the control means (30) comprises clock means.
8. Spinning machine according to any of claims 4 to 7, characterized in that a tacho-generator associated with the spindle drive is connected to the control means (30).

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