EP0480357A1 - Ring spinning machine - Google Patents

Abstract

In a spinning machine, tangling between the drawing equipment (S4) and the spindles (S1) can be avoided when the machine is stopped due to the fact that, when the spinning machine is slowed down prior to stoppage, the operating speed in the drawing equipment is firstly reduced and then the speeds of the spindles only after a selectable time lag (DW, DW1) stipulated in a program memory. The increase in tension thereby occurring in the yarn between the drawing equipment (S4) and the spindles (S1) can prevent the formation of tangling or thread loops, as a result of which fewer thread breaks occur. <IMAGE>

Description

The invention relates to an operating method for a ring spinning machine with a drive device for the spindles and a further drive device for the drafting system.

In practice, after a ring spinning machine has been switched off, more or less strong jigging on the yarn between the drafting system and the spindles is observed. This formation of a curl can occur if the tension in the yarn is too low with a certain twisting of the yarn. The decrease in tension is due to the fact that after a ring spinning machine has been switched off, the thread balloon at the spinning position disappears, as a result of which there is an excessive length of yarn between the drafting system and the spindle. Twisted yarns are more prone to swaying than twisted yarns. In order to avoid the formation of claws, the spindles can be made a few turns after the spinning machine has been switched off in order to reduce the excess length of the yarn, as a result of which the claws should be pulled out. The associated slight increase in the number of twists in the yarn between the drafting system and the spindle, however, can increase the tendency to form a crimp, especially in the case of twisted yarns, by means of a twist coefficient of the value 100.

It is an object of the invention to provide an operating method for a ring spinning machine which avoids the formation of cranks when the spinning machine is switched off for different yarn qualities.

This object is achieved in that the speeds for the drafting system and the speeds of the spindles when the spinning machine is shut down or when it is started up are not reduced or increased proportionally to one another, but independently, depending on a predetermined program, so that the yarn between the drafting system and the spinning cops after Switching off the spinning machine has more or less rotations than during continuous spinning. Advantageous developments of the invention are described in the subclaims. If single motors are provided as drive devices for the spindles of the drafting system, it is advisable to provide at least one frequency converter consisting of a rectifier and an inverter, with the speed of the speed at a random point in time before switching off the spinning machine or for shutting down before switching off Drive motor for the drafting system is reduced, and the spindle shaft speed of the spindle motor is deflected only after a time interval. In the case of higher twisted yarns, however, it is easier to avoid the formation of claws by first reducing the speed of the spindle motor and only then the speed of the drafting system. In the first case, the claw formation is countered by delivering less yarn, which increases the tension in the yarn. In the latter case, the twist of the yarn is reduced, which also lowers the tendency to jiggle. The same effects can be achieved in that the speed reduction in the drafting system or in the drive device for the spindles is not initiated at specific points in time pushed against one another, but rather that the speeds increase or decrease during the lowering of the speeds in the drafting device or in the drive device for the spindles be lowered less. By avoiding the formation of claws, the likelihood that yarn breaks will occur during the restart of the spinning machine is reduced.

• Figur 1 eine schematische Darstellung von Teilen einer Spinnmaschine,
• Figur 2 ein Schaltbild für eine Spinnmaschine,
• Figur 3 eine andere Variante der Schaltung der Einzelmotoren und
• Figur 4 ein Drehzahl-Zeit-Diagramm mit der Darstellung verschiedener Möglichkeiten, das vorgeschlagene Betriebsverfahren durchzuführen.

The invention is described in detail below with reference to the figures. Show it:

• FIG. 1 shows a schematic illustration of parts of a spinning machine,
• FIG. 2 shows a circuit diagram for a spinning machine,
• Figure 3 shows another variant of the circuit of the individual motors and
• Figure 4 is a speed-time diagram showing various ways to carry out the proposed operating method.

In FIG. 1, spindles S1 are driven by a drive device M1 via a gear GE1. In the simplest case, the drive device M1 can be a speed-controlled, electrical spindle motor. A shaft WE can lead to a transmission GE2 and this to a countershaft transmission V, which is connected to a transmission GE for the drafting device S4. In the countershaft transmission V, different output speeds can be selected for the GE transmission. As an alternative to driving the S4 drafting system via the shaft WE and the countershaft transmission V, a M4 drafting system motor, e.g. a synchronous motor. The spindle motor M1 and the drafting gear motor M4 or the countershaft transmission V are connected to a controller R, which specifies the target frequencies FS for the spindle motor M1 and the target frequency FS 'for the drafting gear motor M4 via connecting lines between controller and spindle motor M1 or drafting gear motor M4. A connecting line between the controller R and the countershaft transmission V may transmit the specified switching function FS "for the countershaft transmission. The controller receives the specified programs for lowering the speed of the spindle motor M1, the drafting gear motor M4 or for the switching function FS" of the countershaft transmission V von a program memory P. Depending on the yarn to be produced in the spinning machine, various programs can be called up.

In FIG. 2, a controller R controls, via a setpoint generator S, to which it transmits the setpoint frequency FS, an inverter W1, which supplies alternating current to motors M1 ... M4. The inverter W1 is about a rectifier G and a DC voltage intermediate circuit GZ with direct current. A capacitor K can be arranged in the DC voltage intermediate circuit GZ and can absorb electrical energy fed back via the inverter W1 when the spinning machine is shut down. The rectifier G is usually supplied by an AC voltage source W with 3-phase AC. A switch SA is located between the inverter W1 and the drafting motor M4 and the drafting motor M4 can be switched on. A servomotor SM is provided for the changeover, the switching function FS "being transmitted by the controller R. In normal operation of the spinning machine, operation is now carried out, for example, at a constant setpoint frequency FS ', so that the state of the setpoint generator S remains unchanged. The switch function FS" of the switch SA also remains unchanged, for example in the position between the frequency divider T4 and the drafting motor M4. When the controller receives a shutdown pulse AI, for example from an operator station, the setpoint frequency FS of the inverter W1 is lowered via the setpoint generator S. As a result, motors M1 ... M4 are braked. If the switch SA now remained in the original position with the frequency divider T4, the speeds of the spindle motor M1 and the drafting motor M4 would be reduced in a fixed ratio. By interrupting the power supply to the drafting system motor M4, the drive speed in the drafting arrangement S4 can now be reduced earlier and more than in the spindle drive while the general speed level is being reduced in the spinning machine. The motors M1 to M4 are preferably designed as synchronous motors.

According to FIG. 3, as in FIG. 2, a rectifier G is connected to an AC voltage source W. In addition to the inverter W1 for the spindle motor M1, a second inverter W2 for the drafting motor M4 is connected in the DC intermediate circuit GZ. The controller R, in which the program memory P is shown as a component, controls both inverters W1 and W2 by transmitting the set frequencies FS or FS 'via connecting lines. When the controller R receives a shutdown pulse AI, the target frequency FS 'in the inverter W2 is first lowered, while the target frequency FS of the inverter W1 is only reduced at a later point in time. This operating mode is preferable for weakly twisted yarn as described in the introduction. In the case of a more twisted yarn, it may be expedient to first reduce the target frequency FS and only later the target frequency FS '. The program memory P must be designed in such a way that program changes can be carried out in a simple manner on the spinning machine if this is necessary when changing over to another yarn to be produced.

The various options for carrying out the operating method are explained below using FIG. 4. The ordinate in the diagram shows speed N, time T runs in the direction of the abscissa. The spindle speed is designated NSA or NSB, while the drafting device speed is designated NW1, NW2, NW3 depending on the program. In a spinning machine according to the prior art, for example, at time TA3, the spindle shaft speed NSB is continuously reduced from point C to point D to point E, to a standstill, due to a shutdown pulse AI. At the same time, the drafting unit shaft speed NW3 drops from point H via point O in proportion to the spindle shaft speed NSA. TG indicates a point in time from which the speed is reduced more than before.

According to the invention, after receiving a shutdown pulse AI in the controller R at the time TA1, the drafting shaft speed NW2 can already be reduced from the point H ", while the spindle shaft speed NSB initially remains constant until the time TA3 and is only then reduced. Between the times TA1 and TA3, at which the speed of the corresponding motors is reduced, is the time difference value DW1.

In another mode of operation, the shutdown pulse AI is received in controller R at time TA2. The drafting system shaft speed NW2 is then abruptly reduced from point H 'to the value at point L in accordance with FIG. 4 and then continuously reduced further, while the spindle shaft speed NSA is still kept at the original level up to point C and only then drops.

In a further operating mode, the speeds of the spindle motor M1 and the drafting motor M4 are simultaneously reduced when receiving a shutdown pulse AI at the time TA3, the spindle shaft speed NSB running over time from point C to point D and the drafting shaft speed NW3 from point H to point H The drafting system motor M4 is then braked more strongly up to the point L 'because its target frequency FS' is reduced more, as a result of which the drafting device shaft speed NW3 drops to a lower level NW2 at point L '. Furthermore, the drafting device shaft speed NW2 then becomes constant reduced to zero to point O and then further to point E. While all of the speed curves shown in FIG. 4 can be run with the circuit according to FIG. 3, the drafting device speed NW2 can only be changed by leaps and bounds using the principle described in FIG Line train H "-H'-L. When the switch SA according to FIG. 2 is actuated into the interruption position, the drafting system according to line NW3 runs out earlier than the spindles via the points H-O'-E '.

As mentioned at the beginning, it can also be expedient to lower the spindle shaft speed NSA before the drafting system shaft speed. In this case, it is assumed that the shutdown pulse AI is received in controller R at time TA4. The spindle shaft speed NSA is then lowered from point C 'to points D and E. Only at a later point in time TA3 is the drafting system shaft speed NW3 at point H, via point O, likewise reduced to zero at point E. In this case, the spinning yarn between drafting device S4 and spindle S1 is rotated less until the spinning machine comes to a standstill, thereby preventing the formation of claws when the yarn is turned higher.

Label list

• AI shutdown pulse
• B battery
• C points on lines in Figure 4 diagram N, T
• D
• E "
• H "
• L "
• O
• ^Q
• DW1 difference value
• DW2 "
• FS set frequency
• FS '"
• FS "switching function
• FG 'cutoff frequency
• G rectifier
• GE gearbox
• GE1 "
• GE2
• GZ DC link
• K capacitor
• M1 spindle motor
• M4 drafting motor
• M2 additional engine
• M3 "
• M measuring device (voltage)
• ML signal line
• N speed
• NG limit speed
• NO Original spindle shaft speed
• NSA spindle shaft speed
• NSB "
• NSB '
• NSB "
• NW1
• NW2
• NW3
• R controller
• P program memory
• S setpoint generator
• S1 spindles
• S4 drafting system
• SA switch
• SM actuator
• T time
• TX restart time
• TA time
• TA1
• TA2
• TA4 "
• TB "
• TB '"
• TG time limit
• V countershaft transmission with actuator
• WE wave
• W AC voltage source
• Wl inverter for Ml
• W2 inverter for M4

Claims (7)

1. Operating method for a spinning machine with a drive device for the spindles and a further drive device for the drafting system, characterized in that the speeds (NSA, NW1) for the drafting system (S4) and the spindles (S1) during shutdown and when the spinning machine is started up not proportionally, but independently reduced or increased depending on a specified program, so that the yarn between the spindles (S1) and the drafting device (S4) has more or less twist during this phase and thus at a standstill than during continuous spinning. 2. Operating method for a spinning machine according to claim 1, with at least one spindle motor M1 for driving the spindles (S1) and with at least one further drafting motor (M4) for drawing roving, with a frequency converter which consists of at least one rectifier (G) and one Inverter (W1), characterized in that the speed (NW1, NW2) of the drive motor (M4) for the drafting system is first reduced at an arbitrary time (TA1, TA2) to switch off the spinning machine or to shut it down before switching off the spinning machine and that the spindle shaft speed (NSB) of the spindle motor (M1) is only lowered after a time interval (TA3-TA1 = DW1 or TA3 - TA2). 3. Operating method according to claim 2, characterized in that to reduce the drafting shaft speed (NW3) with a switch (SA) between the inverter (W1) and the drafting motor (M4) it is switched off prematurely. 4. Operating method according to claim 2 or 3, characterized in that a controller (R) after receiving a shutdown pulse (AI) from an operating station of the spinning machine first the target frequency (FS ') for an inverter (W2) of the drafting motor (M4) a predetermined program, and that after a time interval (TA3 - TA2 or TA3 - TA1) the target frequency (FS) for the inverter (W1) of the spindle motor (M1) is reduced. 5. Operating method according to claim 1, characterized in that after receiving a shutdown pulse (AI) in a controller (R) the spindle shaft speed (NSA) is first lowered and the drafting shaft speed (NW3) is only lowered after a time interval (DW2). 6. Spinning machine according to claim 3, characterized in that a controller (R) is connected via a setpoint generator (S) to an inverter (W1) for changing the frequency of drive motors, and that the drafting system motor (M4) by means of a servomotor (SN) and an associated switch (SA) can be switched off prematurely. 7. Spinning machine according to claim 2, characterized in that in a DC voltage intermediate circuit (GZ) of a frequency converter at least one inverter (W1) and a further inverter (W2) are each provided for a spindle motor (M1) and a drafting motor (M4), and that the desired frequencies (FS, FS ') for the inverters (W1, W2) can be output by a controller (R) according to a predetermined program and are stored in a program memory (P) for the respective yarn.

Images