DE2122112A1 - Device for evaluating the winding speed on cross-winding machines - Google Patents

Description

AKTIENGESELLSCHAFT GEBRUEDER LOEPFE, WETZIKON (SWITZERLAND)

Device for evaluating the winding speed on cross-winding machines.

The invention relates to a device for evaluating the winding speed on cross-winding machines and to the Control of functions of the package winder and the additional devices arranged on it, in particular of yarn clearers.

According to a known proposal, unwanted cuts of yarns by electronic yarn cleaners at startup and The winding process is prevented from running out by means of a speed discriminator, which is dependent on the speed of the To be wound up yarn dependent signal is generated by which the sensitivity of the yarn clearer is controlled. According to one embodiment of this known proposal occurs this in that there is at least one electrical contact with each revolution of the grooved drum driving the cheese is pressed briefly once. A storage capacitor connected in parallel to the contact is charged via a resistor and discharged again with each contact. The voltage obtained in this way is smoothed with the help of an RC element} a control signal is obtained that is relatively small at the nominal speed and increases when the cheese starts and stops. This control signal improves the detection of coarse threads in electronic yarn clearers and improves the response of the Prevents yarn clearer on short, portable yarn errors at low winding speed.

The object of the invention is to create a device for evaluating the winding speed on cross-winding machines which ' to control various functions of additional devices mounted on the machine and the package winder itself

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can be used, which also has the disadvantages of mechanically operated Avoids contacts for generating a control signal and in particular a more precise evaluation of the winding speed allows.

The device according to the invention is characterized by a magneto-electric pulse generator interacting with the winding elements of the machine and an electronic pulse interval evaluation unit to which the pulses generated by the pulse generator are fed and a circuit for generating a sawtooth voltage, the amplitude of which corresponds to the time interval between two successive ones Pulse is proportional, and contains a bistable circuit that flips as soon as the sawtooth voltage has reached a certain amplitude.

According to a preferred embodiment of the invention the output signal of the pulse interval evaluation circuit is fed to the length measuring channel of an electronic yarn clearer in order to reduce the To compensate for the influence of the winding speed on the length scale of the length measuring channel. This ensures that the yarn clearer always responds evenly to the length of the faults in the yarn, regardless of the winding speed.

The invention will now be explained in more detail with reference to a few exemplary embodiments and the drawings.

Figures 1 to 3 show embodiments of the device according to the invention in which the pulses to be evaluated are derived from the rotating core of the cheese; according to the embodiments shown in Figures 4 to 6, the pulses are derived from the rotating grooved drum. In particular, show

1 shows an embodiment of the device with a pulse interval evaluation circuit,
Fig. 2 shows the interaction of the device of FIG. 1 with a

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triboelectric thread monitor,

3 shows the interaction of the device of FIG Diameter sensing device for the purpose of triggering a change of the cheese,

Fig. ^ A further embodiment with a modified pulse interval evaluation circuit,

5 shows a detailed circuit diagram of the evaluation circuit of FIGS. 4 and

6 shows the interaction of those shown in FIGS Device with a yarn clearer to compensate for the influence of the winding speed on the length measurement of the yarn errors.

In the exemplary embodiment according to FIG. 1, the thread 1 is wound from the pay-off bobbin 2 (spinning cop) onto the take-up bobbin 3 (cross-wound bobbin), which is driven by a grooved drum 32, see FIG. With the coil 3, its core 5 rotates, onto which the coil sleeve 6 is pushed. In the core 5, a permanent magnet 7 is mounted, and the winder is a fixed solenoid 8 mounted. Every time the magnet 7 moves past the solenoid 8, a voltage pulse 9 is induced in the solenoid 8. The permanent magnet 7 and the solenoid 8 together form a magneto-electric pulse generator.

In the pulse interval evaluation circuit 10 , the time interval 11 between two consecutive pulses 9 is measured. For this purpose, the pulses 9 are transformed in a pulse shaper 12 into rectangular pulses 13 that are well-defined with regard to length and amplitude. The pulse shaper 12 can be, for example, a monostable multivibrator or an amplifier stage controlled to saturation.

The pulses 13 then reach the sawtooth circuit 14, in which a sawtooth-shaped voltage

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course 16 is generated, the amplitude 15 of each sawtooth being proportional to the associated pulse spacing 11.

The sawtooth voltage 16 is then applied to the bistable circuit 17, which changes from a voltage state 18 to the other state 19 flips as soon as the voltage 15 has reached a certain amplitude value. The circuit 17 can for example be a bistable multivibrator.

The output voltage of the bistable circuit 17 can be a Relays or logic circuits can be fed to amplifiers and electromechanical devices such as ^ Magnetic switch to intervene in the mechanism of the winding machine or its auxiliary units such as yarn clearers, thread monitors, etc.

In the Ausführungsbexspiel according to Figure 2 it is shown how the The output of the bistable circuit 17 is linked to the output of a thread monitor provided with a triboelectric transducer can be. Suitable triboelectric converters are described in detail in Swiss Patent No. 479 478. On the one hand it becomes the output voltage of the circuit 17 and on the other hand the output voltage of the triboelectric Thread monitor 21 placed on an anti-coincidence gate 20. k The running thread is generated in the triboelectric thread monitor 21 1 on a friction body 22 potential fluctuations in the form of a noise voltage, which by means of an electrode 2 3 a Thread monitor circuit 24 is performed. The thread monitor circuit 24 converts the noise voltage into a DC voltage in such a way that if the noise voltage is present in the output, a constant DC voltage occurs; when the thread is at a standstill or missing, the noise voltage and the DC voltage disappear. At the output of the anti-coincidence gate 20 a voltage different from zero occurs only if, firstly, the triboelectric The thread monitor is not excited, and if, secondly, the pulse spacing in the magneto-electric pulse

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donor does not exceed a certain threshold, that is if the winding speed is still above a certain value. The output of the anti-coincidence gate actuated in this case the automatic knotting machine of the package winder via relays and electromagnets.

This device offers advantages on cross-winding machines an automatic shut-off and change system for full packages «On In such machines, the drive mechanism of the cheese is automatically activated when the diameter of the bobbin has been reached switched off. Due to its inertia, the cheese continues to rotate for some time, and will continue in this phase Thread spooled. If no special measures are taken, the thread monitor would each time the complete Address standstill and trigger the automatic knotting in an undesired manner; the thread monitor alone cannot decide whether the thread is really broken or whether it has come to a standstill because the cheese was stopped to change.

If, according to FIG. 2, the output of the triboelectric thread monitor 21 with the output of the bistable circuit 17 in the specified manner with the aid of the anti-coincidence gate 20 logically linked, so now in the case of thread breaks or empty cops, even in the run-out phase, until immediately before the real standstill of the package must be knotted. The triboelectric thread monitor is particularly suitable for this device good because, even at low thread speeds, it is always on, largely regardless of thread material and thread thickness emits a clean thread run signal. As a result, the critical winding speed at which the bistable circuit 17 flips, can be kept low, and the phase that can no longer be automatically knotted is practically negligible.

In a modification of the embodiment example of FIG. 2, the logical link can instead be by means of an anti-coincidence gate

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by means of two relays connected to the output lines of the bistable circuit 17 and the triboelectric thread monitor 21 are connected, take place. Also a link with mechanical links, for example by electromagnets operated is possible; the electromagnets are then energized by the circuits 10 and 24.

According to the exemplary embodiment according to FIG. 3, in cross-winding machines with automatic bobbin changing the device according to the invention can be used to with full cheese to trigger the package change within the shortest possible time. A diameter sensing device 25 provides when the cheese has reached a predetermined diameter their drive and prepares the automatic change. The device according to the invention is in this embodiment designed in such a way that the bistable circuit 17 only tips over immediately before the cross-wound bobbin comes to a standstill, and thus the command to carry out the cheese change prepared by the discharge device 25 to the automatic change system gives.

According to FIG. 3, the diameter sensing device consists of a pair of contacts 25 which, when the desired diameter is reached is closed by the coil carrier 26. As a result, an electromagnet 27 is excited, which shuts down the drive of the cheese. An electromagnet 28, which triggers the automatic changeover, is, however, only excited when the pair of contacts 29 is through a second relay 30 is closed; this occurs when the bistable circuit 17 falls below the critical value The winding speed drops.

This linking of the diameter scanning by means of the contact pair 25 with the actuation of the contact pair 29 is achieved that the package change immediately after Standstill of the full package can be made.

In known, similarly acting devices is mediated

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a diameter sensing device drives the cheese shut down and a fixed time interval then changed the cheese. The time required for the bobbin to run out depends however, from various influences such as thread material, winding speed, diameter of the full bobbin, bearing friction, Temperature and other variables, and consequently a large time reserve must be provided for the time interval mentioned will; however, the efficiency of the winding machine decreases by an amount corresponding to this time reserve.

In the embodiment according to FIG. 4, a piece is ferromagnetic Material, for example a piece of soft iron 31, built into the grooved drum 32. Two permanent magnets 33 are arranged on a soft iron core 34 around which a solenoid 35 is wrapped. The solenoid 35 is penetrated by the magnetic flux of the permanent magnets 33. This river changes every time when the soft iron piece 31 moves past the permanent magnet 34, and it becomes similar to the example 1 pulses 9 induced in the solenoid. The magnetoelectric pulse generator in this example consists of the moving iron piece 31, the fixed permanent magnet 33, the iron core 34 and the solenoid 35.

The pulses 9 are in turn fed to a pulse interval evaluation circuit 10, where they are converted by the pulse shaper 12 into neat * rectangles 13 and where the sawtooth voltage 16 is then formed in the circuit 14.

The sawtooth voltage 16 is fed to a holding circuit 36 which, at the time of the arrival of a pulse 13 each existing voltage amplitude 15 holds up to the point in time of the arrival of the next pulse 13. It will be in the Holding circuit 36 thus forms a staircase voltage 37 in which the height of the staircase 38 corresponds to the last amplitude 15 the sawtooth voltage corresponds to 16; this amplitude in turn

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- 8 is proportional to the associated pulse interval 11.

According to FIG. 5, the iron piece 31 induces pulses in the solenoid 35 9. In the pulse shaper 12, by means of a transistor 39, a magnetic field is generated by each pulse 9 in an inductance 40 built up, and by the voltage induced thereby becomes ^ er Sawtooth circuit 14 controlled a transistor 41 to saturation. The resistor 42 is used to limit the current. One off the transistor 41 and a work resistor 43 existing amplifier stage is strongly fed back via a resistor 44, whereby it works as an operational amplifier and there is a virtual ground potential at base 45. For this Basically, the magnetic field in the inductance 40 slowly decreases during the pulse gaps and is generated at the collector of the Transistor 41 the desired sawtooth voltage 16, the amplitude 15 of which is proportional to the corresponding pulse spacing 11.

FIG. 5 also shows the structure of the holding circuit sketched in FIG. 4 36. With the help of a resistor 46 and a diode 47, the sawtooth voltage 16 becomes a square-wave voltage 48 generated at intermediate point 50, the amplitude 49 of which corresponds to the respective last amplitude 15 of the sawtooth voltage 16. In the pulse gaps of the square wave voltage 13 is the intermediate point 50 by means of the diode 47, which conducts in this phase held at negative potential. If a pulse 13 occurs at point 51 of pulse shaper 12, diode 47 is blocked, and the intermediate point 50 assumes the potential of the point 52 of the sawtooth circuit 14. Via a transistor 5 3 and resistor 54 formed emitter follower, a capacitor 55 is charged. A diode 56 prevents the capacitor from discharging 55 in the gaps between the square-wave pulses 48. The amplitude 38 occurring at the capacitor 55 is equal to that Amplitude 49 of the last square pulse 48, with which the circle 36 supplies the required stair voltage 37.

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According to the embodiment of FIG. 6, one can use the Staircase tension 37 the length measurement of yarn defects in an electronic yarn clearer 57, 60, which has both a thickness channel as well as a length measuring channel, also called length channel for short, affect in such a way that with increasing Tension 38 the length scale is stretched in the length channel. This measure is necessary for the following reason: by the The yarn flaws to be eliminated by the electronic yarn clearer are, in addition to the thickness or the cross-section, also the Measured length; this length measurement is traced back to the measurement of the time that elapsed between passes from the beginning of the error and failure end elapses. In known yarn clearers, the length of the measured Zext interval is except for the Error length also depends on the thread speed. As a result, it can occur in the start-up phase and the run-out phase of the winding process It can happen that insignificant short irregularities in the yarn appear longer as a result of this change in dimension and are discharged by the cleaner in an undesirable manner, which leads to redundant knots and machine downtimes.

According to FIG. 6, the scanning head 57 of the electronic yarn clearer supplies an electrical signal from a continuous yarn error 58 Signal in the form of a pulse 59 which is fed to the yarn clearer circuit 60. The length channel 6H, 67 des Circle 60 has the task of determining the duration 62 of the pulse 59 and the result in the form of a voltage amplitude 63 to play back. For this, in the input part 6 »+ of the length channel the pulse 59 is transformed into a rectangle 65 of the same length 62 and an arbitrary height 66 that is the same for all pulses 65, for example with the help of a Schmitt trigger. In the second part 67 of the length channel, a Miller integrator the length 62 of the pulse 65 is measured and represented in the form of the amplitude 63 of the triangular pulse 68. Of the Miller integrator consists of a resistor 69, a Miller capacitor 70 and a transistor 71 and working

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resisted 72 composite amplifier. The input 74 of the Miller integrator is opened and closed in the rhythm of the square-wave pulses 65 via a diode 7. When a pulse 65 is present, the collector-side end of the capacitor 70 is discharged via the transistor 71 with a constant current, so that a triangular pulse with the amplitude 63 is produced. The steepness 75 of the flank 68 of the triangular pulse depends on the voltage that is applied to the free end of the resistor 69. If the free end of this resistor 69 is connected to the output of the holding circuit 36, the respective last amplitude 38 of the staircase voltage 37 determines the slope 75 and thus the amplitude 63, which is the length scale of the length channel, which is the ratio of the amplitude 63 to the length 62 of pulse 65 is determined. The required dependence of the length scale on the winding speed is obtained in the sense that at high, i.e. operational, winding speed, the length scale is small compared to the length scale at low winding speed, as is the case when the winding machine is started and stopped.

The device described can be robust and operationally reliable Unit are formed, which can also be attached to existing winding machines with little effort. A small permanent magnet 7 or a small piece of iron 31 is sufficient to ensure a reliable coupling between the Produce winding device 5, 32 and thus the thread on the one hand and the electronic evaluation circuit 10 on the other hand. In the magneto-electric pulse generator, a magnetic field directly influences the flow of current in an electrical circuit, i.e. There is a direct conversion of magnetic field energy into electrical energy by moving through the rotational movement the agitating organs changing in intensity Magnetic field generates current pulses · So there are no magneto-mechanical means such as reed contacts or mechanical ones

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• Means like cam switch usage. Within the scope of the invention In addition to the means mentioned, which are based on the law of induction, there are other magneto-electric converters such as Hall generators and similar magnetic field sensitive semiconductor elements.

The device according to the invention is expediently designed so that it is insensitive to dust, fluff and dirt and requires practically no maintenance. For winding machines that disengage the grooved drum to stop a winding station, the magneto-electric pulse generator is advantageously connected to the Grooved drum attached. The speed of rotation of the grooved drum is due to the variable diameter of the cheese a more precise measure of the thread speed than the speed of rotation of the cheese. Experience shows However, that there is also a magnetoelectric pulse generator coupled to the cross-wound coil with the associated pulse interval evaluation circuit provides an evaluation of the thread speed that is sufficiently accurate for many purposes.

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Claims (1)

PATENT CLAIMS Device for evaluating the winding speed on cross-winding machines, characterized by a magneto-electric interacting with the winding members of the machine Pulse generator and an electronic pulse interval evaluation circuit to which the pulses generated by the pulse generator are fed and the one circuit (IM-) for generating a sawtooth voltage, the amplitude of which is proportional to the time interval between two consecutive pulses, and contains a bistable circuit (17) which flips as soon as the sawtooth voltage has reached a certain amplitude. Device according to claim 1, characterized in that the magneto-electric pulse generator at least one on the core (5) of the take-up reel or on the grooved drum (32) fixed permanent magnets (7,31) and a stationary solenoid (8,35). 3. Apparatus according to claim 1, characterized in that the pulse interval evaluation circuit contains a holding circuit (36) which converts the sawtooth voltage into a step voltage corresponding amplitude generated. 4. Apparatus according to claim 1, characterized in that the output of the pulse interval evaluation circuit (10) and the output of a thread monitor (21) to the inputs of a link member (20) are connected. 5. Apparatus according to claim 4, characterized in that the thread monitor has a triboelectric converter (22, 23) as a thread feeler element. 10 9 8 5 0/1096 6. The device according to claim 1, characterized in that the output signal of the bistable circuit (17) with a Device (25) for sensing the diameter of the cheese cooperates to change a full cheese initiate. 7. The device according to claim 1, characterized in that the output of the bistable circuit (17) with an electronic Yarn cleaner (57, 60) is connected to operate it when a certain yarn speed is exceeded to set and to put out of operation when falling below a certain yarn speed. 8. The device according to claim 1, characterized in that the output of the pulse interval evaluation circuit with the length measuring channel (64 ·, 67) an electronic yarn clearer is connected to the influence of the winding speed on the To compensate for the length scale of the length measurement channel. 9. Device according to claims 3 and 8, characterized in that that the output of the holding circuit (36) with the length measuring channel (64,67) of the electronic yarn clearer connected is. 1 Ü 9 β ^ 'ί / j (i Q b