US3921877A - Electronic thread monitor for textile machines - Google Patents

Electronic thread monitor for textile machines Download PDF

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Publication number
US3921877A
US3921877A US421782A US42178273A US3921877A US 3921877 A US3921877 A US 3921877A US 421782 A US421782 A US 421782A US 42178273 A US42178273 A US 42178273A US 3921877 A US3921877 A US 3921877A
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United States
Prior art keywords
thread
shut
voltage
threshold
electrical quantities
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Expired - Lifetime
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US421782A
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English (en)
Inventor
Walter Gith
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Oerlikon Textile GmbH and Co KG
Original Assignee
W Schlafhorst AG and Co
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Priority claimed from DE2259389A external-priority patent/DE2259389C3/de
Application filed by W Schlafhorst AG and Co filed Critical W Schlafhorst AG and Co
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H63/00—Warning or safety devices, e.g. automatic fault detectors, stop-motions ; Quality control of the package
    • B65H63/06—Warning or safety devices, e.g. automatic fault detectors, stop-motions ; Quality control of the package responsive to presence of irregularities in running material, e.g. for severing the material at irregularities ; Control of the correct working of the yarn cleaner
    • B65H63/062—Electronic slub detector
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2701/00—Handled material; Storage means
    • B65H2701/30—Handled filamentary material
    • B65H2701/31—Textiles threads or artificial strands of filaments

Definitions

  • ABSTRACT Electronic thread monitor means for textile HltClllllCS with a sensing element that is influenced direct! or indirectly by the thread motion, for comerting the mechanical input into electrical quantities which serve to actuate the shut0ff device of the textile machine when these electrical quantities fall below a predeier mined value. response value, for a predetermined time interval, shut-off threshold The electrical quantities generated by the sensing element change the shut-off threshold inversely proportionally to the thread velocity.
  • the invention relates to an electronic thread monitor for textile machines with a sensing element which is in fluenced directly or indirectly by the thread motion. for converting the mechanical quantities into electrical quantities which serve for operating the shut-off device of the textile machine if these electrical quantities exceed or fall below a predetermined value. the so-called response value, for a predetermined time interval. the so-called shut-off threshold.
  • Electronic thread monitors for textile machines i.e.. winding machines. warping machines or cutting machines have sensing elements of the most varied kinds such as. for instance. optical. capacitive or piezoelectric types. which convert the mechanical quantities (diameter. roughness. velocity. tension, etc.) into electri cal quantities (voltage, current, frequency).
  • the response of an electronic thread monitor occurs, for instance. as a function of the presence of the thread. of the magnitude of the thread tension, or of the intensity or velocity of the thread motion. It is known that a response ofthe electronic thread monitor as a function of the thread motion results in the shortest possible shutoff time. as the thread motion changes its state immediately if the thread is interrupted. In the case of a break of the thread, for instance, the thread velocity drops very considerably. generally to zero. In some cases. a negative thread velocity can even occur due to the tension acting on the thread.
  • the shut-off device of the textile machine is operated if the measured quantity exceeds or falls below the response magnitude. i.e. a predetermined measurement value.
  • shutt ng otl' the textile machine namely that time interval. during which the magnitude exceeded or fell below the response value.
  • the so-called shut-0ff threshold a thread break actually exists.
  • most textile machines are run at different speeds for ditferent threads. and the noise holes are longer. the lower the thread velocity. This leads to the need to choose the shutoff threshold relatively long. so that a 2 stopping of the textile machine due to a noise hole alone is reliably avoided. This. however. has the result in high-speed textile machines that during the longer shut-off time. the ongoing part of the broken thread is removed that much farther from the stopped part.
  • the starting phase of the thread i.e.. the time until the thread has reached its normal velocity.
  • the noise holes also become larger and can lead to a shutdown of the machine.
  • the shut-off threshold is set for normal operation. without the occurrence of the thread break. ln order to avoid this low speed error.
  • the solution to this problem is that the electrical quantities generated by the sensing element serve to change the shut-off threshold interval inversely proportionally to the thread velocity.
  • the proportionality need not be a linear function here. but may also follow an exponential function.
  • lt is essential that the shut-off threshold interval and therefore. the time during which the magnitude exceeds or falls below the response value. becomes smaller, the greater the thread velocity. At high thread velocities even a very briefinterruption or reduction of the velocity leads to a shut-off of the textile machine, while at the low thread velocities the above-mentioned noise holes do not yet lead to crossing the shut-off threshold.
  • the change of the shut-off threshold interval which is inversely proportional to the thread velocity. can be achieved on the one hand by providing that the electrical quantities generated by the sensing element are always inversely proportional to the thread velocity. but on the other hand also by bringing the electrical quantities which are generated proportional to the thread velocity. into a relationship of inverse proportionality to the shut-off threshold interval.
  • the time constant of an electric energy storage device can serve as shut-off threshold.
  • a capacitor which is controlled by the generated electrical quantities and whose adjustable charge. e.g.. the charging voltage. is a measure for the response value.
  • the charging time constant as well as that for the discharge of the energy storage device can be used as the shut-off threshold.
  • a maximum charge as well as a minimum charge can be a measure for the response value.
  • the generated electrical quantities serve on the one hand for the predetermined charging of the electric energy storage device. and on the other hand. for varying the time constant of the discharge circuit connected to the energy storage device in such a manner that its time constant becomes smaller. the larger the value of the generated electrical quantity.
  • the electrical quantities generated by the sensing element are available in the form of electric voltages, it is advantageous to feed these voltages first to a highpass amplifier and to rectify them subsequently preferably in a full-wave rectifier.
  • a capacitor charged to a predetermined voltage by means of a voltage limiter, e.g., a Zener diode can serve as the energy storage device.
  • a controlled resistance for instance, a transistor.
  • FIG. I is a diagram of the electric voltage corresponding to the thread velocity during a starting operation after one second and after five seconds.
  • FIG. 2 is a block diagram of an embodiment of the invention.
  • FIG. 3, is a schematic diagram of the circuit of FIG. 2.
  • the electric voltage U corresponding to the thread velocity is plotted at definite times as the curve A.
  • this voltage U correspond to the r.m.s. value of the noise voltage.
  • the points a, b, c and e will be seen voltage dips caused by the so-called noise holes, while at the point (1 a voltage drop due to a broken thread is illustrated, where the thread was taken along by other machine parts or adjacent threads immediately after the break and the voltage is thereby generated again.
  • the line 8 indicates the response value, i.e., that electric voltage corresponding to a predetermined thread velocity which, if not reached. will cause the textile machine to be shut off.
  • the noise holes a. h. c and e can also drop down to the voltage zero under certain circumstances.
  • the curve B cannot be put so low that it is reliably influenced only by thread brakes.
  • the noise holes c. e are considerably shorter than the voltage dip d used by broken threads. If one compares. for instance. the time interval e, during which the voltage falls below the response value due to the noise hole e. which the time interval d.
  • the left part of FIG. I shows also how at lower velocities and therefore. lower voltages, the time interval u for the noise hole a is of the same order of magnitude as the time interval d for the case of a thread break d. This means that in this velocity range the machine is shut off by a noise hole corresponding to the hole a. In order to avoid this shortcoming, known electronic thread monitors are disconnected during this velocity phase.
  • the present invention is based on the discovery that the disadvantages described of known electronic thread monitors can be avoided if it is possible to change the time interval determining the shutting-off of the textile machine with the velocity.
  • this can be achieved by the provision that the electrical quantity generated by the sensing element. i.e., the voltage according to curve A, serves to change the shut-off threshold in inverse proportion to the thread velocity.
  • the time interval, during which the voltage must fall below the response value according to curve B to effect the shut-down of the textile machine, should therefore be longer, the lower the thread velocity, and it is to become increasingly shorter with increasing thread velocity. While in the case of the righthand region of the time scale in FIG.
  • the shut-off threshold leading to the shutdown of the textile machine is about 20 msec
  • the shut-off threshold should be considerably longer at the lower velocities corresponding to the left-hand region of the time scale. as the thread velocity is considerably lower. If one has, for instance, at the thread velocity according to that of the noise hole a, which is lower by about one-third, a shutoff threshold of msec instead of 20 msec, it will be seen clearly that the noise hole a cannot lead to a shutdown of the textile machine.
  • the thread 1 to be monitored runs through the sensing element 2 as in all present electronic thread monitors.
  • the noise signal present in the form of an AC voltage is fed to a highpass amplifier 3, so that the signal becomes larger and larger with increasing thread velocity.
  • the rectified voltage is fed on the one hand to a voltage limiter 6, and on the other hand, to an analog storage device 7.
  • the limited voltage from 6 is connected to a shut-off delay storage device 8, whose shutoff delay corresponds to the shut-off threshold and is controlled by the voltage of the storage device 7 in an inversely proportional manner.
  • the buffer and threshold-value amplifier 9 triggers via the bus I0 the thyristor switch II, which excites the stop magnet I2 of the textile machine drive. After the thread break is repaired, the circuit ll, l2, l3, I4 is re-energized by the key 13 when the textile machine is started up.
  • FIG. 3 shows an example of an embodiment of the circuit parts 6, 7 and 8 according to FIG. 2.
  • the limiter 6 consists of the resistor 6a, the Zener diode 6b and the diode 6c.
  • the analog storage device 7 consists of the resistors 70, 7h. 72. the diode 7c and the capacitor 7d.
  • the shut-offdelay memory 8 is composed of the capacitor 80. which can be discharged with constant current via the transistor 8a and the resistor 8b.
  • the amplifier 5 supplies a positive output voltage. which corresponds to the thread velocity and is divided down to a desired magnitude by means of the resistors 70, 7b and 7e. At the same time, the voltage behind the diode 6c is limited by the Zener diode 6b to a constant magnitude. which is stored in the capacitor 8c.
  • the transistor 81 is. together with the resistor 8/2. on the one hand an impedance transformer for the memory 7 and. on the other hand. a linear discharge resistor for the capacitor 81.
  • the DC output voltage of the amplifier 5 breaks downv
  • the capacitor 8(' can discharge via the transistor 8a and the resistor 8b. as long as the voltage present at the base of the transistor 8a permits. So that the transistor 8a with the resistor 8b can constitute a constant-current load for the capacitor 8c. the base voltage must therefore be made available long enough.
  • the time constant of the capacitor 7d. discharging via the transistor 8a and the resistor 8b. must be made about 40 times longer than that of the capacitor 80. This means that the magnitude of the discharge current for the capacitor 8c. constant during the discharge time. depends on the magnitude of the voltage stored in the capacitor 7d. Thereby.
  • the last thread velocity prior to the voltage dip due to a break of the thread or a noise hole determined the discharge time of the capacitor 8c in such a manner that a high thread velocity results in a short discharge time and therefore, a low shut-off threshold or a short response time of the stopping magnetic relay 12.
  • a low voltage at the capacitor 7d prior to the breakdown of the voltage supplied by the amplifier 5 causes a slow discharge of the capacitor 8c and therefore. a high or longer shut-off threshold.
  • the switching threshold of the amplifier 9 can be set so that at an accurately fixed partial discharge of the capacitor 8c the amplifier responds, for instance, to a reduction of the charging voltage to to
  • the operating point of the DC voltage amplifier 5 is chosen in the example of the embodiment shown as high as the voltage at the point 7f.
  • the resistance of the resistors 7e and 7b is chosen so that the conduction threshold of the diode 7c and the base threshold of the transistor 8a are balanced.
  • the voltage at the point 7f and therefore. also the operating point of the DC voltage amplifier 5 is about I V. Any further increase of the voltage at the amplifier 5 becomes therefore effective proportionally at the emitter resistor 8b.
  • the point 7fvoltage can be made to track the temperature curve of the diode 7c and the transistor 80 by a thermistor.
  • abmc represents a possible solution with a minimum of expcnditure. which is completely sufficient for many cases of electronic thread monitoring in textile machines.
  • the use of the noise signal as the control quantity for the shut-off threshold. among other things. has further advantage that the noise voltage is composed of the thread velocity and the thread thickness. For the same thread velocity one obtains a higher noise signal with thick threads than with thin threads. In the rectified noise voltage coming from the amplifier 5 are therefore contained two components. which act on the shut-off delay time in the correct sense.
  • electronic thread monitor means for textile machines of the type having a sensing element influenced by the thread motion.
  • Electronic thread monitor means according to claim 1, wherein the time constant, controlled by the generated electrical quantities. of an electric energy storage device. whose charge is a measure for the response value. serves as the shut-off threshold.
  • Electronic thread monitor means wherein said generated electrical quantities cause a predetermined charging of an electric energy storage device. and also vary the time constant of the dischrage circuit connected to said energy storage device. inversely to the magnitude of the generated electrical quantity.
  • said energy storage device is a capacitor which is charged to a predetermined voltage by means of a voltage limiter, and whose discharge circuit comprises a controlled resistance, whose resistance can be controlled.
  • Electronic thread monitor means wherein said controlled resistance is controlled by a capacitor. whose charging voltage is proportional to the input voltage.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Quality & Reliability (AREA)
  • Filamentary Materials, Packages, And Safety Devices Therefor (AREA)
  • Spinning Or Twisting Of Yarns (AREA)
  • Warping, Beaming, Or Leasing (AREA)
US421782A 1972-12-05 1973-12-05 Electronic thread monitor for textile machines Expired - Lifetime US3921877A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2259389A DE2259389C3 (de) 1972-12-05 1972-12-05 Elektronischer Fadenwächter für Textilmaschinen

Publications (1)

Publication Number Publication Date
US3921877A true US3921877A (en) 1975-11-25

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US421782A Expired - Lifetime US3921877A (en) 1972-12-05 1973-12-05 Electronic thread monitor for textile machines

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US (1) US3921877A (enrdf_load_stackoverflow)
JP (1) JPS5752308B2 (enrdf_load_stackoverflow)
CH (1) CH565103A5 (enrdf_load_stackoverflow)
GB (1) GB1449219A (enrdf_load_stackoverflow)
IT (1) IT997920B (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4154004A (en) * 1976-10-16 1979-05-15 Lindauer Dornier Gesellschaft Mbh Apparatus for monitoring the draw-in procedure and the tearing-off of sheets of material in dryers, particularly jet dryers
DE3126358A1 (de) * 1980-08-18 1982-04-08 Aktiengesellschaft Adolph Saurer, 9320 Arbon Elektronische faden-ueberwachungs-vorrichtung fuer stickmaschinen
CN108301116A (zh) * 2018-02-07 2018-07-20 江南大学 扁丝经编机用断纱检测系统

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62286824A (ja) * 1986-06-06 1987-12-12 Diesel Kiki Co Ltd 車室内送風装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3391840A (en) * 1965-10-25 1968-07-09 Du Pont Yarn break detector and control circuit
US3688958A (en) * 1970-11-16 1972-09-05 Rydborn S A O Device for sensing thread passage to control machine operation

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3391840A (en) * 1965-10-25 1968-07-09 Du Pont Yarn break detector and control circuit
US3688958A (en) * 1970-11-16 1972-09-05 Rydborn S A O Device for sensing thread passage to control machine operation

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4154004A (en) * 1976-10-16 1979-05-15 Lindauer Dornier Gesellschaft Mbh Apparatus for monitoring the draw-in procedure and the tearing-off of sheets of material in dryers, particularly jet dryers
DE3126358A1 (de) * 1980-08-18 1982-04-08 Aktiengesellschaft Adolph Saurer, 9320 Arbon Elektronische faden-ueberwachungs-vorrichtung fuer stickmaschinen
CN108301116A (zh) * 2018-02-07 2018-07-20 江南大学 扁丝经编机用断纱检测系统

Also Published As

Publication number Publication date
JPS5752308B2 (enrdf_load_stackoverflow) 1982-11-06
CH565103A5 (enrdf_load_stackoverflow) 1975-08-15
IT997920B (it) 1975-12-30
JPS4986644A (enrdf_load_stackoverflow) 1974-08-20
GB1449219A (en) 1976-09-15

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