EP1036869A1 - Verfahren und Vorrichtung zur Überwachung von Schussfaden in Webverfahren oder dergleichen - Google Patents

Verfahren und Vorrichtung zur Überwachung von Schussfaden in Webverfahren oder dergleichen Download PDF

Info

Publication number
EP1036869A1
EP1036869A1 EP00104465A EP00104465A EP1036869A1 EP 1036869 A1 EP1036869 A1 EP 1036869A1 EP 00104465 A EP00104465 A EP 00104465A EP 00104465 A EP00104465 A EP 00104465A EP 1036869 A1 EP1036869 A1 EP 1036869A1
Authority
EP
European Patent Office
Prior art keywords
signal
yarn
rotation rate
feeder
weft
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP00104465A
Other languages
English (en)
French (fr)
Other versions
EP1036869B1 (de
Inventor
Pietro Zenoni
Luca Gotti
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.)
LGL Electronics SpA
Original Assignee
LGL Electronics SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by LGL Electronics SpA filed Critical LGL Electronics SpA
Publication of EP1036869A1 publication Critical patent/EP1036869A1/de
Application granted granted Critical
Publication of EP1036869B1 publication Critical patent/EP1036869B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D51/00—Driving, starting, or stopping arrangements; Automatic stop motions
    • D03D51/18—Automatic stop motions
    • D03D51/34—Weft stop motions

Definitions

  • the present invention relates to a method and a device for weft yarn monitoring in weaving processes.
  • weft feeders which are devices equipped with a fixed drum and with a windmilling arm which winds onto the drum a plurality of turns of yarn which constitute a weft reserve. The turns unwind in a controlled manner from the drum when required by the loom at each beat.
  • sensors which are adapted to detect the presence of the yarn at the input of the feeder. Their purpose is to indicate whether the weft yarn has broken, so that a monitoring system associated with the feeder can send halting information for the loom and halt said loom before the weft reserve of said feeder is used up completely by said loom; this circumstance can cause gaps in the fabric being woven and in any case forces one to rethread the entire feeder, with consequent prolonged suspensions of the weaving process.
  • piezoelectric sensors provided with a piezoelectric plate which acts as a sensitive element and is coupled to at least one ceramic element which acts as a yarn support.
  • the yarn slides on the ceramic element, generating a vibration which is transmitted to the piezoelectric plate, which in turn generates a substantially pulsed voltage which constitutes the yarn presence signal.
  • load cells are also used which are adapted to produce an electric signal which is proportional to the mechanical tension of the yarn.
  • the signal produced by the sensor is processed in a known manner in an amplifier and discriminator circuit, for example of the type shown in Figure 1 and described hereinafter, and is applied to a microprocessor in the form of a high or low digital signal which is present at the output of a final comparator of the circuit; the microprocessor is adapted to generate a loom halt signal if the weft presence signal provided by the sensor is missing.
  • This conventional weft yarn monitoring system has many drawbacks, the main one being the extreme sensitivity of the system to various factors, hereinafter concisely termed weaving factors, such as in particular the roughness and count of the yam, the speed with which the yarn slides on the presence sensor of the feeder and/or the mechanical tension with which it adheres to it.
  • the relation between the signal emitted by the sensor, whether piezoelectric or load-sensing, and the weaving factors is an increasing relation, in that the higher the roughness and/or travel speed and/or contact tension of the yarn, the higher the intensity of the signal emitted by the sensor.
  • the amplification of the presence sensor signal cannot be excessively high and the comparison threshold cannot be excessively low, since this would cause, in the presence of high-value weaving parameters and therefore of a correspondingly high presence signal, an undesirable amplification of the noise associated with the high signal, for example resonance noise which, by exceeding the comparison threshold, would in turn cause the system to fail to intervene.
  • the aim of the present invention starting from the notion of the drawbacks of conventional monitoring methods and systems, is to eliminate them, and within the scope of this aim the invention has the important particular object of providing a monitoring method and device which ensure prompt and assured intervention of the loom halting system even in the presence of highly unfavorable weaving factors, particularly low yarn travel speeds and in the presence of low-count yarns with high surface continuity (for example glossy yarns).
  • Another important object of the present invention is to provide a monitoring device which is simple and reliable and is entirely constituted by solid-state electronic components and has absolutely no mechanical elements that interact with the monitored weft yarn.
  • the invention is based on the concept of monitoring the weft yarn by means of a system which has means for amplifying the signal produced by a weft presence sensor and means for comparing the amplified signal of the sensor with a parametric reference voltage and to correspondingly vary, in said system, the amplification gain and/or the parametric reference voltage as the value of one or more weaving factors varies correspondingly.
  • a monitoring system with an amplifier and a comparator for processing the weft presence sensor signal, in which a signal which is proportional to the rotation rate of the windmilling arm of the feeder is sent to the microprocessor that controls the entire weaving process and provides, on a dedicated output, a system adjustment signal which is inversely proportional to said rotation rate; said adjustment signal being adapted to vary the gain of said amplifier, decreasing as said rotation rate increases and increasing it as said speed decreases.
  • the microprocessor is programmed in order to generate an adjustment datum, in terms of parametric comparison voltage, which is directly proportional to said rotation rate, so as to increase the parametric reference voltage applied to the comparator means as said rotation rate increases and so as to decrease the voltage as the rate decreases.
  • the reference sign T generically designates a weaving loom, for example of the high-speed type; the reference numeral 10 designates a conventional system for feeding the weft yarn F to the loom T; and the reference numeral 20 designates the equally known system for monitoring the weft yarn F.
  • the system 10 substantially comprises a weft feeder 11 with a fixed drum 12 on which a windmilling arm, associated with a rotating disk 13 arranged at the base of the drum, winds a plurality of turns of yarn F, which unwinds from a spool 14; said turns constitute a weft reserve RT.
  • a sensor 15 which is meant to report any yarn breakage to the monitoring system 20, so that the system 20 promptly halts the loom T before said loom uses up entirely the weft reserve RT.
  • the system 20 comprises an amplifier 21, to which the signal s1 from the sensor 15 is applied; the amplifier is followed by a bandpass filter 22, whose output signal s3 is first rectified by a diode D and then filtered by a low-pass filter 23 constituted by a unit R1-C1 with which a resistor R2 for discharging the capacitor C1 is associated.
  • the rectified and filtered output signal s4 is applied to the positive input of a comparator 24 which compares signal s4 with a DC reference voltage VR, providing on its output U a high (digital) signal st when s4 is higher than VR (presence of weft yarn F) and, vice versa, a low signal (lack of weft yarn F) when s4 is smaller than VR.
  • a microprocessor ⁇ P which receives the signal st on a dedicated input, emits on one of its outputs a halting signal AR for the loom T.
  • the above-described monitoring system is improved as shown in Figure 2, in which similar or corresponding components are designated by the same reference numeral and which shows that said improved system, generally designated by the reference numeral 20', comprises an input amplifier 21' of the variable-gain type, driven by the signal that is present at the output of a digital/analog converter 25 which receives in input a datum supplied by the microprocessor ⁇ P.
  • the microprocessor receives, on one of its inputs, a signal sa which originates from the feeder 11 and is proportional to the rotation rate W of the windmilling arm of the feeder and is programmed so that the signal that controls the gain G of the amplifier 21' varies substantially in inverse proportion to the signal sa related to the rotation rate W. Accordingly, the gain G of the amplifier 20' (and, correspondingly, the signal s4 applied to the comparator 24) vary as shown in the chart of Figure 2a, decreasing as the rotation rate W increases and increasing as said rate decreases.
  • the microprocessor ⁇ P of the monitoring system 20'' is programmed so as to generate a datum VR which can vary in direct proportion to the signal sa that corresponds to the rotation rate W and is applied to a converter 25''.
  • a datum VR'' expressed in voltage terms, which is adapted to be applied to the comparator 24, in order to supply a parametric comparison voltage which, as clearly shown in Figure 3a, is directly proportional to the rotation rate W of the feeder 11, i.e., it increases and decreases as said rotation rate increases and decreases.

Landscapes

  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Looms (AREA)
  • Spinning Or Twisting Of Yarns (AREA)
  • Treatment Of Fiber Materials (AREA)
EP20000104465 1999-03-16 2000-03-08 Verfahren und Vorrichtung zur Überwachung von Schussfaden in Webverfahren oder dergleichen Expired - Lifetime EP1036869B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITTO990204 1999-03-16
IT1999TO000204 IT1308812B1 (it) 1999-03-16 1999-03-16 Metodo e dispositivo perfezionati di monitoraggio del filato di tramanei processi di tessitura e simili.

Publications (2)

Publication Number Publication Date
EP1036869A1 true EP1036869A1 (de) 2000-09-20
EP1036869B1 EP1036869B1 (de) 2004-02-25

Family

ID=11417631

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20000104465 Expired - Lifetime EP1036869B1 (de) 1999-03-16 2000-03-08 Verfahren und Vorrichtung zur Überwachung von Schussfaden in Webverfahren oder dergleichen

Country Status (3)

Country Link
EP (1) EP1036869B1 (de)
DE (1) DE60008443T2 (de)
IT (1) IT1308812B1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1445365A3 (de) * 2003-01-22 2005-03-09 Tsudakoma Kogyo Kabushiki Kaisha Verfahren und Vorrichtung zum Detektieren des Schussfadens in einer Webmaschine
EP2075209A1 (de) * 2007-12-28 2009-07-01 L.G.L. Electronics S.p.A. Vorrichtung zum Messen der Fadenspannung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0325793A1 (de) * 1987-12-31 1989-08-02 ROJ ELECTROTEX S.p.A. Schussfadenwächter mit automatischem Einstellen des Verzuges für Schussfadenzuführer in schützenlosen Webmaschinen
EP0570875A2 (de) * 1992-05-22 1993-11-24 Picanol N.V. Verfahren zum Ermitteln einer Kenngrösse für den Betrieb einer Webmaschine und Webmaschine zum Durchführen des Verfahrens

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0325793A1 (de) * 1987-12-31 1989-08-02 ROJ ELECTROTEX S.p.A. Schussfadenwächter mit automatischem Einstellen des Verzuges für Schussfadenzuführer in schützenlosen Webmaschinen
EP0570875A2 (de) * 1992-05-22 1993-11-24 Picanol N.V. Verfahren zum Ermitteln einer Kenngrösse für den Betrieb einer Webmaschine und Webmaschine zum Durchführen des Verfahrens

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1445365A3 (de) * 2003-01-22 2005-03-09 Tsudakoma Kogyo Kabushiki Kaisha Verfahren und Vorrichtung zum Detektieren des Schussfadens in einer Webmaschine
EP2075209A1 (de) * 2007-12-28 2009-07-01 L.G.L. Electronics S.p.A. Vorrichtung zum Messen der Fadenspannung

Also Published As

Publication number Publication date
EP1036869B1 (de) 2004-02-25
DE60008443D1 (de) 2004-04-01
IT1308812B1 (it) 2002-01-11
ITTO990204A1 (it) 2000-09-16
DE60008443T2 (de) 2005-01-13

Similar Documents

Publication Publication Date Title
US4617971A (en) Loom control system
EP0097939B1 (de) Schussfadenwächter für Düsenwebmaschinen
EP2031106B1 (de) Verfahren zur Spannungskontrolle eines Garnes, das von einem negativen Liefergerät an eine Textilmaschine geliefert wird, und Vorrichtung zur Durchführung des Verfahrens
US8397582B2 (en) Method for detecting the stop of the yarn unwinding from a yarn feeder provided with a stationary drum
JP4651821B2 (ja) 糸の走行／停止状態を監視する方法および糸検知器
US4023599A (en) Opto-electronic weft yarn detector
EP0713838B1 (de) Vorrichtung und Verfahren zur Überwachung der Fadenreserve in Schussfadenliefervorrichtungen
EP1036869B1 (de) Verfahren und Vorrichtung zur Überwachung von Schussfaden in Webverfahren oder dergleichen
US3673591A (en) Yarn defect detector apparatus for textile machinery
US4942909A (en) Weft-feeder with automatic adjustment of the delay time, for weft feeders of shuttleless looms
CN1046564C (zh) 扫描纱线的方法和纱线退绕传感器
KR100446361B1 (ko) 직물 방적사의 주행/정지 상태를 모니터하는 방법
US3494236A (en) Circuit system for yarn rejection device
JPH0680226B2 (ja) 織機の緯糸密度監視装置
JPS63218475A (ja) 糸切れ検出装置
JPS63145452A (ja) 経糸群の異常検出装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

17P Request for examination filed

Effective date: 20010226

AKX Designation fees paid

Free format text: DE

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE

REF Corresponds to:

Ref document number: 60008443

Country of ref document: DE

Date of ref document: 20040401

Kind code of ref document: P

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20041126

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20170327

Year of fee payment: 18

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 60008443

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20181002