EP0581745B1 - Improvement of weft feeders for pneumatic looms - Google Patents

Improvement of weft feeders for pneumatic looms Download PDF

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Publication number
EP0581745B1
EP0581745B1 EP93830309A EP93830309A EP0581745B1 EP 0581745 B1 EP0581745 B1 EP 0581745B1 EP 93830309 A EP93830309 A EP 93830309A EP 93830309 A EP93830309 A EP 93830309A EP 0581745 B1 EP0581745 B1 EP 0581745B1
Authority
EP
European Patent Office
Prior art keywords
moving element
feeder according
weft feeder
pin
magnet
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.)
Expired - Lifetime
Application number
EP93830309A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0581745A1 (en
Inventor
Pietro Zenoni
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 EP0581745A1 publication Critical patent/EP0581745A1/en
Application granted granted Critical
Publication of EP0581745B1 publication Critical patent/EP0581745B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D47/00—Looms in which bulk supply of weft does not pass through shed, e.g. shuttleless looms, gripper shuttle looms, dummy shuttle looms
    • D03D47/34—Handling the weft between bulk storage and weft-inserting means
    • D03D47/36—Measuring and cutting the weft
    • D03D47/361—Drum-type weft feeding devices
    • D03D47/362—Drum-type weft feeding devices with yarn retaining devices, e.g. stopping pins
    • D03D47/363—Construction or control of the yarn retaining devices

Definitions

  • the present invention relates to an improvement of weft feeders for textile pneumatic looms with high insertion speed.
  • weft feeders are devices suitable to accumulate a reserve of thread in the form of turns wound on a fixed drum and to feed the loom by unwinding the accumulated turns in an amount equal to the length L of thread required by the loom at each beating; said length being equal to the transverse dimension, or width, of the fabric being formed.
  • the pre-feeder also has the task of pre-measuring said length L, and this task is performed by counting the unwound turns of thread by means of a photoelectric cell.
  • L n ⁇ D
  • n the number of unwound turns
  • D the diameter of the drum of the feeder.
  • the photocell provides for the supply of power to the stop element, the intervention of which is completed when the subsequent last turn (n) is reached.
  • EP-A-363 938 discloses a conventional electromagnetic unit for blocking the weft yarn in a loom weft feeder.
  • the intervention time "t" available to the electromagnetic stop element is extremely limited and is generally comprised between 10 and 20 ms (milliseconds).
  • the above equation (1) yields a value of 7 for n.
  • the aim of the present invention is to achieve these important purposes, and for this reason it relates to a weft feeder for pneumatic looms, with an electromagnetic stop element suitable to block the unwinding of the thread from the drum of the feeder after the counting, performed by means of a photoelectric cell, of a preset number of turns, characterized in that said electromagnetic stop element comprises a permanent magnet which cooperates with a fixed magnetic core provided with a circular opening through which a hollow moving element passes, said moving element supporting a winding through which an energization current flows.
  • the moving element which also supports the thread stopping finger at its end, is fitted without contact engagement on a cylindrical extension of the magnet and is supported so that it can move axially with respect to said cylindrical extension.
  • the moving element is elastically supported, so that it can move axially with respect to the cylindrical extension of the core, by a pair of flat springs which also act as elements for retaining and centering said moving element with respect to said cylindrical extension.
  • the moving element which is of a substantially phonic type and is made of a low specific weight material, has a very small inertial mass and is thus capable of responding without appreciable delays to the electrodynamic actuations to which it is subjected. Furthermore, the presence of the plates for centering and retaining said moving element, which eliminate the sliding friction between said moving element and the fixed core, on one hand helps to improve said response of the moving element to electrodynamic actuations and on the other hand avoids wear, achieving the further object of significantly increasing the duration of the electromagnetic stop element.
  • the reference numeral 10 generally designates a weft feeder for pneumatic looms comprising, in a per se known manner, a fixed body 11, a fixed drum 12 and a rotating disk 13, arranged at the base of the drum and actuated by a hollow drive shaft 14.
  • a hollow rotatable arm 15 is rigidly coupled to the disk 13 and is connected to the shaft 14; the thread F runs in the cavities of the shaft and of the arm and is wound by the disk 13 on the drum so as to form a reserve of thread to be fed to the loom.
  • n equal to the length L of the weft inserted by the loom with said beating, are unwound from the drum 12.
  • the number of turns which unwind is counted by a photocell cooperating with a counter (both not shown) which, when the one before last turn (n-1) is reached, causes the energization of an electromagnetic stop device 16.
  • Said stop device engages the thread against the drum with a stopping finger 17, blocking its unwinding when the last turn (n) is reached.
  • the electromagnetic stop device 16 comprises a permanent magnet 18 contained in a cylindrical skirt 19 which constitutes a fixed magnetic core.
  • a moving element 24 is slideably fitted on said axial pin; said moving element is constituted by a hollow cylindrical case 26, made of material having low relative density, for example cardboard or textile material impregnated with resin, or polymeric material, provided with a winding 27.
  • the stopping finger 17 is provided at the free end of the case and is preferably applied and made of ceramic material or the like.
  • the winding 27 is arranged outside the case 26 at the annular gap 23, and is thus crossed by the lines of the magnetic field produced by the permanent magnet 18.
  • the internal diameter of the case 26 is chosen so that it is significantly greater than the outer diameter of the pin 21, so that there is no contact between said case and said pin.
  • the moving element 24, as a whole, is elastically suspended, so that it can move axially with respect to the pin 21, by a pair of annular flat springs 28 and 29 rigidly coupled to the case 26 and to the skirt 19 and also acting as elements for retaining and centering said moving element with respect to said pin 21.
  • the flat springs 28 and 29 are mutually spaced by an extent "d" which is equal to approximately half of the axial extension of the pin 21.
  • said flat springs are made of steel plate with a thickness comprised between 2 and 6 tenths of a millimeter.
  • they may also be made of textile fiber or cardboard, impregnated with polymeric resin, or of woven or felted glass fiber, also impregnated with polymeric resin.
  • the rigid connection between the case 26 and the springs 28 and 29 is preferably obtained by glueing with polymeric adhesive.
  • An energization current I having an intensity comprised for example between 1 and 2 amperes is made to circulate in the winding 27 and is supplied in a known manner by a generator (not shown) under the control of the counter associated with the photoelectric cell which counts the number of turns.
  • This energization current is directed so as to generate, by interaction with the magnetic field produced by the magnet 18, a magnetomotive force suitable to move the moving element 24, in contrast with the elastic action of the flat springs 28 and 29, in the direction of the arrow F of figure 3, so that in the presence of the current I the finger 17 blocks the thread against the drum 12, preventing its unwinding.
  • the permanent magnet 180 is cylindrical and is supported by a cylindrical extension 191 of the skirt 190 at the annular gap 230 in which the moving element 240 passes; said moving element 240 supports the winding 270, and is formed by a cylindrical sleeve 271 preferably made of textile material impregnated with resin and provided with a rigid bottom 272.
  • the cylindrical sleeve 271 is fitted on the magnet 180 without sliding contact and is guided in its axial movement by a pin 273 which is supported by the bottom 272 and which slideably passes in a guiding and retention bush 192 formed on the fixed magnetic core 190.
  • the stopping finger 17 is provided on the end of the pin 273 opposite to the bottom 272.
  • a helical spring 274 is interposed between the bottom 272 and the magnet 180, actuates the moving element 240 into the thread engagement position shown in figure 4 and provides an elastic thread stopping force which acts on the stopping finger 17.
  • an energization current I' is supplied in the winding 270 of the moving element 240 and, by reacting with the magnetic field of the magnet 180, keeps the moving element 240 in the raised position of figure 5, in contrast with the action of the spring 274. Under the control of said turn counter, the current I' is interrupted when the last turn is reached, and the spring 274 pushes the moving element and the finger 17 into the thread stopping position.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Looms (AREA)
EP93830309A 1992-07-27 1993-07-20 Improvement of weft feeders for pneumatic looms Expired - Lifetime EP0581745B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITTO920643 1992-07-27
ITTO920643A IT1256898B (it) 1992-07-27 1992-07-27 Perfezionamento agli alimentatori di trama per telai ad aria.

Publications (2)

Publication Number Publication Date
EP0581745A1 EP0581745A1 (en) 1994-02-02
EP0581745B1 true EP0581745B1 (en) 1996-09-25

Family

ID=11410641

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93830309A Expired - Lifetime EP0581745B1 (en) 1992-07-27 1993-07-20 Improvement of weft feeders for pneumatic looms

Country Status (3)

Country Link
EP (1) EP0581745B1 (it)
DE (1) DE69305028T2 (it)
IT (1) IT1256898B (it)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1271787B (it) * 1994-12-22 1997-06-09 Roj Electrotex Nuova Srl Unita' elettromagnetica di arresto del filo di trama per porgitrama misuratori
IT1303155B1 (it) * 1998-07-17 2000-10-30 Lgl Electronics Spa Perfezionamento ai dispositivi di arresto del filato, negli apparecchiporgitrama premisuratori per telai di tessitura ad aria.
DE10252604A1 (de) * 2002-11-12 2004-05-27 Iropa Ag Liefergerät

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3774785D1 (de) * 1986-07-15 1992-01-09 Sulzer Ag Verfahren fuer den betrieb eines schussfadenspeichers fuer eine webmaschine.
IT1230561B (it) * 1988-10-14 1991-10-28 Roy Electrotex Spa Unita' elettromagnetica di arresto del filo di trama in porgitrama mi-suratori per telai tessili a getto
DE69018228T2 (de) * 1989-12-29 1995-08-31 Roy Electrotex Spa Schussfadenzubringer für Düsenwebmaschinen.

Also Published As

Publication number Publication date
DE69305028T2 (de) 1997-02-20
DE69305028D1 (de) 1996-10-31
IT1256898B (it) 1995-12-27
EP0581745A1 (en) 1994-02-02
ITTO920643A1 (it) 1994-01-27
ITTO920643A0 (it) 1992-07-27

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