EP0877110A1 - Dispositif pour modifier la géometrie de la foule en correspondance avec la lisière du tissu dans un métier à tisser - Google Patents

Dispositif pour modifier la géometrie de la foule en correspondance avec la lisière du tissu dans un métier à tisser Download PDF

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Publication number
EP0877110A1
EP0877110A1 EP98108446A EP98108446A EP0877110A1 EP 0877110 A1 EP0877110 A1 EP 0877110A1 EP 98108446 A EP98108446 A EP 98108446A EP 98108446 A EP98108446 A EP 98108446A EP 0877110 A1 EP0877110 A1 EP 0877110A1
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EP
European Patent Office
Prior art keywords
shed
carrier bar
warp yarns
yarn carrier
geometry
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.)
Withdrawn
Application number
EP98108446A
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German (de)
English (en)
Inventor
Mikhail Gendelman
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.)
Promatech SpA
Original Assignee
SOMET Societa Meccanica Tessile 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 SOMET Societa Meccanica Tessile SpA filed Critical SOMET Societa Meccanica Tessile SpA
Publication of EP0877110A1 publication Critical patent/EP0877110A1/fr
Withdrawn legal-status Critical Current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
    • D03D47/40—Forming selvedges
    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D49/00—Details or constructional features not specially adapted for looms of a particular type
    • D03D49/04—Control of the tension in warp or cloth
    • D03D49/22—Back rests; Lease rods; Brest beams

Definitions

  • the present invention concerns a device to be applied on looms - particularly air looms - to set a geometry of the shed in correspondence of the fabric selvedge, differing from the geometry of the shed set on the fabric and in particular, to set on the selvedge a symmetrical geometry of the shed.
  • the warp yarns are cyclically parted by the heald frames in order to form the shed into which a weft yarn is inserted at each loom cycle.
  • the parting of the warp yarns is delimited, on one side, by the fabric just being woven and, on the other side, by a deviation bar - named in the sector "yarn carrier bar” - so that, in a parted position and seen from the side, the warp yarns take up a typical rhomboidal configuration.
  • the particular shape of this rhombus is actually referred to as "geometry of the shed" and is apt to determine some characteristics of the fabric obtained.
  • the two parted branches of the warp yarns are of different lengths on the side of the yarn carrier bar, thereby obtaining a different tensioning of the two groups of warp yarns.
  • This type of shed geometry is adopted when wishing to obtain a "thicker" fabric, namely a fabric comprising a higher number of weft yarns per fabric length unit.
  • the different tensioning of the warp yarns, above and below the weft allows in fact such warp yarns, during beating up of the reed, to be positioned offset also in respect of a vertical plane, thereby enabling the beaten up weft to get closer to the previous weft.
  • the object of the present invention is to therefore supply a device allowing to keep a symmetrical geometry of the shed, merely in correspondence of the fabric selvedge, even when the fabric - for the reasons mentioned heretofore - is woven with an asymmetrical geometry of the shed.
  • Another object of the present invention is to supply a device allowing to regulate the tension of the warp yarns in correspondence of the selvedge zone and, in particular, to increase the tension of the warp yarns only in this zone, so as to obtain a perfectly tensioned and stable shed inlet, even in the presence of the strong air jet used to insert the weft yarn.
  • said objects are reached by means of a device to modify the geometry of the shed in correspondence of the fabric selvedge, in a loom comprising a yarn carrier bar, eventually oscillating, to deviate the warp yarns between a warp beam and a set of heald frames, said device being characterized in that, in correspondence of the ends of said yarn carrier bar there are provided deviation rollers apt to cooperate with the sole warp yarns forming the fabric selvedge, the axis of said rollers coinciding with or being parallel to the axis of the yarn carrier bar, and their lateral surface being tangent to the plane formed by the warp yarns in the weaving zone when the geometry of the shed is symmetrical and the shed is closed.
  • said deviation rollers have their axis coinciding with the axis of the yarn carrier bar, and are preferably in the form of idle bushes inserted onto the ends of said yarn carrier bar.
  • said deviation rollers have their axis parallel to the axis of the yarn carrier bar, and are in the form of idle pins mounted upstream of the yarn carrier bar.
  • Fig. 1 and 2 show the different parts of a loom, and precisely: the warp beam S; the warp yarns O; the yarn carrier bar T; the heald frames Q; and the take-up rollers P.
  • the yarn carrier bar T can be set between a position T1, in which the shed geometry is perfectly symmetrical (warp yarns in dashes), and a laterally shifted position T2 (warp yarns in full lines).
  • the warp yarns O are obviously tensioned to an exactly equal extent, during opening of the shed, thanks to the heald frames Q; whereas in the position T2, the upper warp yarns Os are looser than the lower warp yarns Oi.
  • This arrangement - as already said - allows to weave fabrics with a higher number of weft yarns per fabric length unit.
  • two idle bushes 1 are respectively inserted on the two ends of the yarn carrier bar T, the height of said bushes 1 being equal to the height of the group of warp yarns meant to form the fabric selvedge, and the radial thickness of said bushes corresponding to the distance between the two positions T1 and T2 of the yarn carrier bar T.
  • the bushes 1 preferably comprise annular projections at the two opposite ends, such as to form two edges apt to laterally contain the warp yarns carried thereby.
  • the warp yarns O meant to form the fabric selvedge, are forced to follow the outer profile of the bush 1, thereby reaching the heald frames Q with a perfectly symmetrical shed geometry; the first object of the present invention is hence obtained in a very simple and economic manner.
  • the same result is obtained by means of two pins 2, mounted idle on the loom with their axis parallel to the axis of the yarn carrier bar T.
  • the pins 2 are positioned upstream of the yarn carrier bar T - in respect of the warp yarns moving direction - and their length is such that they interfere with the sole warp yarns meant to form the fabric selvedge. As shown in fig.
  • the lateral position of the pins 2 is that in which their peripheral surface is substantially tangent to the plane r formed by the warp yarns in the weaving zone when the geometry of the shed is symmetrical and the shed is closed; in fact, in this position, the warp yarns deviated by the pins 2 are no longer influenced by the oscillating movement of the yarn carrier bar T, foreseen to compensate the warp yarn tension changes, nor by the possible shifting of said bar T into its lateral position T2.
  • the tension of said warp yarns thus no longer follows the profile (dashed line a in fig.
  • the weaver is thus able to choose the optimal tension value to satisfy the opposite requirements of having, on one hand, a properly open and perfectly tensioned shed inlet, and of ensuring, on the other hand, a maximum tension of the warp yarns meant to form the fabric selvedge, such as to cause no undesired warp yarn breakages.
  • the partial tension compensation also of the warp yarns meant to form the fabric selvedge is apt to reduce the perfect symmetry of the shed geometry; thus, to form said selvedge, it is normally preferable to use stronger warp yarns and to keep the position of the pins 2 tangent with the plane formed by the warp yarns in the weaving zone.
  • both the bushes 1 and the pins 2 can simultaneously be mounted on the loom, thereby obtaining the double advantage to constantly maintain a perfectly symmetrical geometry of the shed and to be able to regulate, at will, the tension of the warp yarns meant to form the fabric selvedge.
  • both embodiments of the device allow to obtain a perfectly symmetrical shed geometry on the warp yarns meant to form the fabric selvedge, while the second embodiment even provides for the further possibility to regulate at will the tension of said warp yarns while the shed is being formed. hence allowing to form a perfectly tensioned and symmetrical shed inlet and thereby making the weft yarn insertion step far more reliable.
  • the combination of both embodiments of the device allows to simultaneously obtain all these advantages.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Looms (AREA)
EP98108446A 1997-05-08 1998-05-08 Dispositif pour modifier la géometrie de la foule en correspondance avec la lisière du tissu dans un métier à tisser Withdrawn EP0877110A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT97MI001066A IT1292227B1 (it) 1997-05-08 1997-05-08 Dispositivo per controllare la geometria del passo in corrispondenza della cimossa del tessuto,in un telaio di tessitura
ITMI971066 1997-05-08

Publications (1)

Publication Number Publication Date
EP0877110A1 true EP0877110A1 (fr) 1998-11-11

Family

ID=11377093

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98108446A Withdrawn EP0877110A1 (fr) 1997-05-08 1998-05-08 Dispositif pour modifier la géometrie de la foule en correspondance avec la lisière du tissu dans un métier à tisser

Country Status (2)

Country Link
EP (1) EP0877110A1 (fr)
IT (1) IT1292227B1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19856308A1 (de) * 1998-12-07 2000-06-15 Dornier Gmbh Lindauer Verfahren zur Kompensation der Längungs- oder Spannungsänderung in einer Webkette und Webmaschine zur Durchführung des Verfahrens
US6135163A (en) * 1998-12-07 2000-10-24 Lindauer Dornier Gesellschaft Mbh Method and apparatus for compensating warp thread tension or elongation variations during loom shedding

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH181225A (de) * 1934-09-08 1935-12-15 Grimm Oskar Verfahren und Vorrichtung zur Herstellung eines Gewebes mit grosser Schussdichte.
FR2262139A1 (en) * 1974-02-25 1975-09-19 Mackie & Sons Ltd J Shuttleless loom warp control mechanism - uses deflection rods to give some warps a flabby character during shed changes
FR2339014A1 (fr) * 1976-01-20 1977-08-19 Rueti Te Strake Bv Perfectionnements aux metiers a tisser
GB2266730A (en) * 1992-05-05 1993-11-10 Nuovo Pignone Spa Improvements in a shuttleless loom

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH181225A (de) * 1934-09-08 1935-12-15 Grimm Oskar Verfahren und Vorrichtung zur Herstellung eines Gewebes mit grosser Schussdichte.
FR2262139A1 (en) * 1974-02-25 1975-09-19 Mackie & Sons Ltd J Shuttleless loom warp control mechanism - uses deflection rods to give some warps a flabby character during shed changes
FR2339014A1 (fr) * 1976-01-20 1977-08-19 Rueti Te Strake Bv Perfectionnements aux metiers a tisser
GB2266730A (en) * 1992-05-05 1993-11-10 Nuovo Pignone Spa Improvements in a shuttleless loom

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19856308A1 (de) * 1998-12-07 2000-06-15 Dornier Gmbh Lindauer Verfahren zur Kompensation der Längungs- oder Spannungsänderung in einer Webkette und Webmaschine zur Durchführung des Verfahrens
US6135163A (en) * 1998-12-07 2000-10-24 Lindauer Dornier Gesellschaft Mbh Method and apparatus for compensating warp thread tension or elongation variations during loom shedding
DE19856308B4 (de) * 1998-12-07 2005-02-24 Lindauer Dornier Gmbh Verfahren zur Kompensation der Längungs- oder Spannungsänderung in einer Webkette und Webmaschine zur Durchführung des Verfahrens

Also Published As

Publication number Publication date
ITMI971066A1 (it) 1998-11-08
IT1292227B1 (it) 1999-01-29
ITMI971066A0 (fr) 1997-05-08

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