EP0884263B1 - Self-adjusted modulated thread braking devices for a weft feeder - Google Patents

Self-adjusted modulated thread braking devices for a weft feeder Download PDF

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Publication number
EP0884263B1
EP0884263B1 EP98110510A EP98110510A EP0884263B1 EP 0884263 B1 EP0884263 B1 EP 0884263B1 EP 98110510 A EP98110510 A EP 98110510A EP 98110510 A EP98110510 A EP 98110510A EP 0884263 B1 EP0884263 B1 EP 0884263B1
Authority
EP
European Patent Office
Prior art keywords
springs
stiffness
preloading
braking device
elongation
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
EP98110510A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0884263A1 (en
Inventor
Giovanni Pedrini
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 EP0884263A1 publication Critical patent/EP0884263A1/en
Application granted granted Critical
Publication of EP0884263B1 publication Critical patent/EP0884263B1/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
    • D03D47/364—Yarn braking means acting on the drum
    • D03D47/366—Conical

Definitions

  • the present invention relates to self-adjusted modulated thread braking devices for weft feeders for weaving looms and textile machines in general.
  • the invention relates to modulated thread braking devices of the type disclosed in Italian Patent no. 1,251,209 or in European Patent Application EP 0 826 619 A1, comprising the features of the preamble of claim 1 with a frustum-shaped braking body which is arranged so as to face the fixed drum of the weft feeder, to which it is tangent at a diameter slightly smaller than the maximum one and against which it is pushed, so as to engage it by elastic contact, by corresponding flexible suspension elements.
  • the braking body is rigidly coupled, at its smaller cross-section, to a rigid ring which is suspended elastically, by means of at least one set of three preloaded helical traction springs, from an annular support which surrounds the braking body and can move with respect to the drum by means of a screw-type adjustment mechanism.
  • the helical suspension springs are subjected to a preloading F in a radial direction in order to keep the braking body correctly centered with respect to the annular support.
  • each spring is inclined by a generic angle ⁇ with respect to the radius of said support and stretches, discharging onto the braking body an axial elastic component Ftg ⁇ which can be adjusted by varying, again by means of said mechanism, the axial position of the annular support with respect to the drum of the feeder and therefore the inclination ⁇ of the springs.
  • the contact pressure and accordingly the braking action for an equal adjustment, vary within broad limits. Since the braking action is proportional to the count of the weft thread being processed, it is necessary to have an assortment of uniform units or, briefly, of sets of springs having different stiffnesses in order to adapt the braking action of the frustum-shaped body to the corresponding different thread counts.
  • the axial component of the total elastic tension discharged onto the braking body by the springs of the suspension must be able to vary between zero and 5000 g; this range is usually covered by alternately using two or more sets of springs having increasing stiffness and/or by varying the number of springs of each set.
  • Spring replacement is not easy and besides forcing to stop the loom it must be performed by specialized personnel, since it is easy to make mistakes in replacing one or more springs; imbalanced braking actions are accordingly possible.
  • braking devices references the assembly constituted by the frustum-shaped body, the elastic suspension springs and the annular support.
  • the aim of the present invention is to eliminate these drawbacks, and within the scope of this general aim the invention has the important object of improving said braking devices, improving the elastic suspension of the frustum-shaped body so that said suspension has a nonlinear elastic characteristic which can vary according to a curve which in practice allows to cover, over the adjustment range of the screw-type adjustment mechanism, the entire range of values required for the axial elastic tension that acts on the frustum-shaped body.
  • the aim of the present invention is to provide a braking device which can be used substantially over the entire range of threads being processed without requiring any replacement and/or adjustment.
  • the invention is based on the inventive concept of suspending the frustum-shaped braking body from the annular support by means of at least two sets of identical springs and of assigning to each spring set different stiffnesses and preloadings which are inversely proportional to the stiffness of the springs.
  • the braking device comprises a first set of three springs, which are arranged at 120° to each other and have a modest stiffness and a substantial preloading, deriving for example from a preloading elongation ⁇ L equal to 30-60% of the rest elongation of each spring, and a second set of three springs, which are interposed between the first ones, have a substantial stiffness, for example 100-200% greater than the stiffness of the springs of said first set, and a correspondingly reduced preloading, produced for example by a preloading elongation ⁇ L equal to 1-7% of the rest elongation of each spring.
  • the overall characteristic of the suspension assumes, in accordance with the stated aim and objects, a curvilinear plot which is characterized by an initial portion, corresponding to the minimum values of the adjustment, which has an almost constant gradient, and by a subsequent portion, corresponding to the higher adjustment values, in which the gradient gradually increases according to a substantially exponential rule.
  • the reference numeral 10 generally designates a weft feeder of the conventional type comprising a fixed drum 11 whereon a hollow rotating arm, rigidly coupled to a rotating disk 12 located at the base of the drum, winds a weft reserve in the form of a plurality of turns of thread S.
  • the thread that unwinds from the drum 11 to feed a loom or other textile machine passes through a finger 13 which is coaxial to the drum 11 and is subjected, during its unwinding motion, to the action of a modulating braking device, generally designated by the reference numeral 14, having the purpose of keeping said thread under tension and of modulating said tension as a function of the advancement speed of said thread.
  • the braking device 14, interposed between the drum 11 and the finger 13, comprises a frustum-shaped braking body 15 which is arranged so as to face the drum 11, whereto it is tangent at its rounded end part along a circumference which is slightly smaller than the maximum circumference of said drum.
  • a frustum-shaped braking body 15 which is arranged so as to face the drum 11, whereto it is tangent at its rounded end part along a circumference which is slightly smaller than the maximum circumference of said drum.
  • the annular support 16 is supported by a carriage 18 which can move axially with respect to the drum 11, by means of a screw mechanism 19, in order to vary the static tension that pushes the frustum-shaped braking body 15 against the drum 11.
  • the elastic suspension 17 is formed by a plurality of radial helical springs M which are connected, at one end, to a rigid ring 20 arranged at the smaller cross-section of the frustum-shaped body 15 and, at the other end, to the annular support 16 ( Figure 2).
  • each spring discharges onto the frustum-shaped braking body 15 an axial elastic component Ftg ⁇ , where F is the radial pretensioning tension of the springs M.
  • the elastic suspension 17 comprises at least two sets of identical springs which have different stiffnesses and preloadings which are inversely proportional to the stiffness of the springs of each set.
  • the improved braking device comprises a first set of three identical springs M1 which are arranged at 120° to each other and have a limited stiffness "c", for example between 0.10 and 0.25, and a substantial preloading which is suitable to ensure correct centering of the frustum-shaped body 15; for example, a preloading value produced from a preloading elongation ⁇ L equal to 30-60% of the rest elongation L 0 of the springs.
  • a second set of three springs M2 is associated with the first set of three springs M1; the springs of said second set are interposed between the springs M1 and are likewise mutually spaced by 120°.
  • the springs M2 of the second set of three has a significantly greater stiffness "c", for example between 1 and 4, and instead have a significantly reduced preloading, for example equal to a preloading elongation ⁇ L' equal to 1-7% of their rest elongation L' 0 .
  • the characteristic of the suspension assumes the shape plotted in Figure 4, which shows that it varies according to a curve K in which the initial portion A has an almost constant gradient and a subsequent portion B has a gradient which gradually increases according to a substantially exponential rule.

Landscapes

  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Looms (AREA)
EP98110510A 1997-06-11 1998-06-09 Self-adjusted modulated thread braking devices for a weft feeder Expired - Lifetime EP0884263B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITTO970511 1997-06-11
IT97TO000511A IT1292765B1 (it) 1997-06-11 1997-06-11 Perfezionamento ai dispositivi di frenatura modulata autoregolata del filato per apparecchi alimentatori di trama a macchine tessili

Publications (2)

Publication Number Publication Date
EP0884263A1 EP0884263A1 (en) 1998-12-16
EP0884263B1 true EP0884263B1 (en) 2002-04-03

Family

ID=11415778

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98110510A Expired - Lifetime EP0884263B1 (en) 1997-06-11 1998-06-09 Self-adjusted modulated thread braking devices for a weft feeder

Country Status (3)

Country Link
EP (1) EP0884263B1 (enrdf_load_stackoverflow)
DE (1) DE69804535T2 (enrdf_load_stackoverflow)
IT (1) IT1292765B1 (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1609303B (zh) * 2003-10-23 2010-09-01 爱吉尔电子股份公司 用于纺织机的喂纱器的调制制动装置
EP2623650A1 (en) 2012-02-02 2013-08-07 Iro Ab Yarn feeder and yarn brake

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITTO20120875A1 (it) 2012-10-09 2014-04-10 Lgl Electronics Spa Dispositivo frena-trama per alimentatori di filato a tamburo fisso.
CN105177830B (zh) * 2015-09-28 2018-06-05 嵊州市中森电子有限公司 一种喷气织机用节能储纬器

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5316051A (en) * 1991-09-20 1994-05-31 L.G.L. Electronics S.P.A. Self-adjusting thread braking device for weft feeder units
IT1251209B (it) * 1991-09-20 1995-05-04 Lgl Electronics Spa Dispositivo di frenatura autoregolante del filato per apparecchi alimentatori di trama.
IT1259551B (it) * 1992-04-22 1996-03-20 Lgl Electronics Spa Dispositivo elettropneumatico per l'infilaggio automatico di apparecchi alimentatori di trama a macchine tessili ed apparecchio alimentatore di trama incorporante detto dispositivo
IT1261331B (it) * 1993-11-05 1996-05-14 Lgl Electronics Spa Perfezionamento ai dispositivi di frenatura modulata positiva del filato per apparecchi alimentatori di trama.
IT239803Y1 (it) * 1996-09-03 2001-03-13 Lgl Electronics Spa Dispositivo di ritegno a sgancio rapido del supporto portafreno diapparecchi alimentatori di trama per macchine tessili
DE19638618A1 (de) * 1996-09-20 1998-03-26 Iro Ab Fadenbremse

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1609303B (zh) * 2003-10-23 2010-09-01 爱吉尔电子股份公司 用于纺织机的喂纱器的调制制动装置
EP2623650A1 (en) 2012-02-02 2013-08-07 Iro Ab Yarn feeder and yarn brake

Also Published As

Publication number Publication date
EP0884263A1 (en) 1998-12-16
ITTO970511A1 (it) 1998-12-11
DE69804535D1 (de) 2002-05-08
DE69804535T2 (de) 2002-10-02
ITTO970511A0 (enrdf_load_stackoverflow) 1997-06-11
IT1292765B1 (it) 1999-02-11

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