Classifications

• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D51/00—Driving, starting, or stopping arrangements; Automatic stop motions
  • D03D51/06—Driving, starting, or stopping arrangements; Automatic stop motions using particular methods of stopping
  • D03D51/08—Driving, starting, or stopping arrangements; Automatic stop motions using particular methods of stopping stopping at definite point in weaving cycle, or moving to such point after stopping
  • D03D51/085—Extraction of defective weft

Definitions

• the present invention relates to a method for performing the automatic extraction of faulty weft yarns from the shed of a gripper weaving loom.
• the method has been devised to allow the automatic extraction of weft yarns which have become detached from the grippers during carrying or during exchange of the weft yarn between the carrying gripper and the drawing gripper.
• the method according to the present invention can be applied to all those cases of a faulty yarn where there has been no interruption in the continuity of the weft yarn itself.
• the Applicant has finally managed to devise a method for extracting the faulty wefts which can be applied to gripper looms, according to which the faulty weft is extracted on the weft insertion side of the loom, although with the same weft peeling effect already obtained for air looms and described in the aforementioned European patent.
• the extraction method may be realized without the need for special additional devices in the loom - except obviously for the actual device for picking up and extracting the broken weft - and without modifying the basic operating parts of the loom and in particular the grippers.
• the aforementioned method for the extraction of faulty weft yarns from the shed of a gripper loom is therefore characterized by the following steps: a) deactivating the weft cutting means and the weft feeding devices and at the same time stopping the loom; b) moving the loom backwards, bringing it back into the position where the faulty yarn was inserted; c) selecting the weft feeding device on the same weft where faulty insertion occurred and inserting a new weft across the shed by means of the carrying gripper and the drawing gripper of the loom; d) stopping the loom as soon as the new weft has emerged from the weft receiving side of the loom; e) recovering the new weft launched and hence the faulty weft connected thereto, on the weft insertion side; f) moving the loom backwards, bringing it back into the position where the faulty weft was inserted.
• Fig. 1 is a schematic plan view of the loom illustrating insertion of a faulty weft
• Figs. 2 and 3 are views similar to Fig. 1 which illustrate the initial steps of separation of the faulty weft from the warp yarns, with a peeling effect;
• Fig. 4 is a view similar to that of Fig. 1 which shows the final step of extraction of the faulty weft into the pneumatic/mechanical winding device;
• Fig. 5 is a schematic side view of the loom, on the weft insertion side, during the final stage of extraction of the faulty weft into the pneumatic/mechanical winding device.
• the sensor S detects the fault and sends a stop signal to the loom, immediately deactivating the weft feeding movement of the fingers F and the cutting means M.
• the loom therefore performs, as mentioned above, an idle stroke during which the weft A is beat up by the reed against the fabric T being formed.
• suction of a nozzle 1 oriented perpendicularly with respect to the weft, is activated, thus ensuring that the weft A is kept tensioned so as to avoid being gripped by mistake during an idle stroke of the loom.
• the loom stops and automatically performs an idle stroke backwards so as to free the faulty weft A from the warp yarns.
• a loop is formed with the weft yarn A' still attached to the faulty weft A, using for this purpose the pair of carrying and drawing grippers C and R, as illustrated in Figs. 2 and 3, during execution of a forwards stroke of the loom performed at very low speed.
• the same finger F of the weft feeding device where stoppage for the faulty weft occurred - indicated by the reference 3 in Figs. 2 and 3 - is reselected, excluding with suitable control means the cutting means M and raising at the same time the weft guide G from the working position shown in continuous Iines in Fig.
• the holding device of the drawing gripper R is structured so as to open when leaving the shed, without however allowing the loop formed by the weft A-A' to come out of the eyelet formed by the hook of the gripper R.
• a pneumatic/mechanical extraction device E of a type known per se, schematically illustrated by way of example in Fig. 4.
• devices of the type described in the abovementioned European patent or in the patent EP-A2-200 168 may be used.
• the devices in question are ones which combine a sucking function capable of drawing the weft yarn inside a suction mouth of the device itself, where intermittent or continuous mechanical recovery of the weft yarn is performed.
• Such a suction device is normally unable to draw directly the yarn inside its own suction mouth 5.
• the device E is equipped with a hook 6 operated, by a pneumatic cylinder or by other known means, so as to move in a linear path between an extended position where it interferes with the path of the weft yarn A-A' so as to pick up the latter and a position close to the suction mouth 5 into which the weft yarn A-A' may be directly sucked in by the suction air stream inside the pneumatic/mechanical device E.
• the loom at this point, is ready to start again, after performing one of the ordinary automatic restart programs with one or more idle strokes in order to eliminate the signs of stoppage.
• the consent command is issued to the weft feeding device, the latter is able to lower the finger 3 so that the carrying gripper C picks up the weft yarn A', carrying it inside the shed.
• the cutting means proceed to cut, in the usual manner, said weft yarn, the tail end of which is then completely sucked in by the pneumatic/mechanical device E and then discharged in a manner known per se.
• the pneumatic/mechanical device is then repositioned for a new extraction operation and weaving is resumed in the normal manner.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Looms (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=11372318

Family Applications (1)

Country Status (4)

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Family Cites Families (4)

• 1995
  • 1995-10-06 IT IT95MI002038A patent/IT1276828B1/it active IP Right Grant
• 1996
  • 1996-10-04 WO PCT/EP1996/004333 patent/WO1997013902A1/en active IP Right Grant
  • 1996-10-04 EP EP96934547A patent/EP0853693B1/de not_active Expired - Lifetime
  • 1996-10-04 DE DE69607973T patent/DE69607973T2/de not_active Expired - Fee Related

Non-Patent Citations (1)

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