EP0350776A1 - Elektrischer Laser-Kettfadenwächter - Google Patents

Elektrischer Laser-Kettfadenwächter Download PDF

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Publication number
EP0350776A1
EP0350776A1 EP89112266A EP89112266A EP0350776A1 EP 0350776 A1 EP0350776 A1 EP 0350776A1 EP 89112266 A EP89112266 A EP 89112266A EP 89112266 A EP89112266 A EP 89112266A EP 0350776 A1 EP0350776 A1 EP 0350776A1
Authority
EP
European Patent Office
Prior art keywords
lamina
warp
loom
photoelectric
stop motion
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Withdrawn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
EP89112266A
Other languages
English (en)
French (fr)
Inventor
Luigi Pezzoli
Luigi Favini
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.)
Vamatex SpA
Original Assignee
Vamatex 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 Vamatex SpA filed Critical Vamatex SpA
Publication of EP0350776A1 publication Critical patent/EP0350776A1/de
Withdrawn legal-status Critical Current

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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
    • D03D51/20—Warp stop motions
    • D03D51/28—Warp stop motions electrical

Definitions

  • the present invention concerns an electronic warp stop motion device employing sensors with beams of coherent light produced by a laser source, for use in weaving looms.
  • warp stop motion devices of the mechanical, electrical or electronic type, apt to signal the breakage of the warp yarns in a weaving loom and to accordingly stop the loom.
  • These devices usually comprise rows onto which the laminae supported by the warp yarns drops in case of yarn breakage, thereby signalling - each device according to its own working and signalling means - that a yarn has broken and, in the most improved devices, also the position (approximate or exact) of the broken yarn, so as to allow repairing the yarn itself.
  • each of the known warp stop motion devices has considerable draw­backs: with the simpler and more economic devices it is usually difficult and it takes longer to detect the broken yarn; the more improved devices may require, according to the type of row used, the use of sophisticated materials and devices, and may involve constructive difficulties which are often too expensive. Furthermore, each of said devices almost always requires the use of laminae differing from those of the other devices, according to its working characteristics, with obvious negative conse­quences on the weaving. Finally, in the case of electrical devices, the detection of the breakage point and the actual working of the warp stop motion device can often be conditioned by the additional resistance determined by the dirt of the environment.
  • the device according to the present invention which is of the type wherein the breakage of a warp yarn, causing the dropping of a corresponding lamina, interrupts a luminous beam between the sending part and the receiving part of one of a plurality of photoelectric cells, provided to each control a corresponding row of warp yarns and to signal said breakage and stop the loom, and which is characterized in that said photoelectric cells use beams of coherent light produced by a laser source.
  • the circuit feeding the loom motor is disconnected, stopping the loom, and the breakage is generically signalled.
  • a second, more complete and advantageous, embodiment of the warp stop motion device provides for a laser source at two energy levels, so as to obtain beams of coherent light of different colourings, and for means to commute said source from the first level (to which there corresponds a colourless or soft coloured luminous beam) to the second level (to which there corresponds a deep coloured luminous beam which is particularly evident) when said first beam is interrupted - between the sending part and the receiving part of the corresponding photoelectric cell - by the dropped lamina.
  • the deep coloured beam which settles between the sending part of the photoelectric cell and the dropped lamina, allows the inspection personnel - warned by the usual generic signaling of the loom stopping - to easily and immediately detect said dropped lamina and thus the broken warp yarn.
  • the position of the dropped lamina (and thus of the broken warp yarn) is furthermore electronically detected, by providing the device according to the invention also with means to compare and process the times taken by the luminous coherent laser beam sent by the sending part of the photoelectric cell to reach the dropped lamina and, respectively, the receiving part of the photoelectric cell, and with means apt to indicate in digits the corresponding distance between the lamina interrupting the beam and the sending part of the photoelectric cell, the second of said comparison times being calculated thanks to the connection by means of optic fibres of the sending and receiving parts of the photoelectric cells.
  • the second and third embodiment of the warp stop motion device according to the invention add to the advantage of safety and reliability - provided by using the relatively simple and economic means of the first embodiment of the invention - also that, which is very important for productivity purposes, of being able to detect with extreme precision and rapidity the position of the dropped lamina, and thus of the broken warp yarn, for a prompt restart of the loom, thereby reducing both the dead stopping times of the machine and the personnel required to control a certain number of machines.
  • the device according to the invention also introduces the importtant simplification of eliminating from the loom the conventional rows - special bars, of different type according to the laminae being used, which require a delicate and costly machining - replacing them by simple nickel-plated spacing bars, of a single type, already used for other operations in the field of textile workings (for example, in order to draw the groups of laminae or drop wires of the rows for selvedge thread drafting). Furthermore, since the working of the device according to the invention is based on the interruption of luminous beams, it is possible to use for all the looms any type of drop wires, among the many kinds existing on the market.
  • the warp stop motion device can be advantageously used both in cotton mills and in silk weaving, thereby unifying the whole warp stop motion devices for the various types of looms, with the only precaution of using low power laser sources for security purposes in respect of the personnel concerned (in practice, powers not exceeding about 0.5 mW are adopted in order to avoid resorting to the specific protections which would otherwise be required).
  • the warp stop motion device comprises a laser source S, suitably fed, which energizes a plurality of photoelectric cells (only one of them being illustrated) positioned sideby-side on a horizontal plane parallel to the warp yarns.
  • the beam r of coherent light sent by the sending part 1 of each photoelectric cell - perpendicular to said yarns - normally reaches the receiving part 2 of the same cell, which is associated to a commutator C of the circuit feeding the loom T.
  • the warp yarns of the loom - of which only the yarn f is shown - each support in known manner a lamina or drop wire 3, above the beams r, on vertical planes which substantially contain said yarns f and which are parallel one to the other and perpendicular to said beams.
  • the laser source S produces, through the sending part 1 of the photoelectric cells, beams of coherent light which, in normal conditions, reach the receiving part 2 of said photoelectric cells and thus keep the commutator C in a closing position, with the motor of the loom T duly fed and in running conditions.
  • the loom runs regularly, even in the presence of dirt and considerable dust, thanks to the high capacity of penetration of the coherent beams r.
  • the corresponding drop wire 3 When instead one of the warp yarns f breaks, the corresponding drop wire 3, no longer supported, drops and bears onto a spacing bar (not shown in fig. 1, but similar to the bar 11 shown in fig. 4), thereby interfering with the beam r and interrupting it.
  • the receiving part 2 of the corresponding photoelectric cell no longer energized by the beam, causes the commutator C to move into its opening position, so as to stop the working of the loom T whose motor is no longer fed by current.
  • a warning signal 4 is emitted from the circuit controlled by the commutator C, in order to call the attention of the inspecting personnel.
  • the advantage provided by this first simple embodiment of the invention lies in the possibility to be able to conveniently produce a warp stop motion device with photoelectric sensors apt to guarantee, with a very simple construction and low costs, a safety and a reliability which could not be previously obtained. Nevertheless, in the device heretofore described, in order to find the broken warp yarn it is necessary to search in the most conventional manner for the dropped wire which has interrupted the beam 2 between the sending and receiving parts of the photoelectric cell of its row.
  • the laser source is a source Ss at two energy levels, which can be commuted from one level to the other by means of an associated switch D controlled by the commutator C, while the remaining part of the device is substantially unchanged in respect of the previous embodiment of fig. 1.
  • the beam r (which will normally send a white or soft coloured light) is cut off by the dropped wire 3, not only does it cause - as in the previous case - the stopping of the loom and the signalling of the breakage, but the opening of the commutator C causes furthermore the operation of the switch D.
  • the laser source Ss then changes from the operation at a normal steady energy level to the operation at a different energy level, to which there corresponds a deep coloured beam r - which can be noticed at once by the inspection personnel - between the sending part 1 of the photoelectric cell controlling the row to which the broken warp yarn belongs, and the respective lamina 3 which has dropped onto the spacing bar. This clearly visible coloured beam allows to quickly and exactly detect the broken yarn.
  • the warp stop motion device of fig. 2 is completed with the addition of electronic means to compare and process the times taken for the beam r to move from part 1 of the photoelectric cell to the dropped wire 3 and, respectively, to the part 2 of the same cell.
  • the first of these times is measured by means of receivers 5 of the beam reflected by the lamina or dropped wire 3, while the second time is measured thanks to a connection by means of optic fibres 6 between part 1 and part 2 of the photoelectric cell.
  • the processing of the above times involves the calculation and display, in a suitable warning panel 7, of the distance in mm between the dropped wire 3 and part 1 of the photoelectric cells, for the immediate and precise detection of the broken warp yarn, the row pertaining to which is besides clearly evidenced by the fully perceptible changed colouring of the beam r which has been interrupted.
  • Fig. 4 of the drawings shows an example of practical realization of the warp stop motion device according to the embodiment of fig. 3, with three photoelectric cells representing as many rows, having their sending and receiving parts enclosed in protection cases, 8 and 9 respectively, and the optic fibres 6 protected by a tube 10.
  • the warp stop motion device adds to the advantages of simplicity and reliability provided by the warp stop motion device shown in fig. 1, also that - which is very important for productivity purposes - of being able to detect with extreme precision and rapidity the position of the dropped wire, and thus of the broken warp yarn, for a prompt restart of the loom, thereby reducing both the dead stopping times of the machine and the personnel required to control a certain number of machines.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Looms (AREA)
EP89112266A 1988-07-15 1989-07-05 Elektrischer Laser-Kettfadenwächter Withdrawn EP0350776A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT8821400A IT1226331B (it) 1988-07-15 1988-07-15 Dispositivo guardiaordito elettronico a raggi laser.
IT2140088 1988-07-15

Publications (1)

Publication Number Publication Date
EP0350776A1 true EP0350776A1 (de) 1990-01-17

Family

ID=11181205

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89112266A Withdrawn EP0350776A1 (de) 1988-07-15 1989-07-05 Elektrischer Laser-Kettfadenwächter

Country Status (2)

Country Link
EP (1) EP0350776A1 (de)
IT (1) IT1226331B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0915633A1 (de) * 1997-11-07 1999-05-12 Laserpromotions B.V. Methode und Apparatus zur Ansteuerung von Vorrichtungen
BE1011182A5 (nl) * 1997-07-14 1999-07-06 Wiele Michel Van De Nv Lancetteninrichting met bewakingsinrichting voor een weefmachine.
FR2784697A1 (fr) * 1998-10-20 2000-04-21 Setb Dispositif de tension et de detection de casse des fils de poil, pour tissage du velours faconne

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2034485A1 (en) * 1970-07-11 1972-01-20 Sick, Erwin, 7808 Waldkirch Warp monitor - using divided laser beam under the warps for breakage to be converted to a stop signal
FR2150357A1 (de) * 1971-08-23 1973-04-06 Nordiska Maskinfilt Ab
DE2628664A1 (de) * 1976-06-25 1977-12-29 Jaeger Emil Kg Fadenrisswaechter
EP0234630A1 (de) * 1986-02-14 1987-09-02 Picanol N.V. Vorrichtung zum Lokalisieren eines Schussfehlers in Webmaschinen mit Schussfadenwächterlamellen

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2034485A1 (en) * 1970-07-11 1972-01-20 Sick, Erwin, 7808 Waldkirch Warp monitor - using divided laser beam under the warps for breakage to be converted to a stop signal
FR2150357A1 (de) * 1971-08-23 1973-04-06 Nordiska Maskinfilt Ab
DE2628664A1 (de) * 1976-06-25 1977-12-29 Jaeger Emil Kg Fadenrisswaechter
EP0234630A1 (de) * 1986-02-14 1987-09-02 Picanol N.V. Vorrichtung zum Lokalisieren eines Schussfehlers in Webmaschinen mit Schussfadenwächterlamellen

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE1011182A5 (nl) * 1997-07-14 1999-07-06 Wiele Michel Van De Nv Lancetteninrichting met bewakingsinrichting voor een weefmachine.
EP0915633A1 (de) * 1997-11-07 1999-05-12 Laserpromotions B.V. Methode und Apparatus zur Ansteuerung von Vorrichtungen
US6043477A (en) * 1997-11-07 2000-03-28 Laserpromotions B.V. Apparatus and method for operating devices
FR2784697A1 (fr) * 1998-10-20 2000-04-21 Setb Dispositif de tension et de detection de casse des fils de poil, pour tissage du velours faconne

Also Published As

Publication number Publication date
IT8821400A0 (it) 1988-07-15
IT1226331B (it) 1991-01-08

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