FR2698383A1 - A method for detecting the positioning of a yarn in a multi-bar loom such as, in particular, a Jacquard lace loom, loom and detection device designed for implementing the method. - Google Patents

Abstract

Method for detecting the positioning of a yarn (3) in a multi-bar loom such as in particular a Jacquard lace loom comprising at least one movably mounted needle bar and at least one movably mounted slaughter bar. According to the invention, a signal is emitted in the area of the needle bar and the variations in the signal are detected after each passage of the needle bar. The subject of the invention is also a multi-bar loom such as in particular a Jacquard loom and a detection device for implementing the method.

Description

The subject of the present invention is a method for detecting

  positioning a yarn in a multi-bar loom such as in particular a Jacquard lace loom, such a loom as well as a detection device designed for the implementation of the method. It will find its application in all sectors of the economic activity in which one wishes

  to make lace by means of a multi-skilled

  bars such as including a Jacquard loom.

  Currently, to make lace, it uses trades, including Jacquard type looms comprising at least one movable needle bar substantially vertically and at least one slider bar movable substantially horizontally which cooperate with a sheet of threads in order to achieve the

  patterns or contours of the lace.

  In practice, given the high operating rate of these trades and, the large number of son constituting the web, it is common that one of the threads breaks or is positioned in an unwanted manner. its poor positioning generates the making of embroidery articles that have defects and irregularities in the patterns, which can go up to holes, which is conceived diminishes the appearance

  aesthetic sought with such items.

  As soon as such a defect is detected, it is necessary to stop the operation of the loom and detected with precision the localization of the wire broken or badly positioned this

  which, one conceives it is long, complex and tedious.

  In addition, depending on the nature of the yarn used (yarn guimpe for making patterns, embroidery yarns for the achievement of contours) and the type or nature of the pattern to be made, the number of stops of the multi profession -Bars such as including a Jacquard loom can be high, which decreases the efficiency of the installation and generates an additional cost to the manufacture of such items. Detectors, especially optical detectors, are known for determining the positioning of the yarns inside the sheet at the level of the multi-bar loom, such as, in particular, a lacy Jacquard loom. However, in practice, such optical detectors can only be used to determine the positioning or the breakage of son of the warp type, which limits the capacity of use. Indeed, given the architecture and the design of the multi-bar trade such as in particular a Jacquard loom, it is not possible to be able to use such optical detectors to determine the positioning of a wire of a web when these son are

of the guimpe type.

  The object of the present invention is to overcome the drawbacks of currently known devices by providing a method for detecting the positioning of threads in a multi-bar loom such as in particular a Jacquard loom, such a loom and a detection device for its implementation. which make it possible to precisely determine the positioning of wires which

  whatever their nature and number within a tablecloth.

  Another object of the present invention lies in the fact that the method and the detection device according to the invention allow an optical location of the broken or incorrectly positioned wire, which facilitates its

  detection and intervention of the operator.

  Another object of the present invention also lies in the fact that this method and the device for detecting the positioning of a wire ensures optimal operation of the multi-bar machine such as in particular a Jacquard machine, in particular avoiding the unwanted stops resulting from the presence of defects in

  wires or parasitic elements.

  Another advantage of the method and of the device according to the invention is that they make it possible to detect, depending on the nature of the wire used, faults likely to generate a stoppage in operation of the

  multi-bar trade such as in particular a Jacquard loom.

  Another advantage of the method and the device according to the invention is that they are simple to implement and that they provide reliable results.

  whatever the capacity of operation of the multi-

  bars such as including a Jacquard loom.

  Other purposes and advantages of this

  invention will appear during the description that will

  to follow which is only indicative and which has not

for the purpose of limiting it.

  To this end, the method for detecting the positioning of a yarn within a sheet in a multi-bar loom, such as in particular a lacy Jacquard loom comprising at least one mobile needle bar and a movable slaughter bar. is characterized by the fact that: a signal is emitted in the area of the needle bar, the variations of the signal are detected after

  each pass of the needle bar.

  The subject of the invention is also a multi-bar loom such as, in particular, a Jacquard loom for carrying out the method which is characterized by the fact that it comprises: means for emitting a signal in the zone of the bar of needles, means for detecting variations in

  signal after each pass of the needle bar.

  The invention also relates to a detection device designed for the implementation of the method. The present invention will be well understood in the

  reading of the following description, accompanied by drawings

  in the appendix, among which: FIG. 1 is a schematic view showing the positioning and the movement of a bar

  needles and a slaughter bar in a multi-skilled

  bars such as in particular a Jacquard lace loom, FIG. 2 is a schematic view which illustrates the device for detecting the positioning of a wire according to the invention, FIG. 3 is a schematic view which illustrates the focusing of the light signal at 4 is a schematic view illustrating the variation of the attenuation of the light signal over time when the wire does not break, FIG. 5 is a schematic view illustrating the attenuation of the light signal. as a function of time when the yarn is a guimpe type broken yarn, FIG. 6 is a schematic view illustrating the attenuation of the light signal as a function of time when the yarn is a broken elastic elastane yarn as marketed under the broken lycra mark, FIG. 7 is a schematic view which illustrates the operating flow chart of the calculating means of the detection device according to the invention, FIG. 8 is a schematic view that

  shows an example of how a multi-skilled

  bars such as a Jacquard loom equipped according to the invention.

  The subject of the present invention is a method for detecting the positioning of a yarn in a sheet in a multi-bar loom such as, in particular, a lacy Jacquard loom, such a loom and a detection device.

for its implementation.

  Currently, for making lace, multi-bar looms are used, such as, for example, Jacquard looms which comprise at least one needle bar 1 mounted, notably substantially vertically, as illustrated by the arrow F1 in FIG. 1, and at least one felling bar 2 mounted, in particular substantially horizontally, as shown by the arrow F 2 by cooperating with a multitude of threads 3 constituting a sheet in order to make the patterns

and / or the contours of the lace.

  According to the invention, as illustrated in FIG. 8, this multi-bar loom, such as in particular a Jacquard loom, is equipped with the operation of the felling bar 2 and the needle bar 1 of a device which comprises: means 4 for transmitting a signal in the area of the needle bar 1, means 5 for detecting the variations of the signal after each passage of the needle bar 1. In addition, the means 4 emit a signal substantially in the area of the needle bar 1 and, the means 5 detect, substantially in the area of the slaughter bar 2, the passage of the needle bar 1

  and, with a delay, the passage of wire 3 if necessary.

  The means 4 for transmitting a signal consist of a laser diode 6 diffusing a signal

  visible light in the form of a beam 7.

  For example, it may be a collimated laser diode with a power of 5 milli-watts which emits a light beam 7 at a wavelength of 670 nanometers, that is to say corresponding to a radiation visible red, with a divergence radius of 0.3 milliradians along a length of 32 millimeters and a

diameter of 11 millimeters.

  Of course, the specific characteristics of the laser diode 6 may be variable, in particular from appropriate settings or, in other embodiments, the means 4 for transmitting a signal may be of any other type capable of generating and

send an optical signal or not.

  The means 5 for detecting the variations of the signal after each passage of the needle bar 1 are constituted here by a photodiode 8 associated with a convergent lens 9, as more particularly shown in FIG. 3. The spectral amplitude of the photodiode is For example, between 350 and 1150 manometers and its field of determination of the light beam 7 is variable depending on its positioning and the characteristics of the convergent lens 9, which here has a diameter of 20 millimeters and a distance

  focal length also 20 millimeters.

  A surprising and unexpected aspect of the use of an optical transmitter 4 such as a laser diode 6, is to allow signaling and optical identification of each wire, including broken wire or poorly positioned, which facilitates its operation. detection and intervention of the operator by limiting the time of immobilization and non-operation of the trade. The device also comprises means 10 for processing the detected signal constituted here by a computer 11 associated with an amplifier 12 to amplify the characteristics of the detected signal and to facilitate its

treatment.

  The computer 11 is here constituted by a microcontroller which operates according to an algorithm, as illustrated in FIG. 7, implementing the various steps of the detection method of the

  positioning a wire according to the invention.

  According to this method, a signal is emitted in the area of the needle bar 1 and the variations are detected.

  signal after each pass of the needle bar 1.

  For this, after the emission of the light signal 7, the processing means of the computer 11 are initialized until the needle bar 1 passes through the beam 7 and, until the needle bar is

beam output.

  This initialization and this synchronization of the progress of the algorithm from the positioning of the needle bar 1 may in other embodiments also be obtained for example by means of a proximity detector or electrical signals.

issued from the machine.

  After this synchronization step, it is checked that, if necessary, the wire cut the beam, in the direction of the arrow Fl, of the needle bar 1 for a period corresponding to the movement time Si, as illustrated in FIG. 4, between two successive passages of the needle bar 1, no change in the light signal, that is to say, any attenuation thereof, is detected that there is no wire broken So, according to the algorithm, we start again the synchronization step, that is to say, waiting for the bar

  Needles 1 crosses the beam again.

  On the other hand, if a wire has cut the beam, that is to say that a light attenuation has been detected, it means that this wire has irregularities corresponding either to its bad positioning or its break, or to the presence of defects of the thread such as a knot or parasitic elements on the needle bar 1. To avoid an unwanted stop of the operation of the multi-bar loom such as in particular a Jacquard loom, resulting for example from an irregularity of the yarn or a parasitic element, several detections of the successive signal attenuation of the signal are made, before stopping the operation of the loom. For example, in the embodiment shown, five successive detections of a cut of the beam by the wire before controlling the stop of the multi-bar trade such as in particular a Jacquard loom. As soon as the fault has been located, and the wire has been replaced, the algorithm operation is restarted. According to the invention, it should also be noted that it is possible to determine the defect of positioning of the wire or

  its break according to its nature.

  Thus, the detection of the incorrect positioning or breakage of a guimpe yarn is obtained by a light attenuation of the signal as illustrated in FIG. 5 or, in the case of an elastane-based elastic yarn. for example marketed under the trademark Lycra by a light attenuation of the signal as illustrated

in Figure 6.

  Of course, in other embodiments, it is quite possible, depending on

  own operating capacities of the multi-skilled

  bars such as including a Jacquard loom to change the different steps of this algorithm to get a

  optimal operation of this profession.

  It should also be noted that other forms

8 2698383

  of the present invention, could have been

  envisaged without departing from its scope.

Claims (8)

  A method for detecting the positioning of at least one yarn of a sheet in a multi-bar loom such as, in particular, a lacy Jacquard loom, comprising at least one mobile needle bar (1) and a slaughter bar ( 2) mobile, characterized in that: a signal is emitted in the area of the needle bar (1), the variations of the signal are detected after   each passage of the needle bar (1).   Process according to Claim 1, characterized in that the signal obtained is discriminated to determine the positioning defect of the wire (3) in according to its nature.   3 Process according to claim 1, characterized in that: a light signal is emitted substantially in the area of the needle bar (1), and in the area of the slaughter bar (2) the passage of the needle bar (1) and, with a delay, the passage of the wire (3), if necessary, the signal detected is processed with calculating means to determine the successive variations of the signal.   4 Process according to Claim 1, characterized in that the broken thread is optically marked   or poorly positioned by the said signal.   Method according to claim 1, characterized in that the stop of the job after   the detection of several variations of the signal.   6 Multi-bar trade such as in particular a loom Jacquard loom, comprising at least one movable bar of needles (1) mounted and a slider bar (2) mounted movably, allowing the implementation of the method according to claim 1 , characterized in that it comprises: means (4) for transmitting a signal in the area of the needle bar (1), means (5) for detecting variations   signal after each pass of the needle bar (1).   7 multi-bar trade such as in particular a loom Jacquard loom according to claim 6, characterized in that it comprises: means (4) for emitting a light signal substantially in the area of the needle bar 1, means (5) for detecting, substantially in the area of the felling bar (2), the passage of the needle bar 1 and, with a delay, the passage of the wire (3) where appropriate.   8 multi-bar trade such as in particular a loom jacquard loom according to claim 6, characterized in that the means (4) for transmitting a signal consist of a laser diode (6) diffusing a light beam 7.   9 multi-bar craft such as in particular a loom Jacquard loom according to claim 6, characterized in that the means (5) for detecting the signal are constituted by a photodiode (8) cooperating with means (10) for trapping the signal constituted by a computer (11) associated with a signal amplifier 12. 10 Device for detecting the positioning of at least one wire of a web designed for the implementation   process according to any one of claims 1 to 5.