Abstract:
Method and apparatus for optically monitoring filling yarns inserted into a guide duct ( 10 ). Substantially collimated light rays are generated and directed transversely to the guide duct ( 10 ) onto photo-detectors ( 23 ), with the detection of interruption of the light rays by the fillings determining those positions which are assumed by the fillings when being inserted into the guide duct ( 10 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a method and apparatus for optically monitoring filling yarns, hereafter “fillings”, being inserted into a shed using essentially collimated light rays directed transversely to a guide duct onto photo-sensitive detectors, with detection of the interruption of the lightbeams by fillings, and to a detector with which to implement the method. 
     2. Description of the Related Art 
     It is known form U.S. Pat. No. 3,853,408 to direct a bundle of collimated light rays transversely to a filling guide-duct onto a plurality of photo-detectors mounted in a row transversely to the guide duct. Interruption by a filling of the light beams to the photo-detectors is detected and so processed by an analyzer that the presence of a filling is recognized. 
     SUMMARY OF THE INVENTION 
     The objective of the invention is to improve the method of the initially cited kind. 
     This problem is solved in that the particular filling positions shall be detected which these fillings assume when being inserted into the guide duct. 
     The method of the invention not only allows detecting the presence of a filling, but also and foremost its position in the guide duct. 
     In an implementation of the invention, when two or more fillings are inserted simultaneously, the positions of all fillings and hence the presence of all fillings shall be detected. 
     In another implementation of the invention, the filling positions shall be detected twice or more in sequence during insertion. As a result, not only is it possible to distinguish whether a filling was in fact inserted, or for instance if only a filling fluff or a filling segment moved through the guide duct, but also changes in the filling positions in this guide duct. Moreover advantageously, filling insertion shall be monitored when two or more fillings are inserted simultaneously. Because the fillings move relative to one another when being inserted into the yarn guide duct, it is possible therefore to ascertain during one of the detection procedures whether two or more fillings lie adjacent to each other, that is, whether two or more fillings are present. 
     To facilitate adjusting the device inserting the fillings, another implementation of the invention provides that the filling positions during one insertion and/or changes in the filling positions shall be displayed. As a result and for instance in the case of an airjet weaving machine, herein loom, an operator is able to so set the functions of the main and auxiliary airjet nozzles that the fillings shall be inserted into a specified zone of the guide duct. 
     The problem is solved by a filling detector in which an analyzer is fitted including a device for determining the filling&#39;s positions when they enter the guide duct. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further features and advantages of the invention are shown in the following description of the illustrative embodiments shown in the drawings. 
     FIG. 1 schematically shows part of a loom fitted with a filling detector of the invention, 
     FIG. 2 is a section along line II—II of FIG. 1 on a larger scale, 
     FIG. 3 is a section along line III—III of FIG. 2, 
     FIG. 4 is a section along line IV—IV of FIG. 3, 
     FIG. 5 is a cutaway of a guide duct fitted with a filling detector and containing a filling, 
     FIG. 6 is a plot of signals received by a filling detector in the absence of a filling, 
     FIG. 7 is a plot of the signals received by a filling detector in the presence of one filling, 
     FIG. 8 is a cutaway of a guide duct holding two fillings and fitted with a filling detector, 
     FIG. 9 is a plot of the signals received by a filling detector from two fillings, 
     FIG. 10 is a section similar to that of FIG. 2 of a modified design of a filling detector, 
     FIGS.  11 - 13  are plots of the signals received by the filling detector of FIG. 10 in the absence of a filling, in the presence of one filling and in the presence of two fillings, and 
     FIG. 14 is a section similar to that of FIG. 2 of another embodiment of a filling detector of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a loom&#39;s batten  1  to which is mounted a reed  2 . Two main jet nozzles  4 ,  5  are mounted at the insertion side  3 . Several auxiliary jet nozzles  6  are mounted along the reed  2  on the batten  1 . A filling detector  8  is mounted on the side  7  opposite the insertion side longitudinally after the reed. The filling detector  8  is followed after the length of the reed  2  by a so-called auxiliary reed  9  along which auxiliary jet nozzles  6  also are mounted. 
     The fillings  11 ,  32  blown-in by the main jet nozzles  4 ,  5  are guided inside a guide duct  10  from the insertion side  3  to the opposite side  7 . The guide duct  10  is also shown in FIG.  2  and is constituted of U-shaped cutouts in the dents  12  of the reed  2 , of a clearance  13  in the filling detector  8  and of U-shaped cutouts in the dents  14  of the auxiliary reed  9  corresponding to the dents  12  of the reed  2 . The U-shaped cutouts of the dents  12  of the reed  2  and of the dents  14  of the auxiliary reed  9  and the clearance  13  of the filling detector  8  are configured consecutively in a row. A filling  11 ,  32  is blown-in in a known manner by the main jet nozzle  4  or  5  and the auxiliary jet nozzles  6  through the guide duct  10  from the insertion side  3  to the opposite side  7 . In general a so-called stretching nozzle  15  is mounted longitudinally after the auxiliary reed  9  on the batten  1  to keep the inserted filling  11 ,  32  taut after its insertion. 
     The filling detector  8  of FIGS. 2 through 4 contains a light source  16  generating a bundle of light rays  17  directed onto a prism  18  mounted in the housing  19  of the filling detector  8 . The light rays are deflected by curved mirrors  20 ,  21  from below to above to the clearance  13  of the filling detector  8  and as a result they pass inside the portion of the guide duct  10  formed by the clearance  13  substantially from below to above and run substantially parallel to one another. The mirrors  20 ,  21  may consist of curved facets of the prism  18  coated with a specular material. Preferably the housing  19  is made of plastic to allow casting the prism  18 . The refraction of the prism  18  and the curvature of the mirrors  20 ,  21  are selected in such manner that the light rays  22  shall be substantially collimated and form a beam across the depth (direction of arrow A in FIG. 2) of the guide duct  10 . 
     The filling detector  8  contains a plurality of photo-detectors  23  to detect the substantially collimated light rays  22 . The photo-detectors  23  are mounted in the vicinity of the upper boundary of the guide duct  10  and are substantially configured in a row running transversely to the guide duct  10  in the direction of its depth (direction A), and as a result the light rays  22  impinge on the photo-detectors  23 . The photo-detectors  23  are connected to an amplifier  24  housed in the housing  19 . Illustratively the photo-detectors  23  are photoelectirc sensors emitting a voltage proportional to the light intensity of the light rays  22  incident on them. 
     The light source  16  consists of a bulb or a light-emitting diode (LED) mounted in the housing  19 . The housing  19  is fitted with an aperture  25  to allow the light rays  17  from the light source  16  to reach the prism  18 . The light source  16  is connected by electrical leads  46  to a loom control unit  26  also receiving and processing signals from the amplifier  24 . 
     By selecting an appropriate curvature for the mirrors  20 ,  21 , light rays  22  may be generated which not only are substantially collimated but also fill the guide duct across its width at essentially constant light intensity. For that purpose the mirrors  20 ,  21  may be designed in such manner that they concentrate the reflected edge rays more. 
     In the embodiment shown, the photo-detectors  23  are consecutively mounted in a row in the depth direction (Arrow A) whereby they are able to receive all the light rays  22 . The detectors  23  are juxtaposed in a support  27 . Together with electronic components, the photo-detectors  23  are molded into the support  27 , simultaneously fitted with contacts  28  electrically connected to the detectors  23  and electrically connected by leads  35  to the amplifier  24 . Electric leads  34  run from the amplifier  24  to the control unit  26 . The support  27  illustratively is bonded to the housing  19 . 
     The filling detector  8  cooperates with an analyzer  29  to process a plot of the signals received from the photo-detectors  23  to allow determining a filling position, that is the position of a filling in the depth direction (direction A) of the guide duct in the vicinity of the filling detector  8 . Illustratively the analyzer  29  will be part of the control unit  26 . The electric leads  34  run to the analyzer  29 . A display  55  is connected to the analyzer  29  and shows a plot of the position of the filling(s) and thereby allows an operator to monitor the filling position(s) when setting up the equipment. 
     The processing of the signals from the photo-detectors  23  for the purpose of plotting the position of a filling in the guide duct  10  in the vicinity of the filling detector  8  is shown in FIGS. 5 through 9. The plots show the (amplified) signal S against the guide-duct depth P. The plot  30  of FIG. 6 is for the absence of a filling and corresponds almost to a straight line because all light rays—which are of approximately identical light intensities—were received. Even though the received signals are shown as a continuous line, actually they are a row of adjacent short line segments of which each length corresponds to the width of the particular detectors  23 . If for instance twenty photo-detectors  23  are mounted adjacent to each other, they will then produce twenty corresponding short signal segments which together form a nearly continuous line. The width of the photo-detectors  23  in the depth direction of the guide duct  10  (direction A) is comparatively minor. It is less than the diameter of a typical filling being processed. 
     If a filling  11  or  32  is present in the vicinity of the filling detector  8 , some of the light rays  22  will be interrupted and the photo-detectors masked by the filling  11 ,  32  shall receive significantly less light. FIG. 7 shows a corresponding plot  30 A. In the zone of those detectors  23  to which the light rays  22  were interrupted by the filling  11  or  32 , said interrupted rays no longer directly reach the photo-detectors  23  and the emitted signal is in substantially attenuated form. This plot  30 A can be analyzed by ascertaining the particular segment  31  of a signal which is substantially attenuated relative to the other zones. Each signal emitted by this detector  23  is then compared with that emitted from it in the absence of a filling. If the signal is less than for absence of signal, a filling will be present. By analyzing which detector  23  emits a lesser signal, the particular position of the filling  11 ,  32  which it assumes relative to the depth of the guide duct  10  can be determined. If no weaker signal is received, no filling  11 ,  12  is in the vicinity of the filling detector  8 . 
     The position of a filling  11  or  32  can be determined several times consecutively in the vicinity of, and by, the detector  8  and using the analyzer  29 . Thereby it is feasible to ascertain the changes in time of the position of the filling  11 ,  32  during a filling insertion. By using statistics, for instance implemented by the analyzer  29 , a mean position of the filling  11  or  32  can be determined as well as the displacement by which a filling  11  or  32  changes its position relative to said mean position. Illustratively in this case it is possible to empirically adjust the control of compressed air to the main jet nozzles  4 ,  5  and to the auxiliary jet nozzles  6 , and/or the configuration of the auxiliary jet nozzles  6  in such manner that the range of displacement shall be minimized. Each parameter may be varied and the effect of such a change on displacement then may be ascertained to globally optimize filling insertion. 
     The filling detector  8  of the invention is also suited for looms inserting two or more fillings simultaneously into a shed. For instance two fillings  11 ,  32  each are moved by associated main jet nozzles  4 ,  5  into the guide duct  10  and then are blown farther by the auxiliary jet nozzles  6  through this guide duct  10 . As illustratively shown in FIG. 8, two fillings  11 ,  32  in that case will be in the vicinity of the filling detector  8  in the guide duct  10 . This scenario leads to a plot  30 B of FIG. 9 comprising two segments  31 ,  33  wherein the received signals are substantially attenuated relative to the other portions. The received-signal plot  30 B can be analyzed in such manner as to determine whether two mutually distinct segments  31 ,  33  are present that indicate the presence of two fillings  11 ,  32 . 
     Because sometimes the two fillings  11 ,  32  in the vicinity of the filling detector  8  may be superposed in a direction B perpendicular to the direction A, the filling detector  8  of the invention might then only detect the presence of one filling. However, because the fillings  11 ,  32  move erratically, namely both in the direction A as well as in the direction B, there shall always be a time at which the fillings  11 ,  32  are mutually adjacent and thereby result in two mutually distinct segments  31 ,  33  in the plot. Consequently the filling positions are checked several times consecutively to unambiguously determine whether two fillings  11 ,  32  are present in the guide duct, namely when at one or at several times two segments  31 ,  33  different from each other are determined by the plot  30 B. 
     The same mode may be used also when three or more fillings are inserted at the same time. In the case of three fillings, three different segments will be looked for in the plot. In the case of four fillings, four different segments will be looked for in the plot, etc. Moreover the positional changes in time of several fillings can be ascertained simultaneously, for instance their dispersions about a mean value. 
     Because the light rays  22  essentially are collimated, the invention offers the advantage that the signals received by the photo-detectors  23  will be sharply different when the fillings  11 ,  32  break the light rays. Moreover the substantially collimated light rays  22  also offer the advantage that the height positions of the fillings  11 ,  32  in the guide duct  10  (direction B in FIG. 2) only little affect the signals received from the photo-detectors  23  only a little. 
     In the embodiment of FIG. 10, the photo-detectors  23  of the filling detector  8  are mounted above the guide duct  10  in the manner of the embodiment of FIGS. 2 through 4. The light rays  17  of the light source  16  however are deflected by mirrors  36  and  37  and are guided from below to above through the guide duct  10 . The mirrors  36  and  37  are mounted in a recess  38  of the housing  19 . The analyzer  29  is mounted in the vicinity of the amplifier  24  in the housing  19  and is connected by electric leads  39  to the control unit  26 . The filling detector  8  operates as in the embodiment of FIGS. 2 through 4. 
     In the embodiment of FIG. 10, the set of light rays  22  varies in intensity over the depth of the guide duct  10  and accordingly, in the absence of a filling in the guide duct  10 , the plot  40  of FIG. 11 will be seen. If a filling  11  or  32  of FIG. 5 is present, it results in a plot  40 A shown in FIG.  12 . The position of the filling  11  or  32  can be determined by comparing the plot  40 A of FIG. 12 with the plot  40  of FIG.  11 . If two fillings  11 ,  32  are present, there will be a plot  40 B as in FIG.  13 . In this case the position of the fillings  11 ,  32  can be determined by comparing the plot  40 B of FIG. 13 with the plot  40  of FIG.  11 . This filling detector  8  also allows determining the positions of the fillings  11 ,  32  at different times and in sequence and consequently the dispersion relative to a mean position or presence of two fillings  11 ,  32  may be ascertained. 
     In another variation (not shown) of the invention, the photo-detectors  23  are mounted underneath the guide duct  10  whereas the light rays  22  from the light source are guided in such a way that they pass from above through the guide duct  10  to the photo-detectors  23  below. 
     Furthermore the signals from the photo-detectors  23  can be guided directly, that is without passing through an amplifier  24 , to the analyzer  29 . 
     FIG. 14 shows an embodiment of a filling detector  8 , the light source for which is a bulb  41  emitting a concentrated, focused light ray  47 . The bulb  41  is fitted with a support  42  to allow moving it, and thus the focused light ray  47 , to-and-fro in order to generate a reciprocating light ray. The support  42  cooperates with two electromagnets  43 ,  44  controlled from the control unit  26  through electric leads  48 . The support  42  rests pivotably in a housing  45  also receiving the electromagnets  43 ,  44 . Using the electromagnets  43 ,  44  to tilt the support  42 , the light beam  47  of the bulb  41  moves to-and-fro. This light beam is so deflected by mirrors  36 ,  37  that it runs in the form of light rays  22  through the guide duct  10  in the direction of its depth, these light rays  22  being substantially collimated across the depth of the guide duct  10 ; that is, a light ray  22  is generated for each position of the support  42  and of the bulb  41  which runs through the guide duct  10  and which shall be substantially parallel to each other light ray  22  passing through the guide duct  10  for another position of the support  42  and the bulb  41 . In this process the light rays  22  move between the zone defined by the outer light rays  22 A and  22 B. By operating a comparatively high frequency of tilting, an effect is achieved whereby a substantially continuous field of essentially parallel light rays  22  can be detected by the photo-detectors  23 . 
     By appropriately designing the mirrors  36 ,  37 , the rate of tilting the support  42  can be controlled in such manner that the light rays  22  shall sweep the guide duct  10  over its depth with nearly constant light intensity. Illustratively the tilting rate of the support  42  can be raised when the light ray  47  of the bulb  41  is directed at sites on the mirrors  36 ,  37  that focus the light rays more than when the light ray of the bulb  41  is aimed on other sites of the mirrors  36 ,  37 . In the shown embodiment, therefore, the tilting rate of the support  42  will be relatively higher when this support is closer to the electromagnets  43 ,  44  than when it is mid-way between the electromagnets  43 ,  44  because the mirrors  36 ,  37  focus the light rays more near the edge of the guide duct  10  than at its center. This feature further prevents the light ray  47  being deflected toward the mirrors  36 ,  37  when the support  42  is very close to the electromagnets  43 ,  44  because at that time the speed of the support  42  approaches zero. 
     The depth of the guide duct  10  (direction A) denotes the direction transverse to the guide duct  10  and perpendicular to the drop wires  12  of the reed  2  and being essentially perpendicular to the light rays  22 . The width or depth position of fillings  11 ,  32  is determined thereby, that is the position of the fillings  11 ,  32  in the transverse direction of the guide duct  10 . 
     In an omitted embodiment of the invention, the position of the filling(s) is determined by two filling detectors of which the substantially collimated light rays cross each other. The position of the filling(s) is then determined in two directions, and as a result the absolute position of the filling(s) in the guide duct  10  can be determined geometrically. 
     Furthermore, besides their position, the thickness of the fillings  11 ,  32  can be determined from the plots  30 A,  30 B,  40 A,  40 B, by ascertaining the width of the segments  31 ,  33 . As a result the filling detector  8  also allows ascertaining differences in thicknesses of the fillings  11 ,  32 . 
     The invention is not restricted to blowing the fillings  11 ,  32  using compressed air from main jet nozzles  4 ,  5  and auxiliary jet nozzles  6  through the guide duct  10 . The invention also applies when fillings are conveyed in different manners through the guide duct  10 . Illustratively such conveyance may be implemented using water from a main nozzle configured in the manner of the main jet nozzles  4 ,  5  at the reed&#39;s insertion side  3 , using a projectile or in another similar manner. 
     The dents  12 ,  14  also are not mandatorily of the shape shown in the drawings. Illustratively they may assume a shape as disclosed in U.S. Pat. No. 3,853,408. 
     In an embodiment (not shown) of the invention, a filling detector  8  is mounted between the auxiliary reed  9  and the stretching nozzle  15 . Again, a filling detector  8  mounted in such manner may be used in addition to the filling detector  8  between the reed  2  and the auxiliary reed  9 . 
     It is quite easy moreover to mount a filling detector  8  not on the batten  1  but in stationary manner on a loom frame not shown. In this case however the filling detector  8  must be configured in such manner that, in the approximately rearmost position of the batten  1 , namely when the reed is far from the beat-up line and a filling  11 ,  32  is inserted in the guide duct  10 , this guide duct  10  and the filling detector  8  shall be substantially flush. 
     Besides a prism  18  and/or mirrors  20 ,  21 , the filling detector  8  also may contain in addition one or more lenses to produce light rays  22  which are essentially directed in collimated manner through the guide duct  10 . 
     Obviously modifications of the above described method and/or of the illustrative embodiments of filling detector can be carried out within the skill of experts without thereby avoiding the scope of protection which is to be determined solely by the attached claims.