Title of Invention

A DEVICE FOR SCANNING YARN

Abstract

895/CHEIVP/2005 ABSTRACT "A DEVICE FOR SCANNING YARN" A device for scanning yam (2), which is moved in its longitudinal direction in a measurement gap (1), with a light beam (3) from a light source, comprising a receiver (5, 6) for light that is reflected on the yam and comprising a unit (9) for processing electrical signals from the receiver, whereas a single light source (4) is provided for emitting light in three wavelength ranges (29, 30, 31), the wavelength ranges being determined by three principal wavelengths (32, 33, 34) and the unit (9) for processing electrical signals from the receiver for received light comprises a processor, which forms a vector (44,45,46) from the values for each of the three predetermined wave¬length ranges and a sum vector (47) from the vectors, characterised in that a region (48, 49, 50) is delimited for the end point (51) of the sum vector (47) in space (42) that indicates whether the electrical signal, which is processed to form a sum vector from the receiver displays a foreign substance in the yam and in that said space forms a cube, which is formed by axes (52, 53,54) along which values for the intensity of three principal wavelengths are plotted. Figure I.

Full Text

The invention relates to a device for scanning yam, which is moved in its longitudinal direction in a measurement gap, with a light beam from a light source, comprising a receiver for light that is reflected on the yam and comprising a umt for processing electrical signals fix)m the receiver. A device of this type is, known for example from EP 0 761 585, in which a light source that emits light, which is both reflected on the yam and also occluded, is provided. The light, which is received by receivers, is converted in a manner known per se into electrical signals for which ranges or threshold values may be provided in order, for example, to recognize foreign substances in the yam. A drawback of this device is that, for example, foreign substances in the yam that are the same colour as the emitted light may not be recognised. However, this is also true, for example, of transport foreign substances in the yarn, such as portions of plastic film, so foreign substances of this type may not thereby be recognised. A further device of this type is known from WO 95/29396, in which three different light sources are associated with a receiver for white light. These three light sources are configured as three light-emitting diodes, each diode emitting light of a different principal wavelength in the visible range. Viewed in the longitudinal direction of the yam, these light sources are arranged one behind another next to the yam and are arranged such that they illuminate the yam and a background that is located behind it and absorbs as much light as possible. The signals that are produced as a result of the reflection of the light on the yam in the receiver are processed such that ratios are formed from the values that are determined for the signals in the individual principal wavelengths, which ratios may in turn be measured on the basis of criteria. A drawback of this device is, in particular, that it is only suitable for evaluating reflected light with yam against a preferably black background. Moreover, the arrangement of three or more diodes at intervals along the yam requires a great deal of space, which may not be available at such points in textile machines that are provided for devices of this type. A further problem with this device is that the activation of the individual light sources has to take into account the movement of the yam and be provided such that flie same point on the yam is always illuminated with light of a different colour. The device as characterised in the claims achieves the object of providing a device of the aforementioned type, which requires little space, which is simpler to activate and which allows foreign substances present in the yam to be recognised more selectively and with greater sensitivity. According to the invention, this is achieved by a device that provides a single light source for emitting hght in at least two wavelength ranges, the wavelength ranges being determined by principal wavelengths. The principal wavelengths detemiine at least two colours in the range of wavelengths of visible light. Preferably, these are the colours red, green or blue. The light source is preferably configured as a light-emitting diode, which can separately emit visible light in three colours in the visible range. The light source and the receiver exhibit principal axes for emitting and receiving light that together span a plane, which is located transversely to the longitudinal direction of the yam. The unit for processing electrical signals from the receiver for reflected light forms a vector in a plane or in a space from the signals in each of the at least two predetermined wavelength ranges, and a sum vector from the vectors for the various signals. A region that indicates whether the electrical signal, which is processed to foim the sum vector, from the receiver displays a foreign substance in the yam is predetermined for the end point of the sum vector in the space. The space, in which the vectors are calculated and/or displayed, preferably forms a cube with axes along which values for the intensity of three principal wavelengths are plotted. The advantages that are achieved by the invention are that the single light source illuminates the yam with the light having different wavelengths substantially from the same point, so the light beams strike the yam at a narrowly delimited angle in all of the wavelength ranges. This light source also requires little space, so a yam measuring head, which may be incorporated at a narrowly delimited location in the spinning or winding machine, may be constructed. Said light source is also substantially more cost-effective than a unit comprising Ught sources for each individual colour. As a plurality of receivers may also be arranged that supply the light reflected on the yam to a unit for processing electrical signals, which processes these signals in exactly the same manner, the entire yam surface facing the receivers may be detected. The use of a plurality of identical receivers for white light allows the colours of the yam to be detected without spectral errors. The evaluation of the obtained signals, the purpose of which is to form a sum vector from the contents of the individual colours, allows specific colours and shades, which correspond to specific materials, to be recognised selectively. However, this also allows foreign substances purposefully to be left in the yam in that they are firstly recognised or in that a range is predetermined for the end point of the sum vector such that certain foreign substances are not even detected. Purposefiil cleansing of the yam with respect to specific impurities or foreign substances allows the performance of the production machines to be substantially improved. The invention will be described below in greater detail with reference to an embodiment and with regard to the accompanying figures, in which: Fig. I is a section through a device according to the invention; Fig. 2, 3 and 4 are each schematic illustrations of part of the device in various phases; Fig. 5 is a schematic illustration of wavelength ranges; Fig. 6 and 7 are each schematic illustrations of the evaluation of the measured signals; Fig. 8 to 10 are each illustrations of a target range for the evaluation; and Fig. 11 and 12 are each illustrations of options for activating the light source of the device. Fig. 1 shows a device according to the invention, for example a measuring head for measuring yam properties or for a yam cleaner, with a measurement gap 1 in which a yam 2 is moved in its longitudinal direction, this longitudinal direction being aligned in this case substantially perpendicularly to the drawing plane. A light beam 3 is generated by a light source 4 and is directed toward the yam 2. Receivers 5 and 6 are arranged for light that is reflected by the surface of the yam. A light-emitting diode, for example what is known as an RGB-LED, such as the NTSM 515 type produced by Nichia (as may be viewed on the Intemet at www.nichia.co.ip"). is provided as the light source. However, it is also conceivable to use other light sources, for example laser-based light sources. A further receiver 7 may also be provided for light that is occluded by the yam 2. The receiver or receivers 5, 6, 7 are connected via a respective line or a bus 8 to a unit 9 for processing electrical signals from the receiver or receivers. The unit 9 consists of a computer comprising a memory, for example of the type known from a microprocessoc, The light source 4 comprises four terminals 10, via which the individual wavelength ranges or colours may be individually activated, hi this example, the single light source 4 and the receiver 6 exhibit principal axes 11 and 12 for emitting and receiving Ught that together span a plane, which is located transversely to the longitudinal direction of the yam and in this case corresponds to the drawing plane. Fig. 2 is a simplified illustration of the light source 4 with three light-emitting diodes 13, 14 and 15, and of the yam 2 with a foreign substance 16 embedded therein. Based on the principal axis 11 of the light source 4 and assuming a direction of movement as indicated by arrow 17, the foreign substance is located just in front of this principal axis. In this case, the yam 2 comprising the foreign substance 16 is illuminated, for example, by red light from the diode 13, which emits light in a range 20 delimited by lines IS and 19. Fig. 3 is an illustration according to Fig. 2, but in which the yam 2 comprismg the foreign substance 16 is located substantially on the principal axis 11. In this case, for example, the yarn 2 comprising the foreign substance 16 is illuminated by green light from the diode 14, which emits light in a range 21 delimited by lines 22 and 23. Fig. 4 is an illustration according to Fig. 2, but in which the yam 2 comprising the foreign substance 16 is located more above the principal axis 11. In this case, for example, the yam 2 comprising the foreign substance 16 is illuminated by blue light from the diode 15, which emits light in a range 24 delimited by lines 25 and 26. Fig. 5 is an illustration of various wavelength ranges over an axis 27 along which values for wavelengths may be plotted. Values for the intensity of a signal may be plotted as a function of the wavelength along an axis 28. In this case, for example, three wavelength ranges 29, 30 and 31 are illustrated by curves that indicate the course of the intensity of the emitted light in the range of their three principal wavelengths 32, 33 and 34. In the following illustrations, for the sake of simplicity, these wavelength ranges may also be illustrated by simple rectangles 35, 36 and 37. Fig. 6 shows a plane 35 that extends between axes 36 and 37. Values for the intensity of each colour of the light, which is reflected by the yam, of the light source 4 may be plotted as vectors along these axes 36, 37. This allows a sum vector 38 to be calculated. Ranges 39, 40, 41, which represent specific properties of the yam, may be predetermined in the plane 35. Such properties may be the type of basic materials from which the yam is made or the type of foreign substances that are found in the yam, In a similar manner to Fig. 6, which applies to light from two different wavelength ranges, Fig. 7 shows a space 42, which is delimited as a cube, for displaying vectors that correspond to the intensity of the received signals in three different wavelength ranges. A comer 43 of the space is in this case intended to serve as a starting point for vectors 44, 45, 46, each of which represents a specific wavelength range. Reference numeral 47 denotes a sum vector which is composed of the three vectors 44, 45 and 46. This space or cube 42 may be divided into various regions. Fig. 8 illustrates one such region 48, Fig. 9 a region 49 and Fig. 10 a region 50. These regions 48, 49 and 50 are intended as target regions for the end point 51 of the sum vector 47. A specific condition for a property of the yam, for example the presence of a specific foreign substance, is or is not ftilfilled depending on whether this end point 51 is or is not located in one of these regions 48, 49, 50. The space 42, which in this case is configured as a cube, is formed by axes 52, 53 and 40 along which values for the intensity of three principal wavelengths are plotted. Fig, 11 shows various wavelength ranges as are known from Fig. 5, in this case plotted over a time axis 55. This provides examples of possible recurring sequences for emitting light through the light source 4. According to a sequence 56, the light source 4 is intended successively to emit light having the colours red, green and blue. A sequence 57 indicates that red-coloured light with decreasing intensity and green-coloured light with increasing intensity are to be emitted simultaneously over a predetermined period. If three colours are used, two or three sequences are produced each with two colours. At the end of the three sequences, the first sequence 57 is started once more. Fig. 12 shows further sequences in a similar manner to Fig. 11. A sequence 58 represents three colours that overlap, but which together produce a respective predetermined overall intensity. A sequence 59, in turn, relates to three colours that are designated R, G and B and that overlap. The intensity of the signals in the three colours is always constant or at a maximum. Those aspects of the mode of operation of the device that are not apparent from the foregoing will now also be described. In order, for example, to recognise a specific foreign substance or a different property in or on the yam 2, the light source is, for example, activated via the terminals 10 such that it emits light only in a limited wavelength range. Said light is reflected on the yam and returned to a receiver 5, 6, which receives it and converts it into an electrical signal, which it transmits via the line or the bus 8 to the unit 9, which stores the signal or a digital value derived therefrom, hnmediately thereafter, the light soiirce 4 is activated such that it emits light in a further wavelength range, etc., so a further signal or a fUrther value may finally be stored in the unit 9. hi the computer of the unit 9, vectors 44, 45 and optionally 46, and therefi-om finally a sum vector 38 or 47, are formed from the stored values. Values that define at least one region 39, 40, 41 or 48, 49, 50 in the plane 35 or in the space 42 are stored in the unit 9, so it is possible by means of comparison to determine whether or not the end point of the sum vector is located in one of these regions. As a result of a comparison of this type, a signal that indicates, for example, the presence of a desired property, such as whether or not a foreign substance is present in the yam, may then be issued from the unit 9 via a line 60. If a further receiver 7 for transmitted light is provided, it may, for example, issue a further signal, which indicates the diameter of the yam, to the unit 9. The influence of the diameter of the yam on the reflected light received may thus be compensated in a known manner. As has already been shown in Fig. 11 and 12, there are various possibilities for activating the light source 4. If, for example, continuous transitions between two or more wavelength ranges are used, as sequences 57 and 58 indicate, the vectors and the sum vector 38, 47 may also be determined at different times during the sequence. The sum vector 38, 47 thus performs a movement in the plane or in the space during the sequence, and it is possible to detect the times or the contents of the wavelength ranges at which the end point is located in a specific range 22. Starting from mixed light from two wavelength ranges, information regardhig properties of the yam that would otherwise not be accessible may thus be obtained. For a separate illumination of the yam according to a sequence 56, the clock frequency at which the individual diodes 13, 14, 15 of the light source 4 are to be activated should be at least sufficiently high that a specific point, such as the location at which a foreign substance 16 is embedded in the yam 2, only moves in a specific period to the extent that it is still located within the regions 20, 21 and 24. In this case, this specific period lasts for three clock pulses or a multiple thereof. As a result of the extremely close spatial arrangement of the diodes 13 to 15 in the single light source 4, the time required for illumination with three wavelength ranges is very short, and it is easily possible to detect such a point three times while it is located in front of the light source 4. If the colours red, green and blue are selected as wavelength ranges, the following arrangement of these and further colours in the space 42 may be seen in the illustration according to Fig. 7; In the comer 43, the intensity of the black colour should be at maximum. In the comer 61, the intensity of the red colour should be at maximum. In the comer 62, the intensity of the green colour should be at maximum. In the comer 63, the intensity of the blue colour should be at maximum. In the comer 64, the intensity of the colour magenta should be at maximum. In the comer 65, the intensity of the colour cyan should be at maximum. In the comer 66, the intensity of the colour yellow should be at maximum and in the comer 67, the intensity of the white colour should be at maximum. It is known/7er se from which formulae said vectors may be calculated. For the sake of completeness, a fiuther example will be added. For the length of the sum vector 47, as is known from Fig. 7 and is denoted in this case by V47, the following applies; IV47I = ^^1^+IVJ^+lV^l^ wherein V44, V45 and V45 denote the length of the vectors 44, 45 and 46. The direction of the sum vector is determined according to knovra rules of trigonometry. A correspondingly adapted calculation may be used for the vectors of Fig. 6. The position of the sum vector 38, 47 provides an indication, for example, as to whether a foreign substance is present, what type it is and whether or not it is dismptive and has to be eliminated. According to Fie. 6, for example, it may be detennined that, for tolerated foreign substances, the end point of the sum vector 38 in Fig. 6 should be located in the region 41 or even in the region 39. In Fig, 7 to 10, for example, it could be assumed that the end point 51 of the sum vector 47 should be located in proximity to the comer 67, in a region 68 that is delimited by a face 69, if no foreign substances are present and the yam is white or almost white, If this end point 51 is located in the regions 48, 49 or 50, then it is assumed that the foreign substance is predominantly blue, green or red. Nevertheless, it may be the case that a foreign substance of this type is per se tolerable. This may the case, for example, for a red foreign substance if the yam is subsequently to be dyed red. WE CLAIM 1. A device for scanning yam (2), which is moved in its longitudinal direction in a measurement gap (1), with a light beam (3) from a light source, comprising a receiver (5, 6) for light that is reflected on the yam and comprising a unit (9) for processing electrical signals from the receiver, whereB a single light source (4) is provided for emitting light in three wavelength ranges (29, 30, 31), the wavelength ranges being determined by three principal wavelengths (32, 33, 34) and the unit (9) for processing electrical signals from the receiver for received light comprises a processor, which forms a vector (44, 45, 46) from the values for each of the three predetennined wavelength range and a sum vector (47) from the vectors, characterised in that a region (48, 49, 50) is delimited for the end point (51) of the sum vector (47) in space (42) that indicates whether the electrical signal, which is processed to form a sum vector from the receiver displays a foreign substance in the yam and in that said space forms a cube, which is formed by axes (52,53,54) along which values for the intensity of three principal wavelengths are plotted. 2. The device as claimed in claim 1, wherein the principal wavelengths determine colours in the range of wavelengths of visible light. 3. The device as claimed in claim 2, wherein the principal wavelengths relate to the colours red, green and blue. 4. The device as claimed in claim 1, wherein the single light source (4) is configured as a light-emitting diode, which separately emits visible light in three colours of the visible range. 5. The device as claimed in claim I, wherein the single light source (4) and a receiver (6) exhibit principal axes (11,12) for emitting and receiving light that together enclose a plane, which is

Documents:

0895-chenp-2005 abstract duplicate.pdf

0895-chenp-2005 abstract.jpg

0895-chenp-2005 abstract.pdf

0895-chenp-2005 claims duplicate.pdf

0895-chenp-2005 claims.pdf

0895-chenp-2005 correspondence-others.pdf

0895-chenp-2005 correspondence-po.pdf

0895-chenp-2005 description (complete) duplicate.pdf

0895-chenp-2005 description (complete).pdf

0895-chenp-2005 drawings.pdf

0895-chenp-2005 form-1.pdf

0895-chenp-2005 form-18.pdf

0895-chenp-2005 form-26.pdf

0895-chenp-2005 form-3.pdf

0895-chenp-2005 form-5.pdf

0895-chenp-2005 pct.pdf

0895-chenp-2005 petition.pdf