Title of Invention

YARN SENSOR

Abstract A yarn senor for optically scanning a yarn (3) moving in its longitudinal direction in a measurement gap (19), in particular for detecting extraneous fibers, having a light source (20), a first receiver (23) for directly transmitted light, two further receivers (21,22) for light reflected from the yarn (3), and having element (24, 25, 26, 27) for transmitting he light between the light source (20), measurement gap (19) and receivers (21, 22, 23). The yarn sensor (6) is embodied such that by means of the receivers (21,22), in the absence of the yarn (3), projected images of opposite wall (62) of the measurement gap (19) are detectable, located essentially on both sides, outsides the area of the wall (62) of the measurement gap (19) that is illuminated by the direct radiation of the light – emitting diode (20). As a result, the interfering influence of parasitic signals is suppressed, and the detection of extraneous fibers is improved. The yarn sensor can be employed in the textile industry in spinning or bobbin – winding machines.
Full Text FORM 2
THE PATENT ACT 197 0 (39 of 1970)
The Patents Rules, 2003 COMPLETE SPECIFICATION
(See Section 10, and rule 13)
TITLE OF INVENTION YARN SENSOR

APPLICANT(S)
a) Name
b) Nationality
c) Address

SAURER GMBH & CO., KG. GERMAN Company LANDGRAFENSTRASSE 45, D - 410 6 9, MONCHENGLADBACH, GERMANY

PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

YARN SENSOR
The invention relates to a yarn sensor for optically scanning a yarn moving in its longitudinal direction in a measurement gap, particularly for detecting extraneous fibers, as generically defined by the preamble to claim 1.
European Patent Disclosure EP 1 018 645 B 1 describes a yarn sensor for detecting extraneous substances in the yarn, in which a white-light light-emitting diode serves as the light source. A white-light light-emitting diode makes it possible to embody the yarn sensor compactly. The broad color spectrum of the white-light light-emitting diode prevents the occurrence of an unequal color sensitivity of the yarn sensor, or the failure to detect some colors. The detected measured values are examined for characteristics that can lead to the conclusion that extraneous substances, such as extraneous fibers, are occurring in the yarn.
European Patent Disclosure EP 0 761 585 Al which defines this generic type describes a yarn sensor that can likewise serve not only to determine the yam diameter, but also to detect extraneous material in the yarn, such as extraneous fibers or contaminants.
In yarn sensors, the deposition of dirt, such as dust and fiber particles, on surfaces of the measurement gap that are unprotected against becoming soiled is unavoidable. It is true that a certain self-cleaning effect occurs in the measurement gap, brought about by the yarn moving through the measurement gap. However, this known self-cleaning effect cannot prevent surfaces in the measurement gap, on which light from the light source shines, from becoming at least temporarily soiled. For instance, if the protective plate between the yarn and the receiver for directly transmitted light becomes soiled, not only is the quantity of light arriving at this receiver reduced, but the dirt particles also reflect the arriving light projected by the light source. The light reflected by the yam, because of the small surface area of the yarn, represents a relatively small signal source. The yarn signal converted into current varies in the nanoampere range. Compared to the small irradiated surface of the yarn, the relatively large, dirty surface of the measurement gap, because of its length, represents a not inconsiderable source of reflection signals. The interfering radiation, which adulterates the outcome of measurement, is also called a parasitic signal. Because of the low intensity of the yarn signal, a high amplification of the signal converted from the incident light at the yarn takes place, but high amplification of the parasitic signals occurs as well. This leads to an impermissibly small useful signal, in proportion to the total signal.
Both the yarn sensor of EP 0018 645 B 1 and the yam sensor of EP 761 585 Al are incapable of overcoming this disadvantage.
It is the object of the invention to improve the known yarn sensor. This object is attained by means of a yam sensor having the characteristics of claim
Advantageous features of the invention are the subject of the dependent claims.
The embodiment of the yarn sensor according to the invention has the effect that essentially only light from the light source that is reflected by the yarn reaches the two receivers for reflected light. Interference and adulteration from parasitic signals can be reduced markedly. The measurement sensitivity of the yam sensor can be adjusted more sensitively.
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The light source is advantageously a light-emitting diode. Light-emitting diodes require only little space and are therefore especially well suited to use at work stations of spinning or bobbin winding machines, where only very limited space is available. The light-emitting diode is preferably embodied as a white-light light-emitting diode. The color spectrum of the white-light light-emitting
diode offers all kinds of possibilities in color recognition. The use of additional light-emitting diodes with light in other colors can be economically dispensed with, and the required space can be kept small. Since a white-light light-emitting diode serving as the sole light source emits light in all the colors needed, a constant sensitivity of the yam sensor to different colors is made possible. A single white-light light-emitting diode comes substantially closer to the model of a point light source than an array of two or more light-emitting diodes.
With an embodiment according to claim 4 or claim 5, such a uniform illumination of the measurement gap is attained that an adulterating influence on the sensor signals generated, which influence is dependent on the position of the yarn in the measurement gap, is maximally averted.
By the embodiment of the yam sensor in accordance with claim 6, U becomes possible for the yam to move in a light that comprises very homogeneous, quasi-parallel radiation. Scattered light that strikes the measurement gap surface outside the intentionally irradiated region is minimized or suppressed entirely. The measurement signals are not attenuated.
If the elements for transmitting the light are separated from the measurement gap by windows, which may include glass plates, protection of the elements for transmitting the light is accomplished.
A diaphragm in accordance with claim 8 limits the beam of light aimed at the yarn in such a way that only areas that cause no reflections that lead to parasitic signals are illuminated.
Also with the disposition of a diaphragm in the beam path of the light reflected by the yarn to the receiver in accordance with claim 9 or claim 10, unwanted reflections that generate parasitic signals can be avoided. The homogeneity of the light in the beam of light aimed at the receiver can be improved.
In the measurement, measurement signals occur that are not useful signals and that make the evaluation more difficult. The embodiment of the yam sensor according to the invention causes the magnitude of the useful signal not to be dependent on the position of the yam in the measurement field. The proportion of the useful signal in the total measurement signal becomes greater because of the elements used and disposed according to the invention. Therefore even extraneous fibers that were not detectable by methods and apparatuses of the prior art can be reliably detected. In an embodiment in accordance with claim 11, this for instance also includes polypropylene (PP) fibers, whose signal exaggeration is as a rule less than the signal incursion caused for instance by colored extraneous fibers. This makes a targeted removal of the PP fibers from the yam possible and thus avoids the occurrence of inadequate quality or even rejection when the yarn is subjected to a dyeing process.
With a yarn sensor according to the invention, the quality of he measurement outcome for the detection of extraneous fibers is improved.
3

Further details of the invention can be learned from the illustrations in the drawings. Shown are:
Fig. 1, a basic illustration of a spinning station;
Fig. 2, a yarn sensor with the housing open;
Fig. 3, an arrangement of elements of the yarn sensor of Fig. 2; and
Fig. 4, a basic illustration of a Lambert area emitter.
Fig. 1 shows a spinning box 1 of an open-end spinning machine, to which a sliver 2 is being delivered. The yam 3 made in the spinning box 1 is drawn off via the draw-off tube 4 by means of the pair of draw-off rollers 5, passes through a yam sensor 6, and via a hoop 8 is wound up, by the reciprocating motion of the yarn guide 9 of a shogging device 7, over a predetermined width into a cross-wound bobbin, or cheese 10. The cheese 10 is driven by means of a friction roller 11. The yam guide 9 is secured to a yarn guide white-light light-emitting diode 12, which is moved back and forth by a yam guide gear 13. The drive of the yarn guide gear 13 is effected by means of a drive device 14. The yarn sensor 6 for monitoring the moving yam 3 is located above the pair of draw-off rollers 5, in the shogging region of the yarn 3. In an alternative embodiment, not shown, the yam sensor 6 may be upstream, instead of downstream, of the pair of draw-ofT rollers 5. The yarn sensor 6 communicates via a line 15 with the control unit
16, which receives the signals emitted by the yam sensor 6. Via a further line
17, the control unit 16 is connected to the drive device 14. The drive device 14 is embodied as an electric motor. Via the line 18, the control unit 16 communicates with further spinning stations, data processing devices, or spinning machines, not shown here.
From Fig. 2, the location of individual components of the yarn sensor 6 relative to the measurement gap 19 and the yam 3 can be seen. The light source, embodied as a tight- emitting diode 20, and the photodiodes 21, 22, which serve to receive the light reflected by the yam 3, are positioned to the right, in terms of Fig. 2, of the measurement gap 19. The photodiode 23 for receiving the light transmitted directly by the light-emitting diode 20 is positioned to the left of the measurement gap 19, in terms of Fig. 2. Elements 24, 25, 26, 27 for transmitting the light are disposed between the light-emitting diode 20 and the measurement gap 19, on the one hand, and between the measurement gap 19 and the photodiodes 21, 22, 23 on the other. The elements 24, 25, 26, 27 for transmitting the light are separated from the measurement gap 19 by windows 28, 29, 30, 31. The windows can provide protection of the elements 24, 25, 26, 27 for transmitting the light against becoming soiled with dust and fluff. The light-emitting diode 20 and the photodiodes 21, 22, 23 each communicate with a signal processing device 36 by means of the lines 32, 33, 34, 35. The signal processing device 36 communicates in turn with the control unit 16 via the line 15, which leads through the housing 37 of the yam sensor 6 to the outside.
Fig. 3 shows an arrangement of components of the yam sensor 6, which is suitable for detecting extraneous substances in the yam 3, As the light source, the light-emitting diode 20 is used, which has approximately the same emission characteristic as a Lambert emitter. The light-emitting diode 20 is embodied as a white-light light-emitting diode. White-light light-emitting diodes emit light with a broad emission spectrum. If a white-light light-emitting diode is used, it is possible to dispense with using a plurality of light-emitting diodes for emitting different colors or for amplifying the emitted light. The abbreviation "LED" is usual for light-emitting diodes. The light emitted by the light-
4
emitting diode 20 passes through the element 24 for transmitting the light. The element 24 includes a film 39, a diaphragm 40 with the aperture 41, a lens 42, a diaphragm 60 with a rectangular aperture 61, and a glass plate 59, through which light passes in succession in the direction of the optical axis 38. The diaphragm 40 has an aperture 41 with a width of 1 mm. The film 39 projects divergent beams of light and has the emission characteristic of a Lambert emitter. As the film 39, the Film type Oracal 8500, translucent series, made by
K.
Grafter is used, for instance. This film has been used previously for advertising labels, that is, in a field that is completely different from use in a yarn sensor for increasing the measurement accuracy, as in the present invention. Downstream of the lens 42, the individual beams of light are oriented quasi-parallel to one another in the direction of the optical axis 38 and are distributed homogeneously over the cross section of the total beam of light. The total beam of light is represented by the two dashed lines 43, 44. The film 39 forms a virtual light source, which is projected to infinity. Along the way of the beam of light between the lens 42 and the image plane of the photodiode 23, the projection of the virtual light source is always present. This projection itself, however, is blurry. This effect is associated with a further homogenizing of the beam of light. The yarn 3 crosses the course of the total beam of light and is projected in the form of a shadow on the photodiode 23. Between the yam 3 and the photodiode 23, the total beam of light passes through both the glass plate 45 and the aperture 46 of the diaphragm 47. Light emitted by the light-emitting diode 20 is reflected by the yam 3. The photodiodes 21, 22 detect some of the reflected light. Between the yam 3 and the photodiodes 21, 22, the reflected light passes through each of the elements 25,26. The elements 25, 26 each include the associated glass plate 48,52, the diaphragm 63, 64, the lens 49, 53, and the aperture 50, 54 of the diaphragm 51, 55, respectively. The elements 25, 26 for transmitting the reflected light are embodied and disposed such that by means of the photodiodes 21,22, if the yarn 3 is absent, projected images of the opposite surfaces, for instance of the diaphragm 40 or of the wall 62 of the measurement gap 19, are detectable. These surfaces are located on both sides, outside the area of the wall 62 of the measurement gap 19 that is illuminated by the direct radiation of the light-emitting diode 20.
Alternatively, the diaphragms 51 and 55 may be dispensed with. The glass plates 48, 52, 59 may, in a further alternative embodiment, be embodied as diaphragms and have rectangular apertures.
Fig. 4 shows the basic illustration of the light-emitting diode 20, whose light-projecting face 56 has the characteristic of a Lambert emitter. From each point 57 of the face 56, a divergent beam 58 is emitted. The light that a Lambert emitter emits can be converted into a homogeneous light with a quasi-parallel beam path; the homogeneity and the parallelism of the light are better than is the case when conventional so-called point light sources are employed.
5
We Claims:
1. A yarn sensor for optically scanning a yarn moving in its longitudinal
direction in a measurement gap, in particular for detecting extraneous
fibers, in which a beam of light from a light source is sent into the
measurement gap, having a first receiver for directly transmitted light, two
further receivers for light reflected from the yarn, and elements for
transmitting the light between the light source, measurement gap and
receivers, characterized in that the light-transmitting element which is
disposed between the light source (20) and the measurement gap (19) includes
a diaphragm (40) and a lens (42), downstream of the light source (20) in the
radiation direction, which are embodied and disposed such that the diaphragm
(40) is projected at least approximately into infinity, and that the light-
transmitting elements (25,26) which are disposed between the measurement gap
(19) and the receivers (21, 22) for reflected light each contain, upstream in
the radiation direction of the reflected light of the receivers (21,22) that
detect the reflected light, one lens (49, 53), embodied and disposed such
that by means of the receivers (21,22), in the absence of the yarn (3), in
each case projected images on the opposite wall (62) of the measurement gap
(19) are detectable, which are located essentially on both sides outside the
projected image of the light source (20) on the opposite wall (62) of the
measurement gap (19) .
2. The yarn sensor of claim 1, characterized in that the light source (20) is a light-emitting diode, whose emission characteristic is designated as a Lambert emitter.
3. The yarn sensor of claim 2, characterized in that the light-emitting diode
(20) is a white light light-emitting diode.
4. The yarn sensor of one of claims 1 through 3, characterized in that a diffusor (39) is disposed between the light source (20) and the diaphragm (40) upstream of it.
5. The yarn sensor of claim 4, characterized in that the diffusor (39) is a film, which from the arriving radiation generates divergent beams of light.
6

6. The yarn sensor of one of claims 1 through 5, characterized in that the
entrance area of the lens (42) disposed upstream of the light source (20) is
embodied such that the radiation in the direction of the optical axis (38) of
the lens (42) has a homogeneous distribution of the luminous intensity, and
the exit area of the lens (42) is embodied such that the radiation arriving
from the entrance area of the lens (42) is made virtually parallel and is projected guasi-parallel to the optical axis (38) of the lens (42).
7. The yarn sensor of one of claims 1 through 6, characterized in that the elements (24, 25, 26, 27) for transmitting the light are separated from the measurement gap (19) by windows (28, 29, 30, 31).
8. The yarn sensor of one of claims 1 through 7, characterized in that a diaphragm (60) with a rectangular aperture (61) is disposed between the lens (42) and the yarn (3).
9. The yarn sensor of one of claims 1 through 8, characterized in that a diaphragm (63, 64) is disposed in the beam path of the light, reflected by the yam (3), to the receiver (21, 22) between the yarn (3) and the lens (49, 53) .

10. The yarn sensor of claim 9, characterized in that the window (48, 52) is embodied as a diaphragm,
11. The yarn sensor of one of claims 1 through 10, characterized in that a signal processing device (36) is arranged to detect and evaluate, besides the usually detected and evaluated signal incursions, signal exaggerations as
well.





Dated this 8th day of September, 2005
HIRAL CHANDRAKANT JOSHI AGENT FOR
SAURER GMBH & CO. KG
7
ABSTRACT


sAyarn senor for optically scanning a yarm (3) moving in its longitudinal direction in a measurement gap (19), in particular for detecting extraneous fibers, having a light source (20), a first receiver (23) for directly transmitted light, two further receivers (21,22) for light reflected from the yarn (3), and having element (24,25,26,27)for transmitting he light between the light source (20), measurement gap (19) and receivers (21,22,23). The yarn sensor (6) is embodied such that by means of the receivers (21,22), in the absence of the yarn (3), projected images of opposite wall (62) of the measurement gap (19) are detectable, located essentially on both sides, outsides the area of the wall (62) of the measurement gap (19) that is illuminated by the direct radiation of the light – emitting diode (20).
As a result, the interfering influence of parasitic signals is suppressed, and the detection of extraneous fibers is improved.
The yarn sensor can be employed in the textile industry in spinning or bobbin – winding machines.
(Fig – 2)
To
The Controller of Patent
The Patent Office
Mumbai

Documents:

1091-MUM-2005-ABSTRACT(22-1-2010).pdf

1091-MUM-2005-ABSTRACT(9-9-2005).pdf

1091-MUM-2005-ABSTRACT(GRANTED)-(3-8-2011).pdf

1091-mum-2005-abstract.doc

1091-mum-2005-abstract.pdf

1091-MUM-2005-CANCELLED PAGES(22-1-2010).pdf

1091-MUM-2005-CANCELLED PAGES(22-2-2011).pdf

1091-MUM-2005-CLAIMS(9-9-2005).pdf

1091-MUM-2005-CLAIMS(AMENDED)-(22-1-2010).pdf

1091-MUM-2005-CLAIMS(AMENDED)-(22-2-2011).pdf

1091-MUM-2005-CLAIMS(GRANTED)-(3-8-2011).pdf

1091-mum-2005-claims.doc

1091-mum-2005-claims.pdf

1091-mum-2005-correspondence(22-1-2010).pdf

1091-MUM-2005-CORRESPONDENCE(31-1-2011).pdf

1091-MUM-2005-CORRESPONDENCE(8-9-2005).pdf

1091-MUM-2005-CORRESPONDENCE(IPO)-(4-8-2011).pdf

1091-mum-2005-correspondence(ipo)-(5-5-2009).pdf

1091-mum-2005-correspondence-received.pdf

1091-mum-2005-correspondenced-others.pdf

1091-mum-2005-correspondenced-received-ver-080905.pdf

1091-mum-2005-description (complete).pdf

1091-MUM-2005-DESCRIPTION(COMPLETE)-(9-9-2005).pdf

1091-MUM-2005-DESCRIPTION(GRANTED)-(3-8-2011).pdf

1091-MUM-2005-DRAWING(22-1-2010).pdf

1091-MUM-2005-DRAWING(9-9-2005).pdf

1091-MUM-2005-DRAWING(GRANTED)-(3-8-2011).pdf

1091-mum-2005-drawings.pdf

1091-MUM-2005-ENGLISH TRANSLATION(22-2-2011).pdf

1091-mum-2005-form 1(7-10-2005).pdf

1091-mum-2005-form 18(14-8-2007).pdf

1091-MUM-2005-FORM 2(COMPLETE)-(9-9-2005).pdf

1091-MUM-2005-FORM 2(GRANTED)-(3-8-2011).pdf

1091-MUM-2005-FORM 2(TITLE PAGE)-(COMPLETE)-(9-9-2005).pdf

1091-MUM-2005-FORM 2(TITLE PAGE)-(GRANTED)-(3-8-2011).pdf

1091-MUM-2005-FORM 26(22-2-2011).pdf

1091-MUM-2005-FORM 3(31-1-2011).pdf

1091-MUM-2005-FORM 3(9-9-2005).pdf

1091-mum-2005-form-1.pdf

1091-mum-2005-form-2.doc

1091-mum-2005-form-2.pdf

1091-mum-2005-form-26.pdf

1091-mum-2005-form-3.pdf

1091-mum-2005-form-5.pdf

1091-MUM-2005-MARKED COPY(22-2-2011).pdf

1091-MUM-2005-PETITION UNDER RULE 137(31-1-2011).pdf

1091-MUM-2005-PRIORITY DOCUMENTS(22-1-2010).pdf

1091-MUM-2005-REPLY TO EXAMINATION REPORT(22-1-2010).pdf

1091-MUM-2005-REPLY TO HEARING(22-2-2011).pdf

1091-MUM-2005-SPECIFICATION (AMENDED)-(22-1-2010).pdf

1091-mum-2005-specification(amanded)-(22-1-2010).pdf

1091-MUM-2005-SPECIFICATION(AMENDED)-(22-2-2011).pdf

abstract1.jpg


Patent Number 248675
Indian Patent Application Number 1091/MUM/2005
PG Journal Number 31/2011
Publication Date 05-Aug-2011
Grant Date 03-Aug-2011
Date of Filing 09-Sep-2005
Name of Patentee SAURER GMBH & CO., KG.
Applicant Address LANDGRAFENSTRASSE 45, D-41069, MONCHENGLADBACH,
Inventors:
# Inventor's Name Inventor's Address
1 OLAV BIRLEM BERNHARD-ROSLER-STRASSE 34, D-41366 SCHWALMTAL,
PCT International Classification Number D05B59/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10 2004 053 735.6 2004-11-06 Germany