WO2002079722A1 - Procede et dispositif de determination d'une variation relative de longueur - Google Patents

Procede et dispositif de determination d'une variation relative de longueur Download PDF

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Publication number
WO2002079722A1
WO2002079722A1 PCT/DE2002/001052 DE0201052W WO02079722A1 WO 2002079722 A1 WO2002079722 A1 WO 2002079722A1 DE 0201052 W DE0201052 W DE 0201052W WO 02079722 A1 WO02079722 A1 WO 02079722A1
Authority
WO
WIPO (PCT)
Prior art keywords
reference marks
drive
conveyor belt
ccd sensor
light
Prior art date
Application number
PCT/DE2002/001052
Other languages
German (de)
English (en)
Inventor
Thomas KÄMPER
Thomas Elbel
Ingo Niewidok
Matthias Wetzel
Original Assignee
Forbo International S.A.
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 Forbo International S.A. filed Critical Forbo International S.A.
Publication of WO2002079722A1 publication Critical patent/WO2002079722A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
    • B65G43/00—Control devices, e.g. for safety, warning or fault-correcting
    • B65G43/02—Control devices, e.g. for safety, warning or fault-correcting detecting dangerous physical condition of load carriers, e.g. for interrupting the drive in the event of overheating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
    • B65G23/00—Driving gear for endless conveyors; Belt- or chain-tensioning arrangements
    • B65G23/44—Belt or chain tensioning arrangements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/02—Details
    • G01N3/06—Special adaptations of indicating or recording means
    • G01N3/068—Special adaptations of indicating or recording means with optical indicating or recording means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/06—Indicating or recording means; Sensing means
    • G01N2203/0641—Indicating or recording means; Sensing means using optical, X-ray, ultraviolet, infrared or similar detectors
    • G01N2203/0647—Image analysis

Definitions

  • the invention relates to a method for the contactless determination of a relative change in length of a drive or conveyor belt by stretching, in which a surface area of the drive or conveyor belt exposes, the reflected light is detected and a changed relative position of the surface area is determined therefrom. Furthermore, the invention relates to a device for performing the method.
  • a system with a camera is known from EP 06 94 756 A 3, for example, which detects reflections of a laser beam that is directed onto a small surface area.
  • the laser beam is reflected differently due to the irregular surface properties of the drive or conveyor belt, which is provided with structuring that is particularly related to production.
  • a characteristic reflection pattern of the belt is created from the reflected light before and after the stretching of the drive or conveyor belt.
  • individual sections can be identified by comparing the surface images and the relative elongation can be determined from the difference in distance. The method can therefore be used with any drive or conveyor belt.
  • the high outlay for the measuring method working with the laser beam has a disadvantageous effect, in which particularly cumbersome protective measures have to be observed in order to rule out any danger to the operating personnel. Furthermore, it has so far not been possible to implement a device which operates using this method and which can be transported without problems table and can therefore also be used on site. Furthermore, even slight deformations caused by stretching lead to an undesirable displacement, which deteriorates the measuring accuracy.
  • the optical system has a lens arrangement which has a high aperture in order to achieve a contrast of the reference mark which is sufficient for the CCD camera.
  • this requires an exact maintenance of the distance between the camera and the tensile specimen, which is unaffected by the elongation, which can only be achieved under laboratory conditions.
  • the surface coordinates of the raster line change due to deformation, so that a permanent correction of the focus is necessary. For this reason, this method cannot be used for measuring the elongation of drive belts or conveyor belts, since such precise focusing requires both the transportation and the CCD camera to be fixed.
  • an adjustable support for the band would have to be created in order to avoid the change in the height of the slightly sagging band associated with the tightening of the band.
  • the invention has for its object to provide a way that allows a simple and reliable determination of the elongation of a drive or conveyor belt. The method should in particular be carried out with little effort.
  • a device for carrying out the method is to be created which, in particular, should be able to be carried along and thus permits problem-free use.
  • a method is therefore provided in which the drive or conveyor belt equipped with two reference marks is detected by a region of a CCD sensor assigned to the reference marks.
  • the resolution that can be achieved thereby allows the distance of the pixels assigned to the respective reference marks to be converted by means of a controller into the distance of the pixels from one another and thus of the reference marks from one another.
  • a particularly advantageous embodiment of the method according to the invention is also achieved if the exposure is set as a function of the intensity of the light reflected by the reference marks, as detected by the CCD sensor.
  • the required contrast of the reference mark is set by direct control of the exposure as a function of the detected intensity and does not require any manual correction.
  • the edge region of the reference marks is grasped and centered.
  • a large number of different reference marks can be used by the method, the exact width of the reference mark in particular being irrelevant for determining the distance.
  • the geometric center and, in a subsequent step, the spacing of the reference marks from one another are determined from the detected edge regions by means of a control unit.
  • reference marks with different dimensions can therefore be used.
  • the undesirable influence of the stretch on the reference marks, which are also subjected to stretching or deformation depending on the design of the fixation can thereby be reduced.
  • a further development of the method is particularly practical in which the measurement is carried out essentially continuously and a signal is generated when a predetermined change in length is reached.
  • the drive or conveyor belt can be subjected to the desired stretching while the measurement is running and a signal can be generated when the set value is reached.
  • safety-relevant values of the elongation can be taken into account, thereby preventing the operating personnel from being endangered.
  • the second-mentioned task of creating a device for determining a relative change in length of a drive or conveyor belt, with an exposure unit and an optical detector for detecting the light reflected from the drive or conveyor belt for carrying out the method is performed according to the invention by a CCD - Sensor designed optical detector with two areas, each associated with a reference mark connected to the drive or conveyor belt, and a linear optic through which the light reflected by the reference marks can be transmitted to the assigned area of the CCD sensor.
  • a CCD - Sensor designed optical detector with two areas, each associated with a reference mark connected to the drive or conveyor belt, and a linear optic through which the light reflected by the reference marks can be transmitted to the assigned area of the CCD sensor.
  • the pixels of the CCD sensor assigned to the respective reference marks can be determined with high accuracy, from which the distance between the reference marks can be deduced.
  • the linear optics transmit a linear image of the same size to the CCD sensor, whose distance from the reference mark is therefore in a predetermined range without affecting the accuracy of the measurement result is variable.
  • the device therefore only needs to be positioned in the area of the reference marks on the drive or conveyor belt for measuring the strain. The distance between the reference marks is then automatically detected and the stretch is calculated. Incorrect handling is therefore largely ruled out, so that the effects of errors caused by improper operation are avoided.
  • the CCD sensor could extend over the entire area of both assigned reference marks. However, it is also particularly favorable if the device has a further CCD sensor and that an area is assigned to each of the CCD sensors. As a result, two comparatively small CCD sensors can be used, which are arranged at a certain distance from one another on the device, as a result of which the production outlay can be reduced.
  • the distance between the CCD sensors is essentially determined by the intended use, and in principle the accuracy of the detection of the relative change in length can be improved by a large distance.
  • the CCD sensor can have a matrix by means of which a two-dimensional image of the reference mark can be acquired and in particular several parallel measurements can be carried out simultaneously, a shift between successive measurements being recorded and corrected by the control.
  • a modification in which the CCD sensor is designed as a line sensor is particularly simple.
  • the outlay for producing the device can be reduced further because only one line is required.
  • the reference marks extend essentially transversely to the direction of expansion and can therefore be reliably detected without the exact positioning or orientation of the device on the drive or conveyor belt being required for this.
  • a particularly advantageous modification of the invention is also created in that the linear optics have a plurality of gradient index lenses arranged next to one another, in order thereby to enable imaging of the same size and thus reliable measurement value acquisition.
  • the reference marks can be fixed on the drive or conveyor belt by means of an adhesive connection.
  • the reference marks can also be attached to an already existing drive or conveyor belt without this requiring substantial intervention on the drive or conveyor belt or without a corresponding appropriate reference mark must be provided.
  • the reference marks are glued on at a suitable point and can then be removed again after the measurement.
  • the reference marks for fixing to the drive or conveyor belt are fixed at a predetermined distance from one another by a holding means.
  • the reference marks are already fixed in their relative position to one another by the holding means and can thus be easily fixed to the drive or conveyor belt.
  • the holding means can then be removed and, if necessary, reused.
  • the holding means can also be designed as an adhesive surface from which the reference marks can be detached as soon as they are fixed to the drive or conveyor belt with their surface facing away from the holding means.
  • the reference marks are equipped with two sections with a different reflectivity, in order in this way to be able to clearly identify the reference marks based on the contrast. Therefore, the reference marks can also be attached to drive belts or conveyor belts that are equipped with patterns or have an irregular light reflection behavior due to their surface properties.
  • the distance between the reference mark and the CCD sensor is essentially determined by the required exposure, with inadequate exposure in particular precluding reliable measured value acquisition.
  • Another particularly advantageous development of the invention is achieved, however, in that the reference marks are self-luminous or luminescent. As a result, the exposure need not take place immediately before the detection of the reference marks by means of the CCD sensor, because the reference mark temporarily emits sufficient brightness for the measurement value acquisition.
  • the reference marks can be passive or luminescent or can also be designed as a self-illuminating reference mark in the form of a luminescent film.
  • the device has means for shielding the reference marks from the ambient light. In this way, the undesired influence of the ambient brightness can be avoided and errors in the measurement value acquisition can be prevented.
  • the agent can also serve as a contact surface for placing the device on the drive or conveyor belt.
  • FIG. 1 shows a schematic diagram of a device according to the invention
  • FIG. 3 shows the reference marks shown in FIG. 1 in a top view
  • FIG. 4 shows a holding means provided for fixing the reference marks shown in FIG. 3.
  • FIG. 1 shows a device 1 according to the invention for determining a relative change in length of a drive or conveyor belt 2.
  • the drive or conveyor belt 2 is equipped with two reference marks 3, 4, which are aligned essentially parallel to one another.
  • the reference marks 3, 4 are exposed for a short time in particular by means of an exposure unit 5 and the reflected light is fed to a respective region 7, 8 of a CCD sensor 9 by means of a linear optic 6.
  • a controller 10 designed as evaluation electronics.
  • the controller 10 uses this to produce a display 11, by means of which, in a desired form of representation, the operator is given the relative elongation as a result of a measurement by an elongation.
  • FIG. 2 shows a side view of the device 1 shown only in sections.
  • the drive or conveyor belt 2 can be seen, which has a reference mark 3 shown in FIG.
  • the light reflected by the drive or conveyor belt 2 or the reference mark 3 is transmitted from the linear optics 6 spaced between the drive or conveyor belt 2 between 2 and 20 mm to an element 12 of the CCD sensor 9, through which an evaluable electrical signal is generated if a predefined, adjustable brightness value is reached.
  • the linear optics 6 generate a linear image of the same size, so that focusing of the light beam for imaging and the associated time-consuming preparation of the measurement value recording can be dispensed with.
  • the linear optics 6, like the CCD sensor 9, are attached to a common circuit board 14 by means of a fixation 13 arranged. This creates a compact design that can be easily accommodated in a portable handheld device.
  • Figure 3 shows two mutually spaced reference marks 3, 4 in a plan view.
  • the reference marks 3, 4 each have a light section 15 and a narrower, dark section 16, which is attached centrally to the light section 15.
  • the contrast generated in this way is reliably detected by means of the CCD sensor 9 shown in FIG. 1, it being possible, for example, to determine the geometric center 17 from the edge regions of the dark section 16.
  • the reference marks 3, 4 are already spaced invariably apart from one another on a common holding means 18 designed as a self-adhesive surface and can thereby be fixed together on the drive or conveyor belt 2 shown in FIG. This further simplifies the attachment of the reference marks 3, 4. Depending on the area of application, these can also be luminescent or self-luminous.
  • FIG. 4 shows one of the reference marks 3 shown in FIG. 3 in a sectional side view.
  • the reference mark 3 like the further reference mark 4 shown in FIG. 3, is detachably attached to the holding means 18 designed as an upper film.
  • a side of the reference mark 3 facing away from the holding means 18 is provided with an adhesive layer 19, which is protected from use by a lower film 20 for protection against environmental influences. After removal of the lower film 20, the reference mark 3 can be fixed to the drive or conveyor belt 2 shown in FIG. 1 without any problems.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Control Of Conveyors (AREA)

Abstract

L'invention concerne un procédé et un dispositif (1) de détermination d'une variation relative de longueur d'une bande d'entraînement ou de transport (2) à la suite d'une dilatation. A cet effet, on dirige au moyen d'une unité d'éclairage (5)un rayon lumineux sur une zone de surface de la bande d'entraînement ou de transport (2), ladite zone comportant deux marques de référence (3, 4). La lumière réfléchie par les marques de référence (3, 4) est détectée par un détecteur optique conçu en tant que capteur CCD (9), comportant deux zones (7, 8) respectivement affectées à une marque de référence (3, 4) de la bande d'entraînement ou de transport (2). La transmission de la lumière réfléchie est effectuée au moyen d'une optique linéaire (6) permettant de transmettre la lumière réfléchie par les marques de référence (3, 4) aux zones respectives du capteur CCD (9). Ainsi, il est possible de mettre en oeuvre un dispositif (1) de manipulation et d'entraînement simples permettant notamment de s'affranchir d'une focalisation provoquant des erreurs de mesure.
PCT/DE2002/001052 2001-04-02 2002-03-22 Procede et dispositif de determination d'une variation relative de longueur WO2002079722A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10116233.2 2001-04-02
DE10116233A DE10116233A1 (de) 2001-04-02 2001-04-02 Verfahren und Vorrichtung zur Bestimmung einer relativen Längenänderung eines Antriebs-oder Förderbandes

Publications (1)

Publication Number Publication Date
WO2002079722A1 true WO2002079722A1 (fr) 2002-10-10

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PCT/DE2002/001052 WO2002079722A1 (fr) 2001-04-02 2002-03-22 Procede et dispositif de determination d'une variation relative de longueur

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DE (1) DE10116233A1 (fr)
WO (1) WO2002079722A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10794686B2 (en) 2017-02-09 2020-10-06 Laitram, L.L.C. Apparatus and methods for measuring belts
US12037201B2 (en) 2021-12-07 2024-07-16 Laitram, L.L.C. Measuring conveyor belt stretch

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005053433B4 (de) * 2005-11-09 2009-05-14 Leuze Electronic Gmbh & Co Kg Verfahren zum Erfassen von Passermarken
DE102012020677B4 (de) * 2012-10-22 2020-07-02 BEUMER Group GmbH & Co. KG Verfahren und Anordnung zum Bestimmen eines Dehnungszustands eines Fördergurts
DE102017116019A1 (de) * 2017-07-17 2019-01-17 Iwis Antriebssysteme Gmbh & Co. Kg Vorrichtung und Verfahren zum Schutz einer Sensorvorrichtung vor Verschmutzung
DE102021200478A1 (de) * 2021-01-20 2022-07-21 Contitech Antriebssysteme Gmbh Vorrichtung und Verfahren zur Ermittlung einer Längsdehnung eines Riemens

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4400882A (en) * 1981-07-31 1983-08-30 United Technologies Corporation System for measuring cable footage
US4806018A (en) * 1987-07-06 1989-02-21 The Boeing Company Angular reflectance sensor
EP0484536A1 (fr) * 1990-05-22 1992-05-13 The Furukawa Electric Co., Ltd. Procede et appareil de mesure de la longueur d'un objet allonge en deplacement
US5291131A (en) * 1992-03-31 1994-03-01 Tsubakimoto Chain Co. Apparatus for measuring elongation of a circulating chain
EP0822389A2 (fr) * 1996-07-29 1998-02-04 Elpatronic Ag Procédé et dispositif pour déterminer et pour vérifier le contour d'un rebord
US6118132A (en) * 1998-09-17 2000-09-12 Agilent Technologies System for measuring the velocity, displacement and strain on a moving surface or web of material

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4400882A (en) * 1981-07-31 1983-08-30 United Technologies Corporation System for measuring cable footage
US4806018A (en) * 1987-07-06 1989-02-21 The Boeing Company Angular reflectance sensor
EP0484536A1 (fr) * 1990-05-22 1992-05-13 The Furukawa Electric Co., Ltd. Procede et appareil de mesure de la longueur d'un objet allonge en deplacement
US5291131A (en) * 1992-03-31 1994-03-01 Tsubakimoto Chain Co. Apparatus for measuring elongation of a circulating chain
EP0822389A2 (fr) * 1996-07-29 1998-02-04 Elpatronic Ag Procédé et dispositif pour déterminer et pour vérifier le contour d'un rebord
US6118132A (en) * 1998-09-17 2000-09-12 Agilent Technologies System for measuring the velocity, displacement and strain on a moving surface or web of material

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10794686B2 (en) 2017-02-09 2020-10-06 Laitram, L.L.C. Apparatus and methods for measuring belts
US12037201B2 (en) 2021-12-07 2024-07-16 Laitram, L.L.C. Measuring conveyor belt stretch

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Publication number Publication date
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