APPARATUS FOR DETECTING ADHERED PORTION OR EDGE OF SHEET
Technical Field The present invention relates to a method of detecting a joint portion and an edge portion of a sheet and an apparatus for the same, and more particularly, to a method of detecting the joint state of the joint portion formed by butting sheets and detecting the edge portion for centering the transferred sheet and an apparatus for the same.
Background Art In general, in products having butt joint portions, such as rubber used in manufacturing tires, textile cord sheets formed of cotton and nylon, steel wire cord sheets, synthetic resin having predetermined thickness and width, and leather, joint states thereof greatly affects the quality and the characteristics. Thus, the joint portions should be precisely examined. In addition, the sheet should be supplied or wound in an aligned state for manufacturing the products. In this regard, it is necessary to accurately detect the edge portion of the sheet. However, since sheets have a variety of butt joint states, e.g., overlapping with or separating from each other at their ends, it is quite difficult to precisely determine the occurrence of a failure to the joint state. To overcome the problems, a displacement sensor of detecting the joint state of a sheet has conventionally been installed at a position corresponding to a joint portion, to detect a curved state and an uneven state of the joint surface, thereby determining the joint state of the sheet. When protrusions or uneven portions exist around the joint portion, however, it is difficult to precisely examine the joint state of the joint portion just by using the displacement sensor. Particularly, when the joint portion is lengthy, the displacement sensor should be transferred in a state in which it is maintained to be parallel with the joint portion; however, reliability of the examination result is lowered in such a case. Meanwhile, a conventional edge detecting apparatus for aligning transferred sheets includes a backlight installed between separate conveyers,
and a photographing unit installed at an upper portion of the backlight, and for taking photographs of the edge portion of the sheet that is transferred by the conveyers. Thus, the photographs photographed by the photographing units are compared with predetermined photographs to center the sheet. However, such apparatus cannot be applied to continuous conveyers and cannot precisely detect the edge portions. In another conventional apparatus for detecting an edge portion of a sheet by aligning and winding, reflection plates are installed at a lower surface corresponding to the edge portion of the sheet or at the edges of a belt. Then, the conventional apparatus irradiates a beam to the reflection plates and detects the reflected amount of the incidence beam to detect the deviation of the sheet or the belt. However, such apparatus aligns the sheet by detecting the reflected amount of the beam, thus reliability of the apparatus is lowered. Furthermore, when the width of the sheet is changed, the locations of the reflection plates and sensors for detecting the amount of beam should be inconveniently rearranged.
Alternatively, an IR sensor is used to detect the edge portions of the sheet.
However, an area detected by the IR sensor is relatively narrow. Thus, it is difficult to detect the edge portions of the sheet when the edge portions are formed in a wave shape or the width of the sheet is changed.
Description of the Drawings FIG. 1 is a diagram illustrating a method of examining joint portions according to an embodiment of the present invention. FIG. 2 is a perspective view schematically illustrating an apparatus for examining joint portions according to the embodiment of the present invention; FIG. 3 is a perspective view illustrating an example of a lens group as means for changing a beam section according to the present invention. FIG. 4 is a perspective view illustrating another example of means for changing a beam section according to the present invention; FIGS. 5 through 7 are photographs illustrating beam patterns according to joint states when irradiating a beam to joint portions; FIG. 8 is a perspective view illustrating a state of detecting edge portions of a sheet according to the embodiment of the present invention; and
FIG. 9 is a perspective view illustrating a state in which edge portions of a sheet, which is wound around a roller, is detected according to the embodiment of the present invention.
Disclosure of the Invention Technical problem To solve the above problems, the present invention provides a method of detecting a joint portion and an edge portion of a sheet that can improve reliability in the detection of the state of the joint portion and the edge portion of the sheet and can be applied to an automated production line and an apparatus for the same.
Technical Solution The present invention also provides a method of adaptively detecting an edge portion of a sheet according to variable sheet widths due to a wide detection range, and an apparatus for the same. According to an aspect of the present invention, there is provided a method of detecting a joint portion of a sheet comprising adjusting a beam section for adjusting the section of a beam, which is irradiated from a beam source, into a rectangle or a stripe; irradiating a beam for irradiating the rectangular or striped beam to the joint portion of a product; inputting an image for photographing the distorted state of the beam irradiated to the joint portion; and comparing images for comparing an image or an image signal input in the input of the image with a predetermined image. or image signal to determine the joint state of the joint portion. According to the present invention, the section changing unit includes a member installed on the axis of the beam, which is generated from the beam generation unit, and having a slot. In addition, the frame includes the transfer unit having a transfer member on which the beam irradiation unit and the photographing unit are installed to transfer the beam irradiation unit and the photographing unit in the X-axis direction and the Y-axis direction. The control unit further includes a monitor for displaying the image photographed by the photographing unit; and a data processor for comparing the photographed image or image signal to a predetermined image or image signal.
Best mode for carrying out the Invention FIG. 1 is a diagram illustrating a method of detecting joint portions and edge portions according to an embodiment of the present invention. The method of detecting joint portions and edge portions according to an embodiment of the present invention includes adjusting a section of a beam, which is generated from a beam source, such as a laser diode, is adjusted into a rectangular or striped shape (step 10), and irradiating the beam whose section has been adjusted into a rectangular or striped shape to joint portions of a product or edge portions of a sheet (step 20). In step 10, a fly eye lens is used to make the energy density of the beam passing through the fly eye lens kept at a uniform level. Also, a slit or a lens having different ratios in the X- axis and the Y-axis directions is used to change the shape of the beam section into a rectangle or stripe. It is preferable that the section of the beam is formed into the stripe and the energy density or the illumination is uniform at each region. In step 20, the beam is irradiated to the joint portion and the edge portion of the sheet, preceded by changing the shape of the beam section. Here, the beam may form a predetermined angle with the joint portion or the edge portion for the beam so as not to coincide with the longitudinal direction of the joint portion of the sheet. If the striped beam corresponds to the longitudinal direction of the joint portion or the edge portion of the sheet, pattern recognition may become difficult to achieve. If irradiation of the beam is completed in step 20, an image input step 30, a comparison step 40, and a recognition step 50 are performed. In step 30, the pattern of the irradiated beam is photographed. In step 40, an image or an image signal input in step 30 is compared to a predetermined image or image signal to detect the joint state of the joint portion or the location of the edge portion and it is determined whether there is a failure at the joint state or not or the alignment state of the sheet. In step 50, the failure in the joint state of the joint portion and the alignment state of the sheet, if any, are recognized. In step 30, the image is preferably photographed using a charge coupled device (CCD) camera using CCD to then be converted into an electrical signal for comparison with predetermined image data. Step 30 may
further include eliminating an after-image, in which the image is photographed in a state in which the striped beam is irradiating to the joint portion or the edge portion of the sheet and the after-image, excluding the striped beam, is eliminated. In step 40, the predetermined beam image and the image obtained in step 30, that is, the striped beam image and the image formed on the joint portion are compared with each other to determine the joint state of the joint portion, in the case where the beam is irradiated to the joint portion. In addition, when the beam is irradiated to the edge portion of the sheet, the distorted locations of the beams are detected to then determine the width or the alignment state of the sheet. In other words, the predetermined coordinates whose image is to be photographed and the coordinates of the distorted locations of the beams are compared to then determine the width and the alignment state of the sheet. When the joint state of the butt joint portion or the alignment state of the sheet is determined in step 40, an alarm may be generated, a lamp may be flickered, or the result may be displayed on a monitor in the recognition state 50, enabling an operator to recognize the result. In a case where the joint state of the joint portion is determined as being failed in step 50, a step of withdrawing a failed product the product having a failed joint portion may be further provided. A location compensation step or a sheet alignment step for compensating the alignment state of the sheet by tilting a conveyer of transferring the sheet or the roller around which the sheet is wound may be further provided, in the case where the alignment state of the sheet is determined as being failed. As described above, according to the method of the present invention, the joint state of the joint portion and the alignment state of the sheet can be detected within a short time regardless of the shape of the product, making the method according to the present invention applied to an automated production line. In addition, the method according to the present invention can automate the unit process. FIG. 2 is a perspective view illustrating an apparatus for detecting joint portions according to the embodiment of the present invention.
Referring to FIG. 2, an apparatus 60 for detecting a joint portion and an edge portion of a sheet may be installed on a transferring path of a sheet 200 having a joint portion 201 or an apparatus for performing a unit process of the production. The apparatus 60 for detecting the joint portion and the edge portion of the sheet includes a frame 61 having supports (not shown), a beam generation unit 71 installed on the frame 61 , a beam irradiation unit 70, a photographing unit 80, a transfer unit 90, and a control unit 100. In detail, the beam irradiation unit 70 installed on the beam axis of the beam generation unit 71 has an optical system 72 for changing the section of the beam and focusing the beam. The photographing unit 80 installed adjacent to the beam irradiation unit 70 takes the photograph of the pattern of the beam irradiated to the joint portion 201 of the sheet 200 or the edge portion of the sheet. The transfer unit 90 transfers the beam irradiation unit 70 and the photographing unit 90 in at least two directions. The control unit 100 compares an image or an image signal photographed by the photographing unit 80 with a predetermined image or image signal to determine the joint state of the joint portion 201. In addition, the apparatus 60 may further include a recognition unit (not shown) for recognizing the joint state of the joint portion or the alignment state of the sheet based on the result of the control unit 100. The apparatus 60 for detecting the joint portion and the edge portion of the sheet will now be described in detail. A laser diode may be used as the beam generation unit 71 of the beam irradiation unit 70, and is not limited thereto. Rather, a structure, which can generate a laser beam having heat energy of not damaging the sheet, may be used as the beam generation unit 71 of the beam irradiation unit 70. In addition, the optical system 72 includes a first lens group 73, which converts the beam generated from the beam generation unit 71 into a parallel beam, and a second lens group 73, which converts the beam passed through the first lens group 72 into a rectangular shape or a stripe shape having uniform energy density, as shown in FIG. 3. A reflection plate or a beam splitter may be installed between the beam generation unit 71 and the first lens group 73 in order to vary the optical path of the beam. The first lens group 73 may be formed of asymmetric lenses or two lenses having a high magnification to form a crossover point of the laser beam
between the lenses. The second lens group 74 is formed of fly eye lenses, wherein the curve at the discharge side of each element lens 74a is asymmetric to one another to form a rectangular or striped beam irradiation pattern. In addition, the optical system may include a third lens 75 for controlling the size and the focusing state of the beam, which is converted by the second lens group 74. The curvature of the discharge side of the third lens 75 has a positive power. Here, the curvatures of the X-axis direction and the Y-axis direction are different to control the focusing distances in the X-axis direction and the Y-axis direction. On the other hand, in order to change the shape of the beam irradiated from the beam generation unit 71 into a rectangle or a stripe, a member 77 having a slit 76 is installed on the optical path, as shown in FIG. 4, 5 and 6. Then, the beam passed through the slit 76 is irradiated to the joint portion 201 or the edge portion 202 of the sheet 200 by using a separate optical system. The photographing unit 80 of taking the photographs of the beam pattern irradiated to the joint portion 201 of the sheet 200 may be formed of a CCD camera 81 using a CCD. In the embodiment of the present invention, the beam irradiation unit 70 and the photographing unit 80 are separated; however, the beam irradiation unit 70 and the photographing unit 80 may be integrally formed. In such a case, the trace from the beam generation unit 71 and the trace for taking the photograph may be located on the same axis line by varying the trace of the beam irradiated from the beam generation unit 71 by using the beam splitter. On the other hand, the photographing unit 80 may further include a filter for. blocking an external light of generating interference to the beam when photographing the striped beam irradiated to the sheet 200. Here, the filter is formed of a polarized light filter. The transfer unit 90 for transferring the beam irradiation unit 70 and the camera 81 includes the optical system 72 including the beam generation unit 71 , a first transfer unit 92 of transferring the transfer member 91 having the camera 81 in the X-axis direction, and a second transfer unit 96 of transferring the first transfer unit 92 in the Y-axis direction. The first transfer unit 92 includes a first guide rail 93, a ball screw 94, and a driving motor 95. Here, the first guide rail 93 is installed above the transfer path of the sheet having the joint portion 201 or above the sheet 200,
and the unit process is performed and the sliding transfer member 91 is installed on the first guide rail 93. The ball screw 94 is installed on the first guide rail 93 to reciprocate the transfer member 91 by being screw combined with the transfer member 91. The driving motor 95 is installed on the first guide rail 93 to rotate the ball screw 94. The second transfer unit 96 having a dove tail shaped section includes a second guide rail 97, which guides the first guide rail 93 in the Y-axis direction, a second slider 98, which slides on the second guide rail 97 by being combined to the first guide rail 93, a second ball screw 99, which is installed along the second guide rail 97 while being screw combined to the second slider 98, and a driving motor 99a, which drives the second ball screw.99. In the descriptions of the first and second transfer units 92 and 96, the ball screws 94 and 99 are used to reciprocate the first and second sliders 91 and 98; however, a hydraulic cylinder or a linear motor may be used to reciprocate the first and second sliders 91 and 98. The control unit 100 further includes a monitor 101 for monitoring the patterns obtained by the beam irradiation unit 70 and the photographing unit
80, and a data processor 102 for comparing the obtained image or image signal to the predetermined image or image signal in order to determine the joint state of the joint portion or the alignment state of the sheet. A recognition unit is provided to recognize the failure of the product to an operator. Here, the recognition unit may be formed of an alarm generator or an on/off lamp. The operation of the apparatus for detecting the joint portion or the edge portion of the sheet and the method of the same will now be described in detail. The joint state and the alignment state of the sheet may be detected by using the apparatus 60 for detecting the joint portion and the edge portion of the sheet. The beam irradiation unit 60 or the sheet 200 is transferred for the joint portion 201 of the sheet 200 to be located under the beam irradiation unit 60. Here, the motors 95 and 99a of the first and second transfer units 92 and 96 are selectively driven to rotate the first and second ball screws 94 and 99, thus the first transfer member 91 and the first guide rail 93 are transferred in
the X-axis direction and the Y-axis direction, respectively. Accordingly, the beam irradiation unit 60 is located at one side of the joint portion 201. In this state, the beam generated from the laser diode as the beam generation unit 71 of the beam irradiation unit 70 is passed through the slit 76 or the optical system 72 to be changed into a stripe shape. The striped beam is irradiated to the joint portion of the product, and the beam is canned in the longitudinal direction of the joint portion by using the transfer unit 90. While the beam is irradiated the joint portion 201 , the beam image pattern is photographed by using the camera 81 of the photographing unit 80, and the control unit 100 determines the joint state of the joint portion based on the beam image pattern. For example, when the beam section is not changed while scanning the beam to the joint portion 201 in the longitudinal direction, as shown in FIG. 5, the joint state of the joint portion 201 is determined as being excellent. When the sections of the beam irradiated to the joint portion 201 are deviated from each other, as shown in FIG. 6, it is determined that the ends of the joint portion 201 overlap each other. As shown in FIG. 7, when the beam irradiated to the joint portion 201 is not deviated but blurred at a portion, it is determined that the ends of the joint portion 201 are separated from each other. When the joint portion 201 is determined as being failed based on the beam image pattern, the recognition unit generates an alarm or turns a lamp on. In order to detect the alignment state of the sheet by using the apparatus for detecting the joint portion and the edge portion of the sheet, as shown in FIG. 8, the beam irradiation units 70 irradiate striped beans to the edges of the sheet 200 to detect the coordinates of the distorted location of the beam that is generated by a step difference between the sheet 200 and a belt. Then, the detected coordinates are compared to predetermined coordinates to determine the alignment state of the sheet 200. In the case where the sheet 200 is wound around a roller as shown in FIG. 9, the sheet 200 may be precisely wound around the roller by detecting the alignment state of the sheet 200. The operations of the beam irradiation units 70 are the same as that of the beam irradiation unit 70 described above, thus the descriptions thereof will be omitted.
In the case where the beams are irradiated to both sides of the sheet as shown in FIG. 8, the width or the length of the sheet may be detected by using the coordinates of the beams. In addition, the degree of evenness of the sheet may be detected by irradiating the striped beam to the surface of the sheet. While the present invention has been particularly shown and described with reference to an exemplary embodiment thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As described above, in a method and apparatus of detecting a joint portion and an edge portion of a sheet according to the present invention, the joint state of a butt joint portion and the alignment state of the sheet can be determined in a short time to then be advantageously applicable to an automated production line. Specifically, the generation of failures can be reduced and the productivity can be improved by applying the apparatus for detecting the joint portion and the edge portion of the sheet to a manufacturing step of tires.