Measuring and testing – Sheet – woven fabric or fiber
Patent
1992-09-04
1994-02-22
Cuchlinski, Jr., William A.
Measuring and testing
Sheet, woven fabric or fiber
340675, G01D 528
Patent
active
052877426
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a device for detecting defects in a web, and in particular, it relates to a device for detecting defective portions, such as a portion of a tear or a portion having insufficient strength in a nonwoven fabric having a network structure or the like.
BACKGROUND ART
Recently, a variety of webs such as films or nonwoven fabrics are manufactured and used for various purposes. Defects in said webs, such as a tear (a portion at which fibers are broken) or a portion having insufficient strength, have occurred during the manufacturing process or the conveying process. To provide high quality products, it is necessary to detect such defects and remove same.
Conventionally, regarding the detection of defects in a film, there are devices for detecting defects in a film, in which light from a light emitter is irradiated on a surface of the film, and the amount of light passing through the film is measured with a detector arranged on the back side of the film. However, in conventional detecting devices, it is possible to accurately detect defects when said defects of the film exist in a relatively broad area, but it is difficult to accurately detect defects when defects of the film exist in a relatively narrow area. Also, since conventional detecting devices includes a complex means for the determination of defects, conventional detecting devices are expensive and the operation thereof is complex.
Moreover, conventionally, there are no devices for rapidly and reliably detecting defects such as tears in a web having network structures, such as nonwoven fabrics or the like. Therefore, it is necessary that the detection of defects such as tears in a web having network structures, such as nonwoven fabrics or the like, must be done by visual inspection by operators. It is therefore necessary to increase the number of operators, resulting in an increase in manpower in a manufacturing process. Also, visual inspection of defects in a high speed continuous manufacturing process results in the operators becoming fatigued thereby making it difficult to carry out a continuously accurate inspection of defects during the manufacturing process, and accordingly, the inspection of defects is carried out slowly by having to rewind the web after manufacturing the web. Therefore, an inspection of defects is not only laborious, but is also apt to result in a delay in the feedback of defect occurrence during manufacturing. Also, as it is difficult for the operators to maintain constant vigilance over a long time period of time, defects are sometimes overlooked.
SUMMARY OF THE INVENTION
The object of the present invention is to solve the above described problems of the prior art and to provide a device for detecting defects in a web by which defective portions of the web, such as tears and insufficient strength, can be reliably detected and the detection of defective portions can be carried out with less manpower and at a lower cost.
Accordingly to the present invention, there is provided a device for detecting defects in a web comprising a conveying means for conveying a web in a predetermined direction, holding means arranged near said web at least one probe rotatably pivotally attached to said holding means for making contact with the web, detecting means generating an output signal in response to the rotational movement of said probe.
With this arrangement, when the web is normal, the probe slides over the web and does not substantially rotate, and thus the detecting means does not generate a defect output signal. When a defect portion exists in the web, the probe rotates to penetrate the defect portion of the web and protrude under the web, and the detecting means generates a defect detect signal. If the detecting means generates a defect detect signal, it is possible to take the appropriate procedure. For example, it is possible to sound an alarm upon receiving a defect detect signal to request an inspection of the manufacturing process, or to indicate a defect upon receiving a defe
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Aihara Kintaro
Yamazaki Shinji
Bennett G. Bradley
Cuchlinski Jr. William A.
Nippon Petrochemicals Company Ltd.
Polymer Processing Research Inst. Ltd.
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