Radiant energy – Photocells; circuits and apparatus – With circuit for evaluating a web – strand – strip – or sheet
Patent
1997-08-22
1999-08-03
Westin, Edward P.
Radiant energy
Photocells; circuits and apparatus
With circuit for evaluating a web, strand, strip, or sheet
25055912, 356429, G01N 2186
Patent
active
059328886
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a device and a method for measuring a position of an edge of webs or sheets by means of a photoelectric measuring device.
DESCRIPTION OF THE PRIOR ART
A measuring device for the photoelectric measurement of the position of sheet edges in respect to a reference line is known from DE-OS 22 02 087. Light emanating from an illumination device is received by a photoelectrical receiver. A video signal is generated in accordance with the position of the sheet edge which is inserted between the illumination device and the receiver.
The photoelectric receiver element consists of a plurality of individual photo elements arranged one behind the other at short distances.
In connection with this prior art device it is disadvantageous that even the slightest defects or fibers at the sheet edge to be measured lead to erroneous measurements, since these defects have a direct effect on the measurement result.
SUMMARY OF THE INVENTION
It is an object of the present invention to create a device and a method for measuring a position of an edge of webs or sheets by use of a photoelectric measuring device, wherein the actual position of the edge in relation to a measuring device is determined with sufficient accuracy in spite of the presence of small defects or of fibers extending past a vertical projection of the edge, for example so-called anomalies, in the measurement area of the edge of webs or sheets.
This object is attained in accordance with the present invention by means of a device and a method for measuring the position of an edge of webs or sheets which uses a photoelectric measuring device having an illumination device and a photoelectric receiver. At least three measured values of a position of an edge are determined. A measured result is formed in a way which disregards extreme values caused by edge anomalies.
The position of an edge of webs or sheets to be measured is detected in an advantageous manner by the device in accordance with the present invention at a plurality of closely adjoining points along the edge. Because of this, it is possible to neglect measured values of places where edge anomalies occur. The measured values can be processed by means of the method in accordance with the present invention in such a way that a sufficiently accurate determination of the position of the edge takes place.
In addition, it is advantageous that with a not ideally straight edge of the webs or sheets a virtual straight line along a considered area of the edge can be calculated, and that this is used as a measurement of the position of the edge for further processing. A sharp picture of the edge is obtained by means of the use of a light beam with parallel rays. A single illumination device for all photoelectric receivers reduces the components and therefore the cost.
BRIEF DESCRIPTION OF THE DRAWINGS
The device in accordance with the present invention and the method in accordance with the present invention are represented in the drawings and will be described in greater detail below. As shown in the drawings:
FIG. 1, is a schematic side elevation view of a device in accordance with the invention taken perpendicularly in respect to the transportation direction of the web;
FIG. 2, is a schematic side elevation view of the device in accordance with the invention taken in the transportation direction of the web; and
FIG. 3, is a schematic top view of a plurality of photoelectric receivers with the web.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The position of a web or sheet 1 is to be measured sheet in relation to a number of photoelectric receivers 2, with the web being bordered, at least within the measurement area, by an edge 3 extending in the shape of a straight line. This web or this sheet is essentially light-absorbing. This web or sheet 1 is preferably a paper web or a sheet of paper, in particular for use in rotary printing presses, but also be other web- or panel-shaped goods, for example sheet metal or foils. This web or sheet 1 will be
REFERENCES:
patent: 3736063 (1973-05-01), Ohno et al.
patent: 4007992 (1977-02-01), Petrohilos et al.
patent: 4110627 (1978-08-01), Isherwood
patent: 4247204 (1981-01-01), Merlen et al.
patent: 4367487 (1983-01-01), Klein et al.
patent: 4559451 (1985-12-01), Curl
patent: 4662756 (1987-05-01), Duran, Jr.
patent: 4680806 (1987-07-01), Bolza-Schunemann
patent: 4924790 (1990-05-01), Kondo et al.
patent: 5006719 (1991-04-01), Blaser
patent: 5214294 (1993-05-01), Toyofuku
patent: 5229620 (1993-07-01), Pahr
patent: 5301129 (1994-04-01), Mckaughan et al.
patent: 5389789 (1995-02-01), Nguyen
patent: 5489784 (1996-02-01), Koiranen et al.
patent: 5724150 (1998-03-01), Schaede et al.
patent: 5765367 (1998-06-01), Schaede et al.
Koenig & Bauer--Albert Aktiengesellschaft
Luu Thanh X.
Westin Edward P.
LandOfFree
Web or sheet edge position measurement process and device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Web or sheet edge position measurement process and device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Web or sheet edge position measurement process and device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-851846