Betriebsforschungsinstitut Vdeh Institut Fur Angewandte Forschung Gmbh

Peter Bohlander

Heinz-Peter Hippler

Apparatus for adjusting the position of an edge between two surface porti of a moving belt with different spectral reflectivities where required in connection with work or treatment needed along the edge of one of the two surface portions while the belt is moving. It is a pre-requisite condition that the mutually adjacent surfaces of the belt are sufficiently significantly optically detectable which is impaired, for example, in the presence of surface contamination by dirt and the like. In order to obtain a significant signal in such circumstances, the edge region is illuminated and an imaging or focussing lens associated with a beam splitter is arranged in the focus beam. Following the beam splitter the two part-beams pass through one filter each to impinge on in each case a photodiode receiver, each filter blocking passage in that wavelength range in which the other filter is transmissive. The diode potentials which are produced by the two part-beams then are applied in the form of a quotient to control or steer a device which effects transverse displacement of the belt. A sufficiently significant control signal is obtained even if the reflectivity of the surfaces is reduced by scratches, fingerprints or other dirt contamination.

Apparatus for adjusting the position of an edge with surface portions

Apparatus is disclosed for determining the position of a surface in which radiation from an optical radiant source is applied to the surface and, by means of a lens system, an image of the radiation is produced on a photoelectric receiver. A laser serves as the radiant source, and is aimed at an angle of inclination relative to an optical axis of the lens system at a point of a surface which, by virtue of its temperature, emits visible radiation in the same wavelength range as the Laser. The surface extends approximately perpendicularly of the optical axis and is subject to positional variations along the said optical axis. The beam is directed from the irradiated point to the photoelectric receiver through a narrow-band optical filter of which the pass band includes the laser wavelength.

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Dusseldorf, Germany

Peter Bohlander