US 3,994,583 A · Noncontacting method and apparatus for monitoring the speed and travel of a moving article

Abstract

A method and apparatus for monitoring the speed and travel of a moving article (such as a moving sheet of wood veneer) without contacting the article. The apparatus is stationary relative to such an article, and contains an optical imaging system including spaced coaxial positive lenses, and a cylindrical lens, which cooperate to produce, and to project onto a photodetector, a special distorted image of such an article. The projected image consists of moving elongated bands of light, wherein the speed of movement of the bands, and their travel distance in the image, are directly proportional to the speed and travel distance, respectively, of the viewed article. Further, the lenses in the imaging system are so arranged that the appearance of a projected image is substantially independent of changes, within a predetermined range, in the distance between the apparatus and the viewed article.

Claims16

Dependent claims

Apparatus for monitoring the speed and travel of an article along a path, said apparatus in operative condition comprising

imaging means disposed adjacent said path for producing a unidirectionally defocused image derived from an article's movement along the path, with such an image comprising elongated bands of light which move in the image at a common speed and through a common travel distance at all times proportional to those of the article, said imaging means including a lens portion having a cylindrical lens surface whose axis of revolution is normal to the direction of defocusing produced by the lens portion, and
image-receiving means comprising plural spaced light receptors positioned adjacent said imaging means and arranged to be impinged in predetermined succession by such bands for effecting an electrical signal having characteristics which are directly indicative of the speed and travel of the bands.

Apparatus for following the speed and travel of an article along a path comprising

imaging means adapted to be positioned adjacent said path for viewing such an article, and for producing from such viewing, at a receiving station adjacent the imaging means, a projected, distorted, unidirectionally defocused image of the article viewed, with such image comprising elongated parallel bands of light which move in the image at a common speed and through a common travel distance proportional to those of the article, and in a common direction which is at an angle to the bands' longitudinal axes, said imaging means including a lens portion having a cylindrical lens surface whose axis of revolution is normal to the direction of defocusing produced by the lens portion,
each band in the receiving station, along the length of the band, being characterized by substantially uniform intensity, and different bands in the station having different intensities, and
image-receiving means positioned in said receiving station to be impinged by the gands in such an image, and constructed to produce during such impingement an electrical signal which is directly indicative of the speed and travel of the bands, said image-receiving means comprising plural, elongated, laterally spaced light receptors oriented so as to be impinged, but one at a time, by the different moving bands.

Dependencies are inferred from the claim text.

Noncontacting method and apparatus for monitoring the speed and travel of a moving article

Life of this patent

Noncontacting method and apparatus for monitoring the speed and travel of a moving article

Life of this patent

Abstract

Claims16