Method and apparatus for inspecting hollow transparent articles

Abstract

A method of determining a physical characteristic of a hollow transparent article includes positioning the article at an inspection station, creating a scanning light beam which is split into two inspection light beams which are caused to impinge on different portions of the article. A plurality of sensors receive light reflected from the external and internal surfaces of the wall of the article and convert the same into corresponding electrical signals. The electrical signals are based upon the elapsed time from the initiation of the light beam or scanning light beam until arrival of a reflected light beam at least two sensors. The transparent article may, for example, be a container or tube. The inspection light beams are preferably caused to impinge on the article from opposed directions with each impinging on the article within about 70° degrees and preferably about 60° degrees of a radial plane perpendicular to the article. The method may be employed to determine wall thickness of the hollow article and/or shape thereof. The processor, which may be any suitably programmed microprocessor, effects comparison between the electrical signals received from the opto-electrical sensors and stored information with time of arrival of reflected light beams from the object facilitating the processor's determination regarding wall thickness or shape. The invention also provides apparatus for inspecting hollow transparent articles which includes a light source, a scanner for creating a scanning light beam, a beam splitter to convert the light beam into two inspection beams which are caused to impinge on two different portions of the container and a plurality of sensors which receive reflected light beams from the container and emit responsive electrical signals to a processor. The processor receives a time initiation signal from a first sensor and time of receipt of reflected signals from at least two additional sensors.

Dependencies are inferred from the claim text.