Light box for use in web inspection apparatus and method

摘要

An apparatus and method for inspecting and guiding a web utilizes a curved outer convex cloth guiding surface (A) on arcuate sections such as extrusions provided respectively at the top and bottom of the viewing area for guiding cloth and for forming a housing for the light box wherein an inner housing surface (B) is provided opposite the cloth guiding surface (A) on each extrusion. Depending receiving members (C) are provided at each respective end of the arcuate extrusions for serving as a receptacle for guiding and positioning a plexiglass viewing member and back sheet metal wall for forming a light box. A force applying member (D) is provided for controlling sag or bow in an extrusion. Apparatus and method is illustrated including diverging grooves for spreading the web as it passes over the upper section, and circuitry is provided conserving energy by limiting the time the circuitry is energized.