AN APPARATUS FOR OBTAINING VISUAL REPRESENTATION OF MOIRE PATTERN OF PITCH BOUND OR METAL REEDS TO CHECK UNIFORMITY OR NON-UNIFORMITY OF DENT AND AIR-SPACING IN REEDS.

摘要

An apparatus for obtaining visual representation of Moire pattern of pitch bound or metal reeds to check uniformity or non-uniformity of dent and air-spacing in the reeds,, comprising a diffraction grating, a source of light for uniformly illuminating said grating, a projection lens, or a system of projection lenses, for focussing image of said grating on the reeds to be inspected, a frame for mounting said reeds and a screen behind the frame carrying the reeds, for citing Moire pattern so obtained, said screen being preferably attacaed to same stand as for the reed frame.