APPARATUS FOR MEASURING THE DIMENSIONS OF OBJECTS WHICH INCLUDES A CARRIER WHICH TRAVELS ACROSS THE OBJECTS TO BE MEASURED

摘要

An apparatus for measuring the width of a web material includes a carrier which travels across the web. The carrier has mounted thereon a photoelectric transducer and a magnetic induction type pulse generator for enabling exact detection of the opposite edge portions of the web. An elongated magnetically recorded fixed scale extends through the entire travel span of the carrier and is magnetically coupled to the pulse generator. The scale includes finely distributed magnetically recorded marks on the magnetic base thereof, along the lengthwise direction of said scale. A counter counts the pulses which emanate from the pulse generator in the absence of a detected electric signal from the photoelectric transducer, the absence indicating the presence of the web such that the opposite edge portions of the web are readily detected and measurement of the web width made.