Area measuring machines

Claim 1

In a machine for measuring the superficial area of sheet material Workpieces having a multiplicity of measuring wheels extending across the width of said machine and a power-driven feed roll for carrying said workpieces beneath said wheels, the improvement including detecting means associated with each of said wheels for detecting the presence of a workpiece to be measured and subsequently measuring per unit amounts of said workpiece passing each of said wheels comprising a radiation source disposed on one side of said workpiece, a plurality of radiation detectors each associated with one of said measuring wheels and disposed opposite said radiation source and aligned with a radiation beam thereof so that said workpiece between said source and detector interrupts the radiation beam therebetween, said measuring wheels including a circumferential substantially opaque portion having therein transparent portions at regular intervals around said circumference and said wheels are so disposed that said circumferential portions are interposed between said radiation source and associated detectors, signaling means signaling each occurrence of each wheel being rotated a predetermined unit amount when said associated detector indicates said workpiece is interposed between said radiation source and said associated detector, and summing means actuated by said signal means to register the sum of the occurrences of activation of said signaling means.