Photoelectric chopper for distance measurement

摘要: A distance-measuring system is described in which a wheel frictionally engaged with surface along measurements are made. The metering connected to shaft drives portion of photoelectric chopper provides an indication increments metering-wheel travel. includes disk on the plurality windows alternating opaque areas circular path near periphery disk. mask having arc somewhat similar adjacent and spaced short distance away from pair lights photosensors located opposite sides maskdisk set. Each photosensor detects light passing through different and, as rotates, substantially symmetrical variation intensity occurs. minimum area noncollimated source provided nearer than greater number per unit length so that successful chopping beam obtained when apart. mounted ring movably by eccentric constrained move only angularly about its center direction normal chord between two photosensors. This permits phase relation inputs be adjusted readily high precision. Precise adjustment proper construction permit give usable signals at very slue rates.