Non-contact dimensional gage for turned parts

摘要

A non-contact dimensional gage for turned parts which permits in-process gaging for closed loop machine operations. The gage locates three points on the circumference of the cylindrical workpiece which are formed by shadowing the part onto three photo detectors receiving collimated light along three angled optical axes. The photo detectors evaluate the extent of shadowing of the light beams caused by the presence of the workpiece. The output of the photo detectors is a function of the degree of shadowing and accordingly provides a measure of the location of the tangent points of the workpiece. When the workpiece is positioned within the working range of the device such that three of the light beams are partially blocked by the workpiece, the three circumferentially spaced points can be located and consequently the part's diameter can be determined.