Linearity and flatness measuring probe with guide compensation - has laser beam detector on moving armature as reference

摘要

The compensated measuring probe is designed to determine variations in linearity or flatness of a test specimen over which the probe is moved. The transducer comprises a hollow aluminum enclosure (5) which can be evacuated. A support frame on bearings has a cylinder (15) in which slides a piston attached to the probe stem (2). The piston is spring-loaded and its lower end is extended by a grating which moves in a slot between a light source and photoelectric sensor. The output drives a digital counter which displays the excursions of the probe. A laser beam is focussed onto a photoelectric sensor attached to a coil armature moving in a magnetic field. The sensor output is connected to the coils. The upper end of the armature cylinder carries the measuring photoelectric detector.