Apparatus for checking mechanical component parts with optical devices, and relevant protection device and method

Abstract

An apparatus for checking mechanical component parts, such as tools in machine tools, uses optical devices for emitting and receiving a light beam, for example a laser beam, and sensors for detecting the interruption of such light beam. A protection device for at least one of the optical devices includes pneumatic conduits and a nozzle outputting an air stream from a plurality of holes located around the central conduit through which the light beam passes, so generating a tubular shield which embraces the light beam. The protection device further includes a shutter which can be displaced from a rest position, wherein the central conduit is closed and the inside of the protection device is pressurized, to a working position, wherein the nozzle delivers the air stream in the form of a tubular shield. Passing from the rest position to the working position, the shutter assumes an intermediate transit position in which an air blast is outputted through the central conduit for a short time interval. The shutter has cylindrical surfaces and slides inside a shell of the protection device, driven by plane antirotation surfaces, too.