Automatic machine tool rotating pressure measurement safety device - has rotating magnetised piston moving axially in coils under pressure of air or oil filled envelope

摘要

The rotating pressure measurement device forms part of a safety system for an automatic machine tool and is a robust means of providing contactless monitoring of the pressure of the operating medium, e.g. air or oil. In the event press. loss and danger to the machine the machine is automatically shut down. The pressure of an air- or oil-filled operating chamber (4 or 5) of a hydraulic or pneumatic chuck is transferred to a second chamber (13) contg. an annular, spring-loaded piston (14) enclosing the spindle. The piston is partially or fully magnetised. It rotates inside static coils (11,12) with the rotating machine axle. The coils are part of a differential choke or transformer and their currents vary with piston axial displacement under pressure changes. This is detected by a phase sensitive circuit and the machine stopped.