DEVICE FOR SENSING PRESENCE OF WORK IN MACHINE TOOL

摘要

An apparatus utilizes fluid pressure measurements to sense sufficient chucking stock for a chuck with work gripping surfaces. A flexible seal cooperates with a workpiece at a location proximal to the chuck jaws to restrict flow of a pressurized fluid. Flow resistance varies at this location with the presence or absence of sufficient chucking stock. A pressure switch senses the resulting fluid backpressure which varies with the resistance of the flow path and generates a signal indicative of the presence or absence of sufficient chucking stock which is used to control functions of a machine tool.