Abstract: A pneumatic fail-safe sensor system including a probe adapted to monitor the outline of a master pattern as the directed cutter spindle system of an N/C machine tool forms a part is disclosed. When the probe impinges on the master pattern to indicate that the cutter is deviating from the desired path of travel, a valve is opened and causes a pressure drop that actuates a pressure switch. The valve includes a pressurized dome that presses a valve plate against a valve seat. A valve stem is attached to the valve plate and supports the probe. Movement of the probe disturbs the static pressure of an annular chamber contained wholly within the valve seat area and, thereby, creates the pressure drop that activates the pressure switch. Activation of the pressure switch causes an electronic circuit to energize the control system of the N/C machine tool that terminates its operation by deenergizing the blocking valves.

Abstract: A pneumatic fail-safe sensor system including a probe adapted to monitor the outline of a master pattern as the directed cutter spindle system of an N/C machine tool forms a part is disclosed. When the probe impinges on the master pattern to indicate that the cutter is deviating from the desired path of travel, a valve is opened and causes a pressure drop that actuates a pressure switch. The valve includes a pressurized dome that presses a valve plate against a valve seat. A valve stem is attached to the valve plate and supports the probe. Movement of the probe disturbs the static pressure of an annular chamber contained wholly within the valve seat area and, thereby, creates the pressure drop that activates the pressure switch. Activation of the pressure switch causes an electronic circuit to energize the control system of the N/C machine tool that terminates its operation by deenergizing the blocking valves.