US 4,081,734 A · Pneumatic fail-safe sensor system for N/C machine tool

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. In addition to master pattern sensing, the pneumatic sensor also includes means for blowing metal ships and the like away from the tip of the probe.

Claims15

Dependent claims

A pneumatic sensor system comprising:

a pneumatic valve mechanism including a movable element and a valve seat, said valve seat having a cavity formed therein and being adapted for the application of pneumatic pressure into said cavity, said movable element being mounted relative to said valve seat for closure of said cavity to form a pressure sensing chamber, said movable element being displaceable relative to said valve seat for opening said pressure sensing chamber to allow a drop in the pneumatic pressure applied to said cavity;
a probe connected to said movable element in a manner such that displacement of said probe displaces said movable element of said valve mechanism and opens pressure sensing chamber;
pneumatic pressure sensing means connected in fluid communication with said valve seat cavity for sensing drops in pneumatic pressure applied to said cavity;
and,
electronic control means connected to said pneumatic pressure sensing means for detecting when said pneumatic pressure sensing means detects drops in the pneumatic pressure applied to said cavity of said valve seat and for generating control signals in accordance therewith.

2 more elements

A pneumatic sensor comprising:

a dome having a first opening at one end thereof, said dome including a second opening for introducing pneumatic pressure into said dome;
a valve seat affixed to said first opening of said dome, said valve seat including a substantially smooth surface facing said first opening of said dome, said valve seat including a centrally located opening extending from said relatively smooth surface of said valve seat and passing completely through said valve seat, said relatively smooth surface of said valve seat including an annular cavity positioned to surround said centrally located opening, said valve seat including a first aperture for introducing pneumatic pressure into said annular cavity, said valve seat further including a second aperture located between said centrally located opening and said annular cavity, said second aperture extending from said relatively smooth surface of said valve seat and passing completely through said valve seat;
a valve plate having at least one relatively smooth surface mounted and arranged for contacting said relatively smooth surface of said valve seat, said relatively smooth surface of said valve plate extending outwardly over said annular cavity and said second aperture of said valve seat, said relatively smooth surface of said valve plate substantially sealing said annular cavity to prevent pneumatic pressure introduced in said first aperture of said valve seat from reaching said second aperture when said relatively smooth surface of said valve plate contacts said relatively smooth surface of said valve seat;
and
an elongate valve stem having a first end connected to the central region of said relatively smooth surface of said valve plate, said valve stem projecting outwardly through said centrally positioned opening of said valve seat, said valve stem deflectable for moving said valve plate into a position wherein at least a portion of said relatively smooth surface of said valve plate does not contact said relatively smooth surface of said valve seat to permit pneumatic pressure to escape from said annular cavity through said second aperture of said valve seat.

2 more elements

Dependencies are inferred from the claim text.

Pneumatic fail-safe sensor system for N/C machine tool

Life of this patent

Pneumatic fail-safe sensor system for N/C machine tool

Life of this patent

Abstract

Claims15