Electro-pneumatic pressure control system for welding and like apparatus

An electro-pneumatic control system pneumatically connected to a pressure source and electrically connected to an electrical signal source, comprising:

• a selector switch having an electrical input connected to said electrical signal source, and having a first electrical output and a second electrical output;
• a cylinder having a movable piston positioned therein, said cylinder having an extend port and a return port;
• a first regulator valve having a bidirectional port connected to said extend port of said cylinder, having an input port connected to said pressure source, having an exhaust port, and having an electrical actuator connected to said first electrical output of said selector switch;
• and
• a second regulator valve having a bidirectional port connected to said return port of said cylinder, having an input port connected to said pressure source, having an exhaust port, and having an electrical actuator connected to said second electrical output of said selector switch,
• wherein one of said first regulator valve and said second regulator valve is selected with said selector switch as an activated regulator valve, and the other is selected with said selector switch as a non-activated regulator valve, wherein an air flow in said activated regulator valve is from the input port of said activated regulator valve to the bidirectional port of said activated regulator valve, and an air flow in said non-activated regulator valve is from the bidirectional port of said non-activated regulator valve to the exhaust port of said non-activated regulator valve.

An electro-pneumatic pressure control system pneumatically connected to a pressure source and electrically connected to an electrical command signal source which provides a switch control signal and a level control signal, the electro-pneumatic pressure control system comprising:

• a pressure controlled device having a cavity and having a control mechanism which effectively separates the cavity into a first section and a second section, the pressure controlled device having a first port in the first section of the cavity and a second port in the second section of the cavity, the control mechanism having a first face and a second face, the first face facing the first section of the cavity and the second face facing the second section of the cavity;
• a selector switch module having an input terminal connected to the electrical command signal source for receiving the level control signal, a control terminal connected to the electrical command signal source for receiving the switch control signal, a first output terminal and a second output terminal, the selector switch module having a first position connecting the input terminal to the first output terminal and a second switch position connecting the input terminal to the second output terminal, the position of the selector switch being controlled by the switch control signal;
• a first regulator valve having an electronic actuator connected to the first output terminal of the selector switch, a bidirectional port connected to the first port of the pressure control device, an input port connected to the pressure source and an exhaust port;
• and
• a second regulator valve having an electronic actuator connected to the second output terminal of the selector switch, a bidirectional port connected to the second port of the pressure control device, an input port connected to the pressure source and an exhaust port.

An electro-pneumatic pressure control system used in a welding or like application pneumatically connected to a pressure source and electrically connected to an electrical command signal source which provides a level control signal, the electro-pneumatic pressure control system comprising:

• a pressure controlled cylinder having a cavity and having an operating mechanism which effectively separates the cavity into a first section and a second section, the pressure controlled cylinder having an extend port in the first cavity section and a return port in the second cavity section, the operating mechanism having a first face and a second face, wherein the first face forms a boundary of the first cavity section and the second face forming a boundary of the second cavity section;
• a selector switch having an input terminal connected to the electrical command signal source for receiving the level control signal and having a first output terminal and a second output terminal;
• a first regulator valve having an electronic actuator connected to the first output terminal of the selector switch, a bidirectional port connected to the first port of the pressure control device, an input port connected to the pressure source and an exhaust port;
• and
• a second regulator valve having an electronic actuator connected to the second output terminal of the selector switch, a bidirectional port connected to the second port of the pressure control device, an input port connected to the pressure source and an exhaust port,
• wherein connecting the input terminal of the selector switch to the first output terminal of the selector switch places the first regulator valve in an activated state, directing fluid flow from the input port of the first regulator valve to the bidirectional port of the first regulator valve and to the extend port of the pressure controlled cylinder increasing pressure against the first face of the operating mechanism, and places the second regulator valve in a non-activated state, directing fluid flow from the return port of the pressure controlled cylinder through the bidirectional port of the second regulator valve to the exhaust port of the second regulator valve, causing the extension of the operating mechanism from the pressure controlled cylinder, and
• wherein connecting the input terminal of the selector switch to the second output terminal of the selector switch places the second regulator valve in an activated state, directing fluid flow from the input port of the second regulator valve to the bidirectional port of the second regulator valve and to the return port of the pressure controlled cylinder increasing pressure against the second face of the operating mechanism, and places the first regulator valve in a non-activated state, directing fluid flow from the extend port of the pressure controlled cylinder through the bidirectional port of the first regulator valve to the exhaust port of the first regulator valve, causing the retraction of the operating mechanism into the pressure controlled cylinder.