Patent ID: 6860292

Claim:
A control system for an air-operated utilization device, comprising: a first, normally open solenoid valve having a first port, a second port, a vent port, an open position in which the first port is connected to the second port and the vent port is closed, and a closed position in which the vent port is open; a second, normally open solenoid valve having a first port, a second port, a vent port, an open position in which the first port is connected to the second port and the vent port is closed, and a closed position in which the vent port is open; a source of pressurized air connected to both the first port of the first solenoid valve and the first port of the second solenoid valve; and a latching valve comprising a valve spool chamber having first and second ends, a first passageway having a first end connected to the second port of the first solenoid valve and a second end connected to the first end of the valve spool chamber; a second passageway having a first end connected to the second port of the second solenoid valve and a second end connected to the second end of the valve spool chamber; a third passageway leading from the valve spool chamber at a location between its ends to the air-operated utilization device; a fourth passageway leading from the valve spool chamber at another location between its ends to exhaust; and a valve spool within said valve spool chamber, said valve spool having first and second lands and a passageway groove between the lands, said valve spool having a first position in which it is adjacent the first end of the valve spool chamber, and away from the second end of the valve spool chamber and the valve spool groove connects the third passageway with the fourth passageway, and flow between the first and third passageways is blocked by the valve spool member, and a second position in which the valve spool is away from the first end of the valve spool chamber and adjacent the second end of the valve spool chamber and the valve spool groove connects the first passageway to the third passageway and flow between the second and third passageways is blocked by the valve spool member.