US Patent 7543410 Pneumatically operated system for controlling door operations

A simplified pneumatic door control system provides door control operations for opening, closing, stopping and reversing a door. The door control system includes as control inputs a gas source, a pneumatic motor, a first pilot valve, and pressurized manual check valves. The pressurized manually opened check valves may be used to remotely activate the control system. The control system further includes a second pilot valve, limit triggers, and a braking system. A reversing function of the control system provides the ability to reverse the direction of the door should the door encounter an obstruction upon closing. A second embodiment provides a hold to open control scheme, wherein the door travels only while a pressurized check valve is vented. Corresponding methods for controlling the door are also provided.