Pneumatic pressure control device and pneumatic pressure control method for automatic door

1. A pneumatic control device of auto door, comprising:

a first directional control valve configured to control a direction of a compressed air supplied to a door cylinder for opening and closing a door;

a door detection sensor configured to detect an open/close state of the door;

first and second exhaust lines respectively connected to first and second outlet ports of the first directional control valve; and

second directional control valves installed in the first and second exhaust lines respectively to operably exhaust the compressed air exhausted from the first and second outlet ports according to an emergency stop signal, and capable of changing positions to reduce an exhaust speed of the compressed air in case that the door is not completely open or closed when an operation signal is generated after the emergency stop signal.

2. The pneumatic control device of auto door of claim 1 , further comprising:

first and second lines respectively connected to first and second working ports of the second directional control valve; and

a deceleration valve installed in any one of the first and second lines.

3. The pneumatic control device of auto door of claim 2 , wherein the deceleration valve includes a variable orifice.

4. The pneumatic control device of auto door of claim 1 , wherein each of the second directional control valves is operable to maintain the exhaust speed of the compressed air in case that the door is completely open or closed when the operation signal is generated after the emergency stop signal.

5. The pneumatic control device of auto door of claim 1 , further comprising:

an emergency stop selection portion for generating an emergency stop signal;

an operation initiating selection portion for generating an operation signal which restarts an operation of the door after the emergency stop signal; and

a controller receiving signals from the emergency stop selection portion, the operation initiating selection portion and the door detection sensor and outputting control signals to the first directional control valve and the second direction control valves.

6. The pneumatic control device of auto door of claim 5 , wherein when the controller receives the emergency stop signal, the controller controls that the first directional control valve is switched to be a neutral position.

7. The pneumatic control device of auto door of claim 6 , wherein when the controller receives the operation signal, the controller outputs the control signal before the emergency stop signal to the first directional control valve.

8. The pneumatic control device of auto door of claim 6 , wherein the controller outputs the control signal for reducing the exhaust speed of the compressed air to the second directional control valve by lapse of a predetermined time after outputting the control signal for opening and closing the door to the first directional control valve.

9. The pneumatic control device of auto door of claim 1 , further comprising:

an opening/closing valve installed in a supply line which connects a pneumatic source and the first directional control valve to open and close the supply line.

10. The pneumatic control device of auto door of claim 6 , further comprising an orifice installed valve in a bypass line which bypasses the opening/closing valve.

11. The pneumatic control device of auto door of claim 1 , wherein the first and second directional control valves include a pilot operated solenoid control valve.

12. The pneumatic control device of auto door of claim 1 , wherein the first directional control valve includes 5 port 3 position direction control valve.

13. A pneumatic control method of auto door, comprising:

installing second directional control valves respectively in first and second exhaust lines respectively connected to first and second outlet ports of a first directional control valve;

supplying a compressed air to a door cylinder through the first directional control valve;

detecting an open/close state of the door;

exhausting the compressed air from the first and second outlet ports through the second directional control valves according to an emergency stop signal; and

switching the second directional control valve to reduce an exhaust speed of the compressed air in case that the door is not completely open or closed when an operation signal is generated after the emergency stop signal.

14. The pneumatic control method of auto door of claim 13 , further comprising:

making no changes in positions of the second directional control valve to maintain the exhaust speed of the compressed air in case that the door is completely open or closed when the operation signal is generated after the emergency stop signal.

15. The pneumatic control method of auto door of claim 13 , further comprising:

switching the first directional control valve to a switched position before the emergency stop signal.