Door closer with self-powered control unit

1. A controller for a door closer comprising:

a drive gear configured to rotate in response to movement of a door;

a chain arranged to cooperate with the drive gear to produce linear motion in response to rotation of the drive gear in response to the movement of the door;

a generator responsive to rotational motion to generate electricity to power the controller;

control circuitry disposed to be powered by the generator, the control circuitry including a connection to control a valve in the door closer;

a power management circuit connected between the generator and the control circuitry to store energy and supply voltage to the control circuitry wherein the voltage is increased when the movement of the door does not provide sufficient energy to power the control circuitry;

at least one gear to turn the generator in response to the linear motion of the chain; and

a set of clutch gears disposed between the chain and the at least one gear so that only one direction of the rotational motion is transferred to the generator in response to movement of the door in any direction.

2. The controller of claim 1 further comprising:

a sprocket interconnected with the chain; and

a gear box gear connected to the sprocket to distribute angular rotational torque to prevent reverse torque from inhibiting the movement of the door.

3. The controller of claim 2 further comprising a motor to control the valve in the door closer.

4. The controller of claim 3 wherein the power management circuit further comprises a charge pump to increase the voltage from the generator when the movement of the door does not provide sufficient energy to power the control circuitry.

5. The controller of claim 1 further comprising a motor to control the valve in the door closer.

6. The controller of claim 5 wherein the power management circuit further comprises a charge pump to increase the voltage from the generator when the movement of the door does not provide sufficient energy to power the control circuitry.

7. A door closer comprising:

a spring;

a movable element configured to move in response to movement of a door, the movable element loading the spring;

a valve configured to control movement of hydraulic fluid around the movable element;

a drive gear configured to rotate in response to movement of a door;

a chain arranged to cooperate with the drive gear to produce linear motion in response to rotation of the drive gear in response to the movement of the door;

a generator responsive to rotational motion to generate electricity to control the valve;

control circuitry disposed to be powered by the generator, the control circuitry operable to control the valve;

a power management circuit connected between the generator and the control circuitry to store energy and supply voltage to the control circuitry wherein the voltage is increased when the movement of the door does not provide sufficient energy to power the control circuitry;

at least one gear to turn the generator in response to the linear motion of the chain; and

a set of clutch gears disposed between the chain and the at least one gear so that only one direction of the rotational motion is transferred to the generator in response to movement of the door in any direction.

8. The door closer of claim 7 further comprising:

a sprocket interconnected with the chain; and

a gear box gear connected to the sprocket to distribute angular rotational torque to prevent reverse torque from inhibiting the movement of the door.

9. The door closer of claim 8 further comprising a motor cooperating with the valve to control the valve.

10. The door closer of claim 9 wherein the power management circuit further comprises a charge pump to increase the voltage when the movement of the door does not provide sufficient energy.

11. The door closer of claim 7 further comprising a motor cooperating with the valve to control the valve.

12. The door closer of claim 11 wherein the power management circuit further comprises a charge pump to increase the voltage when the movement of the door does not provide sufficient energy.

13. A method of operating a door closer in response to movement of a door, the method comprising:

producing linear motion in response to rotation of a drive gear caused by the movement of the door;

using a set of clutch gears to turn a generator in only one direction in response to the linear motion, wherein the generator turns in only one direction in response to movement of the door in any direction;

turning the generator to produce electricity to power a controller;

storing energy from the generator to supply voltage to control circuitry in the controller;

increasing the voltage from the generator when the movement of the door does not provide sufficient energy to power the control circuitry; and

controlling a valve in the door closer using the controller.

14. The method of claim 13 further comprising distributing angular rotational torque to prevent reverse torque from inhibiting the movement of the door.

15. Apparatus for controlling a door closer in response to movement of a door, the apparatus comprising:

means for producing linear motion in response to rotational motion caused by the movement of the door;

means for turning a generator in only one direction in response to the linear motion, wherein the generator turns in only one direction in response to movement of the door in any direction;

means for turning the generator to produce electricity to power the apparatus;

means for storing energy from the generator to supply voltage to control circuitry in the controller;

means for increasing the voltage from the generator when the movement of the door does not provide sufficient energy to power the control circuitry; and

means for controlling a valve in the door closer.

16. The apparatus of claim 15 further comprising means for distributing angular rotational torque to prevent reverse torque from inhibiting the movement of the door.