Elevator car door interlock

1. An apparatus for an elevator car to lock and unlock an elevator car door, the apparatus comprising:

(a) an interlock selectively connectable with the elevator car door, the interlock comprising:

(i) a locking member configured to selectively prevent the elevator car door from opening by moving between a disengaged position and an engaged position,

(ii) a first and second sensor, wherein the first sensor is configured to detect whether the elevator car door is closed, wherein the second sensor is configured to detect whether the locking member is in the engaged position,

(iii) a first and second arm, each having an open position and a closed position, wherein the first arm is in the closed position when the elevator car door is closed, wherein the second arm is in the closed position when the locking member is in the engaged position,

(iv) a gate switch mounted on the second arm, wherein the switch is configured to contact the first arm when the first and second arms are in the closed position verifying the first sensor and position of the elevator as closed, and further verifying the second sensor and position of the locking member as in the engaged position; and

(b) a control device in electrical communication with the interlock, the control device in further electrical communication with an elevator controller, wherein the control device communicates a signal to the interlock to prevent the elevator car door from opening unless the elevator car has stopped at a designated landing zone, wherein the switch being in contact with the first arm causes the control device to signal to the elevator controller to allow movement of the elevator car.

2. The apparatus of claim 1 , further comprising a plurality of elevator car sensors configured to detect when the elevator car is positioned at the designated landing zone.

3. The apparatus of claim 2 , wherein the plurality of elevator car sensors are operable to function independently from each other.

4. The apparatus of claim 2 , wherein the plurality of sensors are further configured to be magnetic sensors.

5. The apparatus of claim 1 , wherein the locking member comprises a solenoid and a lock pin, wherein the solenoid is configured to actuate the lock pin.

6. The apparatus of claim 5 , wherein the solenoid is configured to actuate the lock pin to permit the elevator car door to open only when the elevator car is not traveling through a hoistway and the elevator car is positioned at a landing zone.

7. The apparatus of claim 1 , further comprising a portable power supply operable to power the interlock and the control device.

8. The apparatus of claim 1 , further comprising an actuator configured to contact the first arm when the elevator door is closed, wherein the contact with the arm causes the first sensor to signal to the control device that the elevator car door is closed.

9. An interlock apparatus for an elevator car to lock and unlock an elevator car door, the interlock apparatus comprising:

a locking member having a disengaged position and an engaged position, wherein the locking member in the engaged position is configured to prevent the elevator car door from opening;

a first sensor configured to detect whether the elevator car door is in an opened position or closed position;

a first arm having an open position and a closed position, wherein the first arm is in the closed position when the first sensor detects that the elevator car door is in the closed position;

a second sensor configured to detect whether the locking member is in the disengaged or the engaged position by detecting the position of a second arm coupled to the locking member,

the second arm having an opened position and a closed position, wherein the second arm is in the closed position when the second sensor detects that the locking member is in the engaged position; and

a gate switch mounted on the second arm, wherein the switch is configured to contact the first arm when the first and second arms are in the closed position verifying both

the first sensor and position of the elevator car door as in the closed position, and

the second sensor and position of the locking member as in the engaged position.

10. The apparatus of claim 9 further comprising a power supply configured to power the interlock.

11. The apparatus of claim 10 , wherein the power supply comprises a primary supply and a backup supply, wherein the backup supply is configured to automatically provide power to the interlock if the primary supply is unable to provide power.

12. The apparatus of claim 9 , wherein the locking member comprises a solenoid configured to actuate a lock pin, wherein the lock pin is configured to interface with an engagement portion of the elevator car door.

13. The apparatus of claim 9 , wherein the first sensor is a magnetic sensor.

14. The apparatus of claim 9 further comprising an elevator controller, wherein the elevator controller is configured to receive information from the interlock apparatus comprising the position of a select one or both of the first arm and the second arm.

15. The apparatus of claim 9 , further comprising an elevator controller configured to prevent the elevator car from traveling through a hoistway unless the first arm and the second arm are in closed positions.

16. The apparatus of claim 9 , further comprising at least one position sensor configured to detect the position of the elevator car in a hoistway.

17. The apparatus of claim 9 , further comprising a control device, wherein the control device communicates a signal to the interlock apparatus to prevent the elevator car door from opening unless the elevator car has stopped at a designated position in a hoistway.