Crane

1. A tower crane comprising a crane tower, at least one crane cab, at least one crane operator elevator, and at least one crane ladder, wherein the at least one crane operator elevator comprises an elevator car configured to travel in a vertical direction inside a rectangular cross section of the crane tower, wherein access to the at least one crane ladder and the at least one crane operator elevator is secured by an access control system comprising a controller that controls the operation of the at least one crane operator elevator, wherein the at least one crane ladder is secured by one or more access doors including an access door at a lower entrance to the at least one crane ladder, wherein the controller deactivates a power supply of the at least one crane operator elevator as soon as access to the at least one crane ladder via the one or more access doors is enabled, wherein the controller activates the power supply as soon as access to the at least one crane ladder via the one or more access doors is blocked, and wherein access to the at least one crane operator elevator is not blocked by the one or more access doors when the one or more access doors are closed.

2. The tower crane according to claim 1 , wherein one or more guide rails for guiding the at least one crane operator elevator is arranged inside the rectangular cross section of the crane tower in a vertical direction from a base of the crane tower to the at least one crane cab, wherein the tower crane comprises a stationary tower.

3. The tower crane according to claim 2 , wherein an elevator car guide on a side of the at least one crane operator elevator and the one or more guide rails engage with one another to compensate for play due to variances and unevenness of the one or more guide rails.

4. The tower crane according to claim 1 , wherein access to the one or more access doors is enabled or blocked via a mechanical and/or electronic key.

5. The tower crane according to claim 1 , wherein the access control system has one or a plurality of reader units for wireless reception of electronic key data, including data based on an RFID system, an LWID system, or a radio transmission system, wherein reception is provided over an entire length of the at least one crane ladder.

6. The tower crane according to claim 5 , wherein the access control system assures selective access to the at least one crane operator elevator or to the at least one crane ladder.

7. The tower crane of claim 1 , wherein the one or more access doors include an access door at an upper entrance to the at least one crane ladder.

8. The tower crane of claim 1 , wherein the one or more access doors are automatically unlocked or opened as long as the access control system approves access of an authorized person to the at least one crane ladder.

9. The tower crane of claim 5 , wherein the access control system comprises a plurality of reader units.

10. The tower crane of claim 9 , wherein distribution of the reader units on the crane tower enables continuous reception of the electronic key data over a length of the crane tower, and wherein a path of motion of a person can thereby be determined and evaluated in the access control system.

11. The tower crane of claim 10 , wherein only after the person leaves a secured region can power be restored to the at least one crane operator elevator.

12. The tower crane of claim 1 , wherein a lower entry to the at least one crane operator elevator is arranged at a lowermost tower section of the tower crane, and wherein an upper entry to the at least one crane operator elevator is arranged at the at least one crane cab.

13. The tower crane of claim 1 , wherein the access door at the lower entrance to the at least one crane ladder is arranged in a vertical direction above a lower entry to the at least one crane operator elevator.

14. The tower crane of claim 1 , wherein the access door at the lower entrance to the at least one crane ladder is arranged at a lowest entry region to the at least one crane ladder in a vicinity of a base of the crane tower.

15. The tower crane of claim 7 , wherein the upper entrance to the at least one crane ladder is at a top of the crane tower.

16. The tower crane of claim 1 , further comprising, in addition to the one or more access doors which secure the at least one crane ladder, an access door for entering the elevator car.

17. The tower crane of claim 16 , wherein the access door for entering the elevator car is a side door and is configured to slide inwardly into the elevator car.

18. The tower crane of claim 1 , wherein the space requirement for the at least one crane ladder requires approximately two thirds of the rectangular cross section of the crane tower, and wherein the at least one crane operator elevator is located in the remaining rectangular cross section of the crane tower.

19. The tower crane of claim 18 , wherein a shaft of the at least one crane operator elevator occupies approximately half of the remaining rectangular cross section of the crane tower.