US 9,809,422 B2
Crane
Joachim Mayer, Biberach (DE)
Assigned to Liebherr-Werk Biberach GmbH, Biberach an der Riss (DE)
Filed by Liebherr-Werk Biberach GmbH, Biberach an der Riss (DE)
Filed on Oct. 22, 2013, as Appl. No. 14/60,395.
Claims priority of application No. 10 2012 020 819 (DE), filed on Oct. 23, 2012.
Prior Publication US 2014/0110367 A1, Apr. 24, 2014
Int. Cl. B66B 9/00 (2006.01); B66C 23/62 (2006.01); B66C 13/54 (2006.01); B66C 15/00 (2006.01)
CPC B66B 9/00 (2013.01) [B66C 13/54 (2013.01); B66C 15/00 (2013.01); B66C 23/62 (2013.01)] 19 Claims
OG exemplary drawing
 
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.