Patent ID: 8863910

Claim:
An elevator installation including at least two elevator cars, each car having at least one elevator car door and which are moved independently of one another in a common shaft, a plurality of shaft doors in the common shaft, and a safety device, which safety device includes at least one door opening sensor, at least one evaluating unit and at least one data line connected between the at least one door opening sensor and the evaluating unit, the evaluating unit being responsive to a signal from the at least one door opening sensor for evaluating the signal in at least one evaluating process, and for granting an opening authorization to a one of the shaft doors as a result of the evaluating process in dependence on at least one of positions, speeds and travel directions of the at least two elevator cars, comprising: the evaluating unit granting the opening authorization to the one shaft door when the one shaft door is located outside a planned current movement path of a one of the elevator cars to a destination floor.