Patent ID: 7779967

Claim:
A method of operating an elevator installation having at least one upper elevator car and at least one lower elevator car, which cars are both vertically movable substantially independently in a common elevator shaft of the elevator installation, comprising the steps of: a. mounting a first electromechanical switching mechanism in a lower region of the at least one upper elevator car, wherein the first electromechanical switching mechanism includes a weight fastened to an elongate run, the weight applying a downwardly directed force to the run under the influence of gravity to maintain the electromechanical switching mechanism in a travel setting; b. mounting a second electromechanical switching mechanism in an upper region of the at least one lower elevator car vertically below the weight fastened to the run, wherein in the case of an undesired approach of the two elevator cars the weight impinges on the second electromechanical switching mechanism; c. providing a safety circuit of the at least one lower elevator car opened by the weight impinging on the second electromechanical switching mechanism; and d. providing a safety circuit of the at least one upper elevator car opened by a diminishing of the weight force.