Patent ID: 8813919

Claim:
An elevator installation having a first elevator car and at least a second elevator car, wherein a first travel path space crossable by the first elevator car along a travel path thereof and a second travel path space crossable by the second elevator car along a travel path thereof are at least partly coincident, wherein the first elevator car is provided with a first braking device, wherein the second elevator car is provided with a second braking device, and including a safety system for preventing collision of the first elevator car with the second elevator car, comprising: the safety system including a first braking force regulating device for the first braking device of the first elevator car, the first regulating device regulating a braking force of the first braking device; the safety system including a second braking force regulating device for the second braking device of the second elevator car, the second regulating device regulating a braking force of the second braking device, and wherein the safety system for preventing collision of the first elevator car with the second elevator car activates at least one of the first braking device of the first elevator car with the first braking force regulating device and the second braking device of the second elevator car with the second braking force regulating device to prevent a collision of the first and second elevator cars; the safety system including a first measuring device associated with the first elevator car, the first measuring device detecting a retardation of the first elevator car, a second measuring device associated with the second elevator car, the second measuring device detecting a retardation of the second elevator car, and wherein the safety system determines a first target retardation value for the first braking force regulating device and a second target retardation value for the second braking force regulating device; and wherein the safety system, in an operational state in which the first and second elevator cars cross the first and second travel path spaces respectively in a same direction with the first elevator car trailing the second elevator car, determines for the first braking force regulating device the first target retardation value with a greater value than a value of the second target retardation value for the second braking force regulating device.