Lift buffer forces under unfavourable collision conditions

Industrial hydraulic buffers are standard equipment for lift installations especially at lifting speeds greater than or equal to v=1m/s. They are used for the limitation of car accelerations and the reduction of impact loads on structures during processes of kinetic energy reduction. This is realized by a certain buffer force acting along the stroke of the buffer. The product of buffer force and stroke results in the energy dissipated during a buffering process. The intentionally restricted buffer force is a result of the load mass, the load speed and the buffer stroke chosen. The buffer stroke is subject to the requirements of the standard. In order to gain a suitable buffer capacity values of mass and speed rated to applicable standards are considered during design. Nevertheless more unfavourable conditions may occur. This all results out oft he standard applied, EN 81-20 e.g. The contribution discusses the relevant definitions of EN 81-20 and the resulting unfavourable operating conditions. For certain applications suitable buffer designs are evaluated. For these designs the buffer force outcomes are revealed for unfavourable operational conditions. The resulting jerks are evaluated with regard to the jerk requirements of EN 81-20.