A Method for Determining the Initial Distance Between the Elevator Cabin and the Shock Absorber

In elevators, the shock absorber located at the bottom of the shaft serves as the last safety device when the cabin overruns its permitted travel. The initial distance between the cabin and this shock absorber directly influences the impact energy and resulting braking acceleration in an emergency. This paper proposes a method to determine that initial distance using the energy conservation principle combined with distance constraints derived from elevator testing and installation standards (EN 81/TCVN 6396). The method incorporates factors such as floor stopping error, cable elongation, thermal expansion, and installation tolerances, and is illustrated for spring-type buffers. An experimental example demonstrates that the calculated distance yields an optimal correction value based on surveyed load and damping parameters, enabling quick verification for initial design and on-site adjustment. The proposed approach is also applicable to counterweight buffers and can be extended to other types of elevator shock absorbers.