A spring-type buffer device in the elevator pit that decelerates and stops the elevator car in the event of descent beyond the lowest terminal landing.
Full Definition
Spring buffers are energy-storage type buffers used in lower-speed elevators (typically rated speed ≤1.0 m/s per EN 81-20). They consist of a coil or laminated spring mounted on the pit floor directly below the car and (where required) the counterweight. If the car descends below the lowest normal terminal stop — due to a control failure or terminal stopping device failure — the car strikes the buffer, which compresses elastically to absorb kinetic energy and bring the car to rest. After the car is lifted off, the spring returns to its original shape ready for the next event. EN 81-20 mandates that after full compression the buffer must restore the car with no permanent deformation. For higher-speed elevators, oil buffers (energy-dissipation type) are required instead.
