Spring that restores the buffer plunger to its normal extended position after compression.
Full Definition
The buffer return spring in an oil hydraulic buffer (and some spring buffers) ensures the buffer plunger returns to its full extended position after the buffer has been compressed by a car or counterweight impact. EN 81-20 requires that after buffer compression, the buffer must return to its extended position within a defined time (typically ≤120 seconds for oil buffers) before the elevator can be returned to service. A failed return spring that leaves the buffer compressed can result in reduced buffer stroke and inadequate energy absorption in a subsequent impact.
