Moving piston of an oil buffer that absorbs impact energy from the car or counterweight.
Full Definition
The buffer plunger is the cylindrical piston of an oil hydraulic buffer that is driven downward into the oil-filled cylinder when struck by the car or counterweight. As the plunger descends, oil is forced through metering orifices, converting kinetic energy into heat. The orifice geometry determines the deceleration profile—EN 81-20 requires average deceleration ≤1g and peak ≤2.5g. The plunger must return to its full extension within 120 seconds after compression. It is inspected for corrosion, seal condition, and return time during periodic maintenance.
