Door bumpers (also known as door buffers or mechanical safety edges) is an elevator mechanical device that prevents the doors closes when a person or an object blocks the doorway. Door bumpers are commonly found in older elevators and elevators installed in Asia.
When a person or an object comes into contact with the bumpers, the door will immediately retract. Door bumpers usually comes in stainless steel or plastic and they are either round or square. Normally an elevator has two sets of bumpers located on the door's edges, although some only have one bumper.
While door bumpers are relatively safe, they can occasionally malfunction and do not retract when a passenger bumps or hits them. Consequentally, many elevator bumpers have been replaced with infra-red sensors that perform more reliably, and some elevators also had their bumpers replaced with newer ones that have a hidden infra-red beams inside the bumpers (like in Mitsubishi and Shanghai Mitsubishi elevators). Also, many elevator companies nowadays (such as Kone, Schindler, Hyundai, and others) have discontinued the use of mechanical door bumpers due to safety reason and they only use infra red beam sensors for their new elevators (except some country code still need it).