Elevator doors have always been an important safety concern for any passengers entering or exiting an elevator cab. The first safety mechanism that was introduced to the market was the mechanical door edge (sometimes referred to as door bumpers). When a person or object came in contact with the door edge the door edge (or bumper) would compress and the doors would retract. This option is a relatively safe way to protect passengers but it does involve contact with the door which can result in additional maintenance and malfunctions so the infrared sensors were invented.
The early infrared sensor doors consisted of two sensors (or photo eyes) located in the car door jams and when a passenger or object intersected with the infrared beam the door would retract. Since the infrared sensors use solid state components and have no moving parts, they are much more reliable and require less maintenance than the previous mechanical door edge system. They also are a safer alternative because they don’t involve the passengers coming in contact with the actual elevator doors.
The latest technology improvement involves the expansion of the infrared beams. Typically referred to as 3D multi-beam door sensors these products expand the range of door sensors to monitor the hall way and extended elevator cab. This application provides an additional level of safety by allowing increased reaction time for the door to compress if a person or object crosses the infrared beam.
QUESTION OF THE WEEK
“Why does my elevator make a buzzer sound if an object blocks the door for too long?”
The buzzer sound you are referring to occurs when the elevator enters “Nudge Mode” (or Nudge Service). When an elevator door is held open past a certain time usually 30 seconds, it nudges closed while a buzzer or voice sound signals passengers to stand clear of the door. Many people mistake this for a door malfunction but that is not the case, the purpose of nudge mode is to alert passengers to stand clear of the doors so that they can close as designed and the elevator can resume normal operation.
Does your elevator need a free door safety check up? Call or email us today and we will send a certified technician out to survey your equipment!