Glossary term
safety edge
A sprung or sensitive strip on the leading edge of a door that reverses it the moment it touches an obstruction.
What it means
A safety edge is the strip along the closing edge of the door. Press it and the door stops and reopens. On older lifts it is mechanical: a hinged rubber edge that operates a switch when it is pushed in. On newer lifts it is combined with an electronic detector so the door reverses before contact is made at all.
Where you see it
On the closing edge of car doors and on the edge of platform lift gates. On stairlifts and platform lifts, similar sensitive edges are fitted under the footplate and along the carriage.
How it works
The edge is part of the door control loop rather than the main safety circuit. When it operates, the door reverses, waits and tries again. Repeated operation makes the controller give up and park the doors open with a fault, on the assumption that something is genuinely in the way.
Because the edge is sprung, it also absorbs the last few millimetres of closing force. That is why an edge that has hardened with age or has been damaged makes the doors feel harsher even before it triggers a fault.
Why it matters
A working safety edge is the difference between a door that nudges a walking stick and a door that traps it. It is one of the few safety devices an owner can confirm is alive, simply by watching the door reopen when something touches it.
Commonly confused with
Safety edges and light curtains are both door protection but they work differently. An edge reacts on physical contact; a curtain reacts before contact. A door that only reverses when it touches you may have a working edge but a failed curtain, and that is worth reporting even though the door seems safe.
Wear, service and lifespan
Edges are struck constantly and their rubber, springs and internal switches wear. Service work tests the edge along its full length, because an edge can respond at the middle and be dead at the ends. Damaged or missing edge rubber lets the mechanism fill with dirt and fail.
Signs to watch for
- The door does not reopen when the edge is touched.
- The door reopens constantly with nothing in the way.
- The rubber edge is split, hardened or hanging loose.
- Closing feels harder or noisier than it used to.
- The lift logs door faults after several retries.
Troubleshooting safety edge
The door reverses only when pushed hard
What it usually means: A stiff or partly failed edge
Safe check: Report it. Do not test it repeatedly with your hand or an object.
The door reverses constantly with nothing touching it
What it usually means: A stuck or damaged edge switch
Safe check: Look at the edge rubber for splits, dents or trapped debris and report the floor.
The edge rubber is loose or hanging
What it usually means: Physical damage, likely from a trolley
Safe check: Stop using the lift and report visible damage immediately.
How to report it
Report a door that does not reverse as urgent and a door that reverses too often as a nuisance fault. Both are fixed at the door, but only one keeps people safe in the meantime, so the difference in wording matters.
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Related terms
Definitions that usually come up alongside safety edge when you are describing a fault.
- light curtain
An array of infra-red beams across the door opening that holds the doors open while anything breaks a beam.
Safety devices
- car door
The powered door on the lift car itself, driven by the door operator and responsible for opening the landing door as well.
Doors and entrances
- obstruction sensor
Any sensor that stops travel when something is in the way — under a stairlift footplate, beneath a platform, or across a doorway.
Safety devices
- entrapment
A passenger stuck in a lift car between floors or behind closed doors, released only by trained responders.
Safety devices
- interlock
A lock and switch combined, so a door cannot be opened unless the car is there and the lift cannot move unless the door is locked.
Safety devices