You may not give to much thought to elevator doors, although there are actually several types and of course the doors are one of the most important and complex parts of any elevator.
The most common door for elevators styles are single slide doors, which means that a single panel slides to open the elevator car, either to the left or to the right. In some elevator cars however, panels from both sides slide inwards to meet in the middle. Freight elevators that need to have plenty of room and a larger doorway often have two panels that slide at different speeds.
Many elevators in high rise buildings use center opening elevator doors, with either two or three speeds. Smaller passenger elevators often utilize two speed doors, although their most common use is in freight and service elevators. The doors straighten out in line with each other when they close, but are hidden away behind one another when inside the car walls.
Some freight elevators also have what are known as vertical bi-parting doors which slide up and down, instead of open from side to side. And some heavy duty freight elevators, including those designed to transport motor vehicles, sometimes have two or three speed center opening doors with up to six panels. If there isn’t much apace around the elevator, a metal door that folds in on itself is common, rather like the door on your pantry closet.
There are two fail safe systems built into modern elevator doors, to ensure the safety of the occupants. Door restrictors are in place to prevent the doors from being opened manually, and the doors are designed to open only when the elevator has stooped at a floor. In addition, the hatch door pick up rollers and car door clutch must be in alignment or the doors won’t open.