2.Missing emergency instructions and emergency operation tool keys, such as machine room
brake release tools, turning devices, triangular keys, etc.
3.Failure of safety and door lock switches, which is relatively serious and likely to cause major
accidents.
4.Failure of overload protection/anti-pinch function/maintenance control/over-swing
protection.This is common;the elevator can still be used normally after failure,but is easy
to be ignored and causes potential hazards.