A toothed drive belt that transmits rotary motion from the door motor to the door hanger carriage in a door operator.
Full Definition
The elevator door timing belt is a toothed (synchronous) rubber or polyurethane belt reinforced with fibreglass or steel cords that connects the door motor drive pulley to the door hanger carriage. Its positive tooth engagement provides precise positional control essential for encoder-based door speed profiling. Belt pitch (typically 5 mm or 8 mm HTD) and tooth profile must match both the motor drive pulley and idler pulleys. Common failure modes include tooth shear, elongation from worn tensioner bearings, and delamination from oil contamination. EN 81-20 requires that loss of drive (e.g., broken belt) does not lead to an uncontrolled door. Replacement intervals are typically 5 years or based on cycle counts per the operator manufacturer's specification.
