Semiautomatic swing doors are produced to solve the problem that automatic doors are not suitable for frequent use. The opening and closing of door leaves are driven by electric motor and mechanism respectively. Not using brushless variable-speed motor equipped with encoder, common electric motor needs a variable-speed drive mechanism which can be equipped with a spring energy-stored device. When the door leaves are opening, the spring is stretched. Then the leaves are closed with the power released by the spring.
Such motor can be closed by the spring tension, so it can also be used in fire doors. As the electric element works only when the door leaves are opening, the stability of semiautomatic swing doors is doubled. But the variable-speed drive mechanism and spring are laid bare. So the service life is affected as they are exposed to dust and the gantry crane is easily wearing out. Under such circumstances frequent use will make it worse. The gantry crane cannot be sealed up as there is a need for heat dissipation. Besides, the complexity of mechanism makes the size and weight larger, which will weaken the beauty of doors.
