Almost all automatic door closers have adjustable closing speed and locking speed. The locking speed is adjusted to be able to lock the movable leaf according to the hardness of the latch, without generating unnecessary impact on the door frame. The adjustment of the whole closing speed is not affected by the locking speed.
For the exterior doors of buildings, the opening resistance is a very important function. The automatic door closer should not only prevent the excessive opening of the movable fan due to the large thrust of people, but also prevent the damage of the door body caused by excessive opening of the movable fan in case of strong wind when opening. Generally speaking, only high-end door closers have this function. Lagging door closing is a special function, which aims to make the movable fan stay in the open position for a period of time and then close the door. This function is very important when children and the elderly pass. The adjustable closing force is the sign of a high-grade automatic door closer, which can accurately adjust the level of closing force. The closing force is usually the specific performance of a certain type of door closer, but sometimes the closing force will also change. For example, when the winter wind is strong, the outer door may need a large closing force. When the summer wind is small, the closing force required is small, making it easier to open the movable fan.
