This type of opener is designed to be used with overhead doors. It is the most widely used type of electric operator in residential properties. Its power unit is installed on the ceiling and connected to the door via a system which consists of a rail, trolley and moving arm. It is different from the jackshaft opener which is installed on the wall beside the door and uses pulleys and cables to open and close it.
There are three traditional overhead garage door opener types depending on the component which is used for driving the trolley up and down the track. These are chain drive, belt drive and screw drive openers. The direct-drive units are the latest addition to the group. These devices have a fixed chain staying in a rail and a motor which moves along the chain instead of the traditional trolley. The modern overhead openers have safety reversal mechanism and wirelessly controlled operation.