The torsion spring lift mechanism encompasses the combined efforts made by the torsion spring and cables to move the door, yet the position, condition, and type of cable drums and tracks also play a vital role. The ultimate goal is the movement of the door in its full opening and closing position. Though, the door must also stay on the ground when shut and remain open without sliding down and, in fact, in various heights. When the door is open (above mid-way) the bottom rollers are found below the curved track in standard garage doors. In such a position, the door would want to slide down. Thanks to the torque developed by the spring the door remains open.
They are wound up when the door must open, move on the side where the winding cone is found, and remain stationary at the other end. They spin and the shaft passing through the spring moves along. This movement creates torque and transfers power to the drum, which is actually pulling the cable up. Thanks to this torque the door remains open. This is the lifting power of the springs created by the movement of the coils and must be close to the power (weight) of the door.
When we talk about the lifting power of the springs, we actually mean the power to open the door. In other words, the weight lifted from the floor. Though, when the door is closed down and must remain shut without jumping up, the power of springs is once more useful. Actually, the weight of the door must be a bit greater than the power of the springs so the door will remain closed.