A torsion spring works by keeping energy in several twistings in the spring. The twisting force applied to the spring causes a proportional amount of energy to build up. Unwinding the spring pushes the tension to the same or opposite strength, making the spring uncoil. Then it unravels using the energy the springs built.

The twisted spring is around a steel beam above the garage door, with counterbalancing steel cables connected on both sides. When the garage door opens, a winding cone turns. The spring uncoils and lets the energy wrap the cables and raise the garage door. The same thing happens when the garage door becomes lowered.