Traditionally torsion springs were used as part of the mechanism on a mousetrap. Torsion springs can store a strong force and deploy instantly. On a smaller scale they are used in small devices like cameras to operate the various pop-out doors. Harmless in these small, weak devices torsion springs show their real power in other appliances and products. Garage door torsion springs have the power to counterbalance a garage door, and if fitted correctly can operate successfully for many years.

Garage door torsion springs (in more detail) are part of a counterbalance system, wound tightly on a steel shaft, cable drums are at both ends of the system. Usually you will find this mechanism mounted above the garage door. When the door rises, the springs slowly unwind, the tension stored in the springs can lift the door, this is done by turning the shaft - which turns the cable drums. The same principle exists when the door is lowered down. The cables now unwrap themselves from the drums and the springs are wound back ot full tension, holding the door firmly in place.

Installing one of these forms of mechanism is pretty simple, but can be very dangerous to amateurs. It's been known for incorrectly installed tension springs too cause some serious trouble and damage to people and their possessions. It's generally recommended to have these springs installed by a professional - you can still do the rest 'on the cheap' by doing it yourself, but it's important for your families well being to get the safety bit right.

Every garage door should be installed with a restraint cable (why? because if the extension spring breaks, which they can and will over time folks, your bang in trouble). A cable going through the center should restrain a spring if it breaks.

But you shouldn't have to worry, most overhead systems are installed with garage door torsion springs.These systems don't require a restraint cable (they have a shaft going through the torsion spring which will restrain the spring if it happens at any time it happens to snap. Extension springs are practically obsolete compared to torsion springs. It's much easier to balance the weight of a garage door with a torsion spring compared to it's counterpart.