These garage door parts counterbalance the weight of the door. The force of the spring has to match the weight of the door. In this way, appropriate balance is achieved. The door can open and close properly and stay securely in place. Due to the role which they play in the stability and operation of the door, the springs are under great tension. If they are not handled properly in case of maintenance, repair or replacement, they can cause injury.
There are two types of garage door springs. Torsion springs stay on a metal shaft above the door. They provide balance by applying torque to the shaft through special drums at its ends. Residential doors require a single torsion spring to operate. Extension springs are installed above the horizontal tracks of the door. Most residential garage doors require two of them - one on each side. They stretch and contract as the door moves.