| 摘要 |
A counter balance system for an overhead door assembly is provided. The overhead door assembly includes a door frame, an overhead door, and a door lifting assembly. The door lifting assembly includes an extension spring, a cable, and a pulley assembly. The pulley assembly guides the cable as the door is moved between a raised open position and a lowered closed position. A pulley of the pulley assembly is mounted so that an axis of rotation of the pulley remains perpendicular to a portion of the first cable extending between the pulley and a lower portion of the overhead door as the door is moved between the raised open position and the lowered closed position. |
