| 摘要 |
<p>A counterbalance system (10) for an upwardly acting door (D) movable on tracks (T, T) between a closed position and an open position having, a drive tube (31) adapted to be mounted above the door in the closed position, a cable drum assembly (30) mounted proximate each end of the drive tube, a cable connecting each cable drum assembly and the door, a cylindrical member (40) on the cable drum assembly, a cable receiving surface (42) on the cylindrical member extending laterally between the door and the tracks and receiving multiple layers (F, S) of the cable during movement of the door from the closed position to the open position, whereby the cable avoids engagement with the door during movement between the closed position and the open position.</p> |
