| 摘要 |
<p>A counterbalancing mechanism (10) for a door (D) movable between a closed position proximate a door frame (12) and an open position displaced therefrom including a pair of drums (100, 100) for reevin g lengths of cable (C) thereabout which are affixed to the door (D), shafts (70) for freely rotatably mounting the drums thereon, a pair of brackets (60, 60) mounted in spaced relation on the door frame, one of the brackets supporting each of the pair of shafts, a drive tube (30) extending between the pair of drums and being non-rotatably affixed thereto, a coil spring (80) positioned interiorly of the drive tube, said coil spring having one end (82) thereof non-rotatably affixed to the drive tube and the other end (81) non-rotatably affixed to the shaft, and a tension adjusting mechanism (110) for normally restraining the shafts and for effecting rotation of the shafts to selectively adjust th e torsional forces in the coil spring.</p> |
