| 摘要 |
<p>A method and device for applying a pre-tensioned force to a spiral window balance. The spiral balance includes a containment tube, a spiral rod and a torsion spring that traverses the length of the containment tube. The device includes a pre - tensioning insert that is contained within an anchorage fixed within the upper end of t he containment tube. At least one boss formed at the base of a bore within the pre-tensioni ng insert defines a channel that receives the upper end of the spiral rod. To apply a pre-tensioned force to the spiral balance, the lower end of the spiral rod is pulled from the lower end of the containment tube, turned a number of revolutions and reinserted into the containment tube without being allowed to rotate. The upper end of the spiral rod is non - rotatably retained within the channel by the boss to prevent it from losing its pre- tensioned force.</p> |
