| 摘要 |
The disclosure sets forth an apparatus and method for counterbalancing a roll-up door (20). A first threaded shaft (78) is concentrically disposed around a torsion shaft (34) and a spring (60) is also disposed around the torsion shaft (34). The spring (60) has a first end (64) and a second end (66). The first end (64) of the spring (60) is secured to a first anchor plate (68) that is threadably mounted to threads onto the threaded shaft (78). The second end (66) of the spring (60) is fixed relative to the torsion shaft (34). When the threaded shaft (78) is rotated, the first anchor plate (68) moves along the threaded shaft (78), thereby longitudinally stretching the spring (60) a predetermined distance. A first stop prevents the movement of the first anchor plate (68) along the threaded shaft (78) eyond a predetermined position so that further rotation of the threaded shaft (78) winds the spring (60) thereby applying a predetermined counterbalancing torque on the torsion shaft (34). |
