| 摘要 |
<p>The retracting shutter haulage mechanism is for use with roller blinds or roller-mounted doors. It has a housing containing a worm (23) driven by hand or motor, and a wheel (22) meshing with the worm. Wheel teeth and worm are cut so that the mechanism is self-locking in any position. The housing can comprise two cast shells screwed together, and incorporating all the moving parts. Worm and wheel shafts can both work in steel bushes. It is impossible to move the blind either way by pulling on it.</p> |
