| 摘要 |
<p>A drive assembly for a roller blind includes a housing (1) having a projecting shaft (10). A first gear (11) is contained within the housing co-axial with the shaft, and a second worm gear (12) is drivably engaged with the first gear (11) and rotatable by a wand which projects from the housing via a universal joint member (7). A clutch member in the form of a spring (13) encircles the shaft with a pair of circumferentially spaced tangs (14 and 15). Rotation of a drive member (16) by means of the wand and gear wheels (11,12) causes the spring (13) to release its grip on the shaft (10) allowing rotation of the spigot (4). Rotation of the spigot (4) other than by the drive member (16) causes the spring (13) to tighten its grip on the shaft and thereby resist rotation of the spigot.</p> |
