| 摘要 |
A clutch assembly is provided to prevent over tensioning of the spring motor of a window shade. The clutch assembly includes sleeve means, connected to one end of the spring motor, having an axial bore formed with internal threads which are engageable with threads formed along the window shade dowel, and also having sleeve locking means operable to engage retaining means formed on the interior surface of the window shade tube. The clutch assembly is operable to permit tensioning of the spring motor a predetermined number of turns of the window shade tube in one direction and then prevent further tensioning of the spring motor without restricting rotation of the tube in such one direction.
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