| 摘要 |
<p>A bi-directional spring clutch (11, 13, 15, 17) further including a ratchet (43) and pawl (23) so as to permit substantial torque to be transmitted to the shade roller only in one direction. In the other direction, the roller is nearly free to rotate so that the weight of the shade material depending from one side of the roller exerts a torque on the roller which prevents reverse rolling.</p> |
