| 摘要 |
<p>The tubular winding drum for a roller-blind accepts splined spigots (24) in each end. Each spigot rotates freely about a wall-mounted stub-axle (9) of which one is fixed against rotation. The axles are connected by a coil spring (12) which acts to promote winding rotation, and one of the spigots includes a locing mechanism. The mechanism uses two balls (34, 35) each floating in a contoured chamber formed by grooves in the mating revolving surfaces of the spigot and an enlarged end (15) of the axle. The balls move out under centrifugal forces to allow fast rotation. During pauses in rotation the upper ball (35) drops to engage grooves (41, 47) and lock the spigot to the axle. The system allows the blind to the set at a desired height, and unwinding rotation dislodges the ball.</p> |
