| 摘要 |
A venetian blind comprises a windup drum for a lifting strap firmly fitted to a drive shaft. Lateral hub portions of a drum are provided with teeth which serve as contact surfaces for two setting straps. Supporting twines for tiltable slats are suspended from the setting straps whose both ends are connected to the associated one of the other strap by connecting plates which act as stop members. Bearing brackets of the drive shaft, accommodated in a supporting housing of the blind, are provided at their bottom with guide webs, for the setting straps and the lifting strap. Stop lugs provided on a bearing bracket in the housing, cooperate on one side with the connecting plate and on the other side with an engaging member of setting strap. During lifting of the blind, the lugs limit the open position of the straps, and during lowering of the blind, they set the predetermined oblique position of the slats. Pawls, which are radially displaceable in the windup drum, cooperate with the engaging member to close the slats if lifting strap is in its wound-off position. To secure the slats against wind action, i.e. in their open position against closing, or in a predetermined position against further opening, lock cams cooperating with teeth portions of the drum are provided on setting straps.
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