| 摘要 |
The invention relates to a drive for a roller shutter door having an intercepting device preventing said door from coming down. The drive and the intercepting device are designed as a unit and comprise a worm and two worm wheels which mesh therewith and are connected to each other such that they are fixed in terms of rotation. The second worm wheel meshes with the worm such that, when the first worm wheel is driven by the worm, the second worm wheel runs along free of loading. When the drive of the first worm wheel fails owing to defective engagement, blocking takes place, however, between the second worm wheel and the worm or an outer stop against which the second worm wheel can move owing to a force component arising from the engagement between worm wheel and worm.
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