| 摘要 |
A retractable projection screen having a projection screen surface, a lower batten fixed adjacent the bottom of the projection screen surface, an upper batten fixed adjacent the top of the projection screen surface, a winch mandrel, a cable adapted to be fixed to the upper batten and wound around the winch mandrel and an outer roller on which the projection screen surface is wound. An electric motor is coupled to the winch mandrel to rotate the mandrel, thereby raising and lowering the projection screen surface.
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