Patent ID: 8453707
Filing Date: 2013-06-04
Classification: E06B

Abstract:
1. A drive arrangement for a roller curtain covering an opening defined by a frame, the arrangement comprising: a drum for mounting horizontally across one side of the opening, the drum having an axis of rotation and axially opposite ends; a pair of hollow drive shafts mounted concentrically inside respective said opposite ends of said drum, said drive shafts each having a diameter less than a diameter of said drum, said drive shafts being fixed against rotation with respect to said drum; a pair of coaxial tension shaft portions received through respective said hollow drive shafts, each said tension shaft portion having an inner part extending beyond a respective said drive shaft inside said drum, and an outer part extending beyond a respective said drive shaft outside said drum; at least one torsion spring associated with each said tension shaft portion, each said torsion spring comprising a coil surrounding a respective said inner part, each said coil having a first end fixed to said inner part and a second end fixed to said drum; means for fixing each said tension shaft portion against rotation with respect to said door frame; and a pair of drive motors operatively connected to respective said hollow drive shafts for synchronously rotating said drive shafts in order to coil a roller curtain on said drum.