Two-motor drive arrangement for a roller curtain

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 coaxially in respective said opposite ends 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.