SCREEN WITH HEAD RAIL, BOTTOM RAIL AND MIDDLE RAIL AND A FIRST CONTROL UNIT FOR THE MIDDLE RAIL AND A SECOND CONTROL UNIT FOR THE BOTTOM RAIL

摘要

The invention relates to a screen, comprising a first control unit (610) comprising a first drive shaft (612) and at least one first cord spool (630) rotatable with the first drive shaft for winding and unwinding a first lift cord (634) extending between a head rail and a middle rail; a second control unit (620) comprising a second drive shaft (622), and at least one second cord spool (632) rotatable with the second drive shaft for winding and unwinding a second lift cord (636) extending between the head rail and the bottom rail; and a shaft rotation limiting system (100) comprising a threaded shaft arranged on and rotatable in unison with one of the first and the second drive shafts, a coupling element threaded on said threaded shaft, wherein the coupling element is associated with and rotatable in unison with the other drive shaft.