The invention relates to a spring operated roller blind system, wherein the roller blind (1) comprises an adjusting mechanism (30) for adjusting an end position of the flexible sheet member. The adjusting mechanism comprises a spindle (36) and a connecting member (31) that is connected to the roller shaft for rotation around the spindle. The adjusting mechanism further comprises a first bearing (7) for the roller shaft that defines a first end position for the connecting member (31). At least one of the bracket connectors (21) comprises a pin (33) for detachable mounting in a cooperating recess (35) on the adjusting mechanism, wherein the pin and the recess have an unround cross section.