the guide member 13 includes an insertion arbor 15 introducable into an insertion opening 11 or 12 and an inlet funnel 16 which as will be noted from fig2 projects from the face wall 2 from the side of the inlet funnel 16 remote from the insertion arbor 15 two tabs 17 project which serve to aligningly introduce the guide member 13 into a roller blind guide the inlet funnel is as will be noted from fig3 formed tapered toward the roller blind guide so that the individual strips of the roller blind are reliably fed to the slit 14 when rolling off the roll in fig5 of the drawings a cross section of an assembled roller blind box has been illustrated the roller blind box is connected with its lower longitudinal wall to the top portion of a window frame 18 at the left hand side of the window frame as viewed in the drawing the roller blind guide 19 is connected thereto the face wall 3 carries a bevel wheel drive 20 on the bearing spigot 8 which is connected to the face wall 3 by means of screws 21 a two piece gear rod 22 leads to the bevel wheel drive the parts of said rod being connected to one another by a universal joint 23 in this use of the roller blind box the slit 14 aligned with the roller blind guide 19 is disposed at the left hand side of the lower longitudinal wall for this reason the guide member 13 has been pushed into the.