Abstract: A roller blind structure has an elongated tubular member which is mounted for rotation and displacement in elongated openings in two spaced-apart brackets. Coaxially secured to the tubular member is a pulley. The roller blind screen is secured to the tubular member, and a cord for rotating the tubular member is secured to the hub of the pulley. A tubular sleeve having a downwardly directed opening for the cord has an axial projection sliding against an upper horizontal surface of the bracket to prevent the sleeve from rotating but to allow it to be displaced with the pulley A guiding and locking means is provided at a vertical spacing below the sleeve and serves to guide the cord relative to the sleeve and to lock the cord in any desired position. For the latter purpose, it has a spring-influenced locking arm.