Motorized roll-up device for venetian blinds

Venetian or folded blind cord or tape roll-up device having a casing (1), an electric motor (2) mounted within said casing, two cord or tape roll-up drums (12, 14) mounted within said casing, at least one output shaft (3, 4, 11) connected to said motor and said two roll-up drums to drive said two roll-up drums, control means (20) connected to said motor to sense a blockage of said motor and to stop said motor from rotating said at least one output shaft, said roll-up device further comprising a cylindrical cage (9) mounted in said casing,

• said at least one output shaft having a cylindrical cage output shaft (4, 11) rotatably mounted within said cylindrical cage,
• a screw member (6) attached to said cylindrical cage output shaft (4, 11) to rotate with said cylindrical cage output shaft,
• an axially traveling stop member (7), attached to said screw member to move axially on said screw member,
• internal cage means (8) connected to said axially traveling stop member to prevent said axially traveling stop member from rotating relative to said cage and to axially move said axially traveling stop member on said screw member when said cylindrical cage and said screw member are rotated relative to each other,
• blocking means (17, 21) connected to said casing to selectively allow said cylindrical cage to rotate relative to said casing and to prevent rotation of said cylindrical cage relative to said casing,
• first stop means connected to said cylindrical cage to selectively stop the axial travel of said axially traveling stop member on said screw member to cause a first blockage of said motor when said blind is in a first selected position, and
• a second stop means to cause a second blockage of said motor when said blind is in a second selected position.