Patent ID: 8851143

Claim:
A single pull rope driving device for a window curtain comprising: a bracket ( 1 ); a rotation driving device ( 3 ) mounted to the bracket ( 1 ) and including a pull rope ( 12 ); a reeling drum ( 2 ) rotatably mounted to the bracket ( 1 ) or the rotation driving device ( 3 ), with the reeling drum ( 2 ) adapted to release/wind a curtain cloth ( 26 ) by pulling the pull rope ( 12 ); a gear ( 7 ) rotatably mounted to the bracket ( 1 ) or the rotation driving device ( 3 ), with the gear ( 7 ) jointly rotatable with the reeling drum ( 2 ), with the gear ( 7 ) including a plurality of teeth ( 7 a ); an actuating member ( 13 ) mounted on the pull rope ( 12 ) and located below the gear ( 7 ) in a vertical direction; a rack ( 9 ) movable in the vertical direction and including upper and lower ends ( 91 ) and ( 92 ) spaced from each other in the vertical direction, with the upper end ( 91 ) of the rack ( 9 ) including at least one tooth ( 10 a ) releasably engaged with the plurality of teeth ( 7 a ) of the gear ( 7 ), with the lower end ( 92 ) of the rack ( 9 ) located below the gear ( 7 ) in the vertical direction and actuatable by the actuating member ( 13 ); and a return spring ( 11 ) coupled to the rack ( 9 ), with the return spring ( 11 ) biasing the rack ( 9 ) to a disengagement position in which the at least one tooth ( 10 a ) of the rack ( 9 ) is disengaged from the plurality of teeth ( 7 a ) of the gear ( 7 ), with the gear ( 7 ) and the reeling drum ( 2 ) rotatable in a releasing or winding direction by pulling the pull rope ( 12 ) downward without actuating the rack ( 9 ), wherein if the actuating member ( 13 ) is actuated by pulling the pull rope ( 12 ) to move the rack ( 9 ) downward in the vertical direction, the at least one tooth ( 10 a ) of the rack ( 9 ) is moved to engage with the plurality of teeth ( 7 a ) of the gear ( 7 ) and drives the gear ( 7 ) and the reeling drum ( 2 ) to rotate in the releasing direction.