One-way driving mechanism for cordless window blind

A one-way driving mechanism for a cordless window blind, comprising:

• a casing;
• a reeling unit having two volute spring gears and a volute spring, the two volute spring gears being rotatably provided in the casing and meshed with each other, the volute spring being connected with the two volute spring gears and capable of being wound around one of the two volute spring gears;
• two cord units each having a cord gear and a cord, each of the two cord gears being rotatably provided in the casing and meshed with one of the volute spring gears respectively, each of the cords having one end connected to a corresponding the cord gear in such a way that each of the cords is capable of being wound around or unwound around the corresponding cord gear by the rotating of the corresponding cord gear;
• and
• two one-way clutch units each having a clutch wheel and a position-securing member, each of the two clutch wheels being rotatably provided in the casing and encircled with a single loop by a corresponding the cord, each of the clutch wheels being hollow in shape and having an internally toothed peripheral portion, each of the position-securing members being fixedly provided in the casing and having at least one elastic arm and at least one ratchet tooth, which is connected with the at least one elastic arm and has a one-way meshing relationship with the internally toothed peripheral portion of a corresponding the clutch wheel.