Cordless blind device for external power drive

A cordless blind device for external power drive, comprising:

• a winding roll rotatably coupled to a pair of fixing brackets disposed at both ends thereof;
• a screen configured to be wound on or unwound from the winding roll;
• a weight connected to a lower end of the screen and applying torque in a first direction, the screen being unwound in the first direction from the winding roll by gravity;
• an elastic member applying torque in a second direction, the screen being wound in the second direction by applying elasticity to the winding roll;
• and
• a power conversion module disposed in at least one of the pair of fixing brackets and including a first driving shaft connected to the winding roll, a second driving shaft connected with a driving device connector, and a gear box connecting the first driving shaft and the second driving shaft, and configured for transmitting power in two directions,
• wherein the second driving shaft is disposed in perpendicular to the first driving shaft, and
• wherein the driving device connector includes a tool insertion groove recessed coaxially with the second driving shaft, such that an external driving device configured to provide a rotational force is to be detachably coupled to the driving device connector through the tool insertion groove to transmit the rotational force to the second driving shaft.