Patent ID: 11125011

Abstract:
The present invention provides a cordless blind apparatus and a method of adjusting the balance of a cordless blind apparatus. The cordless blind apparatus includes a roller, a screen wound or unwound on the roller, and a torsion spring contracting or stretching by rotating with the roller, in which an increasing ratio of torque applied to the roller by the screen and an increasing ratio of torque applied to the roller by the torsion spring are matched to each other through the correlation equation satisfied by parameters as the wire diameter ‘d’ of the torsion spring, the Young's modulus ‘E’ of the torsion spring, the diameter ‘D’ of the torsion spring, the winding number ‘N’ of the torsion spring, the density ‘ρ’ of the screen, the thickness ‘t’ of the screen, the width ‘S’ of the screen, the radius ‘R’ of the roller, and gravitational acceleration ‘g’.