Abstract: A window covering is provided according to the present application, to achieve automatic extending or retracting of a window covering curtain. The window covering includes: a rotating shaft for extending and retracting control, a wound sheet spring and a cord winding box. The extending and retracting of the window covering curtain is achieved by winding the curtain pull cord via the cord winding box, and the force transmission between the wound sheet spring and the cord winding box is achieved by gear transmission. A spring wound sheet is provided inside the wound sheet spring. One proper wound sheet spring is chosen according to the weight of the window covering curtain to allow the window covering curtain to maintain a balance state of force without under the effect of an external force, to fix the extending or retracting state of the window covering curtain.

Abstract: A window covering is provided according to the present application, to achieve automatic extending or retracting of a window covering curtain. The window covering includes: a rotating shaft for extending and retracting control, a wound sheet spring and a cord winding box. The extending and retracting of the window covering curtain is achieved by winding the curtain pull cord via the cord winding box, and the force transmission between the wound sheet spring and the cord winding box is achieved by gear transmission. A spring wound sheet is provided inside the wound sheet spring. One proper wound sheet spring is chosen according to the weight of the window covering curtain to allow the window covering curtain to maintain a balance state of force without under the effect of an external force, to fix the extending or retracting state of the window covering curtain.