Cordless window shade

Abstract

A cordless widow shade includes at least an upper track, a lower track, a shade assembly and an automatic winding means. The upper track has a holding trough to hold the automatic winding means and wire directing sets close to two sides thereof to direct a first lift cord and a second lift cord of the shade assembly. The automatic winding means has a retaining set to hinge a transmission assembly. The transmission assembly includes a first transmission wheel, a second transmission wheel and an elastic element. The elastic element is an S-shaped elastic reed with two ends coupling on the first and second transmission wheels. Through rotation of the automatic winding means, retraction and extension of the cordless window shade can be controlled to facilitate operation.

1 . A cordless window shade, comprising:
 an elongated upper track which has a first wire directing set and a second wire directing set at two sides;   a lower track spaced from the upper track at a lower side;   a shade assembly which is located between the upper track and the lower track and has a slat and a lift cord assembly; and   an automatic winding means which is located in the upper track and coupled with the shade assembly and has a retaining set and a transmission assembly hinged inside.   
     
     
         2 . The cordless window shade of  claim 1 , wherein the automatic winding means includes an elastic element. 
     
     
         3 . The cordless window shade of  claim 2 , wherein the elastic element is an S-shaped elastic reed. 
     
     
         4 . The cordless window shade of  claim 3 , wherein the transmission assembly includes a first transmission wheel and a second transmission wheel, the elastic element having two ends coupling with the first transmission wheel and the second transmission wheel. 
     
     
         5 . The cordless window shade of  claim 4 , wherein the first transmission wheel has a boss on an upper side that has a first latch trough and a second latch trough corresponding to each other and an indented annular portion in a middle section thereof, the second transmission wheel having another indented annular portion corresponding to the first transmission wheel. 
     
     
         6 . The cordless window shade of  claim 4 , wherein the first transmission wheel has a first latch trough and a second latch trough that are formed on two layers corresponding to each other. 
     
     
         7 . The cordless window shade of  claim 1 , wherein the lift cord assembly coupling with the automatic winding means is a double-set lift cord assembly. 
     
     
         8 . The cordless window shade of  claim 1 , wherein the retaining set includes at least an upper pressing board, a lower pressing board and a retaining element. 
     
     
         9 . The cordless window shade of  claim 8 , wherein the upper pressing board and the lower pressing board are pivotally coupled with a first strut, a second strut and a third strut between them, the upper pressing board being hinged with a first roller and a second roller on two sides thereof corresponding to the first strut and the third strut. 
     
     
         10 . The cordless window shade of  claim 9 , wherein the first roller and the second roller consist of multiple roller sets. 
     
     
         11 . The cordless window shade of  claim 1 , wherein the upper track has a plurality of apertures running through the bottom thereof to latch the first wire directing set and the second wire directing set. 
     
     
         12 . The cordless window shade of  claim 11 , wherein the apertures are more than one. 
     
     
         13 . The cordless window shade of  claim 11 , wherein the first wire directing set and the second wire directing set have respectively an extensible latch element extended from the bottom thereof that have respectively a first threading hole and a second threading hole formed in the center. 
     
     
         14 . The cordless window shade of  claim 11 , wherein the first directing set and the second wire directing set have respectively a wire directing post of different heights.