Cord lock for venetian blind

Claim 1

In a venetian blind, the combination comprising a headrail channel having a bottom wall with a cut-out, front and back walls upstanding from said bottom wall, and inturned upper lips on said front and back walls and terminating in downwardly facing edges; and, a cord lock structure integrally fabricated of plastic and comprising a pair of generally vertical front and back structure walls having lowered edges seated on said channel bottom wall and a pair of spaced generally vertical side structure walls extending between said front and back structure walls and combining therewith to define an opening between said front, back and side structure walls communicating downwardly through said cut-out, upwardly facing front and back shoulders externally on said front and back structure walls beneath and in retaining engagement with the respective inturned lip edges of said front and back channel walls to retain said structure downwardly on said channel bottom wall, said front and back shoulders respectively terminating inwardly in forwardly and rearwardly facing wall portions upstanding above said shoulders between and for engagement with said front and back wall lips to restrain forward and backward movement of said structure in said channel, a fixed guide member extending generally horizontally forwardly and rearwardly between said front and back structure walls and spaced over said opening for guiding a lift cord upwardly through said opening and laterally outwardly from said structure, generally upright slots in said front and back structure walls extending downwardly generally from the elevation of said guide member and defining way means, and a jamming element shiftable up and down in said way means toward and away from cord jamming relation with said guide member, said jamming element having a frictional surface for frictional engagement with a lift cord and elevation thereby into said jamming engagement.