Patent ID: 6176290
Filing Date: 2001-01-23
Classification: E06B

Abstract:
A device for adjusting an upper slat group and a lower slat group of a Venetian blind, with the upper slat group being linked with one of two cross shafts which are fastened pivotally with an upper rail of the Venetian blind, and with the lower slat group being linked with other one of the two cross shafts, said device comprising:a seat fastened with one end of the upper rail of the Venetian blind;an upper worm wheel and a lower worm wheel, which are pivoted to said seat and are coupled respectively with the two cross shafts; an upper worm rod and a lower worm rod, which are pivoted to said seat and are respectively engaged with said upper worm wheel and said lower worm wheel, said upper worm rod and said lower worm rod being provided with a center hole whereby said center hole is provided with a retaining portion;a movable stem having an upper segment which is located in said seat and is engageable with said center holes of said upper worm rod and said lower worm rod, said upper segment being provided with a driving portion and a contact portion, said movable stem further having a lower segment which is located in the outside of said seat and is fastened with a control lever; anda coil spring disposed in said seat and fitted over said movable stem such that one end of said coil spring urges said seat, and that other end of said coil spring urges said contact portion of said movable stem, and further that said coil spring pushes said movable stem to locate at an upper stop point;said driving portion of said movable stem being retained in said retaining portion of said upper worm rod at such time when said movable stem is located at said upper stop point, said driving portion of said movable stem being retained in said retaining portion of said lower worm rod at such time when said movable stem is pulled by an external force.