Operating device for a venetian blind to control raising and lowering of the slats and to adjust tilting angle of the slats

An operating device for a Venetian blind which includes an elongated top housing, a horizontally disposed shaft journalled in the top housing, a plurality of horizontal slats suspended one above another from the top housing, each of the slats having two opposite longitudinal sides, a bottom rail disposed below the slats, a plurality of pull ropes, each of the pull ropes having a first end which passes through the housing and through the slats and which is mounted to the bottom rail, and a second end which extends out of the housing, a plurality of pairs of tilting cords disposed on the opposite longitudinal sides of the slats and having upper ends secured to the shaft and lower ends mounted on the bottom rail, and plurality of suspending strings disposed below each of the slats and interconnecting the tilting cords, said operating device comprising:

• a hollow base adapted to be disposed in the top housing, said hollow base including a pair of side plates which form a receiving space therebetween, and a limiting rod extending transversely between said side plates and disposed at a peripheral portion of said receiving space, said hollow base being adapted to permit
• a locking seat mounted pivotally to said side plates and disposed in said receiving space on one side of said limiting rod such that the pull ropes are extendible between said locking seat and said limiting rod;
• and
• a biasing member mounted on said hollow base for biasing said locking seat to pivot toward said limiting rod so that said locking seat is adapted to clamp releasably the pull ropes against said limiting rod;
• wherein said biasing member includes a retaining rod extending transversely between said side plates and disposed at another peripheral portion of said receiving space opposite to said limiting rod, and a pair of torsion springs, each of which is sleeved on said retaining rod and has a first end abutting against a respective one of said side plates of said hollow base and a second end, said second ends of said torsion springs being connected to one another to form a biasing portion which abuts against said locking seat for biasing said locking seat to pivot towards said limiting rod.

An operating device for a Venetian blind which includes an elongated top housing, a horizontally disposed shaft journalled in the top housing, a plurality of horizontal slats suspended one above another from the top housing, each of the slats having two opposite longitudinal sides, a bottom rail disposed below the slats, a plurality of pull ropes, each of the pull ropes having a first end which passes through the housing and through the slats and which is mounted to the bottom rail, and a second end which extends out of the housing, a plurality of pairs of tilting cords disposed on the opposite longitudinal sides of the slats and having upper ends secured to the shaft and lower ends mounted on the bottom rail, and plurality of suspending strings disposed below each of the slats and interconnecting the tilting cords, said operating device comprising:

• a hollow base adapted to be disposed in the top housing, said hollow base including a pair of side plates which form a receiving space therebetween, and a limiting rod extending transversely between said side plates and disposed at a peripheral portion of said receiving space, said hollow base being adapted to permit extension of the second ends of the pull ropes and the shaft into said receiving space;
• a locking seat mounted pivotally to said side plates and disposed in said receiving space on one side of said limiting rod such that the pull ropes are extendible between said locking seat and said limiting rod;
• and
• a biasing member mounted on said hollow base for biasing said locking seat to pivot toward said limiting rod so that said locking seat is adapted to clamp releasably the pull ropes against said limiting rod;
• wherein said locking seat is formed with a teethed retaining protrusion for enhanced friction with the pull ropes, and
• wherein said side plates of said hollow seat are formed with aligned pivot holes, said locking seat having opposite first and second tubular extensions mounted pivotally on said side plates in said pivot holes, said locking seat further including a retaining sleeve which is sleeved securely on said first tubular extension and which is formed with said retaining protrusion.