Patent ID: 7168476
Filing Date: 2007-01-30
Classification: E06B

Abstract:
1. A cordless activating device for a venetian blind having multiple slats, the cordless activating device comprising: a central reeling device having a U-shaped mounting bracket; a bottom; a front wall having a top edge; and a string channel defined longitudinally through the front wall; a rear wall having a string channel defined longitudinally through the rear wall; a recess formed between the front wall and the rear wall; a positioning post formed on the bottom of the U-shaped mounting bracket inside the recess and having a distal end; a ratchet post formed on the bottom of the U-shaped mounting bracket inside the recess and having: an outer surface; a distal end; and a non-circular section formed on the outer surface near the distal end of the ratchet post; and an annular toothed ring formed on the bottom of the U-shaped mounting bracket and around the ratchet post; a resilient coiling device mounted on the U-shaped mounting bracket; and having a spring spool mounted on and attached securely to the positioning post with a screw and a washer set and having a top; a take-up real rotatably mounted on the ratchet post below the non-circular section and having a bottom; a top; an outer surface; a coil spring chamber being annular and defined longitudinally in the bottom of the take-up reel; multiple teeth formed radially on the bottom of the take-up reel around the coil spring chamber to selectively engage the annular toothed ring; a spring reeling area defined around the outer surface of the take-up near the bottom; a string reeling area defined around the outer surface of the take-up reel above the spring reeling area; and an S-shaped recoiling spring being a specifically designed coiled band-type spring that provides a restitution force and has an internal end attached to the spring spool; and an external end attached to the spring reeling area on the take-up reeling; and a clutch selectively causing multiple teeth on the bottom of the take-up reel to engage or disengage from the annular toothed ring in the U-shaped mounting bracket, and being composed of: a coil spring mounted inside the spring chamber in the take-up reel and pressing against the bottom of the U-shaped mounting bracket to selectively disengage the multiple teeth on the bottom of the take-up reel from the annular tooth ring; and a cam assembly mounted on the take-up reel and selectively pressing the take-up reel down so the multiple teeth on the bottom engage the annular toothed ring to hold the take-up reel in place, wherein the cam assembly comprises: a lower cam mounted inside the cam recess on the top of the take-up reel and slidably on the ratchet post and having a non-circular hole defined through the lower cam and corresponding to and non-rotatably engaging the non-circular section on the ratchet post; an abutting top face; multiple convex segments formed on the abutting top face; and multiple concave segments formed alternately with the convex segments on the abutting top surface; and an upper cam rotatably mounted above the lower cam on the ratchet post with a screw and washer and having a central hole defined through the upper cam to make the upper cam to mount rotatably around the distal end of the ratchet post; a top surface; an abutting bottom face that presses against the abutting top surface of the lower cam; multiple convex segment formed alternately with the concave segments on the abutting bottom face and selectively pressing against the convex segments of the lower cam to move the lower cam down; and an activating lever formed on and extending radially from the top surface of the upper cam to rotate the upper cam and having a distal end; two string-guides mounted on the bottom of the venetian blind on opposite ends of the central reeling device; and a main string attached to the resilient coiling device on the central reeling device, winding around and extending between the two string-guides and connecting to two branched strings that adapt to extend down through the slats of the venetian blind.