Patent ID: 7198089

Claim:
A pull cord operation mechanism for blinds comprising: a) a fixing mount having: i) a base board; ii) two side walls, one of the two side walls is located on each of two opposing sides of the base board; iii) a slide groove located in a top of each of the two side walls; iv) a reinforcing support plate protruding upwardly from a middle of the base board and having a C-shaped pivoting groove with an upper opening concentrically aligning with the slide groove of each of the two side walls; v) a rectangular through hole located in the base board between the reinforcing support plate and a first side wall of the two side walls; vi) two engaging slots located above the rectangular through hole, a first engaging slot of the two engaging slots is located in the reinforcing support plate, a second engaging slot of the two engaging slots is located in the first side wall; and vii) two guiding recesses, one of the two guiding recesses is located below each of the two engaging slots, one of the two engaging slots communicating with the rectangular through hole through each of the two guiding recesses; b) a control member connected to the fixing mount and having: i) a linking shaft; and ii) two roller ends located on opposing sides of the linking shaft, each of the two roller ends have a diameter larger than a diameter of the linking shaft, each of the two roller ends has a cord passage located through a first end thereof and a limiting stop ring located on one side of the cord passage of each of the two roller ends, a first roller end of the two roller ends has an adjusting area and a pull cord hole located on a second end thereof, the adjusting area including a plurality of abutting facets and curved sliding facets, a pull cord is inserted through the pull cord hole and secured to the first roller end; and c) a retaining member connected to the fixing mount and having: i) an annular pivoting rod; ii) a linking section having a first end located on a first end of the annular pivoting rod; iii) a retaining hook located on a second end of the linking section and having a guide slope located on an upper edge thereof; and iv) an actuation section located on a second end of the annular pivoting rod, the actuation section tilting downwardly at a predetermined angle and having a plurality of cord passage holes located therein.