A transmission assembly for a roller blind having a blind cloth device with a blind cloth, a lower bar mounted on a lower side of the blind cloth, a connecting cord connected securely to the lower bar and a lift cord connected to the lower bar and the transmission assembly comprising:
- a mounting frame being hollow and having two open ends and a bottom being adapted to connect with a blind cloth device;
- at least one winding device mounted in the mounting frame and each one of the at least one winding device having
- a mounting sleeve being hollow, mounted securely in the mounting frame and having
- two open ends;
- an internal surface;
- and
- an inner thread formed on the internal surface of the mounting sleeve;
- a winding jacket being hollow, rotatably mounted in the mounting sleeve and having
- two open ends respectively extending out of the open ends of the mounting sleeve;
- an external surface;
- an internal surface;
- an outer thread formed around the external surface of the winding jacket and screwed with the inner thread of the mounting sleeve;
- and
- two ball recesses formed in the internal surface of the winding jacket and formed through one of the open ends of the winding jacket;
- two winding balls rotatably and respectively mounted in the ball recesses of the winding jacket;
- and
- a stopping ring mounted on a corresponding open end of the winding jacket through which the ball recesses are formed, the stopping ring having two stopping arms respectively mounted in the ball recesses of the winding jacket;
- and
- a roller rotatably mounted in the mounting frame, securely connected to the winding jacket of the at least one winding device, being adapted to the blind cloth of the blind cloth device and having;
- an external surface;
- and
- two ball grooves formed in the external surface of the roller and respectively aligning with the ball recesses of the winding jacket of the at least one winding device to hold the winding balls between the ball grooves of the roller and the ball recesses of the winding jacket of the at least one winding device;
- a coil spring mounted securely in the roller and having
- an inner end mounted securely in the roller;
- and
- an outer end;
- a spring axle mounted in the coil spring between the ends of the coil spring and having an inner end and an outer end;
- a turning element connected to the inner end of the spring axle and having
- an inserting end mounted securely in the inner end of the spring axle;
- and
- a mounting end;
- a torsional spring mounted securely in the mounting end of the turning element;
- a major damper connected securely to the inner end of the coil spring that is securely mounted in the roller, the major damper connected securely to the torsional spring and having
- an inner side;
- and
- a turning rod formed on and protruding from the inner side of the major damper and mounted securely and abutting securely the torsional spring;
- and
- a positioning device mounted securely in the roller, rotatably abutting the outer end of the spring axle and having
- a rotating mount being hollow, mounted securely in the roller and having
- two open ends, and one of the open ends of the rotating mount rotatably abutting the outer end of the spring axle;
- an internal surface;
- and
- a ball channel formed longitudinally in the internal surface of the rotating mount;
- a rail mount mounted in the rotating mount and having
- a mounting segment extending through one of the open ends of the rotating mount and connected securely to the outer ends of the coil spring and the spring axle;
- and
- a rail segment formed with the mounting segment of the rail mount, the rail segment mounted in the rotating mount and having
- an external surface;
- an inner side;
- an outer side;
- an inner flange formed around and protruding from the external surface of the rail segment at the inner side of the rail segment and having an inner surface;
- an outer flange formed around and protruding from the external surface of the rail segment at the outer side of the rail segment and having an inner surface;
- two inner guiding protrusions formed on and protruding inward from the inner surface of the inner flange at intervals;
- two outer guiding protrusions formed on and protruding inward from the inner surface of the outer flange at intervals;
- two first guiding blocks formed on and protruding from the external surface of the rail segment between the flanges, the inner guiding protrusions and the outer guiding protrusions at intervals;
- two second guiding blocks formed on and protruding from the external surface of the rail segment between the flanges, the inner guiding protrusions, the outer guiding protrusions and the first guiding blocks;
- a first rail formed in the rail segment of the rail mount between the guiding blocks and the inner flange;
- and
- a second rail formed in the rail segment of the rail mount between the guiding blocks and the outer flange and communicating with the first rail;
- and
- a positioning ball rotatably mounted between the ball channel of the rotating mount and the rails of the rail mount between the inner guiding protrusions, the outer guiding protrusions, the first guiding blocks and the second guiding blocks.