Abstract: A ladder drum for adjusting and regulating the angular orientation and closure of horizontal slats of a venetian blind, of the type incorporating ladder cords or tape ladders, having a polygonal profiled structure comprising a series of planar sidewalls defining a substantially hollow interior. The number of sidewalls defining the polygonal structure is greater than four sidewalls, and less than or equal to twelve sidewalls, with each adjacent plane sidewall having an internal angular orientation in the range of 90° to 150°. To enhance the uniform closure of the slats of a horizontal blind, the polygonal ladder drum is more preferably in the form of an uneven hexagon that is formed from injection molded plastics. The opposing top and bottom sidewalls are greater in dimension than the mediate sidewalls, and have attachment means to insert various widths of ladder tape. The mediate sidewalls have at least two opposing access slots to insert and retain ladder cords in a counter balanced relation.

Abstract: A side cover of a roller blind frame rail for closing an opening of a tail end of the roller blind frame rail. The side cover includes: a closing board as a main body, the closing board having a fixing rest shelf perpendicularly projecting from the closing board and positioned adjacent to an upper edge thereof, two vertical breaking flutes being respectively formed on two sides of an inner face of the closing board, the breaking flutes extending through the closing board from a lower edge of the closing board to the upper edge thereof; a locating post projecting from a center of the inner face of the closing board; and three insertion plates perpendicularly projecting from the inner face of the closing board. The three insertion plates are a transverse insertion plate and two vertical insertion plates.

Abstract: A ladder drum for adjusting and regulating the angular orientation and closure of horizontal slats of a venetian blind, of the type incorporating ladder cords or tape ladders, having a polygonal profiled structure comprising a series of planar sidewalls defining a substantially hollow interior. The number of sidewalls defining the polygonal structure is greater than four sidewalls, and less than or equal to twelve sidewalls, with each adjacent plane sidewall having an internal angular orientation in the range of 90° to 150°. To enhance the uniform closure of the slats of a horizontal blind, the polygonal ladder drum is more preferably in the form of an uneven hexagon that is formed from injection molded plastics. The opposing top and bottom sidewalls are greater in dimension than the mediate sidewalls, and have attachment means to insert various widths of ladder tape. The mediate sidewalls have at least two opposing access slots to insert and retain ladder cords in a counter balanced relation.

Abstract: A ladder drum for adjusting and regulating the angular orientation and closure of horizontal slats of a venetian blind, of the type incorporating ladder cords or tape ladders, having a polygonal profiled structure comprising a series of planar sidewalls defining a substantially hollow interior. The number of sidewalls defining the polygonal structure is greater than four sidewalls, and less than or equal to twelve sidewalls, with each adjacent plane sidewall having an internal angular orientation in the range of 90° to 150°. To enhance the uniform closure of the slats of a horizontal blind, the polygonal ladder drum is more preferably in the form of an uneven hexagon that is formed from injection molded plastics. The opposing top and bottom sidewalls are greater in dimension than the mediate sidewalls, and have attachment means to insert various widths of ladder tape. The mediate sidewalls have at least two opposing access slots to insert and retain ladder cords in a counter balanced relation.

Abstract: A ladder drum for adjusting and regulating the angular orientation and closure of horizontal slats of a venetian blind, of the type incorporating ladder cords or tape ladders, having a polygonal profiled structure comprising a series of planar sidewalls defining a substantially hollow interior. The number of sidewalls defining the polygonal structure is greater than four sidewalls, and less than or equal to twelve sidewalls, with each adjacent plane sidewall having an internal angular orientation in the range of 90° to 150°. To enhance the uniform closure of the slats of a horizontal blind, the polygonal ladder drum is more preferably in the form of an uneven hexagon that is either formed from injection molded plastics or a metal die stamping. The opposing top and bottom sidewalls are greater in measurement than the remaining mediate sidewalls, with at least two opposing mediate sidewalls having attachment means to insert and retain ladder cords in a counter balanced relation.

Abstract: A side cover of a roller blind frame rail for closing an opening of a tail end of the roller blind frame rail. The side cover includes: a closing board as a main body, the closing board having a fixing rest shelf perpendicularly projecting from the closing board and positioned adjacent to an upper edge thereof, two vertical breaking flutes being respectively formed on two sides of an inner face of the closing board, the breaking flutes extending through the closing board from a lower edge of the closing board to the upper edge thereof; a locating post projecting from a center of the inner face of the closing board; and three insertion plates perpendicularly projecting from the inner face of the closing board. The three insertion plates are a transverse insertion plate and two vertical insertion plates.

Abstract: A Venetian blind includes a plurality of horizontal slats which are positioned at a predetermined distance vertically and a lifting and rotating control unit. Each of the slats includes a transversely extended central portion having a curved cross section, and two wing portions horizontally extended from and along two opposite transverse edges of the curved central portion. The lifting and rotating control unit includes a lift cord vertically extended through openings provided on the slats, two ladder cords vertically located at two transverse sides of the slats, and a plurality of cross rung cords separately located below the slats and connected at two ends to the two ladder cords, such that the cross rung cords each have two end portions in contact with lower sides of the two wing portions. With the above arrangements, the slats may be smoothly rotated in an effort-saving manner to overlap one another to provide effective light blocking function.