Telescopic tube of upper beam of vertical type venetian blind

Abstract

A telescopic tube of an upper beam of a vertical type Venetian blind includes a major/minor telescopic upper beam, two rows of sliding clamp blocks, two linkage actuated members, and two guide straps wherein the major/minor telescopic upper beam has opposite grooved guide tracks symmetrically extending inwards at the open bottom side thereon for the guide straps to be adapted therein, and the sliding clamp blocks are serially linked via X-shaped linking bars each pivotally joined to the others in linkage connection. The linkage actuated member, inverted U-shaped, is precisely bridged at the opposite grooved guide tracks thereon. When the two rows of the sliding clamp blocks are activated by the X-shaped linking bars, clamping parts of the sliding clamp blocks disposed at the front section of each row thereof are sequentially displayed at a movement slot of the linkage actuated member therein till a clamping part located at a retaining hole of an adjustment block therein is pulled to activate the linkage actuated member moving smoothly forwards therewith along the guide straps at the grooved guide tracks therein. Thus, pulling force is synchronically formed at both the front and middle sections of each row of the sliding clamp blocks, evenly unfolding the sliding clamp blocks of both the front and rear sections thereof at the same time and equidistantly display blades attached at the clamping parts thereof to achieve the overall beauty as well as the best sheltering effect of the vertical type Venetian blind thereof.