Abstract: The present invention relates to a telescopic drinking straw or double sucking tube in which a synthetic resin tube section having a smaller diameter is inserted into a synthetic resin tube section having a larger diameter. In the sucking tube, a flange which is in tight contact with the inner surface of the larger tube section is formed on the smaller tube section, while a convex portion supporting the smaller tube section is formed on the inside of the larger tube section. Both the larger and smaller tube sections are produced from materials having different compositions from one another, so that leakage of fluid from a joint portion of the larger and smaller tube sections as well as shaky motion of the smaller tube section are prevented by these arrangements.

Abstract: A two-stage type of freely elongatable sucking pipe comprising a larger-diameter pipe (e.g. for use as a drinking straw) member and a smaller-diameter pipe member inserted in the larger-diameter pipe member wherein the larger-diameter pipe member has a smaller diameter at the tip thereof to be brought into close contact with the outside surface of the smaller-diameter pipe member and/or the smaller-diameter pipe member has an expanded tip kept in close contact with the inside surface of the larger-diameter pipe member, the larger-diameter pipe member being made of a propylene type of polymer having a melt flow index of 7 to 14 g/10 min and stiffness of 10000 to 13000 kg/cm.sup.2, and the smaller-diameter pipe member being made of polypropylene homopolymer having a melt flow index of 7 to 14 g/10 min and stiffness of at least 13500 kg/cm.sup.2.

Abstract: A double-pipe combining device comprising a revolver, at least one pipe combining means arranged on the outer surface of the revolver, and at least one cam mechanism, the pipe combining means comprising a first pipe receiving means, a second pipe receiving means, and a slidable pipe pusher, the cam mechanism being arranged to move the pipe pusher forward and backward within one rotation of the revolver, the double-pipe combining device being arranged to automatically combine the larger-diameter pipe and smaller-diameter pipe, through the reciprocating movement of the pipe pusher, only by placing those pipes respectively in the two pipe receiving means and rotating the revolver.