A paper straw 10 is comprised of an elongated paper tube 30 and a bending structure 20 composed in the tube 30. The bending structure 20 is comprised of a plural stiff part 21 and a plural soft part 22 alternately turn around thereof and make a tubular form. The paper tube is made from paper or the material made from plant. The stiff part 21 may have a large thickness and the soft part 22 may have a smaller thickness.

A corrugating machine for forming a flexible paper drinking straw by forming annular corrugations in a tube, including a plurality of corrugating elements and means for moving the tube against the corrugating elements. Each of the corrugating elements is spaced apart from each other in both a lateral direction and a forward direction. The corrugating machine includes an assembly spool and a drum mounted to a side of the assembly spool for rotation about a common axis. A mandrel is mounted to the drum for reciprocation into and out of the spool assembly, to carry the tube against the corrugating elements mounted in an arc defined about the common axis.

An apparatus and a method for shaping tubular elements (100), preferably made of paper, to make straws. In particular, a flexible shaped portion, defined by a succession of annular ridges and throats, is made on each tubular element (100) by means of internal shaping members (32) and external shaping members (35) mutually cooperating with each other.

A corrugating machine for forming a flexible paper drinking straw by forming annular corrugations in a tube, including a plurality of corrugating elements and means for moving the tube against the corrugating elements. Each of the corrugating elements is spaced apart from each other in both a lateral direction and a forward direction. The corrugating machine includes an assembly spool and a drum mounted to a side of the assembly spool for rotation about a common axis. A mandrel is mounted to the drum for reciprocation into and out of the spool assembly, to carry the tube against the corrugating elements mounted in an arc defined about the common axis.

A corrugating machine for forming a flexible paper drinking straw by forming annular corrugations in a tube, including a plurality of corrugating elements and means for moving the tube against the corrugating elements. Each of the corrugating elements is spaced apart from each other in both a lateral direction and a forward direction. The corrugating machine includes an assembly spool and a drum mounted to a side of the assembly spool for rotation about a common axis. A mandrel is mounted to the drum for reciprocation into and out of the spool assembly, to carry the tube against the corrugating elements mounted in an arc defined about the common axis.

A machine for forming a flexible paper drinking straw by forming annular corrugations in a tube includes a plurality of corrugating elements and means for moving the tube against the corrugating elements. Each of the corrugating elements is spaced apart from each other in both a lateral direction and a forward direction. The corrugating machine includes an assembly spool and a drum mounted to a side of the assembly spool for rotation about a common axis. A mandrel is mounted to the drum for reciprocation into and out of the spool assembly, to carry the tube against the corrugating elements mounted in an arc defined about the common axis.

Machine (10) comprising a feed unit (16) configured to feed a plurality of tubular elements, preferably made of paper, toward different working units (18, 19, 20, 21) configured to automatically carry out different workings on the tubular elements (12), including a deformation to make a bellows (13), a cut to make a pointed end (14), or an end cut obliquely, a bending in correspondence with the bellows and a packaging of each straw, the deformation being carried out before the cut.

Machine (10) to produce straws (11), preferably made of paper, comprising a feed unit (16) configured to feed a plurality of tubular elements, preferably made of paper, to different working units (17, 19, 20, 21) configured to automatically carry out different workings on the tubular elements (12), including at least one cut to make a pointed end (13), or an end cut obliquely, a deformation to make a bellows (14), a bend in correspondence with the bellows (14) and the packaging of each straw (11).

A drinking straw includes a cylindrical sidewall having a longitudinal axis and a flexible region formed in the sidewall. The flexible region including a plurality of segmented sections separated from each other by inward annular corrugations. Each corrugation has a height parallel to the longitudinal axis and a depth transverse to the longitudinal axis. The height of each corrugation is one and a half times greater than the depth of the corrugation.

A straw (1) made from paper or paper-like material and comprising a tubular body (3) having a circumference formed by a wall (5) surrounding a central axis and a bendable part extending axially along the central axis (6), wherein said bendable part comprises at least two corrugated profiles (8A-D) provided in the wall, and each corrugated profile comprises inward corrugations (9A-D) and outward corrugations (10A-D) being positioned one after the other in axial direction along the central axis, and a system and method to produce the straw.