Patent ID: 8511133

Claim:
An expander for tubular elements, comprising: a first head member, having a first end and an opposite second end, a protruding first conical face being formed at the second end, external diameters of the first conical faces are reduced from the first end to the second end, a first threaded hole being formed on the first head member and extending from the first end to the second end, a plurality of restriction slots being formed on the first conical face, the restriction slots being spacedly arranged on the first conical face around an extending direction of the first threaded hole; a rotating portion, a protruding second conical face being formed at an end of the rotating portion, a threaded rod section in a predetermined length being formed and extends away from the rotating portion from a tip of the second conical face, the threaded rod section being inserted through the first threaded hole from the second end of the first head member, the first head member being screwed with the threaded rod with the first threaded hole so that the first conical face and the second conical face face each other; a plurality of expanding members, being arranged around the threaded rod section and being sandwiched between the first conical face and the second conical face, a first inclined face and a second inclined face being formed on two ends of an inner face of each expanding member respectively, the first inclined face abutting against the first conical face, the second inclined face abutting against the second conical face so that a face of each expanding member opposite to the threaded rod section is parallel to a longitudinal direction of the threaded rod section, a rib being formed on the first inclined face of each expanding member, the rib being slidably disposed in one of the restriction slots so that each expanding member is unable to rotate relative to the first head member; at least one tightening structure, disposed on the expanding members so that the expanding members tend to approach the threaded rod section; wherein when the rotating portion is rotated to reduce a distance between the first head member and the rotating portion, the expanding members are pushed outward by the first conical face and the second conical face to move away from each other; wherein the longitudinal direction of the threaded rod section defines a longitudinal axis, a summation of lengths of the first conical face and the second conical faces along the longitudinal axis is larger than a length of each expanding member along the longitudinal axis.