Patent ID: 8337375

Claim:
An apparatus for making a tube having a polygonal cross-section with at least one sheet band, the apparatus comprising: a shaft extending along a longitudinal axis, comprising a free end and rotatable about the longitudinal axis, the shaft being configured to rotate about the longitudinal axis to take up at least one sheet band to form a tube around the shaft, the shaft comprising a plurality of edges extending along the longitudinal axis such that the at least one band is wound around the plurality of edges to form a tube having a polygonal cross-section, the shaft comprising: a shaft body extending along the longitudinal axis, a first belt mechanism supported by the shaft body and comprising pulleys and a first belt looped over the pulleys to form a first circulation loop of the first belt, wherein the first circulation loop comprises a first conveyor section extending along the longitudinal axis, wherein the first belt is configured to circulate along the first circulation such that a portion of the first belt passes the conveyor section, wherein the portion of the first belt is configured to frictionally engage with an inner surface of the tube and transfer the tube toward the free end during the passage of the conveyer section, a second belt mechanism supported by the shaft body and comprising pulleys and a second belt looped over the pulleys to form a second circulation loop of the second belt, wherein the second circulation loop comprises a second conveyor section extending along the longitudinal axis, wherein the second belt is configured to circulate along the second circulation loop such that a portion of the second belt passes the second conveyor section, wherein during the passage the portion of the second belt is configured to frictionally engage with an inner surface of the tube and transfer the tube toward the free end during the passage of the second conveyor section; and a drive mechanism coupled to the shaft to rotate the shaft about the longitudinal axis and circulate the first and second belts; wherein a distance between the conveyor sections of the first and second belt mechanisms is adjustable for allowing the size of the tube's cross-section to be changed.