Stretch rod and a method and an apparatus for manufacturing hollow bodies using the stretch rod

摘要

The rod (1) has a crest (12) including a set of elevations and/or cavities (14) in a surface of the crest, opposite to a form of circular cylinder. The rod is in contact with a concave inner side of a preform at multiple areas that are separated from each other. The crest has a polygonal cross-section (17) perpendicular to a longitudinal axis of the rod, where the crest surface has regularly or irregularly arranged fingers (15). A maximum radial edge distance of the crest cross-section is larger than a radial edge distance of a cross-section of a remaining part of the rod without the crest. An independent claim is also included for a method for shaping a preform in a hollow body.