Packaging box, tube, and blank, and method and apparatus for forming the same

A tube for forming a packaging box, comprising:

• a perimeter wall having a first layer and a second layer being mutually parallel and arranged for defining a void therebetween,
• wherein the perimeter wall is provided with a first fold line and a second fold line, the first and second fold lines connecting the first layer to the second layer at opposite ends of the first layer and the second layer,
• wherein the first fold line and the second fold line are mutually parallel,
• wherein a distance around the perimeter wall from the first fold line to the second fold line measured in a first plane perpendicular to the first and second fold lines in a first rotational sense is the same as a distance around the perimeter wall from the first fold line to the second fold line in the first plane in a second rotational sense, the perimeter wall being configured such that when the first layer and the second layer are relatively translated away from each other, the first fold line can be fully unfolded such that the perimeter wall has a continuous surface including the first fold line.

A contiguous blank for forming a packaging box, comprising:

• a contiguous portion for defining the perimeter wall of the packaging box, the contiguous portion having a first portion and a second portion,
• wherein the contiguous portion is provided with a first fold line connecting the first portion to the second portion at a first end of the first portion and a first end of the second portion and a second fold line connecting the first portion to a tab portion at the another end of the first portion,
• wherein the first fold line and the second fold line are mutually parallel, and are both mutually parallel to another end of the first portion, and
• wherein a distance along the contiguous portion from the first fold line to the second fold line measured in a first direction perpendicular to the first and second fold lines is the same as a distance from the first fold line to the second end of the first portion.