Cigarette Pack Lid Flap Alignment via Linear Fold-Line
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Solution Overview
Problem
Conventional cigarette packs with curved lower lid edges face difficulties in creating a double layer flap due to the impossibility of folding a flap about a curved edge, leading to misalignment and an unacceptable appearance.
Innovation Solution
A pack design featuring a lid with a lower front wall edge that includes a linear fold-line formed by partial cutting, allowing the flap to align properly with the remainder of the edge, and a body with a matching upper edge profile for a flush closure, incorporating a curved and linear section closure line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a curved lower lid edge is used to provide an aesthetically pleasing closure line, then the visual appearance of the pack is improved, but it becomes impossible to fold a flap about the curved edge to create a double layer for structural strength
Solution Approach 1:
The lower lid edge is segmented into two distinct portions: a curved portion for aesthetic appearance and a straight portion for functional flap attachment. This segmentation allows each portion to serve its specific purpose - the curved portion provides visual appeal while the straight portion enables proper flap folding and double layer creation for structural strength.
Solution Approach 2:
Different portions of the lower lid edge are given different geometric qualities - the curved portion optimizes for aesthetics while the straight portion optimizes for structural function. This local differentiation allows the pack to achieve both visual appeal and structural integrity without compromise.
2Ease of manufacture
If a crease is used to form the fold-line for the flap, then the manufacturing process is simplified, but the flap may misalign or create steps relative to the adjacent curved edges resulting in a visually unacceptable appearance
Solution Approach 1:
The fold-line is pre-formed with a straight configuration that extends from the curved portion of the lower lid edge. This preliminary straight section provides a reliable reference line for flap attachment, ensuring that the flap folds precisely and aligns perfectly with the curved edges, eliminating misalignment and step formation while maintaining ease of manufacture.
3Area of stationary object
If the fold-line is positioned close to the curved lower edge to maximize the flap area, then the double layer coverage is improved, but the flap becomes difficult to fold and align properly with the curved edge
Solution Approach 1:
The fold-line transitions from a curved configuration (which would follow the curved edge) to a straight configuration (introducing a linear dimension). This dimensional change simplifies the folding operation while the fold-line remains positioned close to the curved edge, maximizing flap area coverage. The straight fold-line acts as a linear approximation that maintains proximity to the curve without requiring complex curved folding.
Data Source
Figure 1
Figure 2~3
AI summary
A pack for smoking articles comprising a lid (9) and a body (2) formed from a material having a thickness is disclosed. The lid has a front wall (13) with a lower front wall edge and a flap (17) attached to a portion of said lower front wall edge by a fold- line (17a) formed by partially cutting through the thickness of the material so that, when the flap is folded about said fold- line so as to lie against an inner surface of the lid front wall, said portion of the lower front wall edge to which the flap is attached is aligned with the remainder of the lower front wall edge.