Asymmetrical Mitre Angles in Hinged Lid Packs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional smoking article packs with hinged lids face issues with panel misalignment and delamination during manufacturing, leading to suboptimal sealing and increased opening force due to uneven mitre angles and sharp edges, which affect the pack's structural integrity and user experience.
Innovation Solution
A pack design featuring asymmetrical mitre angles between the lid and box edges, with a steeper angle on one side and a shallower angle on the other, along with an inner frame and projecting tabs for secure closure, and a method of manufacturing that aligns panels during folding to minimize misalignment and facilitate easier opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional symmetrical mitre angles are used in hinged lid packs, then manufacturing is simpler, but panel misalignment and delamination occur during manufacturing
Solution Approach 1:
The patent applies asymmetry by configuring different mitre angles on opposite sides of the pack. Specifically, the first mitre angle between the lid and box edges is different from the second mitre angle on the opposite side. This asymmetrical configuration compensates for manufacturing variations and panel misalignment that occur during the folding and assembly process, thereby improving panel alignment and preventing delamination.
2Reliability
If steep mitre angles are used on both sides, then sealing is improved, but opening force increases due to sharp edges
Solution Approach 1:
The patent applies local quality by making each side of the pack have different mitre angle characteristics optimized for its specific function. One side has a steeper mitre angle optimized for sealing reliability, while the opposite side has a shallower mitre angle optimized for reducing opening force and preventing sharp edges. This localized optimization allows each side to perform its specific function effectively without compromising the other.
3Reliability
If symmetrical projecting tabs are used, then closure is secure, but manufacturing and adjustment are less flexible
Solution Approach 1:
The patent applies asymmetry to the projecting tabs configuration, where tabs on opposite sides of the inner frame have different dimensions or positions. This asymmetrical tab configuration allows for adjusted closure security on each side to compensate for manufacturing variations and panel misalignment, providing both secure closure and manufacturing flexibility.
Data Source
AI summary
A pack (10) for smoking articles comprises a front wall (13) and a rear wall (14) connected by opposing side walls. The pack comprises a box portion (11) having an open end and a lid (12) hingedly connected to the box portion along a hinge line (19) on the rear wall of the pack and moveable to selectively open or close the open end. The lid (12) includes a front wall, a top wall, a rear wall and first and second opposing side walls. At least a portion of the lower edge of the lid front wall extends horizontally and parallel to the hinge line (19). An angle between the rear wall and a mitre defined where the lower edge of the first lid side wall abuts the box upper edge on a first side wall of the pack is greater than a corresponding angle between the rear wall and a corresponding mitre defined where the lower edge of the second lid side wall abuts the box upper edge on a second, opposite side wall of the pack (10). A method of manufacturing such a pack (10) is also disclosed.