Interfolded Paper Sheet Stack With Starter Fold for Easy Unfolding
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Solution Overview
Problem
Existing stacks of folded paper sheets, such as tissue paper, do not allow for optimal unfolding when withdrawn from a dispenser, as they only double in size along the parallel folding lines used for interfolding, resulting in a less than ideal opening and gripping experience.
Innovation Solution
The implementation of a stack of folded paper sheets with a starter fold formed by a first folding line and additional folding lines that intersect to create a more stable and easily unfoldable configuration, allowing sheets to expand to more than double their original size after withdrawal, while maintaining a small footprint and ease of interfolding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If sheets are folded along three folding lines to achieve 1/4 size reduction, then the stack footprint is reduced, but the sheets only unfold to double their size when withdrawn
Solution Approach 1:
The folding process is segmented into distinct stages: first folding along the longitudinal centerline to create the starter fold, then folding along two parallel transverse folding lines for interfolding. This segmentation allows the starter fold to serve its gripping function while the parallel folds enable compact stacking, resolving the contradiction between compact footprint and easy unfolding.
Solution Approach 2:
The solution introduces a third dimension of unfolding by having the sheet unfold not only along the two parallel transverse folding lines but also along the longitudinal starter fold. This multi-directional unfolding in different dimensions allows the sheet to expand to more than double its folded size, overcoming the limitation of single-dimensional unfolding.
2Reliability
If parallel folding lines are used for interfolding, then consecutive sheets can be interfolded, but the sheet opening is perceived as less than optimum
Solution Approach 1:
The starter fold is created in advance by folding along the longitudinal centerline before the sheets are stacked and interfolded. This preliminary action ensures that when a user grasps the protruding starter fold and withdraws the sheet, the sheet is pre-configured to unfold along multiple lines, providing optimal opening without requiring additional manual manipulation.
3Area of stationary object
If the stack is made compact with reduced footprint, then storage and dispensing space is reduced, but gripping and unfolding becomes more difficult
Solution Approach 1:
The starter fold is extracted as a separate functional element that protrudes from the compact stack. By taking out this gripping portion from the main folded body, the design allows users to easily grasp the protruding starter fold without needing to manipulate the entire compact stack, thus maintaining ease of gripping while preserving compact footprint.
Data Source
AI summary
A stack of paper sheets, particularly for use as dispenser napkins, includes a plurality of folded sheets. Each folded sheet is folded along a first folding line so that a part of a free edge opposite to the first folding line is located on an outer surface of the folded sheet and inward of the outer peripheral edges of the folded sheet, whereby a starter fold is formed. Each folded sheet is further folded along a second folding line non-parallel to the first folding line, the second folding line separating the folded sheet in two panels connected at the second folding line. Two consecutive folded sheets are interfolded so that one panel of one folded sheet is disposed between two panels of the consecutive folded sheet. Also, a method for manufacturing such a stack and folding the sheets included in the stack as well as a dispenser containing such a stack are disclosed.