Sewn stack of absorbent sheets
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Solution Overview
Problem
Consumers seek easily accessible, aesthetically pleasing, and convenient absorbent sheet products for quick cleanup in home or work areas, requiring a dispensing format that combines functionality with home decor while being easy to manufacture and mount in various locations.
Innovation Solution
A stack of absorbent sheets with a first line of stitching for binding and a second line of unbalanced stitches for easy separation, using threads with different properties or tensions to facilitate individual sheet removal without perforations, allowing for rapid manufacturing and versatile mounting options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single line of stitching is used to bind sheets together, then the binding is simple and manufacturing is easier, but individual sheets cannot be easily separated from the stack
Solution Approach 1:
The single line of stitching is segmented into two distinct lines: a first line with balanced stitches for binding and a second line with unbalanced stitches for separation. This segmentation allows each line to serve a specific function, resolving the contradiction between binding simplicity and sheet separation ease.
Solution Approach 2:
Different local qualities are applied to different portions of the stitching line. The first line uses balanced stitches with equal thread tension for strong binding, while the second line uses unbalanced stitches with unequal thread tension for easy separation. This local differentiation resolves the contradiction by optimizing each stitching line for its specific purpose.
2Ease of operation
If perforations are added to individual sheets to enable separation, then sheet separation becomes easier, but manufacturing complexity and production time increase
Solution Approach 1:
The separation function is extracted from the sheet material itself (perforations) and transferred to the stitching mechanism (unbalanced second line of stitches). This eliminates the need for perforations in the sheets, maintaining ease of separation while simplifying manufacturing and increasing production speed.
Solution Approach 2:
The mechanical separation method of perforations is replaced with a stitching-based separation mechanism. The unbalanced stitches create a mechanical advantage that allows easy sheet removal without requiring physical perforations in the sheet material, thereby simplifying manufacturing.
3Strength
If balanced stitches are used throughout, then the binding is strong and uniform, but individual sheets cannot be easily removed from the stack
Solution Approach 1:
Symmetry is broken by introducing an asymmetric second line of stitches with unbalanced thread tension. While the first line maintains symmetric balanced stitches for strong binding, the second line uses asymmetric unbalanced stitches that create a weak point for easy sheet removal, resolving the contradiction between binding strength and sheet removal ease.
4Productivity
If double needle sewing apparatus is used to create two lines of stitching simultaneously, then manufacturing efficiency increases, but device complexity increases
Solution Approach 1:
Two stitching operations are merged into a single double needle sewing apparatus. The apparatus creates both the balanced first line and unbalanced second line of stitches in one pass through the sheet stack, increasing manufacturing efficiency while the complexity is managed through integrated design.
Data Source
AI summary
The invention relates to a stack of absorbent sheets, such as paper towels, toilet tissue, napkins, facial tissue and the like. The stack is sewn with a first line of stitching disposed adjacent to a first edge of the bound stack, such as the top edge. The stack further comprises a second line of stitches, which may be disposed adjacent to the first line of stitches. The second line of stitches comprises an unbalanced stitch to facilitate separation and removal of individual sheets.