Elastic Sheet Joining Layout for Fracture-Free Roller Drawing
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Solution Overview
Problem
The existing methods for manufacturing stretch sheets, where nonwoven fabrics are joined using a joint member, result in uneven rigidity leading to potential fractures when drawn between rollers, as the joint member creates areas of different tensile strength along the fabric.
Innovation Solution
A method involving a joining step where a first end of one nonwoven fabric is intermittently joined with the second end of another nonwoven fabric in a cross direction using double-sided tape or adhesive, with the joint length exceeding the drawing pitch of the rollers' teeth, to maintain consistent tensile strength and prevent fractures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a joint member is used to join nonwoven fabrics, then the nonwoven fabrics can be connected continuously, but the rigidity becomes uneven at the joint portion causing fractures during drawing
Solution Approach 1:
The patent removes the joint member from the system entirely and instead uses a self-sealing mechanism where the nonwoven fabric itself is heated to melt and bond the ends together, eliminating the source of rigidity unevenness while maintaining continuous supply capability
Solution Approach 2:
The patent changes the physical state of the nonwoven fabric by applying heat to melt the thermoplastic resin, transforming the fabric from a solid state to a molten state and back, enabling self-bonding at the joint portion without external joint members, thus maintaining uniform rigidity
2Strength
If the joint portion is made continuous in the cross direction, then the joining strength is improved, but the stress concentration increases causing fractures during drawing
Solution Approach 1:
The patent segments the joint portion into discrete locations along the conveyance direction while maintaining continuity in the cross direction, creating multiple small bonding points rather than one large continuous bond, which distributes stress and prevents concentration at any single point
Solution Approach 2:
The patent applies local heating only at specific joint portions rather than uniformly across the entire fabric, creating localized bonding zones with appropriate strength while leaving other areas unchanged, thus avoiding overall stress concentration
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for continuous drawing of nonwoven fabrics without fractures, maintaining high productivity and ensuring the stretch sheet's integrity by distributing stress evenly across the joint areas.
Implementation Method 1
the joint portion is joined by a double-sided tape or an adhesive
Data Source
Figure 1
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AI summary
A method for manufacturing a stretch sheet draw a nonwoven fabric 3 conveyed in a continuous state by teeth 51t, 52t formed on an outer circumferential surface of a pair of rotating rollers 51, 52 by passing the nonwoven fabric through a gap between the rotating rollers meshing with each of the teeth. The method includes a step of joining a first end of the first nonwoven fabric roll 11 and a second end of the other nonwoven fabric roll through a joint portion. The joint portion is arranged intermittently in a cross direction that crosses the conveyance direction.