Extensible Fastening Member with Stiffness Gradient
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Solution Overview
Problem
Wearable article fastening members, such as those in diapers, face issues with buckling, flipping, and tearing due to uneven force distribution and material stiffness, leading to suboptimal performance and comfort.
Innovation Solution
The design of fastening members with an integrally-formed construction, where the end region material is coextensive with the extensible zone, and the use of a stretch laminate with varying moduli of elasticity to manage tension forces and reduce buckling and tearing, along with a reinforced end region for increased tensile strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the panel region of the fastening member is made longer to maximize skin coverage and distribute forces, then comfort and appearance are improved, but the likelihood of buckling and flipping increases
Solution Approach 1:
The patent applies local quality by creating a stiffness gradient within the fastening member. The panel region has a first modulus of elasticity optimized for force distribution and skin coverage, while the tab member has a second, higher modulus of elasticity to resist buckling and flipping. This localized differentiation of material properties allows each region to perform its specific function optimally without compromising the other.
2Ease of operation
If the fastening member is made more extensible and pliable to improve comfort, then wearer comfort is enhanced, but the likelihood of buckling and flipping increases
Solution Approach 1:
The patent implements local quality by assigning different mechanical properties to different regions. The panel region contacting the wearer's skin is made highly extensible and pliable with a lower modulus of elasticity for comfort, while the tab member extending beyond the panel is made stiffer with a higher modulus of elasticity to maintain structural stability and prevent buckling during movement.
3Ease of operation
If a shorter tab member is used to allow easy grasping and placement, then ease of application is improved, but longitudinal force components concentrate creating buckling risk
Solution Approach 1:
The patent applies parameter changes by modifying the modulus of elasticity parameter of the tab member. By increasing the stiffness (second modulus of elasticity) of the tab member relative to the panel region, the structure can maintain a compact, easily graspable form while distributing longitudinal force components more effectively, thereby reducing buckling risk despite the shorter length.
4Reliability
If robust materials are used to prevent buckling and tearing, then durability is improved, but the material becomes stiffer and less comfortable against skin
Solution Approach 1:
The patent resolves this contradiction through local quality by using different material compositions or structures in different regions. The panel region uses softer, more compliant materials with lower modulus of elasticity for skin comfort, while the tab member uses more robust, stiffer materials with higher modulus of elasticity for durability and resistance to buckling and tearing.
5Shape
If the fastening member geometry is optimized for fit and force distribution, then fit quality is improved, but lateral tension forces create longitudinal force components causing buckling
Solution Approach 1:
The patent addresses this geometric contradiction by applying local quality through a bifurcated structure with differentiated stiffness. The panel region is optimized for fit and force distribution with appropriate geometry and lower stiffness, while the tab member extends perpendicularly with higher stiffness to counteract the longitudinal force components generated by lateral tension, preventing buckling while maintaining overall fit quality.
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 effectively reduces buckling, flipping, and tearing, enhancing the durability and comfort of fastening members while maintaining extensibility and pliability, thus improving the overall performance and appearance of wearable articles.
Implementation Method 1
the use of a stretch laminate with varying moduli of elasticity to manage tension forces and reduce buckling and tearing
Data Source
AI summary
A wearable article with an extensible fastening member having a fastener proximate its end is disclosed. The fastening member may be highly extensible, and may have construction features and shape characteristics that affect distribution of force components when the fastener is in use, and reduce the chances of buckling or flipping of the fastening member along its edges, and the chances that the edges of the fastener will be lifted away from a surface to which it is attached. The fastener and material forming an accompanying landing zone on the article may be selected to form a fastening combination having performance attributes that provide further resistance to unintended pop-off under wearing conditions.