Zipper Teeth Using NPR Foam for Stronger Interlocking
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Solution Overview
Problem
Conventional fasteners and closure devices, such as zippers, bottle caps, and rivets, lack the necessary structural properties to efficiently and securely fasten objects due to limitations in material properties, particularly in terms of Poisson's ratio, which affects their deformation and interlocking capabilities.
Innovation Solution
The use of negative Poisson's ratio (NPR) materials, either alone or in combination with positive Poisson's ratio (PPR) materials, in the construction of fasteners, such as zippers, bottle caps, and rivets, to enhance their structural integrity and interlocking performance through the incorporation of NPR foam materials, metal foams, and composite structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional positive Poisson's ratio materials are used in fasteners, then the fasteners can be manufactured with standard materials, but the fastening strength and interlocking capability are insufficient
Solution Approach 1:
The patent employs composite materials combining positive Poisson's ratio (PPR) and negative Poisson's ratio (NPR) materials to create fasteners with enhanced mechanical properties. The NPR material component provides exceptional strength, rigidity, and interlocking capability through its unique deformation characteristics, while the PPR material provides ease of manufacture and compatibility with standard manufacturing processes. This composite approach resolves the contradiction by achieving superior fastening strength through NPR material properties while maintaining manufacturability through the inclusion of conventional PPR materials.
2Reliability
If NPR materials are used to enhance fastening capability, then the interlocking performance improves, but the structural complexity increases
Solution Approach 1:
The patent applies local quality by incorporating NPR material specifically in critical regions of the fastener where interlocking performance is most needed, such as the engagement surfaces and load-bearing components. The fastener structure combines NPR material zones for enhanced interlocking with PPR material zones for structural support and manufacturing ease. This localized application of NPR material achieves superior interlocking performance without requiring the entire fastener structure to be complex, thereby resolving the contradiction between reliability and device complexity.
3Duration of action of stationary object
If NPR foam materials are used in fasteners, then the durability and stress resistance improve, but the manufacturing process becomes more complex
Solution Approach 1:
The patent employs preliminary action by pre-fabricating NPR material components with optimized geometries and properties before assembly into the final fastener. The NPR foam material is manufactured with specific cellular structures and mechanical properties in advance, then integrated with PPR material components through standardized joining processes. This preliminary preparation of NPR components allows for controlled manufacturing of the complex material while maintaining overall production efficiency, resolving the contradiction between durability and ease of manufacture.
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
The integration of NPR materials into fasteners improves their strength, durability, and fastening ability, enabling them to securely interlock and maintain their performance over time, even under stress or aging, by providing unique deformation characteristics that balance rigidity and elasticity.
Implementation Method 1
at least some of the zipper teeth comprise a negative Poisson's ratio (NPR) foam material having a Poisson's ratio of between 0 and −1
Implementation Method 2
Forming the zipper teeth from an NPR foam material comprises heating and compressing a positive Poisson's ratio (PPR) foam material to form the NPR foam material
Data Source
AI summary
The disclosure describes a zipper including two rows of zipper teeth, in which at least some of the zipper teeth include a negative Poisson's ratio (NPR) foam material having a Poisson's ratio of between 0 and −1, and a slider movably attached to one of the rows of the zipper teeth and configured to connect the two rows of zipper teeth when the slider is moved in a first direction and to disconnect the two rows of zipper teeth when the slider is moved in an opposite direction.