Multi-Layer Shoe Insole Structure for Flex and Penetration Resistance
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Solution Overview
Problem
Existing shoe insoles face issues with flexibility, durability, and recyclability, particularly in safety shoes, due to bonding across the entire surface leading to shear forces and limited reuse potential, and materials like metallic and composite insoles suffer from corrosion, flexibility, and environmental damage.
Innovation Solution
A multi-layered shoe insole with a layered structure featuring a forefoot, midfoot, and heel area, connected via a rigid connection allowing relative mobility between layers, primarily in the forefoot and heel areas, using non-metallic materials like fiber-reinforced composites, and a shell or coating for protection, enabling high flexibility, torsional rigidity, and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insole is made of fiber composite material to provide penetration resistance, then safety requirements are met, but flexibility is reduced and foot support is negatively impacted
Solution Approach 1:
The insole is divided into multiple layers (first layer, second layer, third layer) with different functions. The first and second layers provide penetration resistance, while the third layer provides flexibility and comfort. This segmentation allows each layer to optimize its specific function without compromising the others.
Solution Approach 2:
Different regions of the insole have different properties. The forefoot area has reduced bonding between layers to allow flexibility, while the heel area maintains stronger bonding for stability. This local differentiation resolves the contradiction between overall rigidity and local flexibility.
2Reliability
If the insole is made thicker to meet safety requirements, then penetration resistance is improved, but the shoe loses visual appeal and flexibility
Solution Approach 1:
The protective function is segmented into multiple thin layers rather than one thick layer. This achieves the required penetration resistance (meeting safety standards) while keeping the overall thickness minimal to preserve the shoe's visual appeal and flexibility.
3Reliability
If multi-layered insoles are used to counteract flexibility issues, then support is improved, but shear forces occur between layers and durability is reduced
Solution Approach 1:
The bonding between layers is not uniform throughout the insole. The bonding is reduced or absent in the forefoot area to allow natural flexion without generating shear forces, while maintaining adequate bonding in the heel area for stability. This local differentiation prevents delamination and improves durability.
Solution Approach 2:
The insole is designed to be dynamic rather than rigid. The layers are allowed to move relative to each other in the forefoot area during flexion, accommodating natural foot movement without creating damaging shear forces that would reduce durability.
4Reliability
If metallic material is used for the insole, then penetration resistance is achieved, but corrosion occurs and flexibility is reduced
Solution Approach 1:
The insole uses composite material construction with a first layer and second layer made of different materials. This combination provides penetration resistance equivalent to or exceeding metallic materials while avoiding corrosion. The composite structure integrates the advantages of different materials to resist both penetration and environmental degradation.
Data Source
Figure 1~2
Figure 3~4b
Figure 4c~5
AI summary
The invention relates to a multi-layered shoe insole (10) for incorporation into a shoe (1), in particular into the shoe sole (3), comprising a layer structure (10') with several layers (11) arranged one above the other, wherein the shoe insole (10) has a forefoot area (12), middle area (13) and heel area (14), wherein the middle area (13) is arranged between the forefoot area (12) and the heel area (14), characterized in that the several layers (11) are connected to each other via a fixed connection (15), in particular in the middle area (12), such that the several layers (11) in the forefoot area (12) and/or in the heel area (14) are movable relative to each other when bent.