Dual-Hardness Outsole Wedge for Forefoot Pressure Reduction
Solution Overview
Problem
Conventional medical shoes with overly rigid soles require patients to walk in a specific manner to reduce weight-bearing pressure on affected areas, leading to non-compliance and delayed healing due to unintended pressure on the forefoot during toe-off phase.
Innovation Solution
A dual-hardness outsole with a front section, middle section, and rear section, where the middle section forms a wedge with a soft center and harder lateral portions, reducing pressure on the forefoot by distributing weight more evenly and providing cushioning and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an overly rigid sole is used in medical shoes to reduce weight-bearing pressure on the forefoot, then the structural stability is improved, but the patient compliance deteriorates due to unnatural walking requirements
Solution Approach 1:
The outsole is divided into regions with different hardness properties: a harder rear portion for stability during heel strike and midstance, and a softer forefoot portion that allows natural toe-off movement. This local differentiation maintains overall sole stability while permitting compliant walking patterns.
Solution Approach 2:
The patent changes the physical parameter of hardness across different regions of the outsole. By varying the hardness parameter from rear to forefoot, the shoe maintains structural stability where needed while providing compliance where natural movement is required, resolving the contradiction between stability and ease of operation.
2Stress or pressure
If a rigid sole with elevated forefoot is used during midstance phase, then the weight-bearing pressure on the forefoot is reduced, but the natural walking cycle is disrupted requiring toe-lifting
Solution Approach 1:
The outsole is segmented into distinct functional zones: a rear portion that remains elevated during midstance to protect the forefoot, and a forefoot portion that contacts the ground naturally during toe-off. This segmentation allows pressure reduction on the forefoot while maintaining natural walking mechanics.
Solution Approach 2:
The outsole design dynamically adapts to different phases of the gait cycle. During midstance, the rear portion is elevated to reduce forefoot pressure; during toe-off, the softer forefoot portion contacts the ground to enable natural propulsion. This dynamic behavior resolves the contradiction between pressure reduction and walking naturalness.
3Stress or pressure
If the rear area of the sole is made larger than the front area, then the weight-bearing pressure on the forefoot is reduced, but the shoe requires unnatural walking manner
Solution Approach 1:
The outsole employs local quality differentiation where the rear portion has greater surface area and harder material properties for weight bearing, while the forefoot portion has smaller area and softer properties for natural contact during toe-off. This resolves the contradiction by allowing pressure redistribution without forcing unnatural walking patterns.
Data Source
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AI summary
A dual-hardness outsole includes a front section, a middle section, and a rear section, at least the middle section of the outsole including a wedge having a bottom surface which extends below another bottom surface of at least one of the front and rear sections such that the wedge carries more weight than the other bottom surface. The outsole comprises a hard portion and a soft portion that are secured to each other and together form the wedge, a cross-sectional profile of the hard and soft density portions being such that a center portion of the wedge is softer than opposite lateral portions thereof.