Liquid-Filled Elastic Midsole for Ankle Stress Reduction
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Solution Overview
Problem
Conventional running shoes with air-based cushioning systems inadvertently increase the stress on the ankle joint by returning stored energy as an additional force impulse, counteracting the intended goal of reducing musculoskeletal strain during running.
Innovation Solution
A multi-layer sole construction featuring a rigid outsole, an elastic midsole with an open-cell foam structure filled with a liquid medium and surrounded by a gas-tight skin, and optional insole padding, which absorbs and dissipates energy by shifting the medium from the heel to the ball area during gait, reducing stress on the ankle joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air-filled cushioning systems are used in the sole, then cushioning effect is improved, but stress on the ankle joint increases due to energy return
Solution Approach 1:
The patent replaces gas-filled air cushions with liquid-filled chambers (water, glycerin, or other viscous liquids) in the cushioning elements. The liquid medium provides cushioning through compression while its viscosity dissipates energy rather than returning it elastically, thereby reducing the harmful rebound effect on the ankle joint while maintaining reliable cushioning protection.
Solution Approach 2:
The invention changes the physical parameter of the cushioning medium from gas (air) to liquid (water, glycerin, or other liquids). This parameter change transforms the cushioning mechanism from elastic energy storage and return to viscous energy dissipation, eliminating the rebound impulse that stresses the ankle joint while preserving the cushioning function during impact absorption.
2Use of energy by moving object
If spring-like cushioning elements are used, then energy recovery is improved, but stress on the musculoskeletal system increases
Solution Approach 1:
The patent employs liquid-filled cushioning chambers instead of spring-like elastic elements. The liquid medium absorbs impact energy through compression and dissipates it via viscous flow, preventing the elastic rebound that would otherwise return energy to the musculoskeletal system and cause additional stress.
Solution Approach 2:
The invention converts the harmful elastic rebound effect into a beneficial energy dissipation mechanism. By using viscous liquids instead of elastic gases or springs, the previously harmful energy return is transformed into useful energy absorption and dissipation, protecting the musculoskeletal system while still providing effective cushioning.
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 solution effectively cushions the heel and forefoot, reducing the additional stress on the ankle joint by controlling the flow of the medium, thereby alleviating the burden on the musculoskeletal system during running.
Implementation Method 1
The open-cell structure of the elastic material allows the medium to shift within the midsole, thus absorbing some of the impact
Implementation Method 2
the damping effect can also be controlled by the viscosity of the liquid to be displaced within the foam structure
Data Source
Figure 1~3
AI summary
The invention relates to footwear, the sole of which has a multilayer structure, i.e. at least one outer sole (3), an optional inner sole, and an intermediate sole (2) that is made of an elastic material having an open cell structure which is provided with a gas-tight and liquid-tight outer skin and which is filled with at least one fluid medium.