Regenerative Shoe Midsole With Locked Leaf Spring Energy Return
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Solution Overview
Problem
Existing athletic footwear midsoles fail to efficiently capture and return energy during foot strikes, resulting in energy loss and suboptimal propulsion.
Innovation Solution
A regenerative midsole structure with an energy capture mechanism in the heel region and a connector transferring energy to a forefoot energy storage and release device, utilizing a leaf spring assembly and over-center linkage to store and release energy as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a traditional resilient foam midsole is used, then energy absorption and ground reaction force attenuation are provided, but energy return to the wearer is insufficient
Solution Approach 1:
The midsole is divided into functionally distinct segments: an energy capture mechanism in the heel region, a connector system, and an energy storage and release device in the forefoot region. This segmentation allows each component to perform its specific function optimally, with the heel capturing impact energy and the forefoot releasing it for propulsion
Solution Approach 2:
The energy capture mechanism in the heel region captures and stores impact energy during the heel-strike phase before the toe-off phase. This preliminary energy capture allows the system to have energy available for release when needed, improving propulsion efficiency without adding weight to the propulsive elements
2Loss of energy
If energy is stored in the forefoot region, then energy can be returned during toe-off, but the mechanism becomes more complex
Solution Approach 1:
The leaf spring assembly serves multiple functions: it stores energy when compressed by the connector during heel-strike, provides structural support to the forefoot region, and acts as the energy release mechanism during toe-off. This multi-functionality reduces the need for separate components, thereby managing complexity while achieving energy return
Solution Approach 2:
The over-center linkage mechanism automatically locks the leaf spring assembly in its compressed position after energy capture, and the trigger mechanism allows automatic release when the wearer applies sufficient forefoot pressure. This self-regulating behavior reduces the need for complex control systems
3Reliability
If an over-center linkage is used to lock the leaf spring assembly, then energy is held securely, but the mechanism complexity increases
Solution Approach 1:
The complex over-center linkage mechanism is extracted and positioned in a dedicated space within the forefoot region, separate from the main leaf spring assembly. This extraction allows the linkage to perform its locking function reliably while being contained in a specific zone, managing overall structural complexity through spatial organization
4Loss of energy
If a connector extends from heel to forefoot, then energy is transferred across the midsole, but the structure becomes more complex
Solution Approach 1:
The connector is designed with locally optimized properties: it is positioned and dimensioned to efficiently transmit compressive forces from the heel region to the forefoot region, with its geometry and material properties tailored to the specific loading conditions in each location along its length
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
Enhances energy return to the wearer, potentially exceeding 100%, improving propulsion and reducing energetic cost of running while minimizing impact stress and injury.
Implementation Method 1
an energy capture mechanism positioned in a heel region and elastically deformable under pressure of a heel-strike by the wearer
Implementation Method 2
The energy storage and release device has a leaf spring assembly movable between a first expanded position and a second compressed position
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A sole structure for a shoe is provided with a regenerative midsole having an energy storage and release device is provided with a leaf spring assembly movable between a first unloaded position and a second loaded position. A locking linkage cooperates with the leaf spring assembly to lock the leaf spring assembly in the second loaded position. The locking linkage cooperates with the leaf spring assembly so that as the locking linkage is moved to a locked position, the leaf spring assembly is moved to the second loaded position. A trigger is connected to the locking linkage. Actuation of the locking linkage based on a wearer input releases the locking linkage to an unlocked position and allows the leaf spring assembly to move to the first unloaded position and thereby return stored energy to the wearer.