Composite Shoe Plate With Progressive Stiffness for Turf Toe Protection
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Solution Overview
Problem
Existing footwear solutions for preventing turf toe and big-toe injuries, such as carbon-fiber shoe inserts and toe rocker soles, compromise flexibility and stability, leading to potential falls or reduced athletic performance.
Innovation Solution
A fiber-composite shoe plate with a progressive longitudinal bending stiffness (PLBS) characteristic, integrated into the midsole, which increases stiffness upon reaching a threshold bend angle, achieved through structural interference, anisotropic properties of fiber-composite materials, or material properties like bulk modulus, to provide enhanced protection without compromising flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid carbon-fiber shoe inserts with Morton's extension are used, then big toe hyperextension is prevented, but flexibility and athletic performance are reduced
Solution Approach 1:
The shoe plate employs a progressive stiffness mechanism where the effective stiffness increases with the degree of bending. At small bend angles (normal walking), the plate remains flexible. At large bend angles (hyperextension territory), the stiffness progressively increases to prevent injury. This dynamic stiffness adaptation resolves the contradiction between flexibility and protection.
Solution Approach 2:
The shoe plate's bending stiffness parameter changes progressively based on the bend angle. The structure transitions from a flexible state at low bend angles to a progressively stiffer state at high bend angles through geometric nonlinearities and material behavior, allowing the same structure to provide both flexibility and protection.
2Object-affected harmful factors
If rocker-style soles are used, then pressure under the ball of the foot is reduced, but gait is altered and risk of falls increases
Solution Approach 1:
The shoe plate provides localized protection specifically at the big toe region while maintaining normal sole geometry elsewhere. This localized approach prevents big toe hyperextension without altering the overall gait mechanics or forcing the wearer to adapt their walking pattern, thus avoiding the increased fall risk associated with rocker soles.
3Ease of operation
If softer, more flexible athletic shoes are used, then agility is improved, but stability for the forefoot is reduced
Solution Approach 1:
The shoe plate maintains flexibility during normal forefoot movement to preserve agility, but automatically increases its stiffness when the big toe approaches hyperextension angles. This dynamic response provides forefoot stability precisely when needed without compromising the overall flexibility and agility of the shoe.
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 shoe plate effectively prevents hyperextension of the big toe by increasing stiffness at a threshold bend angle, maintaining flexibility and stability, thus reducing the risk of injuries and enhancing athletic performance.
Implementation Method 1
Another approach is based on the anisotropic properties of fiber-composite materials. Consider that for an identical geometry, a composite beam having its fibers aligned in the force-loading direction will be significantly stiffer than a beam whose fibers are not so aligned
Implementation Method 2
One approach relies on structural interference. For this approach, features at the forefoot of the shoe plate are arranged so that once threshold bending/deflection is attained, further deflection cause the features to contact or otherwise interfere with one another
Data Source
AI summary
A shoe plate, which is integrated into footwear, is provided. The shoe plate is relatively less stiff up to a threshold degree of bending, at which point the shoe plate transitions to regime in which the shoe plate becomes relatively stiffer. This occurs at a location proximal to the forefoot of the shoe plate.