Composite Ankle-Foot Orthosis for Balanced Stiffness and Flexibility
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Solution Overview
Problem
Existing ankle-foot orthoses (AFOs) lack sufficient support for both medial and lateral ankle portions, provide minimal foot support, are prone to material failure due to stiffness and flexibility imbalances, and have high manufacturing costs and variability.
Innovation Solution
Ankle-foot orthosis (AFO) constructed with a spiraling section using continuous fiber-reinforced thermoplastic composite (CFRTP) laminates, strategically embedded in a thermoplastic base material, allowing for injection molding to achieve balanced stiffness and flexibility, and enabling complex designs with adjustable features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If AFOs are made from hand lay-up carbon fiber to provide sufficient strength and flexibility, then the desired strength and flexibility are achieved, but the construction becomes tedious and expensive
Solution Approach 1:
The patent uses composite materials consisting of a thermoplastic matrix material combined with reinforcement elements (such as carbon fiber, glass fiber, or aramid fiber) to achieve the desired strength and flexibility. This composite construction allows for sufficient mechanical properties while enabling more efficient manufacturing processes compared to traditional hand lay-up methods.
Solution Approach 2:
The patent employs injection molding technology to manufacture the AFO, changing the manufacturing parameter from manual assembly to automated molding. This allows for consistent reproduction of complex geometries and reinforcement patterns without tedious hand construction, thereby improving manufacturing ease while maintaining strength requirements.
2Strength
If AFOs are made from compression-molded carbon fiber to be sufficiently stiff and strong, then strength and stiffness are improved, but flexibility is reduced and the AFO becomes prone to material failure
Solution Approach 1:
The patent uses composite materials consisting of a thermoplastic matrix material combined with reinforcement elements (such as carbon fiber, glass fiber, or aramid fiber) to achieve the desired strength and flexibility. This composite construction allows for sufficient mechanical properties while enabling more efficient manufacturing processes compared to traditional hand lay-up methods.
Solution Approach 2:
The patent applies reinforcement elements strategically at specific locations within the AFO structure where maximum strength and stiffness are required, rather than uniformly throughout. This localized reinforcement approach maintains overall flexibility while providing strength where needed, preventing material failure without compromising the AFO's dynamic performance.
3Strength
If thickening regions are added to provide strength at the interface between footplate and ankle strut, then material failure is prevented, but user discomfort and additional weight are created
Solution Approach 1:
The patent uses composite materials consisting of a thermoplastic matrix material combined with reinforcement elements (such as carbon fiber, glass fiber, or aramid fiber) to achieve the desired strength and flexibility. This composite construction allows for sufficient mechanical properties while enabling more efficient manufacturing processes compared to traditional hand lay-up methods.
Solution Approach 2:
The patent applies reinforcement elements strategically at specific locations within the AFO structure where maximum strength and stiffness are required, rather than uniformly throughout. This localized reinforcement approach maintains overall flexibility while providing strength where needed, preventing material failure without compromising the AFO's dynamic performance.
4Ease of operation
If complex shapes such as spiraling sections are added to extend from footplate to posterior portion, then anatomical support is improved, but balancing stiffness and flexibility becomes difficult
Solution Approach 1:
The patent uses composite materials consisting of a thermoplastic matrix material combined with reinforcement elements (such as carbon fiber, glass fiber, or aramid fiber) to achieve the desired strength and flexibility. This composite construction allows for sufficient mechanical properties while enabling more efficient manufacturing processes compared to traditional hand lay-up methods.
Solution Approach 2:
The patent employs injection molding technology to manufacture the AFO, changing the manufacturing parameter from manual assembly to automated molding. This allows for consistent reproduction of complex geometries and reinforcement patterns without tedious hand construction, thereby improving manufacturing ease while maintaining strength requirements.
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 AFO offers improved durability, flexibility, and reduced manufacturing costs while allowing for customizable fit and enhanced support, addressing material failure and manufacturing inefficiencies of traditional AFOs.
Implementation Method 1
constructed with a spiraling section using continuous fiber-reinforced thermoplastic composite (CFRTP) laminates, strategically embedded in a thermoplastic base material
Implementation Method 2
allowing for injection molding to achieve balanced stiffness and flexibility
Data Source
AI summary
An ankle-foot orthosis forming a monolithic structure and include at least two different material components. The first material component has at least one tape layer consisting of a continuous fiber-reinforced thermoplastic composite, and a second polymeric material component surrounds at least in part the tape and includes a thermoplastic material into which the first material component is embedded. A resin material of the first material component is bonded to the second polymeric material component.