Variable Stiffness Orthotic Flexible Member for Propulsion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current orthotics and ankle-foot orthoses lack effective force delivery systems that enhance biomechanical function and propulsion efficiency, particularly for individuals with impairments, as they primarily focus on replacing lost function rather than improving motion efficiency.
Innovation Solution
A flexible member made from unidirectionally aligned carbon fibers, pre-impregnated with epoxy resin, is designed to store and release energy, providing a desirable force profile that enhances propulsion by varying stiffness and flexibility across the foot, mirroring the natural gait cycle to amplify spring potential and propulsion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional foot orthotics are designed with equal or constant stiffness along their length to provide support, then structural stability is improved, but gait efficiency and propulsion are worsened
Solution Approach 1:
The orthotic device incorporates variable stiffness characteristics along its length, with different regions having different flexibility properties. The forefoot region is designed with greater flexibility to enhance propulsion during toe-off, while the rearfoot region maintains higher stiffness for structural support. This local differentiation of mechanical properties allows the device to simultaneously provide structural stability and improve gait efficiency by mimicking the natural compliance of the human foot.
Solution Approach 2:
The orthotic device transitions from a static, constant-stiffness design to a dynamic system that adapts its mechanical response throughout the gait cycle. The variable stiffness construction allows the device to be more compliant during loading response and mid-stance, then progressively stiffer during terminal stance and toe-off to maximize propulsion. This dynamic adaptation mirrors natural foot mechanics and improves overall gait efficiency.
2Reliability
If orthotic devices focus on substituting lost function with mechanical structures, then support and alignment are improved, but propulsion enhancement is worsened
Solution Approach 1:
The orthotic device utilizes changes in material and structural parameters along its length to achieve different functional zones. By varying the stiffness, thickness, and material composition from the rearfoot to the forefoot, the device maintains reliable support and alignment in the posterior regions while creating a progressive increase in flexibility toward the toe region. This parameter variation enables the device to deliver enhanced propulsion force during toe-off without compromising overall structural support.
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 flexible member effectively increases propulsion and plantarflexion rate, assisting impaired individuals and athletes by using the body's energy to enhance walking and running efficiency, improving balance and forward movement.
Implementation Method 1
The flexible member is made from unidirectionally aligned carbon fibers, pre-impregnated with epoxy resin, and is designed to store and release energy
Data Source
Figure 1~3
Figure 4A~4B
Figure 4C~4D
AI summary
Flexible members are provided that define (i) a toe platform region, (ii) a longitudinal arch pad region, (iii) a heel region, and (iv) a center axis; and include a plurality of fiber layers of varying lengths. The fiber layers each include a plurality of unidirectionally aligned fibers that are angled at between about 10° and 20° relative to the center axis such that the plurality of unidirectionally aligned fibers are angled medially from the heel region to the toe platform region. The flexible members may be used as orthotics, orthotic inserts or as an orthotic footplate that is joined with respect to a brace structure to function as an ankle foot orthosis. The flexible member improves biomechanical function, including biomechanical function of the foot, ankle and knee, and advantageously imparts propulsive force in connection with a user's gait by storing and releasing an individual's own energy to assist in walking and/or standing.