C-Shaped Spring Prosthetic Leg Energy Storage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lower-leg prostheses with single energy-storing/releasing members lack sufficient vertical spring compliance and control over plantar and dorsiflexion, leading to an unnatural gait and discomfort during walking and other activities.
Innovation Solution
The use of elongated curved energy-storing/releasing members, such as C-shaped springs, operably connected to a prosthetic socket and footplate, with a modular design allowing for customization and adjustment, including a forward pivot point to enhance leverage and energy storage/release, mimicking natural foot mechanics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single energy-storing/releasing member is used in a lower-leg prosthesis, then the device complexity is reduced, but the vertical spring compliance and control over plantar/dorsiflexion are insufficient
Solution Approach 1:
The prosthesis divides the energy-storing/releasing function into multiple separate members (first and second energy-storing/releasing members) instead of using a single member. Each member can be independently configured with specific curvature, material properties, and dimensions to provide distinct compliance characteristics, thereby achieving sufficient vertical spring compliance while maintaining manageable device complexity through modular segmentation.
2Ease of manufacture
If conventional energy-storing/releasing members are used, then the manufacturing process is simple, but the gait appears unnatural and causes discomfort
Solution Approach 1:
The energy-storing/releasing members are configured with specific curved geometries (e.g., arc-shaped cross-sections, curved longitudinal profiles) that mimic the natural biomechanics of the human foot and ankle. This curvature enables the members to store and release energy in a manner that replicates natural gait mechanics, providing smooth transitions during walking while remaining manufacturable using conventional forming techniques for curved structural elements.
3Reliability
If multiple energy-storing/releasing members are used, then the control over plantar and dorsiflexion is improved, but the device complexity increases
Solution Approach 1:
Each energy-storing/releasing member is designed with locally optimized properties including specific curvature radii, thickness variations, material distributions, and attachment geometries tailored to their individual functional roles. This allows each member to contribute specifically to either plantar flexion or dorsiflexion control, achieving comprehensive control over footplate movements while keeping each individual member relatively simple in design and easy to manufacture.
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
This configuration provides a smooth and natural stride by effectively storing and releasing energy, offering improved control over footplate movements and comfort during various activities, while being adaptable to different patient needs and applications.
Implementation Method 1
two elongated curved energy-storing/releasing members (1, 2)... effectively storing and releasing energy... C-shaped springs
Data Source
AI summary
A prosthetic lower leg uses one or more generally C-shaped spring elements between the patient's socket and a footplate assembly. The respective connections between (a) those one or more elements and (b) that socket and that footplate can be configured to provide a lightweight and economic prosthesis that effectively mimics the feel and performance of a normal human foot. The prosthetic spring element is generally C-shaped, and can have a substantially constant thickness along its length, lending itself to being fabricated by automated processes such as filament winding. One or more of the generally C-shaped spring elements can be incorporated into other prostheses and/or other devices.