Prosthetic Foot Leaf Spring Design for Natural Roll-Over
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Solution Overview
Problem
Existing prosthetic feet lack lateral roll-over movement and are often complex and costly, limiting their use in high-volume applications and areas with limited technical infrastructure, while also failing to provide a natural foot action on uneven terrain.
Innovation Solution
A prosthetic foot design featuring resilient forefoot and heel members with elongated curvilinear leaf springs and a unitary lower foot member, connected by elastomeric adhesive, allowing for energy storage and release while simulating natural foot movement without articulate spring members, and requiring minimal maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prosthetic feet incorporate articulate spring members to simulate natural foot action, then performance characteristics and comfort are improved, but device complexity and production cost increase
Solution Approach 1:
The prosthetic foot is divided into multiple independent leaf spring elements (forefoot leaves and heel leaves) that are stacked and connected. Each leaf spring acts as an independent articulating element, collectively providing the desired natural foot action without requiring complex mechanical joints. The segmentation allows simple individual components to achieve complex overall functionality.
Solution Approach 2:
The patent employs composite construction by stacking multiple leaf spring layers and connecting them with elastomeric adhesive material. This composite approach combines the flexibility of leaf springs with the damping properties of elastomeric material, achieving natural foot simulation through material composition rather than complex mechanical articulation.
2Reliability
If prosthetic feet use composite materials technology to improve performance characteristics, then mobility and comfort are improved, but lateral roll-over movement capability is lost
Solution Approach 1:
The leaf springs are designed with curved profiles and varying thicknesses that allow dynamic deformation in multiple directions. The elastomeric adhesive connections between leaves permit controlled relative movement, enabling the structure to adapt dynamically to lateral forces and terrain variations, providing roll-over movement capability.
3Ease of operation
If prosthetic feet incorporate multiple moving parts to simulate natural foot action, then comfort and performance are improved, but maintenance requirements and production cost increase
Solution Approach 1:
The elastomeric adhesive material provides self-damping and self-adjusting properties, automatically absorbing shocks and adjusting to loading conditions without requiring external maintenance. The leaf spring structure naturally returns to its original position after deformation, providing self-service functionality that reduces maintenance needs.
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 design provides improved roll-over movement and stability on uneven terrain, reducing production costs and maintenance needs while maintaining comfort and natural foot action, as demonstrated by a 14-15° adjustment when stepping on obstacles compared to 7° with previous designs.
Implementation Method 1
a resilient upper forefoot member extending forwardly and downwardly from the attachment unit through the ankle region towards the toe region, said forefoot member comprising at least one elongated curvilinear forefoot leaf spring
Implementation Method 2
The resilient upper forefoot member is connected to, and extends from the attachment unit through the ankle region towards the toe region, said forefoot member comprising at least one elongated curvilinear forefoot leaf spring
Implementation Method 3
The upper surface of the resilient lower foot member is attached to the forefoot member at said toe region and to the heel member in the heel region
Data Source
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AI summary
A prosthetic foot device (10) having a toe region (11), an ankle region (12) and a heel region (13), said device comprising - an attachment unit (14) configured to be connected to a coupling device and/or to stump of an amputee; - a resilient upper forefoot member (16) extending from the attachment unit (14) through the ankle region (12) towards the toe region (11), said forefoot member (16) comprising at least one elongated curvilinear forefoot leaf spring (17) and at least one longitudinally extending parting slot (20) dividing the toe region (11) in at least two parts: - a resilient heel member (22) extending from the attachment unit (14) through the ankle region (12) towards the heel region (13), said heel member (22) comprising at least one elongated curvilinear heel leaf spring (23); - a resilient lower foot member (25) attached to the forefoot member (16) at said toe region (11) and to said heel member (22) in the heel region (13), wherein said lower foot member (25) is laterally unitary along the longitudinal length thereof.