Composite Rivet Prosthetic Foot Assembly for Flexible Energy Return

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Solution Overview

Problem

Prosthetic feet often fail to provide a desired level of flexibility, stability, and energy return due to increased stiffness, which can lead to reduced mobility and potential injury in users.

Innovation Solution

The use of composite rivets to secure components of prosthetic feet, such as sole plates and keels, with unidirectional or bidirectional fiber layers, minimizing thickness and maintaining flexibility while providing enhanced stability and energy return, using carbon pre-preg and thermoset resin for securement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional metal components and composite materials are combined in prosthetic feet, then strength and durability are improved, but stiffness increases which reduces flexibility and natural gait

Engineering Contradiction:

ImprovestrengthVSAvoidflexibility

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent employs composite rivets made from carbon fiber reinforced polymer materials to replace traditional metal fasteners. These composite rivets provide sufficient structural strength to secure the keel to the sole plate while having lower stiffness characteristics compared to metal, thereby maintaining the flexibility and natural gait of the prosthetic foot.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If composite rivets are used to secure keel and sole plate, then flexibility is maintained, but connection strength may be insufficient

Engineering Contradiction:

ImproveflexibilityVSAvoidconnection strength

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

The rivets are constructed from composite materials, specifically carbon fiber reinforced polymer, which provide high strength-to-weight ratio and adequate connection strength while maintaining flexibility. The composite material properties allow the rivets to securely fasten the keel to the sole plate without transferring excessive stiffness to the forefoot area.

Inventive Principle:

Principle #40Composite materials

3Strength

If metal fasteners are used to attach keel and sole plate, then connection strength is sufficient, but thickness and weight increase

Engineering Contradiction:

Improveconnection strengthVSAvoidweight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent substitutes traditional metal fasteners with composite rivets made from carbon fiber reinforced polymer. These composite rivets achieve adequate connection strength between the keel and sole plate while significantly reducing the weight of the prosthetic foot, thereby improving overall performance and user comfort.

Inventive Principle:

Principle #40Composite materials

4Reliability

If rigid materials are used in forefoot area, then durability is improved, but natural gait and energy return are reduced

Engineering Contradiction:

ImprovedurabilityVSAvoidnatural gait

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The composite rivets provide sufficient durability for securing the structural components while their lower stiffness compared to metal allows the forefoot area to maintain natural flexibility. This enables the prosthetic foot to replicate the natural gait cycle and provide adequate energy return during the push-off phase.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS12575949B2Prosthetic/orthosis spring layer(s) with composite rivet(s)

Publication Date: 2026.03.17 CAMP SCANDINAVIA

AI summary

Composite materials with certain functional or securement parameters are provided herein. Layered composite prosthetic with spring layers and composite rivets are provided. Fiber reinforced layers are grouped into keel, sole plate or other component and these components are configured to provide a spring action for the prosthetic alone or in combination. One or more composite rivets are installed to secure components together.