Prosthetic Foot Insert Spring System for Stability and Flexibility

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Prosthetic foot inserts face challenges in achieving a balance between good standing and walking properties while minimizing material load, as existing designs often compromise on stability and flexibility due to material constraints.

Innovation Solution

A prosthetic foot insert design featuring a roof spring and a rigid, convex base spring with a rear coupling element, allowing for three-point bending and improved elastic properties, along with a compact structure and adjustable coupling elements to distribute load effectively, utilizing less material while maintaining performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a rigid forefoot lever is used to improve standing stability, then standing properties are improved, but walking properties deteriorate due to reduced flexibility

Engineering Contradiction:

Improvestanding stabilityVSAvoidwalking flexibility

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The forefoot lever is designed with dynamic characteristics through the integration of the base spring and roof spring system. The base spring provides rigid support under tension for stability, while the roof spring extends forward to provide flexible adaptation during walking. This dynamic configuration allows the structure to transition between rigid and flexible states based on loading conditions, resolving the contradiction between standing stability and walking flexibility.

Inventive Principle:

Principle #15Dynamics

2Weight of moving object

If material load is reduced to minimize weight, then weight is reduced, but load-bearing capacity deteriorates

Engineering Contradiction:

Improveprosthetic foot weightVSAvoidload-bearing capacity

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The prosthetic foot employs a composite spring system combining the base spring and roof spring. The base spring, which is rigid under tension, works in conjunction with the roof spring to distribute and bear loads. This composite structure achieves high load-bearing capacity with reduced material usage by optimizing the functional contribution of each spring component rather than relying on a single heavy material.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The base spring is designed to be rigid under tension, changing its mechanical parameter based on the direction of force applied. This parameter change allows the spring to provide maximum strength when needed for load-bearing while maintaining a lightweight structure, effectively resolving the contradiction between weight reduction and load-bearing capacity.

Inventive Principle:

Principle #35Parameter changes

3Length of stationary object

If a continuous upper spring and continuous lower spring with continuous elastomeric join are used to reduce structural height, then structural height is reduced, but forefoot stiffness increases excessively

Engineering Contradiction:

Improvestructural heightVSAvoidforefoot stiffness

Core Design Contradiction:

Length of stationary objectVSStrength

Solution Approach 1:

The spring system is segmented into distinct functional components: the base spring for heel compliance and the roof spring for forefoot flexibility. This segmentation allows each component to be optimized independently - the base spring provides the necessary compliance with reduced height, while the roof spring extends forward to provide appropriate forefoot flexibility without excessive stiffness.

Inventive Principle:

Principle #1Segmentation

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 enhances load-bearing capacity and flexibility, allowing for better utilization of elastic properties with reduced material usage, achieving improved standing and walking characteristics.

Implementation Method 1

the elastic properties of the latter are better utilized

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

allows a three-point bending of the base spring

Methodology Applied

Scientific EffectBending: Deformation

Implementation Method 3

serves as a hinge point or hinge mechanism about which the base spring can swing

Methodology Applied

Scientific EffectHinge mechanism: Hinge

Implementation Method 4

about which the base spring can swing

Methodology Applied

Scientific EffectRotation:

Implementation Method 5

elastic bending inside the coupling element is provided

Methodology Applied

Scientific EffectElastic bending: Elasticity

Data Source

PatentUS10299942B2Prosthetic foot insert and prosthetic foot

Publication Date: 2019.05.28 OTTOBOCK SE & CO KGAA

AI summary

A prosthetic foot insert with upper attachment member, a roof spring extending forwards from the upper attachment means, and a base spring coupled to the roof spring at least two points. A rear coupling element is provided for supporting the base spring, and a free space is formed between the coupling element, the roof spring and the base spring. The base spring, in the heel area, protrudes rearwards as a free lever beyond the rear coupling element.