Magnetic Prosthetic Attachment System for Rotation Control

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Solution Overview

Problem

Existing prosthetic attachment systems face challenges in providing a reliable and comfortable attachment method that prevents rotation and separation of the prosthesis from the residual limb, while minimizing weight, cost, and complexity, and ensuring safety and mobility.

Innovation Solution

The use of magnetic repulsive forces between implanted magnets and attachment magnets, specifically samarium cobalt or neodymium iron boron magnets, to retain and rotate the prosthesis on the extremity, with a mounting ring to manage the attachment flaps and prevent rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If magnetic repulsive forces are used to retain the prosthesis, then the attachment system becomes lightweight and comfortable, but the reliability of the attachment may be compromised

Engineering Contradiction:

Improveweight of attachment systemVSAvoidreliability of prosthesis attachment

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent implements a dual-magnet system where a first magnet is implanted in the bone and a second magnet is attached to the prosthesis. These magnets are positioned to create repulsive forces that prevent both separation and rotation of the prosthesis. The system includes multiple magnets arranged to provide redundant attachment points, ensuring that if one magnetic connection fails, others can maintain secure attachment. This beforehand cushioning through redundant magnetic connections resolves the contradiction between lightweight design and reliable attachment.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Stability of the object's composition

If magnets are used to prevent rotation of the prosthesis, then rotational control is improved, but the device complexity increases

Engineering Contradiction:

Improverotational control of prosthesisVSAvoidcomplexity of attachment system

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical rotational control mechanisms (such as hinges, locks, or adjustment devices) with a magnetic field-based system. By strategically positioning multiple magnets with specific polarities, the system creates magnetic repulsion forces that naturally prevent rotation of the prosthesis relative to the bone. This substitution of mechanical complexity with magnetic field control achieves rotational stability while maintaining a simpler overall device architecture.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a secure magnetic attachment is used to prevent separation, then the reliability of attachment is improved, but the ease of doffing the prosthesis may be compromised

Engineering Contradiction:

Improveattachment securityVSAvoidease of doffing prosthesis

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts the permanent attachment function from the magnetic system by implanting one magnet in the bone and making it permanent, while the other magnet is attached to the prosthesis and can be removed. This allows the user to easily detach the prosthesis by removing the second magnet from the prosthesis, while the implanted first magnet remains in place. This extraction of the permanent component to the bone and the removable component to the prosthesis resolves the contradiction between secure attachment and ease of doffing.

Inventive Principle:

Principle #2Taking out (Extraction)

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 solution provides a secure, comfortable, and lightweight attachment system that effectively prevents rotation and separation of the prosthesis, enhancing the user's control and mobility without adding unnecessary weight or complexity.

Implementation Method 1

at least one attachment magnet creating a repulsive force with an implanted magnet that retains said prosthesis on an extremity

Methodology Applied

Scientific EffectMagnetic repulsive force: Magnetism

Implementation Method 2

The prosthesis is rotationally controlled on the extremity by magnetic repulsive forces between an implanted non-linear anti-rotation magnet and an anti-rotation flap magnet

Methodology Applied

Scientific EffectMagnetic repulsive force: Magnetism

Data Source

PatentUS8632607B2Strapless prosthetic arm

Publication Date: 2014.01.21 ALFRED E MANN FOUND FOR SCI RES

AI summary

Permanent magnets or electromagnets or a combination of such magnets are provided to retain a prosthetic device on an extremity or limb, such as an amputated arm. The prosthesis utilizes the opposing forces, which are developed by virtue of like magnetic poles being in proximity to each other, to urge the prosthesis to remain attached to the extremity. The prosthesis is prevented from rotation by virtue of a centering force that is provided by an attachment magnet in the prosthesis being placed between two implanted magnets. A removable mounting ring is placed over the prosthesis to maintain it on the extremity.