Upper Arm Prosthetic Force Amplifier for Smaller Users
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Body-powered prosthetic hands are often difficult for smaller humans, including children and women, to operate due to size and strength limitations, and they may not fit properly as users grow, leading to premature abandonment.
Innovation Solution
An upper arm prosthetic system incorporating a force amplification apparatus and an adjustable elbow apparatus, both made from 3D printable structures, which includes a support wearable on the partial arm to amplify input forces and transfer them to a terminal unit, enabling easier operation of a prosthetic hand with adjustable components for better fit and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If body-powered prosthetic hands are designed for standard adult sizes, then they provide adequate strength and functionality for adults, but they become difficult to operate and cause premature abandonment by smaller users including children and women
Solution Approach 1:
The prosthetic hand incorporates adjustable components including an adjustable elbow apparatus with variable flexion angles and a terminal unit with adjustable finger digit configurations. These dynamic adjustments allow the same prosthetic device to adapt to different user sizes and strengths, making it operable by both smaller users (children, women) and larger users (adults) without requiring size-specific customization
Solution Approach 2:
The prosthetic system allows modification of key parameters including elbow flexion angle, finger digit length, and gripping force characteristics. By changing these parameters, the prosthetic can be optimized for different user profiles - smaller users can adjust to reduced leverage requirements while maintaining adequate gripping strength, and larger users can adjust for increased leverage capacity
2Ease of operation
If prosthetic hands are made smaller to fit children and smaller adults, then they may be easier to operate for these users, but they reduce the gripping strength and functional capabilities needed for effective use
Solution Approach 1:
The prosthetic incorporates adjustable finger digit mechanisms that allow smaller users to configure the terminal unit with appropriate digit lengths and articulation points. The adjustable elbow apparatus enables optimization of leverage ratios - smaller users can adjust to configurations that maximize mechanical advantage, thereby achieving adequate gripping strength without requiring oversized components that would compromise ease of operation
3Ease of manufacture
If prosthetic hands are designed with fixed sizes, then they are simpler to manufacture and maintain, but they cannot accommodate user growth in children or body changes in adults, leading to premature abandonment
Solution Approach 1:
The prosthetic hand is divided into modular segments including a separate adjustable elbow apparatus and a terminal unit with independently adjustable finger digits. This segmentation allows individual components to be adjusted or replaced without redesigning the entire prosthetic, enabling accommodation of user growth and body changes while maintaining manufacturing simplicity through standardized modular interfaces
Solution Approach 2:
The prosthetic incorporates adjustable mechanisms that allow post-manufacturing configuration changes. The adjustable elbow apparatus permits modification of flexion angles, and the terminal unit allows adjustment of finger digit configurations. These dynamic adjustment capabilities enable a single manufactured design to serve users throughout growth and body changes, eliminating the need for complete redesign or replacement
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 system allows smaller users to operate prosthetic hands more effectively by amplifying input forces and accommodating growth, enhancing the usability and longevity of the prosthetic devices.
Implementation Method 1
a force amplifier rotatably engaged with the support and configured to receive input forces from an input member engageable with a harness wearable on the body, amplify the input forces into output forces
Implementation Method 2
The force amplifier may be rotatable relative to the support during the operative movements to maintain a generally linear alignment between the input member and the force amplifier
Data Source
AI summary
Various aspects of upper arm prosthetic system for a human subject having a body and a partial arm are described. According to one aspect, the system may comprise any one or more of a force amplification apparatus, a terminal unit apparatus, and/or an adjustable elbow apparatus. Each apparatus may be body-powered and/or comprise 3D printable structures. Related upper arm prosthetic apparatus, kits, methods, and systems also are described.