Prosthetic Hand Force Transfer Elements Using Composite Materials
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Solution Overview
Problem
Conventional manufacturing methods for prosthetic arms and hands are costly and difficult to scale for small batches, requiring specialized equipment and resulting in high production costs, while alternative methods like 3D printing offer lower strength materials.
Innovation Solution
A prosthetic apparatus comprising 3D-printed polymeric components and laser-cut or water-jet cut metallic components, where the 3D shapes resemble human hand digits and 2D shapes are rotatably engaged to form force transfer elements, enabling an adaptive grasp with a reduced weight and increased strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional manufacturing methods (molding or stamping) are used to produce prosthetic arms and hands, then strong parts can be produced, but the manufacturing cost is high and it is difficult to produce economically in small batch quantities
Solution Approach 1:
The prosthetic hand is divided into multiple separate components (digits, force transfer elements, connectors) that can be manufactured independently using different methods. This segmentation allows 3D printing to be used for complex polymeric parts while conventional methods are used for metallic components requiring high strength, enabling cost-effective small batch production without sacrificing overall structural integrity
Solution Approach 2:
The prosthetic hand combines multiple materials with different properties: polymeric materials (3D printed) for digits and body parts requiring flexibility and complexity, and metallic materials (conventionally manufactured) for force transfer elements requiring high strength. This composite approach allows each material to be used where it provides the most benefit, achieving both strength and cost-effectiveness
2Ease of manufacture
If additive manufacturing methods like 3D printing are used to produce prosthetic arms and hands, then lower-cost manufacturing is achieved, but the base materials have lower strength than conventional methods
Solution Approach 1:
Different regions of the prosthetic hand are assigned different materials based on their specific functional requirements. High-strength metallic materials are used locally in force transfer elements where strength is critical, while polymeric materials are used in digits and body parts where flexibility and complex geometry are more important. This local differentiation allows cost-effective 3D printing to be used where appropriate while maintaining high strength where needed
Solution Approach 2:
The design intentionally combines polymeric and metallic materials in a composite structure. The 3D printed polymeric components provide complex geometries and flexibility at lower cost, while conventionally manufactured metallic components provide high strength for force transfer. This composite material strategy resolves the contradiction between manufacturing cost and material strength
3Adaptability or versatility
If myoelectric arms with sensors and actuators are used, then more functions are provided, but the cost is higher than mechanical arms
Solution Approach 1:
The prosthetic hand incorporates dynamic elements such as movable digits, adjustable force transfer elements, and spring mechanisms that enable adaptive grasping. These dynamic features provide functional versatility without requiring expensive sensors and actuators, achieving adaptability through mechanical design rather than electronic control
Solution Approach 2:
The prosthetic hand uses passive mechanical elements like springs and flexible components that automatically adapt to grasping forces and object shapes without requiring active control systems. The force transfer elements and digit mechanisms self-adjust during operation, providing versatile function through self-regulating mechanical behavior rather than expensive electronic control
Data Source
AI summary
Low-cost prosthetic apparatus, methods, kits, and systems with improved force transfer elements are disclosed. For example, the prosthetic apparatus may comprise: a plurality of first components manufactured from a first material to define 3D shapes with exterior surfaces resembling digits of a human hand; and a plurality of second components manufactured from a second material to define 2D shapes that are rotatably engageable with the 3D shapes to define force transfer elements operable to close the digits around an object responsive to a pull force applied to the force transfer elements, wherein the first material is different from the second material. Methods for manufacturing and assembling prosthetic apparatus also are disclosed along with related kits and systems.