Segmented Hand Prosthesis Drive with Elastic Force Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hand prostheses lack a natural appearance and effective functionality, as they often rely on rigid drive mechanisms that do not accurately replicate the complex movements of human fingers, leading to unnatural appearance and increased mechanical stress.
Innovation Solution
A hand prosthesis design featuring a chassis with articulated finger prostheses that utilize a force transmission unit allowing swiveling movements about multiple axes, incorporating a first drive in the chassis and a second drive within the finger prosthesis, with a pressure-yielding or flexurally elastic coupling to mimic natural finger movements and reduce mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid drive mechanism is used to move finger prostheses, then the mechanical strength and reliability are improved, but the natural appearance and movement accuracy deteriorate
Solution Approach 1:
The drive system is segmented into multiple independent drives (first drive in chassis, second drive in finger prosthesis) rather than a single rigid mechanism. This segmentation allows each drive to handle specific movement aspects independently, achieving both reliability and natural appearance through distributed control of complex finger movements.
Solution Approach 2:
The force transmission unit transitions from a rigid connection to a dynamic, flexible coupling that yields under pressure and is elastic under bending. This dynamic behavior allows the system to adapt to varying load conditions, maintaining mechanical reliability while enabling natural, compliant finger movements that improve appearance.
2Power
If a rigid coupling is used between drive and finger prosthesis, then the force transmission efficiency is improved, but the mechanical stress and damage risk increase
Solution Approach 1:
The force transmission unit's mechanical properties are changed to be pressure-yielding and bending-elastic. This parameter change allows the unit to transmit tensile forces efficiently (maintaining power transmission) while yielding under compressive loads (reducing stress), thus resolving the contradiction between force transmission efficiency and stress resistance.
Solution Approach 2:
The pressure-yielding characteristic converts harmful impact forces and overloads into beneficial elastic deformations. When excessive force is applied, the force transmission unit yields elastically instead of transmitting the full force to the drive, protecting the system while maintaining efficient force transmission during normal operation.
3Measurement precision
If a complex mechanism with central drive is used to replicate finger movements, then the movement accuracy is improved, but the device complexity and size increase
Solution Approach 1:
The complex finger movement control is segmented into multiple simple drives located at different positions (chassis and finger prosthesis). Each drive handles a specific aspect of movement with simple mechanics, avoiding the need for a complex centralized mechanism while achieving accurate replication of natural finger movements through coordinated action.
Solution Approach 2:
The drive system utilizes multiple spatial dimensions and locations rather than a single centralized drive. The first drive in the chassis and second drive in the finger prosthesis operate in different spatial positions, enabling complex three-dimensional finger movements through simpler individual drive mechanisms.
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 achieves a more natural appearance and improved functionality by allowing complex finger movements without increasing the prosthesis size or complexity, while minimizing mechanical stress through the use of a flexible force transmission unit that absorbs impact forces and ensures precise closing movements.
Implementation Method 1
the force transmission unit may comprise a cable, stranded wire or fiber via which the tensile forces are transmitted
Implementation Method 2
the force transmission unit has an elastomer component, by which it is possible to set the flexure or elasticity of the force transmission unit over a wide range
Implementation Method 3
For coupling the force transmission unit to the drive and the finger prosthesis, bearing bushings are embedded in the force transmission unit
Data Source
AI summary
A hand prosthesis includes a chassis and a finger prosthesis articulated to the chassis. A first drive is located in the chassis and is coupled via a force transmission unit to the finger prosthesis for moving the finger prosthesis about a first swiveling axis relative to the chassis. A second drive is located within the finger prosthesis and moves the finger prosthesis about a second swiveling axis relative to the chassis and relative to the first swiveling axis.