Powered Prosthetic Thumb Multi-Axis Motion for Natural Dexterity
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Solution Overview
Problem
Existing prosthetic thumbs do not provide a natural range of motion and dexterity, limiting the ability of amputees to perform daily tasks effectively.
Innovation Solution
A powered prosthetic thumb with a lower, middle, and upper assembly that allows for rotation about multiple axes, including a pinch axis and a lateral axis, utilizing mechanical connections and actuators to mimic the natural movement of a human thumb.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing prosthetic thumb designs are used, then the device complexity is reduced, but the range of motion and dexterity are limited
Solution Approach 1:
The prosthetic thumb is divided into three distinct assemblies: lower assembly (including mount and actuator), middle assembly (including rocker, coupler, and swaying chassis), and upper assembly (including digit). This segmentation allows each component to contribute to specific movements, enabling rotation about multiple axes (pinch axis, lateral axis, and intermediate axis) while maintaining manageable complexity through modular design.
Solution Approach 2:
The mechanism incorporates dynamic elements including a rocker that rotates about a rocker axis, a coupler that rotates about a clutch axis, and a swaying chassis that enables rotation about a lateral axis. These dynamic components work together to provide adaptive movement across multiple degrees of freedom, allowing the thumb to naturally adjust its position and orientation during grasping and manipulation tasks.
2Ease of operation
If existing prosthetic thumb designs are used, then the manufacturing cost is reduced, but the ability to perform daily tasks is limited
Solution Approach 1:
The prosthetic thumb includes a clutch mechanism that enables automatic lateral rotation of the upper assembly about the lateral axis. The system uses mechanical communication between the clutch, bevel gears, and actuator to achieve self-contained operation, reducing the need for complex external control systems while maintaining ease of operation for daily tasks.
Solution Approach 2:
The multi-assembly design provides universal functionality by enabling rotation about multiple axes (pinch axis for opening/closing, lateral axis for side-to-side movement, and intermediate axis for additional positioning). This multi-functionality allows a single device to perform various daily tasks including grasping, manipulating objects, and forming different hand positions, replacing what would otherwise require multiple simpler mechanisms.
Data Source
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AI summary
Features for a powered prosthetic thumb are described. The thumb provides for rotation of a digit that mimics the natural movement possible with a sound thumb. The thumb may attach to a full or partial prosthetic hand or socket on a residual limb. The thumb may include an upper assembly, including a prosthetic thumb digit, rotatably attached to a mount about a pinch axis and a lateral axis. The digit may rotate about only the pinch axis, only the lateral axis, or both the pinch and lateral axes simultaneously. A first actuator may actuate to cause rotation of the digit about the pinch axis. A second actuator may actuate to cause rotation of the digit about the lateral axis. The first and second actuators may be actuated together at appropriate speeds to cause rotation about both the pinch and lateral axes simultaneously. A swaying chassis may be rotatably connected with the upper assembly and a lower assembly about various offset axes to provide for rotation about the lateral axis.