Bidirectional Prosthetic Thumb With H-Shaped Rocker Articulation
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Solution Overview
Problem
The loss of a thumb or a thumb segment significantly impairs a person's ability to perform precise tasks and manipulate objects due to reduced control and dexterity, as existing prosthetic solutions fail to mimic natural thumb movements and provide adequate protection and customization.
Innovation Solution
A custom-designed, biomechanically driven prosthetic thumb assembly with an H-shaped rocker and cupped receiving tip that anchors to any length of residual thumb, mimicking natural flexion and extension movements, and is customizable to fit individual user anatomies, using materials like titanium and silicone to ensure comfort and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a prosthetic thumb assembly is designed to anchor to residual thumb, then it provides protection and stability, but it limits the range of motion and natural movement capability
Solution Approach 1:
The prosthetic thumb assembly is divided into multiple segments including a base portion, a movable portion, and a tip portion that can move independently relative to each other. This segmentation allows the distal phalanx to move independently from the proximal phalanx, replicating natural thumb joint movement while maintaining secure anchoring to the residual thumb through the base portion.
Solution Approach 2:
The prosthetic thumb assembly incorporates dynamic elements including a spring mechanism that provides resilient connection between the base portion and movable portion, allowing controlled movement and flexion. The movable portion can dynamically adjust its position and angle relative to the base, enabling natural-looking thumb motion while maintaining secure attachment.
2Ease of operation
If a prosthetic thumb assembly uses complex mechanical structures to enable bidirectional movement, then it improves dexterity and control, but it increases device complexity and difficulty of manufacture
Solution Approach 1:
The prosthetic thumb assembly utilizes the user's own residual thumb movements to actuate the prosthesis. The movable portion is connected through a spring mechanism that converts natural residual thumb motion into functional movement of the prosthetic tip, eliminating the need for complex external control systems or power sources.
Solution Approach 2:
A spring mechanism serves as an intermediary element between the base portion and movable portion, mediating the transfer of motion and force. This simple elastic intermediary enables complex bidirectional movement and dexterity without requiring complex mechanical linkages, motors, or control systems.
3Adaptability or versatility
If a prosthetic thumb assembly is customized to fit individual user anatomies, then it improves comfort and functionality, but it increases manufacturing time and cost
Solution Approach 1:
The prosthetic thumb assembly is designed as a universal device with adjustable components that can accommodate various residual thumb lengths and anatomies. The base portion, movable portion, and tip portion can be configured in different arrangements, and the spring mechanism can be adjusted to fit different user requirements, eliminating the need for complete custom manufacturing for each user.
Solution Approach 2:
The prosthetic assembly allows for parameter adjustments including the length of the movable portion, the stiffness of the spring mechanism, and the angle of articulation. These parameters can be modified to suit different user anatomies and functional requirements without requiring complete redesign or custom manufacturing, enabling customization through simple parameter changes.
Data Source
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AI summary
There is disclosed a biomechanically driven prosthetic thumb assembly (100). Embodiments include an H-shaped rocker (108) and a distal ring (104) configured to receive a user's residual thumb, the distal ring (104) and the rocker (108) each independently and rotatively coupled between a coupling tip (106) and a proximal anchor plate (102) configured for affixing to a hand strap (132) secured to a user. The coupling tip (106) is articulated in response to a pulling force of the H-shaped rocker (108). Additional embodiments include a bidirectional thumb assembly (200) including a ring (222) mounted upon an adjustable ring tendon (210) that is rotatively coupled between a coupling tip (214) and a proximal anchor plate (212), which is rotatively coupled with a hand strap (202) attached to the user. Vertical movement of the residual thumb (100, 200) within the ring (222) actuates the coupling tip (214) within a vertical plane. Lateral movement of the residual thumb within the ring (222) actuates the coupling tip (214) within a lateral plane. Other embodiments are disclosed.