Bidirectional Prosthetic Finger With Adjustable Ring Tendon
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Solution Overview
Problem
Current prosthetic finger solutions lack the necessary functionality and design flexibility to accommodate varying lengths of residual fingers, providing limited dexterity and grip strength, and often require external power sources or are bulky and impractical.
Innovation Solution
A bidirectional biomechanical prosthetic finger assembly featuring a metacarpophalangeal (MCP) pivot, an adjustable ring tendon, and a multiple-finger ring that allows for vertical and lateral movements, mimicking natural finger articulation, and is adjustable to fit any length of residual finger, enabling maximum dexterity and grip strength without external power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a passive prosthetic finger is used, then the appearance is realistic, but the functionality is limited or non-existent
Solution Approach 1:
The prosthetic finger uses the user's own residual finger and adjacent fingers to drive the articulation mechanism. The ring tendon is actuated by the user's natural finger movements, eliminating the need for external motors or power sources. The system serves itself by converting biological motion into prosthetic motion through direct mechanical coupling.
Solution Approach 2:
The ring tendon acts as an intermediary element that transfers force and motion from the user's residual finger and adjacent fingers to the distal coupler. This tendon-based transmission mechanism converts the user's natural finger movements into controlled articulation of the prosthetic finger, enabling bidirectional motion without complex actuation systems.
2Ease of operation
If a motorized prosthetic finger is used, then functionality is restored, but external power sources and bulkiness are required
Solution Approach 1:
The system eliminates external power sources by using the user's own finger movements to drive the articulation mechanism. The residual finger and adjacent fingers directly actuate the ring tendon, which transmits force to the distal coupler, creating a self-powered articulation system that converts biological energy into mechanical motion.
Solution Approach 2:
The patent replaces motorized actuation systems with a purely mechanical tendon-based transmission system. The ring tendon serves as a flexible mechanical link that transfers forces from the user's fingers to the prosthetic articulation mechanism, eliminating the need for motors, batteries, or electronic control systems.
3Adaptability or versatility
If a fixed prosthetic finger design is used, then manufacturing is simplified, but adaptability to varying residual finger lengths is poor
Solution Approach 1:
The ring is designed with longitudinal adjustment capability, allowing it to be dynamically repositioned along the distal coupler to accommodate different residual finger lengths. This adjustment mechanism enables the same prosthetic design to adapt to various amputation levels and user anatomies without requiring custom manufacturing for each case.
Solution Approach 2:
The prosthetic finger design incorporates universal adjustability features that allow it to fit multiple users with different residual finger lengths. The ring's adjustable positioning system enables a single prosthetic model to serve multiple users across different amputation levels, eliminating the need for custom-made prosthetics for each patient.
4Ease of operation
If a body-powered prosthetic finger is used, then no external power is needed, but design flexibility and dexterity are limited
Solution Approach 1:
The prosthetic finger is divided into functionally independent segments: the MCP pivot for lateral movement, the articulation assembly with ring tendon for vertical movement, and the distal coupler for tip articulation. This segmentation allows each component to be optimized for its specific function while maintaining overall design flexibility and adaptability to different user needs.
Solution Approach 2:
The system incorporates dynamic adjustment capabilities through the adjustable ring that can be repositioned along the distal coupler. This dynamic feature allows the prosthetic to adapt to varying residual finger lengths and user anatomies while maintaining full bidirectional articulation capability, enhancing both dexterity and design flexibility simultaneously.
Data Source
AI summary
The disclosure provides apparatus and methods of use pertaining to a bidirectional biomechanical prosthetic finger assembly. One embodiment includes a metacarpophalangeal (MCP) pivot configured for swivelable attachment to a hand of a user, a distal coupler, and an articulation assembly rotatively coupled therebetween. A multiple-finger ring configured to receive a user's residual finger and at least one adjacent finger is disposed upon the articulation assembly, and may be adjusted to a target location based on a length of the residual finger. The articulation assembly is configured to utilize vertical movements of the residual and/or adjacent finger(s) within the multiple-finger ring to articulate the distal coupler within a plane parallel to an x-z plane, and the MCP pivot is configured to utilize lateral movements of the residual finger within the ring to articulate the distal coupler within a plane parallel to an x-y plane. Other embodiments are also disclosed.