3D Printed Prosthetic Wrist Adaptive Grasp
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Solution Overview
Problem
Existing prosthetic systems for hand and wrist amputees often require power sources, increasing cost and complexity, and lack adaptive grasp functionality and customizable sockets.
Innovation Solution
A body-powered upper limb prosthesis fabricated primarily by 3D printing, utilizing a customized socket design and adaptive grasp mechanisms that allow for semi-independent finger movement and thumb rotation, eliminating the need for motors and incorporating a back-lock mechanism for secure object retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If motors and power sources are used to drive prosthetic hand and wrist functions, then functional articulation and gripping capability are improved, but cost and device complexity increase
Solution Approach 1:
The prosthetic hand utilizes the user's own body movements and muscle strength to power the gripping function. The cable-driven mechanism converts pulling motions from the user's arm into finger flexion, eliminating the need for external motors or power sources while maintaining functional capability
Solution Approach 2:
The patent replaces complex motorized mechanical systems with a simpler cable-pulley mechanism. Instead of using motors to drive finger movement, the system uses tensioned cables that translate user-applied forces directly into gripping motion, significantly reducing device complexity
2Adaptability or versatility
If motors and power sources are used to rotate the thumb member, then thumb rotation function is improved, but cost and device complexity increase
Solution Approach 1:
The thumb rotation mechanism is powered by the user's own arm movements through a cable-driven system. As the user flexes or extends their arm, the cable tension changes to automatically rotate the thumb into the appropriate position, eliminating the need for motors or power sources
Solution Approach 2:
The thumb rotation system is designed to be dynamic and adaptive, automatically adjusting thumb position based on real-time cable tension from user movement. This dynamic mechanism replaces static motorized control with a responsive, movement-driven system that reduces complexity
3Ease of manufacture
If standardized prosthetic sockets are used, then manufacturing ease is improved, but adaptability to individual user anatomy deteriorates
Solution Approach 1:
The prosthetic socket is customized to match the specific anatomical characteristics of each user's residual limb. By adapting the socket's shape, size, and structural features to local anatomical variations, the system achieves both ease of manufacture through modular design and high adaptability to individual users
4Device complexity
If body-powered mechanisms are used for finger movement, then device complexity is reduced, but grasp adaptability deteriorates
Solution Approach 1:
The prosthetic hand is divided into independent finger units, each capable of being actuated separately through individual cables. This segmentation allows the simple body-powered mechanism to achieve adaptive grasp by independently controlling each finger's position and movement in response to cable tension variations
Data Source
AI summary
Prostheses include a terminal device, a back-lock mechanism, a wrist, a limb-socket, and a harness system. The terminal device can be a five-fingered mechanical hand that provides a releasable adaptive grasp, and has independently flexible fingers. The limb socket can be 3D printed using a molded model of a remnant limb. The harness strap can encircle an unaffected limb and is coupled to the terminal device with a cable so that a user can control the terminal device. The harness system can include a 3D printed harness ring that couples to the cable.