Finger Motion Assist Mechanism With Constant-Radius Arm Path
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Solution Overview
Problem
Conventional wearable motion assistive devices for finger movement are bulky and heavy, imposing a significant burden on users due to their complex mechanisms and numerous parts.
Innovation Solution
A motion assistive device with a simplified mechanism comprising at least one arm, a connective member, an arm supporting mechanism, and arm driving means, allowing the arm to pivot while maintaining a constant distance from the center of pivot, with optional features like a stopper to restrict proximal phalanx movement and adjustable components for fit and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pivoting mechanism is provided for each joint of each finger, then finger joint movement can be assisted, but the device becomes heavy and complex
Solution Approach 1:
The patent combines multiple pivoting mechanisms into a single integrated mechanism. The arm supporting mechanism includes a base member that can be mounted on the back of the hand, and multiple arms that pivot relative to this base member. This merging of multiple independent mechanisms into one unified structure reduces the total number of parts while maintaining the ability to assist multiple finger joints simultaneously.
Solution Approach 2:
The base member serves as a universal support structure for multiple arms, each capable of assisting different finger joints. The single base member replaces multiple separate mounting structures, and the arms can be configured to work with different fingers, providing multi-functional capability with reduced component count.
2Reliability
If a pivoting mechanism is provided for each joint of each finger, then finger joint movement can be assisted, but the device becomes heavy
Solution Approach 1:
By merging multiple pivoting mechanisms into a single integrated arm supporting mechanism with a common base member, the total weight of the device is reduced. Instead of having separate heavy mechanisms for each finger joint, the patent uses one shared support structure that weighs less than the sum of multiple independent mechanisms.
3Measurement precision
If the arm pivots while maintaining constant distance between connective member and center of pivot, then precise finger motion is achieved, but the mechanism design becomes more constrained
Solution Approach 1:
The patent implements the constant distance constraint by designing the arm mechanism to rotate around a fixed center of pivot, creating a circular arc trajectory for the connective member. This curved path ensures that the distance from the center of pivot to the connective member remains constant during rotation, achieving precise and repetitive finger motion through geometric constraint rather than complex control mechanisms.
Data Source
AI summary
This motion assist device 100 assists with flexing and extending of fingers F1, F2 of a user, the motion assist device 100 comprising: at least one arm 10; at least one connection member 20 configured so as to be capable of connecting the at least on arm 10 to each of the fingers F1, F2; an arm support mechanism 30 that turnably supports the at least one arm 10, the arm support mechanism 30 being configured so as to be mountable on the back Hb of the hand H of the user; an arm drive means 40 that causes the at least one arm 10 to turn; and a stopper 50 that extends from the arm support mechanism 30, the stopper 50 being configured so as to restrict movement of the proximal phalanges of the fingers of the user by being in contact with the proximal phalanges. The at least one arm 10 is configured so as to turn while the distance Dr between the at least one connection member 20 and the turning center Cr of the at least one arm 10 is kept fixed.