Prosthetic Finger Mode Switching for Fine Grasping
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Solution Overview
Problem
Current prosthetic terminal devices either prioritize functionality or cosmetics, failing to provide both fine-motor grasping skills and aesthetic appeal, necessitating users to switch between different devices for various tasks.
Innovation Solution
A prosthetic finger with a fingertip terminal device featuring a main body and a distal gripper with two or more jaws that can open and close, allowing for a switch between gripping and flexion modes, powered by an actuation mechanism such as cables, chains, or wire claws, enabling both precise grasping and cosmetic appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional electric hands are used to achieve cosmetic appearance, then aesthetic appeal is improved, but fine-motor grasping capability deteriorates
Solution Approach 1:
The prosthetic finger is divided into two functional modes: a gripping mode where the terminal gripper jaws can open and close for fine-motor tasks, and a flexion mode where the main body can flex for cosmetic appearance and gross-motor control. This segmentation allows each mode to excel at its specific function without compromise.
Solution Approach 2:
The prosthetic finger incorporates a mode switch that dynamically transitions between gripping mode and flexion mode. In gripping mode, the PIP joint is locked and the terminal gripper is actuated for precision grasping. In flexion mode, the terminal gripper is locked and the main body can flex naturally for cosmetic appearance. This dynamic switching resolves the contradiction between cosmetic appearance and fine-motor capability.
2Adaptability or versatility
If multi-articulating hands are used to achieve conformal grasp and multiple grasp patterns, then adaptability is improved, but fine-motor grasping capability deteriorates
Solution Approach 1:
The prosthetic hand system segments functionality between the multi-articulating hand for gross-motor conformal grasp and the terminal gripper for fine-motor precision grasping. The terminal gripper with two or more jaws provides the precision needed for small objects, while the main body provides cosmetic appearance and gross-motor control.
Solution Approach 2:
The mode switch dynamically locks the PIP joint and terminal gripper in flexion mode to enable main body flexion for conformal grasp, then unlocks to allow terminal gripper actuation for fine-motor precision grasping. This dynamic transition resolves the contradiction between conformal grasp capability and fine-motor precision.
3Adaptability or versatility
If users switch between different terminal devices to perform variety of tasks, then task versatility is improved, but device complexity and user burden deteriorates
Solution Approach 1:
The prosthetic finger integrates multiple functions into a single device: it provides both cosmetic appearance through main body flexion and fine-motor grasping through terminal gripper actuation. The mode switch enables the same prosthetic finger to perform both gross-motor and fine-motor tasks, eliminating the need for users to physically remove and don different terminal devices.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables users to perform tasks requiring fine-motor skills, like tying shoes, while maintaining the gross-motor control and cosmetic appeal of multi-articulating hands, enhancing the utility of prosthetic devices in daily activities and work.
Implementation Method 1
The actuation mechanism is operable by applying and releasing tension to the interconnect element, which drives the tongs to open and close
Implementation Method 2
a distal segment pivotally attached to a distal end of the proximal segment, mimicking a human finger
Implementation Method 3
the lock is a joint lock which engages or disengages the proximal interphalangeal (PIP) joint
Data Source
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AI summary
A prosthetic finger includes a main body and a terminal gripper at an end of the main body for enabling fine-motor grasping skills. The terminal gripper has at least two tongs movable relative to one another. The prosthetic finger includes a gripping mode and a flexion mode. In the gripping mode, the tongs of the terminal gripper are able to move relative to one another while the main body is not able to flex, and in the flexion mode, the main body is able to flex while the at two tongs is not able to move relative to one another.