Prosthetic Hand Palm Rotation With Self-Locking Wrist Joint
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Solution Overview
Problem
Existing prosthetic hands lack ergonomic solutions for adjusting the position of the palm and fingers, particularly in resisting rotation about a lateral axis and securely locking that position.
Innovation Solution
A prosthetic hand with a wrist joint that includes a locking member movable between unlocked and locked positions, allowing selective rotation and secure locking through engagement with an engagement part, featuring resilient biasing and discrete angular positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a wrist connector allows rotation of the prosthetic hand relative to the forearm, then the prosthetic hand can be adjusted in position, but the hand cannot securely hold its adjusted position
Solution Approach 1:
The wrist joint incorporates a dynamic locking mechanism that transitions between a locked state (when the locking member engages the engagement part) and an unlocked state (when disengaged). This allows the system to provide both adjustability during manipulation and stable position holding when locked, resolving the contradiction between ease of adjustment and reliability of position maintenance.
Solution Approach 2:
The locking member is resiliently biased to automatically engage with the engagement part when the palm part is rotated to certain angular positions, providing self-locking functionality. This eliminates the need for additional actuators or complex control systems, achieving reliable position holding through the inherent mechanical design while maintaining ease of manual adjustment.
2Reliability
If a locking mechanism is added to secure the palm position, then the hand can hold its adjusted position, but the device complexity increases
Solution Approach 1:
The locking member and engagement part are integrated into the existing wrist joint structure, combining the locking function with the rotational joint mechanism. The locking member is received within the wrist attachment part and engages with the engagement part that is coupled to the palm part, merging multiple functions into a unified structure that minimizes additional complexity.
Solution Approach 2:
The resilient biasing of the locking member provides automatic engagement and disengagement based on the rotational position of the palm part, eliminating the need for external actuators, motors, or complex control systems. The system uses the natural motion of the wrist joint to drive the locking mechanism, significantly reducing device complexity while maintaining reliable position holding.
3Reliability
If the locking member is resiliently biased to the locked position, then the hand automatically locks at discrete angular positions, but the ease of manual adjustment is reduced
Solution Approach 1:
The resilient biasing of the locking member creates a self-locking mechanism that automatically engages at discrete angular positions without requiring external actuators or complex control systems. The system uses the natural rotational motion of the wrist joint to drive the locking mechanism, providing automatic positioning while maintaining ease of manual adjustment through simple rotational input.
Solution Approach 2:
The resilient biasing of the locking member creates periodic engagement points at discrete angular positions during rotation. As the palm part rotates, the locking member periodically engages with the engagement part at specific angles, providing automatic locking at these discrete positions. This periodic action maintains reliability of positioning while allowing continuous manual adjustment between locked positions.
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 ergonomic adjustment and secure locking of the prosthetic hand's palm position, facilitating user convenience and stability.
Implementation Method 1
A resilient element may extend across an opening in the locking member. The resilient element may abut a shoulder of the wrist attachment part to resiliently resist and limit movement of the locking member.
Data Source
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AI summary
According to an aspect, there is provided a prosthetic hand comprising: a wrist attachment part configured for connecting to a wrist connector; a palm part, the palm part and wrist attachment part being rotatably coupled together to form at least part of a wrist joint; and at least one locking member configured to selectively engage a corresponding engagement part coupled to the palm part, wherein the locking member is movable between an unlocked position, in which the locking member and engagement part are disengaged and the palm part is free to rotate relative to the wrist attachment part, and a locked position, in which the locking member and engagement part are lockingly engaged and the palm part is rotatably locked relative to the wrist attachment part, wherein an end face of the locking member is configured to be flush with an end face of the wrist attachment part when the locking member is in the locked position and the end face of the locking member is configured to be proud of the end face of the wrist attachment part when the locking member is in the unlocked position.