Orthotic Elbow Joint Locking Mechanism for Hemiparesis
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Solution Overview
Problem
Individuals with hemiparesis or hemiplegia face significant difficulties in performing everyday tasks due to weakened or paralyzed upper extremities, which require bimanual coordination and strength, often lacking the necessary muscular power to execute tasks like twisting jars or using utensils.
Innovation Solution
An orthotic device for the upper limb featuring a normally locked elbow and wrist joint that can be released via a lever or button on the distal forearm, allowing the non-paretic arm to configure the paretic arm for holding and movement, incorporating clutch mechanisms and a hand portion with elastic elements and powered actuators for assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the elbow joint is kept locked for stability, then the paretic arm can maintain position, but the user cannot reposition or configure the arm for different tasks
Solution Approach 1:
The elbow joint transitions from a static locked state to a dynamic unlocked state, allowing the arm to be repositioned when needed and stabilized when required. The joint can be unlocked by applying force to the cable mechanism, enabling temporary movement, then re-locked to maintain position.
Solution Approach 2:
A cable mechanism acts as an intermediary between the user's manual input and the elbow joint locking mechanism. The user pulls the cable to unlock the joint, and the joint automatically re-locks when the cable is released, providing controlled transitions between locked and unlocked states.
2Adaptability or versatility
If the orthotic device includes multiple joints and actuators for comprehensive assistance, then task performance capability improves, but device complexity increases
Solution Approach 1:
The orthotic device is divided into separate functional modules: an elbow joint mechanism with locking capability, a wrist joint with rotation freedom, and a hand portion with elastic elements. Each module can be independently controlled or adjusted, allowing comprehensive task assistance while maintaining manageable complexity through modular design.
3Ease of operation
If the release mechanism requires continuous grasping and squeezing to maintain free state, then the arm remains movable, but user fatigue increases
Solution Approach 1:
The elbow joint operates in periodic cycles of locking and unlocking. The user periodically unlocks the joint when repositioning is needed, then the joint automatically re-locks to maintain position without requiring continuous user effort. This transforms continuous action into periodic action, reducing fatigue.
Data Source
AI summary
An orthotic device includes an upper arm section for receiving an upper portion of an arm of a subject, a forearm section for receiving a forearm section of the arm, and at least one elbow joint rotatably coupling the upper arm section and the forearm section. In the orthotic device, the forearm section includes a release control operatively coupled to the at least one elbow joint, where the release control is configured to transition the at least one elbow joint from a restricted motion state to a free motion state when the release control is activated.