Dual-Arm Support with Dynamic Force Transmission for Shoulder Motion
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Solution Overview
Problem
Existing arm support devices are complex, restrictive, and fail to accurately mimic the natural movements of the shoulder joint, particularly during falls or when lifting heavy objects, leading to potential injuries and reduced user comfort.
Innovation Solution
A device with force transmission elements that can move relative to a counter bearing element, allowing for translational and rotational degrees of freedom, and a passive actuator that applies force based on arm position and orientation, using mechanical energy storage systems like springs or elastic elements, integrated into a flexible mounting system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixed joints are used to precisely align joint axes with shoulder joint axes, then support accuracy is improved, but freedom of movement is restricted and injury risk increases during falls or unexpected movements
Solution Approach 1:
The force transmission elements are made movable relative to the counter bearing element, allowing dynamic adjustment during operation. This enables the device to adapt to unexpected movements such as falls while maintaining precise support during normal arm movements, resolving the contradiction between fixed alignment precision and dynamic freedom of movement
2Adaptability or versatility
If multiple joints and connecting frame elements are used to enable various shoulder movements, then movement capability is improved, but device size and structural complexity increase
Solution Approach 1:
The device is divided into independent functional modules: arm support elements with individual force transmission elements, each connected to the counter bearing element through movable connections. This segmentation allows each component to perform its specific function independently, reducing overall structural complexity while maintaining full movement capability
Solution Approach 2:
The movable force transmission elements serve multiple functions: they provide precise force transmission during controlled arm movements, allow unexpected movements during falls, and enable various shoulder joint motions. This multi-functionality eliminates the need for separate mechanisms for each movement type, reducing device complexity
3Use of energy by moving object
If passive actuators with mechanical energy storage are used to support arm weight, then energy efficiency is improved, but device complexity and potential hazard during falls increase
Solution Approach 1:
The passive actuators are combined with movable force transmission elements that can dynamically release stored energy during unexpected movements. This allows the system to maintain energy-efficient support during normal use while safely accommodating falls and unexpected movements, reducing injury risk
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 natural and unrestricted arm movements, including circumduction, while providing support against gravity, reducing the risk of injury and enhancing user comfort and acceptance by mimicking shoulder joint functionality without bulky structures.
Implementation Method 1
using mechanical energy storage systems like springs or elastic elements
Implementation Method 2
using mechanical energy storage systems like springs or elastic elements
Implementation Method 3
at least two force transmission elements that are configured to transmit a counter-force from one of the arm support elements to the counter bearing element
Implementation Method 4
at least one passive actuator that is configured to apply a force on at least one of the arm support elements
Data Source
AI summary
A device for supporting the arms of a user, has support elements for the user's arms, a counter bearing element, and a force transmission element connectable to the counter bearing element. The force transmission element and the arm supports are connected to each other by a joint and are moveable relative to each other about a swivel axis. A force application lever is connected to the joint and extends away from the joint. A passive actuator is connected at one end to the force transmission element and at another end to a point of application on the force application lever. The point of application is moveable on the force application closer to or further from the swivel axis of the joint.