Joint Assembly with Cam Profile and Elastic Body for Motion Assistance
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Solution Overview
Problem
There is a growing need for motion assistance devices that are wearable, provide long-lasting power, are lightweight, and offer limitless motion, particularly for seniors and patients with joint issues, as aging societies face increasing pain and inconvenience from joint problems.
Innovation Solution
A joint assembly that includes a profile ring with a cam profile, a rotor, and an elastic body, which stores elastic potential energy, and a binder that selectively couples the profile ring to either the rotor or a fixed ring, allowing for various operating modes such as passive, active, hybrid, and free modes, using both external power and elastic energy for assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a motion assistance device uses only external power source, then it can provide sufficient power, but it increases device complexity and reduces portability
Solution Approach 1:
The power system is segmented into two independent sources: an external power source (motor) and an internal energy storage element (elastic body). These segments operate independently but can be selectively combined through the binder mechanism, reducing overall system complexity while maintaining sufficient power output capability.
Solution Approach 2:
The joint assembly is designed with multi-functionality to operate in four distinct modes (passive, active, hybrid, free) by selectively engaging different power sources. The binder mechanism enables a single device to universally provide assistance through multiple operational pathways, eliminating the need for separate devices for each power source configuration.
2Duration of action of moving object
If a motion assistance device provides continuous power, then it can support long-duration use, but it increases weight and reduces portability
Solution Approach 1:
The device dynamically switches between power sources based on operational needs. The binder can selectively couple the profile ring to either the rotor (external power) or fixed ring (elastic energy), allowing the system to adapt its power delivery in real-time. This dynamic operation enables long-duration use by alternating between power sources rather than relying on a single heavy continuous power supply.
3Adaptability or versatility
If a motion assistance device allows limitless motion, then it enhances user freedom, but it reduces control precision and assistance effectiveness
Solution Approach 1:
The cam profile is designed with asymmetric geometry that provides different mechanical characteristics at different positions in the rotation cycle. This asymmetric design enables the device to provide precise controlled assistance during specific phases of motion (when the cam profile engages the roller) while allowing freer motion during other phases, thus achieving both control precision and motion versatility.
4Measurement precision
If a motion assistance device uses complex power transmission mechanism, then it can provide precise control, but it increases device complexity and manufacturing difficulty
Solution Approach 1:
The complex power transmission mechanism is extracted and replaced with a simple binder-coupling system. Instead of using sophisticated gear trains or clutch mechanisms, the invention extracts the essential function of selective power source engagement and implements it through a straightforward mechanical coupling that can be easily manufactured and assembled.
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
The joint assembly enables efficient and versatile motion assistance by varying the elastic potential energy based on the operating mode, providing effective support and power to users with joint issues, enhancing their mobility and reducing discomfort.
Implementation Method 1
an elastic body connected to the rotor, the elastic body configured to store an elastic potential energy in response to the rotor rotating relative to the profile ring such that the elastic potential energy corresponds to a shape of the cam profile
Implementation Method 2
a roller connected to the pressurizing portion, the roller configured to contact the cam profile with an elastic force generated by the elastic body
Implementation Method 3
a friction reduction member between a side surface of the elastic body and an inner surface of the cylinder hole, the friction reducing member configured to reduce friction between the elastic body and the rotor
Data Source
AI summary
A joint assembly may include a profile ring including a cam profile, a rotor configured to rotate relative to the profile ring, and an elastic body configured to connect to the rotor, and to store an elastic potential energy corresponding to the cam profile in response to the rotor rotating relative to the profile ring.