Asymmetric Cam Joint Support for Left-Right Leg Interchangeability
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Solution Overview
Problem
Existing knee joint movement support apparatuses require separate manufacturing for left and right legs, increasing costs and necessitating the purchase of both units even if only one side is needed, as they cannot be used interchangeably.
Innovation Solution
A joint support unit with a driving unit featuring a periphery cam, driver, first and second cam grooves, and cam pins that allow for rotational and sliding movements, enabling the same unit to be worn on both left and right legs by adjusting the cam pins' movement based on the stretched state of the links and switching bending directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate apparatuses are manufactured for left and right legs, then the followability to knee joint movement is improved, but the manufacturing cost increases and the device cannot be used interchangeably
Solution Approach 1:
The cam groove is designed with asymmetric geometry where the groove depth and shape differ at different angular positions around the cam perimeter. This asymmetric cam groove configuration enables the same driving unit to generate different motion characteristics for left and right leg applications, achieving proper knee joint followability on both sides without requiring separate apparatuses
Solution Approach 2:
The driving unit is designed with universal applicability to both left and right legs through the asymmetric cam groove mechanism. The single driving unit can adapt to both sides by utilizing the asymmetric cam groove geometry, eliminating the need for separate left and right specific apparatuses while maintaining proper knee joint movement support
2Reliability
If separate apparatuses are manufactured for left and right legs, then the knee joint movement support is optimized, but the device complexity and inventory requirements increase
Solution Approach 1:
The driving unit incorporates an asymmetric cam groove that enables a single unit design to serve both left and right leg applications. This universal design reduces the number of different unit types from two (left and right specific) to one, simplifying inventory management and reducing device complexity while maintaining optimized knee joint movement support
3Reliability
If the cam pin is moved while engaged with the cam groove, then the rotation center can be shifted to follow knee joint movement, but the driving mechanism becomes more complex
Solution Approach 1:
The cam mechanism merges the rotation center shifting function and the driving motion into a single integrated structure. The cam pin moving within the asymmetric cam groove simultaneously achieves both the rotation center shift and the driving action, eliminating the need for separate coupling units and simplifying the overall driving mechanism structure
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 solution allows for a versatile joint support unit that can mimic the movement of an actual knee joint, enabling use on both legs and reducing costs by eliminating the need for separate left and right units.
Implementation Method 1
a periphery cam (32), a driver (33) configured to move around a periphery of the periphery cam
Data Source
AI summary
To provide a joint support unit, etc. capable of being worn on both left and right joints. A joint support unit 20 includes a first link 21 worn on one end side of a knee joint, a second link 22 worn on the other end side of the knee joint, and a driving unit 30 configured to cause the first link 21 and the second link 22 to perform rotational movement, or to relatively perform rotational movement while moving a rotation center and to perform sliding movement.