Prosthetic Knee Four-Bar Linkage Stability Gait
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current prosthetic knees lack tailored solutions for high-activity users, particularly athletes, as they compromise between stability and dynamic performance, leading to suboptimal gait and increased risk of injury during athletic activities like sprinting and running.
Innovation Solution
A multi-axial prosthetic knee with a four-bar geometry and adjustable swing control mechanism, including a flexion stop and block lock, provides enhanced stability and dynamic behavior, allowing for improved gait characteristics and energy storage for efficient sprinting and running, along with an extension lock for fatigue management and audio feedback for user orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a simple non-articulable leg is used, then maximum stability is achieved, but ideal gait and knee flexion during stance and swing phases are not provided
Solution Approach 1:
The prosthetic knee employs a multi-axial articulation mechanism with a four-bar linkage that enables dynamic movement during stance and swing phases while maintaining stability. The knee joint can flex and extend along multiple axes, providing natural gait characteristics while preserving structural stability through the geometric constraints of the four-bar mechanism.
2Reliability
If walking prosthetic knees are used by athletes, then basic stability is provided, but performance and durability are compromised
Solution Approach 1:
The prosthetic knee incorporates adjustable parameters including flexion stops at different angles, variable damping characteristics, and modifiable four-bar linkage dimensions. These adjustable parameters allow optimization for athletic performance while maintaining stability, enabling the same device to adapt to different activity levels and user requirements.
3Device complexity
If a prosthetic knee without load bearing in flexed position is used, then simplicity is maintained, but forward propulsion from starting blocks is lost
Solution Approach 1:
The four-bar linkage mechanism is designed to bear load in flexed positions, enabling the prosthetic leg to support body weight and generate forward propulsion during the start phase from blocks. The geometric configuration allows force transmission through the linkage while maintaining the ability to flex and extend, providing both structural integrity and athletic capability.
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 prosthetic knee offers improved stability and performance for high-activity users by optimizing knee stability and dynamic behavior, reducing the risk of injury and enhancing athletic performance through adjustable features and energy storage mechanisms.
Implementation Method 1
The energy from the flexion (bending of the knee), the angular kinetic energy from a shank portion of the prosthesis is stored in the flexion stop, providing a powerful and fast extension of the shank portion
Implementation Method 2
A friction pad presses against the friction shaft... increases the friction force on the friction shaft, and slow down rotation of the knee just before full extension is reached
Data Source
AI summary
A prosthetic knee for active users has a locking head generally parallel to a vertical axis of the prosthetic knee, a chassis, and a plurality of links connecting the locking head to the chassis. The knee includes a swing control mechanism having a flexion stop connected to the chassis and arranged to control the flexion angle of the knee. The flexion stop extends outwardly from the chassis and obliquely relative to the vertical axis. The knee has an audible feedback mechanism for providing the user with information about the location of the knee. The knee may also have a block lock forming a manually activated mechanism allowing load bearing in a flexed position.