Prosthetic Knee Joint Axial Displacement for Natural Gait Flexion
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Solution Overview
Problem
Conventional prosthetic knee joints fail to replicate the natural human knee joint's ability to increase flexion with increased walking speed, leading to a non-physiological 'harder' gait as walking speed increases, requiring excessive hip muscle effort.
Innovation Solution
A prosthetic device with a distal prosthetic component that is displaceable along the knee joint axis, coupled with a force transmission device converting axial forces into flexion moments, and incorporating adjustable springs and dampers to mimic natural knee joint dynamics, including energy storage and sensor-controlled brakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional prosthetic knee joints are used, then the structure is simple, but the walking gait becomes non-physiological and requires excessive hip muscle effort as walking speed increases
Solution Approach 1:
The patent applies dynamics by making the distal prosthetic component displaceable along the knee joint axis through an axial force, converting linear displacement into rotational flexion moment about the knee joint axis. This dynamic mechanism allows the prosthetic knee to adapt its flexion behavior based on walking conditions, replicating the natural increase in knee flexion with increased walking speed, thereby reducing hip muscle effort while maintaining a relatively simple overall structure
Solution Approach 2:
The patent changes the parameter of knee flexion angle dynamically by converting axial displacement of the distal component into rotational flexion moments. The force transmission device transforms the linear movement parameter into angular rotation parameter, enabling the knee joint to achieve variable flexion angles that match natural gait patterns across different walking speeds
2Adaptability or versatility
If the distal prosthetic component is made displaceable with force transmission device, then natural knee joint dynamics are mimicked, but the device complexity increases
Solution Approach 1:
The patent introduces a force transmission device as an intermediary mechanism between the distal prosthetic component and the knee joint axis. This intermediary converts axial forces acting on the distal component into flexion moments about the knee joint axis, enabling natural knee joint dynamics and adaptability to different walking conditions without requiring complex motorized or electronically controlled systems
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 a more natural and less effortful walking gait by supporting flexion and extension movements, mimicking human knee joint behavior with adjustable resistance and energy assistance, reducing the need for excessive hip muscle engagement.
Implementation Method 1
the prosthetic knee joint can be assigned an energy storage device for storing flexion energy
Implementation Method 2
The prosthetic knee joint can be assigned damping devices
Data Source
AI summary
The invention relates to a prosthetic device for a lower extremity having a prosthetic knee joint having: an upper part, on which a proximal prosthetic component is arranged; a lower part, which is connected to the upper part so as to be pivotable about a knee joint axis; and a distal prosthetic component, on which a prosthetic foot is formed or can be attached, wherein the distal prosthetic component is mounted so as to be displaceable in the direction of the knee joint axis by means of an axial force acting in the longitudinal extent of the distal prosthetic component and a force transmission device is associated with the knee joint, which force transmission device, during the standing phase, converts a displacement or length change of the distal prosthetic component in the direction of the knee joint axis into a flexion moment about the knee joint axis.