Dynamic Force Hinge Joint for Knee Brace
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Solution Overview
Problem
Existing orthopedic knee braces fail to dynamically adjust lateral corrective force, applying consistent pressure throughout the range of motion, which is suboptimal as it does not account for the varying needs at heel strike and flexion.
Innovation Solution
A hinge joint with a condyle cam and driver system that telescopes to adjust the lateral corrective force, extending to apply pressure at heel strike and retracting during flexion, utilizing ramps and a return spring to facilitate this dynamic adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a static ratchet mechanism is used to adjust lateral corrective force, then the force can be adjusted to a fixed position, but the force remains constant throughout the range of motion and increases medial/lateral displacement
Solution Approach 1:
The patent transforms the static ratchet mechanism into a dynamic system where the condyle pad support automatically adjusts its position based on knee flexion angle. The condyle driver and condyle cam work together to create dynamic adjustment: as the knee flexes, the condyle driver rotates and moves the condyle pad support medially, reducing lateral corrective force; as the knee extends, the support moves laterally, increasing corrective force. This dynamic behavior adapts the brace to different phases of gait without requiring manual intervention.
Solution Approach 2:
The mechanism operates autonomously based on the natural motion of the knee joint. The condyle driver is connected to the hinge joint such that knee flexion and extension automatically drive the condyle pad support to appropriate positions. The return spring provides self-regulating force to maintain proper engagement and return the mechanism to its initial position after each cycle, eliminating the need for external control or power source.
2Reliability
If pressure is always applied through a hinge mechanism, then continuous support is provided, but pressure is applied even during flexion when it is not needed
Solution Approach 1:
The mechanism applies corrective force periodically rather than continuously. During the stance phase when the knee is extended or slightly flexed, the condyle pad support is positioned to apply lateral corrective force. During the swing phase when the knee is flexed, the support automatically retracts medially, eliminating pressure. This periodic application of force aligns with the physiological needs of the knee joint during different phases of gait.
Solution Approach 2:
The corrective force is applied locally only when and where needed. The condyle pad support can be independently positioned relative to the condyle, allowing force application specifically during extension while avoiding pressure during flexion. This localized control of force application prevents harmful pressure during phases when the knee does not require corrective intervention.
3Adaptability or versatility
If a telescopic connection is used for manual pad adjustment, then the pad height can be adjusted, but it requires manual intervention and does not dynamically adapt to knee position
Solution Approach 1:
The patent replaces the manual rotation handle and telescopic connection with a mechanically-driven system coupled to the hinge joint. Instead of requiring manual intervention to adjust pad position, the condyle driver is driven by the hinge joint's rotation, automatically translating angular motion into linear displacement of the condyle pad support. This substitution eliminates the need for manual operation while providing continuous dynamic adaptation.
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
This solution allows for minimized pressure on the compromised compartment of the knee during full extension while relaxing the load during flexion, providing optimal support when needed and reducing discomfort.
Implementation Method 1
a return spring that pushes the condyle cam medially as the knee flexes
Implementation Method 2
The interior of condyle cam and condyle driver face each other and are provided with ramps
Data Source
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AI summary
A hinge joint for orthopedic knee braces that enable a wearer or medical professional to quickly and efficiently adjust the lateral corrective force placed on the knee joint so as to apply the force at heel strike (full extension) when it is most needed, but will relax the loading during flexion. The hinge joint, for use in a three point pressure system of a knee brace, has a first part that is connectable to a femoral arm of a knee brace and a second part that is mounted to be able to telescope out of the first part as the leg is extended and to telescope back into the first part as the leg flexes.