Polycentric Knee Brace Hinge for Roto-Translational Joint Tracking
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Solution Overview
Problem
Existing knee braces with single or double hinges fail to adapt to the roto-translational movements of the knee joint, leading to gaps between the protecting cup and the knee brace frames, reducing protection against impacts and causing discomfort and loss of control during flexion.
Innovation Solution
A polycentric hinge with four spaced apart rotation axes and synchronized hinge arms that allow for roto-translation movements, maintaining the protecting cup close to the patella and frames during flexion, ensuring improved protection and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single or double hinge is used to connect the upper and lower frame members, then the knee brace can prevent hyper-rotation,hyper-flexion orhyper-extension of the knee joint, but the hinge cannot adapt to the roto-translational movements of the knee joint, resulting in gaps between the protecting cup and the frames
Solution Approach 1:
The single or double hinge is segmented into multiple hinge arms (first, second, third, fourth hinge arms) with multiple rotation axes. Each hinge arm can rotate independently around its own axis, allowing the structure to accommodate complex roto-translational movements while maintaining protection against extreme knee joint movements.
Solution Approach 2:
The hinge mechanism transitions from a single-axis or dual-axis rotation system to a multi-axis rotation system. The first and second hinge arms rotate around a first rotation axis, while the third and fourth hinge arms rotate around a second rotation axis, adding a dimensional aspect to the movement capability and enabling adaptation to roto-translational paths.
2Strength
If the frames are made of rigid material to offer improved protection against direct impacts, then the protection is enhanced, but the hinge mechanism becomes more complex and the protecting cup movement is restricted
Solution Approach 1:
The hinge mechanism incorporates dynamic elements that allow controlled movement and adaptation. The multiple rotation axes and hinge arms create a dynamic system that can adjust to the natural roto-translational movements of the knee joint, reducing the need for overly complex rigid structures while maintaining protection.
3Stability of the object's composition
If the articulation hinge is used to maintain the protecting cup position, then the cup is held in place, but the outward movement of the hinge during flexion creates gaps that reduce protection
Solution Approach 1:
The hinge mechanism changes its geometric parameters dynamically during knee flexion. The rotation of multiple hinge arms around different axes alters the relative positions and angles of the connection points, allowing the protecting cup to maintain proper positioning relative to the patella throughout the range of motion without creating harmful gaps.
Data Source
AI summary
A polycentric hinge for a knee brace, and knee brace including such hinge. The hinge includes first couple of hinge arms, second couple of hinge arms, and hinge body for hinging together the first couple of hinge arms and second couple of hinge arms. Each hinge arm of the first couple and each hinge arm of the second couple has a first end pivotally enclosed inside said hinge body and a second end pivotally fixed to a mounting frame.The hinge body is provided with pivoting means adapted to engage said first ends to define four different and spaced apart rotation axes extending transversally with respect to a longitudinal axis of the hinge body. The first ends of each hinge arm of the second couple can be connected to each other, so that rotation of the mounting frame causes rotation of both hinge arms around their respective rotation axes.