Polycentric Hinge Integrated Cover Plates
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Solution Overview
Problem
Existing polycentric knee brace hinges are complex and expensive due to numerous components, which complicates their assembly and manufacturing process, while they need to simulate the intricate movements of the knee joint effectively for orthopedic support and rehabilitation.
Innovation Solution
A simplified polycentric hinge design using two cover plates with integrated tubular bearings and recesses, eliminating the need for additional fasteners and components, allowing for ultrasonic welding and reducing weight and complexity, while maintaining strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional polycentric hinge designs with multiple components are used, then the knee joint movement simulation capability is maintained, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple traditional hinge components (cover plates, bearings, fasteners, recesses) into a single integrated polymeric component formed by injection molding. This merging eliminates the need for assembly of multiple parts while maintaining the polycentric hinge's ability to simulate knee joint movement through its geometric design of bearing positions and recess configurations.
2Productivity
If multiple fasteners and intermediate plates are used to assemble hinge components, then the structural strength is maintained, but the assembly time and manufacturing cost increase
Solution Approach 1:
The patent replaces the traditional mechanical assembly system (multiple fasteners, intermediate plates, and mechanical fastening operations) with a single-piece injection-molded polymeric structure. This substitution eliminates the need for mechanical fastening while maintaining structural integrity through the inherent strength of the molded component and its integrated bearing and recess features.
3Weight of moving object
If numerous metal components are used in the hinge assembly, then the durability is ensured, but the weight and manufacturing cost increase
Solution Approach 1:
The patent employs a polymeric material (such as polyethylene, polypropylene, or nylon) for the hinge component, replacing traditional metal materials. This material substitution significantly reduces weight while maintaining durability through the selection of high-strength, wear-resistant polymers that can withstand the mechanical loads and repetitive motion of knee joint simulation.
4Ease of manufacture
If multiple separate components are assembled together, then the manufacturing flexibility is maintained, but the manufacturing cost and complexity increase
Solution Approach 1:
The patent integrates multiple functional segments (cover plates, bearings, fasteners, recesses) into a single molded component with distinct geometric zones that perform each function. This segmentation within a unified structure maintains design flexibility and adaptability while simplifying the manufacturing process to a single injection molding operation, eliminating the need for separate manufacturing and assembly of multiple components.
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 simplified design enables faster and less expensive assembly with reduced weight, increased flexibility, and equivalent or improved strength and durability compared to traditional polycentric hinges with multiple components, while maintaining effective support and control of knee joint movements.
Implementation Method 1
The cover plates may be secured together. The cover plates may be formed of a polymeric material, and the cover plates may be ultrasonically welded together
Data Source
AI summary
A polycentric hinge for an orthopedic device includes first and second hinge arms, and two cover plates, rather than numerous individual parts and fasteners. The first and second cover plates define a plurality of bearings and a plurality of recesses for receiving the bearings, whereby the hinge arms are mounted about the bearings and are pivotable relative to one another while encased by the first and second cover plates.