Orthopedic Hinge With Variable Stiffness for Natural Joint Motion
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Solution Overview
Problem
Existing lightweight orthopedic device hinges lack adaptability to different activity levels, rigidity, strength, and motion control, and fail to dynamically conform to the user's limb shape, particularly between flexion and extension, while providing sufficient support and cooperation with other orthopedic device components.
Innovation Solution
A monolithic hinge body made from a flexible polymeric material that continuously extends from one end to another, with an articulating section that can bend angularly and transversely, featuring a receptacle for an insert to modify stiffness, and a rib for reinforcement, allowing for adjustable flexibility and strength to accommodate varying limb dimensions and motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a robust hinge with multiple parts and structural elements is used, then joint guidance and support are improved, but weight, cost, bulk, and complexity increase
Solution Approach 1:
The patent combines multiple hinge components (articulating section, reinforcement elements, strap mounting features) into a single monolithic body made of polymeric material. This integration maintains the structural support and joint guidance functions of robust hinges while eliminating the weight and complexity associated with multiple discrete parts and fasteners.
Solution Approach 2:
The patent changes the material parameter from traditional metal hinge materials to polymeric materials, which provides sufficient strength and joint guidance while significantly reducing weight. The polymeric material allows the hinge to maintain reliability with reduced mass compared to conventional metal-based robust hinges.
2Weight of moving object
If a lightweight hinge is used to reduce weight, then hinge weight is reduced, but adaptability to different activity levels and rigidity control is limited
Solution Approach 1:
The patent incorporates an insert within the polymeric hinge body that can be selectively positioned or removed to dynamically adjust the hinge's rigidity and range of motion. This allows the lightweight hinge to adapt to different activity levels and provide variable rigidity control, overcoming the limitation of fixed-characteristic lightweight hinges.
Solution Approach 2:
The patent segments the hinge functionality by separating the polymeric body from the insert element. This segmentation allows independent optimization of each component and enables the insert to provide adjustable rigidity and adaptability features within the lightweight polymeric structure.
3Ease of manufacture
If a monolithic polymeric hinge body is used, then manufacturing complexity is reduced, but structural strength may be compromised
Solution Approach 1:
The patent creates a composite structure by embedding an insert within the polymeric hinge body. This composite construction combines the manufacturing advantages of injection-molded polymeric material with the strength-enhancing properties of the insert material, achieving both ease of manufacture and sufficient structural strength.
Solution Approach 2:
The patent applies local quality by concentrating reinforcement features (such as ribs, thicker sections, or strategic insert placement) in specific high-stress areas of the hinge body. This allows the monolithic polymeric structure to achieve necessary strength at critical locations while maintaining overall manufacturing simplicity and lightweight characteristics.
4Ease of operation
If the articulating section protrudes minimally, then interference with natural motion is reduced, but structural support may be insufficient
Solution Approach 1:
The patent concentrates structural reinforcement features within the minimal protruding articulating section, such as internal ribs, optimized wall thicknesses, or strategically placed inserts. This allows the small articulating section to provide sufficient structural support for joint guidance while maintaining minimal protrusion that does not interfere with natural leg motion.
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 hinge provides enhanced strength, stability, and dynamic conformity to the user's limb, minimizing interference with natural motion and allowing for a snug fit, while maintaining structural integrity and adaptability to different limb lengths and activity levels.
Implementation Method 1
The single material structure may be compliant and adapted to flexibly bend not just within an angular range, but also transversely relative to a neutral longitudinal axis of a leg or joint in extension
Implementation Method 2
The articulating portion of the hinge may be reinforced, and may be stiffer at an articulating section to provide angular control of a joint
Implementation Method 3
An insert is arranged for insertion into the receptacle, and can modify the stiffness of the hinge in the angular range
Data Source
AI summary
A hinge has a hinge body forming an articulating section extending between a first end and a second end of the hinge. The articulating section is adapted to bend from a neutral axis when the first and second ends are parallel to an angular range in which the first end is arranged among a plurality of angles within the angular range relative to the second end. The hinge body may define a receptacle along the articulating section, and an insert may be provided for insertion into the receptacle. The insert can modify the stiffness of the hinge in the angular range and is arranged parallel to the neutral axis.