Eccentric Polycentric Tensioning Joint for Orthopedic Braces
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Solution Overview
Problem
Traditional orthoses fail to adequately follow the anatomical variations in joint movement, leading to loss of adherence during limb movement due to their inability to vary the total length of the system, and require laborious fastening methods, increasing production costs.
Innovation Solution
An eccentric and polycentric articulated tensioning joint with two or more parts rotating relative to a fixed part with multiple centers of rotation, allowing for variable distance changes proportionally to the rotation, enhancing stability and reducing the need for additional fastenings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional orthoses with fixed articulated joints are used, then the structure is simple and easy to manufacture, but the orthosis loses adherence during limb movement due to inability to follow anatomical variations in joint movement
Solution Approach 1:
The patent applies the dynamics principle by transforming the fixed joint structure into a dynamic one where the distance between centers of rotation varies proportionally with the rotation angle. The articulated joint allows the bars to rotate about multiple centers of rotation, and the distance between these centers changes as the joint moves, enabling the orthosis to adapt to anatomical variations in joint movement and maintain adherence throughout the range of motion.
2Adaptability or versatility
If standard polycentric articulated joints with parallel axes are used, then the manufacturing is straightforward, but the joint cannot correct varus/valgus misalignments effectively
Solution Approach 1:
The patent applies the asymmetry principle by designing an articulated joint where the centers of rotation are not constrained to parallel axes as in standard polycentric joints. Instead, the centers of rotation are positioned asymmetrically and their relative distance varies with the rotation angle, allowing the joint to correct varus/valgus misalignments while maintaining a manufacturable design through the use of toothed profiles for synchronous motion.
3Reliability
If additional fastenings are added to improve stability, then the adherence during movement improves, but the production cost and complexity increase
Solution Approach 1:
The patent applies the self-service principle by designing an articulated joint that automatically adjusts its geometry to maintain stability during movement. The variable distance between centers of rotation and the symmetrical angular motion of the bars provide inherent stability and equal strap tensioning without requiring additional fastenings or complex adjustment mechanisms, thereby reducing production complexity while maintaining reliability.
Data Source
AI summary
An eccentric and polycentric articulated tensioning joint applied to an orthopedic brace with adjustable angular excursion placed in correspondence of body joints comprises two bars each hinged to a rotation pin, wherein said rotation pins are constrained parallel to each other at a predefined distance, said two bars being connected to each other by means of respective semi-circular toothed profiles present on each bar, so as to be set in synchronous motion relative to each other. Said two bars are associated with a respective pair of loop elements, which are kinetically connected to said bars in such a way as to impart thereto the same rotational movements and partially transform them into relative translational movements along the longitudinal axes of each of the bars themselves, in order to effect linear movements of reciprocal distancing or nearing relative to the rotation centres thereof located on said pins.