Dynamic Knee Brace Joint for Ro-to-Translational Motion
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Solution Overview
Problem
Current knee movement evaluation devices, such as goniometers, fail to accurately measure flexion beyond 30 degrees due to the roto-translational motion of the knee, leading to inconsistent contact points and reduced repeatability, and existing knee braces cannot maintain proper alignment during flexion.
Innovation Solution
A knee brace with a joint system comprising a first plate, femoral arm, tibial arm, and small plate, featuring modified angular and linear scales that account for the roto-translation phase, allowing for precise measurement of knee flexion from 0 to 180 degrees by maintaining constant contact points through the use of pins and graduated scales.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional goniometric system is used to measure knee flexion, then the measurement is simple and straightforward, but the measurement becomes inaccurate beyond 30 degrees due to roto-translational motion causing changing spatial references
Solution Approach 1:
The measurement system transitions from a static goniometer with a fixed center of rotation to a dynamic system where the first plate and pins accommodate the natural roto-translational motion of the knee. The pins slide along the peripheral edge of the tibial arm plate, allowing the center of rotation to move dynamically during flexion, thereby maintaining measurement accuracy throughout the full range of motion.
Solution Approach 2:
The first plate acts as an intermediary element between the femoral arm and tibial arm, mediating the roto-translational motion. The pins on the first plate engage with the peripheral edge of the tibial arm plate, translating the complex knee motion into measurable angular displacement on the graduated scale while accounting for the changing center of rotation.
2Stability of the object's composition
If the knee brace is designed with a fixed center of rotation, then the structure is simple and stable, but the brace cannot maintain proper alignment during flexion beyond 30 degrees
Solution Approach 1:
The joint system replaces the fixed center of rotation with a dynamic mechanism where the first plate and pins accommodate the natural movement of the knee. As the knee flexes beyond 30 degrees, the pins slide along the peripheral edge of the tibial arm plate, allowing the effective center of rotation to shift and maintain proper alignment throughout the full range of motion.
Solution Approach 2:
The knee brace joint is segmented into multiple components: femoral arm, first plate with pins, tibial arm plate with peripheral edge, and second plate. This segmentation allows each component to perform a specific function in accommodating the roto-translational motion, with the pins and peripheral edge working together to maintain alignment stability.
3Adaptability or versatility
If conventional knee braces limit flexion to about 130 degrees, then the device is simpler and sufficient for physiological recovery, but it cannot support athletes requiring hyper-flexion up to 180 degrees
Solution Approach 1:
The knee brace joint system is designed with universal applicability across different user needs. The dynamic first plate mechanism with pins sliding on the peripheral edge provides accurate support and alignment for both physiological rehabilitation (0-130 degrees) and athletic hyper-flexion (0-180 degrees), eliminating the need for different devices for different purposes.
Data Source
AI summary
A device for evaluating motion of a knee and for forming a brace which includes a first plate having four holes therein, a femoral arm, a tibial arm formed with a rectangular portion from which extends to a semi-circular portion having a central opening and an arcuate opening which for a first 25-30 degrees is an arc of a circle, for a subsequent 105-110 degrees is a spiral and is an arc of a circle from 135-140 to 180 degrees, a second plate having five holes therein and a small circular plate having a linear scale centrally thereof, a graduated arcuate scale and another arcuate opening configured to overlap the arcuate opening of the semi-circular portion of the tibial arm.