Adjustable Strut Fluctuation Counting for Accurate Length Measurement
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Solution Overview
Problem
Existing external fixation systems face challenges in accurately and efficiently measuring the length of struts during bone deformity correction procedures, leading to potential human error and time-consuming manual measurements, and x-ray image parallax errors.
Innovation Solution
The implementation of adjustable-length struts with mechanisms such as fluctuation counters, optical sensors, ultrasonic sensors, cameras, and electrically conductive loops to precisely determine strut length, using methods like fluctuation counting, pit shape recognition, and resistance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual measurement methods are used to determine strut length, then the measurement process is simple and does not require additional components, but the measurement is time-consuming and prone to human error
Solution Approach 1:
The patent replaces manual visual estimation and physical measurement with automated detection systems. Optical sensors detect markings on the strut to determine length, while ultrasonic sensors measure distance acoustically. This substitution eliminates human error and reduces measurement time significantly.
Solution Approach 2:
The measurement system is integrated directly into the strut structure, allowing the strut to self-measure its length through embedded sensors and markers. The system automatically detects and reports length changes without requiring external measurement tools or human intervention, enabling continuous monitoring during adjustment procedures.
2Measurement precision
If x-ray imaging is used to measure strut length, then a non-contact measurement method is provided, but parallax errors and radiation exposure occur
Solution Approach 1:
The patent replaces x-ray imaging with optical and ultrasonic sensing systems that detect strut length through non-ionizing methods. Optical sensors read markings on the strut surface, while ultrasonic sensors measure distance through sound waves, completely eliminating radiation exposure and parallax errors associated with x-ray imaging.
Solution Approach 2:
The patent introduces optical markers and ultrasonic transducers as intermediary elements between the measurement system and the strut. These intermediaries enable accurate length detection through light reflection or sound wave propagation, avoiding the need for penetrating radiation and eliminating parallax errors inherent in imaging methods.
3Productivity
If automated sensing systems are implemented to measure strut length, then measurement speed and accuracy are improved, but device complexity increases
Solution Approach 1:
The patent integrates multiple sensing capabilities (optical detection, ultrasonic measurement, magnetic sensing) into a unified measurement system that can determine strut length through various physical principles. This multi-functional approach allows the system to maintain high measurement speed and accuracy while reducing overall complexity by consolidating functions into a single integrated platform.
Solution Approach 2:
The patent divides the measurement system into independent modular components: optical sensors for reading markings, ultrasonic sensors for distance measurement, and magnetic sensors for position detection. Each module operates independently but contributes to the overall length measurement, allowing for easier maintenance, calibration, and replacement without affecting the entire system.
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
Enables accurate, quick, and objective determination of strut length, reducing human error and time consumption, and providing precise adjustments for bone deformity correction.
Implementation Method 1
The free end of the needle is configured to maintain contact with the threaded rod. While the threaded rod moves into or out of the tube, the free end of the needle may be configured to maintain contact with the threaded rod by riding along peaks and valleys of threads of the threaded rod.
Implementation Method 2
As the free end of the needle rides along peaks and valley of threads of the threaded rod, a position of the fluctuation counter may be configured to fluctuate relative to the outer tube. The fluctuation counter may be configured to count a total number of fluctuations as the free end of the needle rides along peaks and valleys of threads of the threaded rod, with one fluctuation corresponding to one complete revolution of the threaded rod.
Implementation Method 3
The strut may include a threaded rod having a first end coupled to the first joint, a tube that receives the threaded rod. The strut may be an adjustable-length strut whereby the threaded rod is moveable axially into or out of the tube.
Data Source
AI summary
A strut for use with an external fixation system may include first and second joints proximate the first and second ends of the strut, the first and second joints configured to couple to first and second rings of the external fixation system. The strut may include a threaded rod coupled to the first joint, a tube that receives the threaded rod, a fluctuation counter coupled to the tube, and a needle coupled to the fluctuation counter. The needle may extend through a bore in the outer tube, and the needle may have a free end in contact with the threaded rod. The strut may be an adjustable-length strut whereby the threaded rod is moveable axially into or out of the tube, and while the threaded rod moves into or out of the tube, the free end of the needle may be configured to maintain contact with the threaded rod.