Rotary Laser Propeller Measurement for Repeatable Blade Geometry
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Solution Overview
Problem
Current methods for measuring pitch, rake, and squareness of marine propellers suffer from repeatability and accuracy issues due to human error, mechanical limitations, and challenges with reflective surfaces, particularly on smaller propellers, which require higher precision and are prone to scratches from contact probes.
Innovation Solution
A precision apparatus with a rotary table and robotic sensor positioning arm equipped with displacement sensors that use laser triangulation to measure distances and angles, providing accurate and repeatable data without physical contact, suitable for smaller propellers with high angles and short chord lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual contact probe machines are used for measurement, then measurement capability is provided, but measurement repeatability and accuracy deteriorate due to human error and mechanical slack
Solution Approach 1:
The patent replaces manual mechanical measurement systems with an automated laser-based optical measurement system. The laser displacement sensor, mounted on a motorized carriage that rotates with the propeller, eliminates human contact and mechanical slack, providing consistent sub-0.001" repeatability through optical triangulation rather than mechanical probing.
Solution Approach 2:
The measurement system performs self-measurement by mounting the laser sensor on the rotating carriage itself. As the carriage rotates with the propeller, the sensor automatically maintains its position and performs measurements without external human intervention, eliminating operator variability and achieving consistent repeatability.
2Productivity
If manual measurement methods are used, then measurement capability is provided, but measurement time increases and productivity decreases
Solution Approach 1:
The measurement system performs continuous measurements as the carriage rotates around the propeller. The laser sensor continuously scans blade surfaces during the rotation, collecting multiple data points along each blade without stopping, thereby reducing total measurement time while maintaining high productivity through uninterrupted data acquisition.
3Measurement precision
If contact probe stylus is used for measurement, then measurement precision is achieved, but propeller surface is damaged through scratching
Solution Approach 1:
The patent replaces mechanical contact probes with a non-contact laser displacement sensor that measures blade surfaces through optical triangulation. This eliminates physical contact and prevents scratching of the propeller surface while maintaining high measurement precision through laser-based distance measurement.
4Manufacturing precision
If traditional manual measurement is used, then measurement capability is provided, but measurement accuracy deteriorates on smaller propellers with high blade angles
Solution Approach 1:
The measurement system is mounted on a dynamic rotating carriage that moves with the propeller rotation. This allows the laser sensor to maintain optimal measurement angles and positions even on small propellers with high blade angles, adapting to the geometry being measured rather than requiring fixed measurement positions that are difficult to achieve on small 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 apparatus delivers measurements with 0.05-0.10″ accuracy, reducing measurement time by 50% and eliminating human error, enabling precise repair and manufacturing of propellers with enhanced data collection and reduced operator intervention.
Implementation Method 1
displacement sensors that use laser triangulation to measure distances and angles
Data Source
AI summary
Apparatuses for measuring parameters of an object may include an apparatus frame. A rotary table assembly may include a rotary table having a diameter or width and carried by the apparatus frame. The rotary table may be configured to support the object for rotation. A rotary table motor may operably engage the rotary table for rotation. A carriage rail may be carried by the apparatus frame. The carriage rail may be disposed in fixed position relative to the rotary table. A sensor carriage may be carried by and configured to traverse the carriage rail. A carriage drive motor may engage the sensor carriage. The carriage drive motor may be operable to displace the sensor carriage along the carriage rail. At least one displacement sensor may be carried by the sensor carriage. The displacement sensor may have a displacement sensor travel path which passes over and traverses the diameter or width of the rotary table as the sensor carriage traverses the carriage rail. The displacement sensor may be configured to measure distances between the displacement sensor and surfaces on the object. Alternative embodiments of the apparatuses are also disclosed.