Paver Screed Transition Mark Reduction via Sensor-Mounted Reference Frame
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Solution Overview
Problem
Paving machines face challenges in maintaining a smooth, even surface due to transition marks caused by changes in the elevation of tow arms, leading to inconsistencies in the paved mat, which existing height adjustment systems struggle to accurately address.
Innovation Solution
A paving machine equipped with sensors and a controller that monitor the transition marks between different surface sections of the mat and adjust the screed assembly to ensure the inner end of the extension plate remains in the same plane as the main screed, using a combination of sensors and inclinometers to measure and correct for slope changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If height adjustment devices are used to keep the rear edges of the basic beam and extendable beam in the same plane, then the transition marks are reduced, but the measurement precision deteriorates due to sensor proximity to vibrating or rotating parts
Solution Approach 1:
The patent introduces an intermediary reference frame (the chassis or fixed mounting structure) to which the sensors are mounted. This intermediary provides a stable, non-vibrating reference point that isolates the sensors from the harmful vibrations and movements of the screed assembly, allowing accurate measurement of the beam heights without direct exposure to the vibrating environment.
Solution Approach 2:
The patent replaces direct mechanical contact or proximity-based measurement with a non-contact sensing approach. The sensors measure the position of the beams relative to the reference frame through the air gap, eliminating the need for physical contact with the vibrating beams and thereby preventing contamination of the measurements by vibration-induced errors.
2Ease of operation
If sensors are mounted close to the basic beam and extendable beam for direct measurement, then the ease of operation is improved, but the reliability deteriorates due to inaccurate readings from vibrations and wear
Solution Approach 1:
The patent uses the chassis or fixed mounting structure as an intermediary reference frame that is neither too far from the beams (maintaining ease of measurement) nor in direct contact with them (avoiding vibration interference). This intermediate reference point allows simple sensor mounting while ensuring reliable, vibration-free measurements.
3Manufacturing precision
If the sensors are positioned to measure the vertical distance from the reference plane, then the manufacturing precision is improved, but the device complexity increases due to precise alignment and calibration requirements
Solution Approach 1:
The patent implements a self-aligning sensor system where the sensors are mounted on the chassis in a configuration that automatically provides the correct measurement geometry during operation. The sensors measure the vertical distance from the reference plane naturally through their mounting arrangement, eliminating the need for complex external alignment procedures or calibration adjustments.
Data Source
AI summary
A paving machine for reducing transition marks in a mat. The paving machine may comprise a frame, a tow arm, a screed assembly, a sensor and a controller. The screed assembly includes a main screed plate and an extension plate. The main screed plate is configured to pave a first surface section of the mat. The extension plate includes an extension trailing edge having an inner end. The extension plate is configured to pave a second surface section of the mat. The sensor is configured to sense transition marks in the mat proximal to an intersection between the first and second surface sections and to transmit data indicative of such to the controller. The controller may be configured to determine from the data received from the sensor when the inner end is disposed above or below the first plane, and move the inner end to the first plane.