Road Finisher Tamper Stroke Adjustment via Eccentric Shaft Rotation
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Solution Overview
Problem
Existing tamper systems for road finishing machines require time-consuming and cumbersome manual adjustments to change the stroke of the tamper bar in response to varying pavement thickness, often necessitating multiple interruptions in operation and the use of tools.
Innovation Solution
A tamper system with an eccentric shaft and bushing that allows for quick and precise adjustment of the tamper bar stroke through reversible motor direction or gear, enabling the tappet to switch between preselected stop positions without tools, by reversing the rotation of the eccentric shaft and adjusting the relative positioning between the eccentric bushing and shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual adjustment of the eccentric bushing is used to change tamper bar stroke, then the stroke can be adjusted to adapt to pavement thickness changes, but the adjustment process is time-consuming and requires multiple interruptions in operation
Solution Approach 1:
The patent pre-positions the tappet at specific stop locations around the eccentric shaft circumference. These predetermined positions correspond to different desired stroke lengths. By preparing these stop positions in advance, the system eliminates the need for time-consuming manual measurement and adjustment during operation changes.
Solution Approach 2:
The patent replaces the traditional manual mechanical adjustment system with an automated motor-driven rotation system. The motor automatically rotates the eccentric shaft to bring the tappet into engagement with the desired stop position, eliminating manual manipulation of the eccentric bushing and significantly reducing adjustment time.
2Adaptability or versatility
If manual adjustment of the eccentric bushing is used to change tamper bar stroke, then the stroke can be adjusted, but the adjustment process is cumbersome and requires use of tools
Solution Approach 1:
The system performs the adjustment operation automatically through the motor-driven rotation mechanism. The motor self-activates to rotate the eccentric shaft and position the tappet at the correct stop location, eliminating the need for operator intervention with tools. The system serves itself by automatically completing the adjustment task.
Solution Approach 2:
The patent extracts the manual tool manipulation step from the adjustment process. By separating the adjustment function into an automated motor-driven operation, the cumbersome manual manipulation of the eccentric bushing with tools is completely removed from the operator's task.
3Adaptability or versatility
If multiple connecting rods with straining rings are adjusted manually to change tamper stroke, then each tamper can be adapted to pavement thickness, but eight or more adjustment operations are required across the working width
Solution Approach 1:
The patent merges the adjustment operations for multiple connecting rods into a single automated operation. The motor-driven system simultaneously or sequentially adjusts all tappets across the working width by rotating the eccentric shaft, consolidating what would be multiple separate manual adjustments into one unified operation.
Solution Approach 2:
The automated motor-driven adjustment system serves multiple tampers across the entire working width simultaneously. A single motor operation can adjust all connecting rods and tampers uniformly, providing universal adjustment capability across the complete screed width rather than requiring individual adjustment of each component.
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 rapid and precise adaptation of the tamper bar stroke to changing pavement thickness without manual adjustments, reducing operational interruptions and simplifying the process of maintaining consistent precompaction across the working width.
Implementation Method 1
as drive of the eccentric shaft a hydraulic or electric motor whose direction of rotation can be reversed
Implementation Method 2
as drive of the eccentric shaft a hydraulic or electric motor whose direction of rotation can be reversed
Implementation Method 3
the stroke of the tamper bar being variable by adjustment of the relative rotational positioning between the eccentric bushing and the eccentric section
Data Source
AI summary
A tamper of a screed having an eccentric shaft including an eccentric section and an eccentric bushing rotatably mounted in a connecting rod driving a tamper bar. The stroke of the tamper bar is adjustable by a relative rotation between the eccentric shaft and the eccentric bushing, and a tappet and a preselection area with two tappet stop positions defining two different tamper bar strokes are provided between the eccentric shaft and the eccentric bushing, enabling adjustment of the tappet to each tappet stop position, by reversing the direction of rotation of the eccentric shaft to switch between the two strokes.