Freewheel Mechanism for Tool-Free Tamper Stroke Adjustment

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Solution Overview

Problem

Conventional tamper devices for road pavers require manual and tool-based adjustments of the tamper bar's stroke length during breaks in operation, which is inefficient and disrupts continuous paving processes.

Innovation Solution

A freewheel mechanism connecting the eccentric tamper shaft and bushing allows for torque-proof engagement during paving and disengagement during stroke length adjustments, enabling manual and tool-free rotation of the bushing relative to the shaft to change the effective eccentricity and thus the tamper bar's stroke length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If manual adjustment of the eccentric bushing is performed during breaks in paving operation, then the stroke length can be changed, but the paving process is disrupted and efficiency is reduced

Engineering Contradiction:
Improvestroke length adjustment capabilityVSAvoidpaving efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The system transitions from a static fixed connection between shaft and bushing to a dynamic freewheel mechanism that allows selective engagement and disengagement. This enables the bushing to be rotated relative to the shaft for stroke adjustment while maintaining torque transmission during operation, resolving the contradiction between adaptability and productivity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The freewheel mechanism acts as an intermediary between the shaft and bushing, allowing relative rotation when torque is absent (during adjustment) while maintaining rigid connection when torque is present (during operation). This mediator enables stroke length changes without disrupting the paving process

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the eccentric bushing is released and manually rotated to adjust stroke length, then the effective eccentricity changes, but the adjustment process requires tools and interrupts operation

Engineering Contradiction:
Improveadjustment easeVSAvoiddowntime during adjustment
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The freewheel mechanism provides self-service functionality by automatically disengaging when the bushing needs to be rotated for adjustment and automatically re-engaging when torque is applied. This eliminates the need for tools and manual release/locking operations, allowing quick adjustment without interrupting the paving process

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The dynamic engagement特性 of the freewheel mechanism allows the system to switch between adjustment mode (disengaged) and operation mode (engaged) seamlessly, reducing adjustment time and maintaining productivity

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If a fixed connection is used between the shaft and bushing, then torque transmission is reliable, but stroke length cannot be adjusted during operation

Engineering Contradiction:
Improvestroke length adjustabilityVSAvoidtorque transmission reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The connection between shaft and bushing dynamically switches between fixed (during torque transmission) and movable (during adjustment). The freewheel mechanism maintains reliable torque transmission when engaged while enabling stroke adjustment when disengaged, resolving the contradiction between adaptability and reliability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The freewheel mechanism serves as a smart intermediary that provides reliable torque transmission during paving operation but allows relative rotation during adjustment. It automatically senses the operational state and adjusts the connection特性 accordingly, maintaining both reliability and adaptability

Inventive Principle:
Principle #24Intermediary (Mediator)

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 easy, tool-free adjustment of the tamper bar's stroke length during operation, improving efficiency and reducing downtime by allowing operators to change the stroke length without interrupting the paving process.

Implementation Method 1

The freewheel mechanism is configured to engage the eccentric tamper shaft and the eccentric tamper bushing when the eccentric tamper shaft is driven to rotate

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

an eccentric tamper shaft extending along a tamper shaft axis and being inserted in the eccentric tamper bushing

Methodology Applied
Scientific EffectEccentric: Eccentric

Data Source

PatentEP3249101B1Tamper device of a paver screed
Publication Date: 2019.05.15 CATERPILLAR PAVING PROD INC
  • EP3249101B1 patent drawingFigure 1
  • EP3249101B1 patent drawingFigure 2
  • EP3249101B1 patent drawingFigure 3~4

AI summary

The present disclosure relates to a tamper device (40) with a tamper bar (42) for a screed assembly (18) of a road paver (10). The tamper device (40) includes an eccentric tamper bushing (50) for adjusting a stroke of the tamper bar (42). The tamper device (40) further includes an eccentric tamper shaft (46) extending along a tamper shaft axis (A) and being inserted in the eccentric tamper bushing (50). The eccentric tamper bushing (50) and the eccentric tamper shaft (46) are connected via a freewheel mechanism (100A, 100B, 100C). The freewheel mechanism allows to adjust the stroke of the tamper bar (42) by rotating the tamper shaft (46) and the tamper bushing (50) relative to each other.