Falling Weight Deflectometer Electric Motor Lifting Mechanism

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Solution Overview

Problem

Existing falling weight deflectometers (FWDs) are inefficient due to the slow process of raising and lowering the weight, particularly when making successive measurements at the same location, leading to prolonged test cycles and reduced productivity when measuring along extensive road surfaces.

Innovation Solution

Integration of an electric motor with a threaded spindle that engages non-self-lockingly with the weight, allowing for immediate return to the top position after each drop, enabling rapid movement of the load plate and force transmission means, and utilizing a motor controller for controlled impacts and positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydraulic lifting means is used to raise and lower the weight, then the weight can be positioned at predetermined heights, but the measurement cycle time becomes relatively long

Engineering Contradiction:
Improveweight positioning capabilityVSAvoidmeasurement cycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the hydraulic lifting mechanism with an electric motor-driven lifting system. The electric motor connects the weight to the load plate through a lifting mechanism, eliminating the need for complex hydraulic components. This substitution reduces system complexity and speeds up the lifting operation, thereby reducing measurement cycle time while maintaining reliable weight positioning capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The load plate serves multiple functions: it acts as both the impact surface for receiving the dropped weight and as part of the lifting mechanism through the electric motor connection. This multi-functionality eliminates separate lifting components and reduces the time required for raising and lowering the weight, directly addressing the measurement cycle time issue.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If separate hydraulic lifting mechanism is used to raise the weight back to top position, then the weight can be reset for next measurement, but the process is relatively slow and reduces efficiency

Engineering Contradiction:
Improveweight reset capabilityVSAvoidtesting rate
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent merges the lifting function directly into the load plate assembly by connecting the electric motor to the load plate. This integrated design allows the load plate to serve dual purposes: transmitting impact forces during measurement and providing the lifting mechanism for resetting the weight. This eliminates separate lifting operations and significantly speeds up the weight reset process, thereby improving testing rate and productivity.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If load plate is raised to transport position and lowered again at each measurement position, then the FWD can move to next location, but this process is a major contributor to long test cycles

Engineering Contradiction:
Improvemobile measurement capabilityVSAvoidposition repositioning time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The load plate is designed to serve multiple functions: it is both the impact surface for receiving the dropped weight and the mounting platform for the electric motor that provides lifting capability. This multi-functionality allows the entire measurement assembly to be quickly raised and lowered as a unified unit, reducing the time required for repositioning between measurement locations while maintaining mobile measurement capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This configuration significantly reduces measurement cycle time, allowing for consecutive measurements at shorter intervals and enhancing the overall testing rate and productivity by simplifying the construction and operation of the FWD, while maintaining adequate impact force and control.

Implementation Method 1

said lifting means comprises an electric motor driving a threaded spindle in engagement with the weight

Methodology Applied
Scientific EffectThreaded spindle mechanism: Screw

Implementation Method 2

a buffer means, a weight adapted to impact said force transmission means via said buffer means

Methodology Applied
Scientific EffectBuffering: Damping

Implementation Method 3

The force transmitting means normally comprises a force sensing means so as to measure the actual impact force

Methodology Applied
Scientific EffectForce sensing:

Data Source

PatentEP3055664B1Falling weight deflectometer
Publication Date: 2019.03.13 DYNATEST INT AS
  • EP3055664B1 patent drawingFigure 1
  • EP3055664B1 patent drawingFigure 2
  • EP3055664B1 patent drawingFigure 3

AI summary

A falling weight deflectometer (1). The falling weight deflectometer comprises a load plate (2) adapted to engage a test surface, a force transmission means (5) adapted to transmit a force to the load plate (2), a buffer means (19), and a weight (8, 9, 10) adapted to impact said force transmission means (5) via said buffer means (19) so as to provide a force to be transmitted to said load plate (2) via said force transmission means, a guide means (14, 20) for guiding said weight (8, 9,10) towards said force transmission means, and a lifting means for lifting said weight to a predetermined height above said force transmission means. The lifting means comprises an electric (15) motor driving a threaded spindle in 17 engagement with the weight (8, 9, 10).