Falling Weight Deflectometer Linear Motor Lifting Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulically operated falling weight deflectometers (FWDs) are inefficient due to slow measurement cycles, especially when making successive measurements, as the hydraulic lifting process is slow and requires significant time for weight retrieval and repositioning, reducing overall survey efficiency.
Innovation Solution
A falling weight deflectometer utilizing multiple linear electric motors for lifting and dropping the weight, eliminating mechanical transmission elements and minimizing internal friction, allowing for faster and more precise weight manipulation, and enabling quicker test cycles with reduced maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydraulic lifting means is used to raise and lower the drop weight, then the FWD can perform measurements, but the measurement cycle time becomes excessively long
Solution Approach 1:
The patent replaces the hydraulic lifting mechanism with an electric motor-driven winding mechanism. The electric motor couples directly to a threaded spindle, eliminating hydraulic fluid dynamics and mechanical linkages. This substitution reduces system complexity and accelerates the lifting operation, directly addressing the slow measurement cycle time caused by hydraulic operations.
Solution Approach 2:
The patent removes the hydraulic lifting means entirely from the system and extracts only the essential lifting function, implementing it through a simplified electric motor-spindle-nut arrangement. This extraction eliminates the time-consuming hydraulic operations while preserving the core weight retrieval and repositioning capability.
2Speed
If permanent engagement between weight and threaded spindle is used, then lifting speed increases, but rotation is imparted to the spindle and motor during free fall reducing efficiency
Solution Approach 1:
The patent segments the lifting and dropping operations into distinct phases. During lifting, the electric motor engages the threaded spindle to raise the weight. During dropping, the engagement is disengaged to allow free fall without rotating the spindle or motor. This segmentation allows high lifting speed while preventing energy loss during the drop phase.
Solution Approach 2:
The patent implements a dynamic engagement system where the permanent magnetic coupling between the weight and spindle can be selectively activated or deactivated. This dynamic control allows the system to switch between engaged mode (for lifting) and disengaged mode (for free fall), optimizing performance for each operational phase and preventing unwanted rotation during dropping.
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 use of linear electric motors significantly reduces cycle time, enhances measurement efficiency, and increases the versatility of the FWD by allowing heavier weights to be lifted, while maintaining reliability and minimizing mechanical wear, thus improving the overall survey process.
Implementation Method 1
lifting means comprising multiple linear electric motors arranged in two motor towers placed at opposite ends of the drop weight
Implementation Method 2
a drop weight adapted to impact said force transmission means via said buffer means so as to provide a force
Implementation Method 3
Between the force transmitting means and the weight an elastic means, e.g. buffers in the form of rubber blocks, is provided in order to create an ideally half-sinusoidal impact force
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A falling weight deflectometer (I) comprising a load plate (2) adapted to engage a test surface, force transmission means adapted to transmit a force to the load plate(2), buffer means (I9), a drop weight (8). The drop weight (8) is adapted to impact said force transmission means via said buffer means (19) so as to provide a force to be transmitted to said load plate via said force transmission means. The falling weight deflectometer further comprises at least one linear electric motor (15) for lifting said drop weight (8) to a predetermined height above said force transmission means.