Vibratory Pile Driver Two-Stage Load Absorber
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Solution Overview
Problem
Existing pile driving and extracting systems face challenges in efficiently absorbing vibration and tension loads, particularly during pile extraction, which can damage supporting cables and hoisting machinery due to the need for manual adjustment of spring stiffness and limited load-absorbing capacity of previous designs.
Innovation Solution
The use of a combination of shear-type and compression-type elastomeric vibration/tension load absorbing elements between the housing and vibratory unit, where the shear-type elements absorb loads by shear-strain and the compression-type elements engage to provide additional absorption when tension exceeds a predetermined level, with a rigid member acting as a stop to prevent further movement and generate an audible warning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual adjustment of spring stiffness is used to adapt to varying tension loads, then the vibration/tension load absorbing capability is improved, but the operation time and labor intensity increase
Solution Approach 1:
The patent employs a dynamic spring system where the stiffness characteristic automatically adapts to varying tension loads. The spring arrangement transitions from a softer state during pile driving (low tension) to a stiffer state during pile extraction (high tension), eliminating the need for manual adjustment while maintaining optimal vibration/tension load absorbing capability throughout operation.
2Device complexity
If a single set of springs is used for both pile driving and extraction, then the device complexity is reduced, but the vibration absorption effectiveness deteriorates under high tension loads
Solution Approach 1:
The patent utilizes springs with variable stiffness characteristics that automatically change their effective stiffness based on the applied tension load. During pile driving with low tension, the springs operate in a softer regime for effective vibration absorption. During pile extraction with high tension, the springs engage in a stiffer regime to handle the increased loads, thus maintaining effective vibration absorption across both operations without requiring multiple spring sets.
3Reliability
If weaker springs are used during pile driving, then the vibration absorption is improved, but the tension load absorbing capacity during extraction deteriorates
Solution Approach 1:
The spring system dynamically adjusts its stiffness characteristic based on operational requirements. During pile driving, the springs operate in a compliant state to absorb vibrations effectively. During pile extraction, when tension loads increase, the springs naturally engage in a stiffer state to absorb the high tension loads, thus simultaneously satisfying both vibration absorption during driving and tension load absorption during extraction.
4Strength
If stiffer springs are used during pile extraction, then the tension load absorption is improved, but the vibration absorption during driving deteriorates
Solution Approach 1:
The springs are designed with variable stiffness characteristics that automatically adapt to the operational state. During pile driving with low tension loads, the springs operate in a softer regime that effectively absorbs vibrations. During pile extraction with high tension loads, the springs naturally engage in a stiffer regime to handle the increased tension, thus maintaining effective vibration absorption during driving while providing adequate tension load absorption during extraction.
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 arrangement effectively absorbs both vibration and high tension loads, preventing damage to equipment and allowing for continuous operation without manual adjustments, while the audible warning alerts operators to maximum load conditions.
Implementation Method 1
the shear-type elements absorb loads by shear-strain
Implementation Method 2
the compression-type elements engage to provide additional absorption when tension exceeds a predetermined level
Implementation Method 3
a combination of shear-type and compression-type elastomeric vibration/tension load absorbing elements
Data Source
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AI summary
A method and apparatus for driving and extracting piles that indudes a vibration/tension load absorber assembly mounted between a housing and the vibratory unit which includes shear-type vibration absorbers connected between the housing and the vibratory unit and operating in combination with at least one compression-type vibration absorber positioned to be compressed between first and second compression plates when the tension load reaches a predetermined level.