Non-linear Spring Vibration Reducing Apparatus for Reciprocating Tools
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Solution Overview
Problem
Traditional passive vibration dampening systems for reciprocating tools, such as jackhammers and road breakers, fail to effectively suppress vibrations in the frequency range of 6-20 Hz, leading to operator fatigue, musculoskeletal issues, and reduced tool performance due to their fixed stiffness and inability to adjust to varying loads.
Innovation Solution
A vibration reducing apparatus with a guide frame and assemblies comprising pivotally attached elongate members and adjustable biasing means, providing decreasing stiffness with increasing compression to effectively reduce vibrations in the 6-20 Hz frequency range, while maintaining operational efficiency and handling comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional springs or dampers are used for vibration suppression, then high damping is needed at resonant frequency, but stiffness increases dramatically with compression which reduces vibration suppression effectiveness
Solution Approach 1:
The patent applies a non-linear spring mechanism where the stiffness dynamically changes with compression. As the operator applies force to the handle, the spring compression increases and stiffness decreases, allowing the system to maintain low stiffness (high damping) at operating conditions while supporting the applied load. This resolves the contradiction by making stiffness a variable parameter rather than a fixed property.
Solution Approach 2:
The invention changes the physical parameter of spring stiffness from a constant value to a variable that depends on compression state. The non-linear spring is designed with specific geometric characteristics that cause its effective stiffness to decrease as compression increases, thereby adapting the damping characteristics to match the operational requirements across different load conditions.
2Productivity
If worker presses down to hold machine tightly for high operational efficiency, then grasping ability increases, but stiffness of traditional springs increases dramatically reducing vibration suppression
Solution Approach 1:
The non-linear spring system dynamically adapts its stiffness to the operator's gripping force. When the operator presses down harder for increased control and efficiency, the spring compression increases which automatically reduces the stiffness, thereby maintaining effective vibration suppression throughout the operational range rather than losing effectiveness under higher loads.
3Object-affected harmful factors
If active damping mechanisms are used to suppress vibration, then vibration attenuation is achieved, but cost and weight dramatically increase affecting overall tool performance
Solution Approach 1:
The patent employs a simple passive mechanical damping system using non-linear springs rather than complex active electronic damping systems with sensors and actuators. This approach achieves effective vibration suppression through clever mechanical design while keeping the system lightweight, simple, and cost-effective, avoiding the penalties of active systems.
4Ease of manufacture
If traditional dampers with same damping coefficient for all frequencies are used, then manufacturing is simple, but vibration suppression is ineffective in specific frequency ranges particularly 6-20 Hz
Solution Approach 1:
The non-linear spring is designed with specific geometric parameters that cause its effective damping characteristics to vary with frequency and amplitude. This allows the single passive element to provide enhanced damping in the problematic 6-20 Hz frequency range while maintaining structural simplicity and ease of manufacture, avoiding the need for complex frequency-selective damping systems.
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 apparatus achieves significant vibration suppression, reducing transmission to operators' hands by up to 70% and improving demolition efficiency, with adjustable parameters allowing customization for specific tools and applications.
Implementation Method 1
Vibration is a type of oscillation characterised by small, limited oscillations in a system in a near balanced state
Implementation Method 2
Passive vibration reducing apparatus... suppressing vibration emitted by a reciprocating tool
Data Source
AI summary
In an aspect of the disclosure there is provided a vibration reducing apparatus for a percussive tool having an axis of reciprocation. The apparatus comprises, a guide frame and at least one member extending across the axis of reciprocation. An assembly extending in a direction of along the axis of reciprocation comprises at least two layers and each layer comprises four interconnected elongate members pivotally attached and rotatable with respect to each other to define a polygon; and the assembly has at least one biasing means. A handle is movably coupled to the guide frame and supported on the assembly. The apparatus provides decreasing stiffness with increasing compression of the assembly under an applied load to the handle for reducing vibration in a predetermined frequency range.