Absorber With Foamed Polyurethane Spring Body
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Solution Overview
Problem
Existing absorbers in hand tools, such as hammer drills, face challenges in effectively dampening kickbacks and vibrations due to their design, which often results in inefficient energy transfer and increased risk of user injury from uncontrolled movements.
Innovation Solution
A compact absorber design featuring a spring body made of closed-pore foamed polyurethane, connected to a rigid plastic support plate and a mass body, which is strategically positioned to minimize tilting and rotating movements, allowing for efficient energy absorption and redistribution, thereby enhancing the tool's stability and user safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional absorber design is used in hand tools, then the structure is simple to manufacture, but the dampening effectiveness is insufficient and energy transfer is inefficient
Solution Approach 1:
The absorber is segmented into distinct functional components: a base plate, a carrier plate, a spring body, and a mass body. This segmentation allows each component to perform its specific function optimally - the spring body for energy storage and the mass body for inertia-based dampening - while maintaining manufacturability through modular assembly
Solution Approach 2:
The absorber employs composite material construction with a spring body made of elastomer (such as closed-pore foamed polyurethane) connected between plastic plates. This combination of materials provides both the elasticity needed for energy absorption and the structural integrity required for mechanical connection, resolving the contradiction between dampening effectiveness and manufacturing simplicity
2Stability of the object's composition
If the mass body is positioned close to the spring body center of gravity, then tilting and rotating movements are suppressed, but the design space for mass body configuration is constrained
Solution Approach 1:
The mass body is strategically positioned with its center of gravity aligned with or close to the spring body's center of gravity, creating a localized mass distribution that specifically suppresses tilting and rotating movements. This local quality adjustment stabilizes the absorber's movement characteristics without requiring changes to the overall absorber structure
Solution Approach 2:
The mass body dimensions are configured such that one dimension (length) is greater than dimensions perpendicular to it, creating an elongated shape that fits within the constrained space between plates while maintaining the desired center of gravity positioning. This dimensional arrangement allows stability optimization within limited configuration space
3Strength
If the spring body has high stiffness in all directions, then structural strength is improved, but the ability to couple with periodic excitation along the working axis is reduced
Solution Approach 1:
The spring body exhibits directionally varying stiffness characteristics - higher stiffness in lateral directions to provide structural strength and stability, while maintaining appropriate compliance along the working axis to effectively couple with periodic excitation. This anisotropic stiffness distribution resolves the contradiction between strength and excitability
Solution Approach 2:
The spring body's stiffness parameters are optimized to have different values in different spatial directions, with greatest stiffness along assembly direction for structural integrity and lowest rigidity along working axis for excitation coupling. This parameter differentiation allows simultaneous achievement of strength and adaptability
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 absorber effectively dampens vibrations and kickbacks, improving the tool's stability and reducing user exposure to harmful movements by utilizing a spring body with varying stiffness directions and a mass body design that suppresses tilting, ensuring efficient energy absorption and redistribution.
Implementation Method 1
the elastomer is injected with a foaming agent
Implementation Method 2
a spring body having an elastomer
Implementation Method 3
the spring body undergoes shearing, which shifts the roof surface parallel to the base surface
Implementation Method 4
the spring body connected between the housing and the mass body exerts a restoring force on the mass body in a rest position
Implementation Method 5
Due to its high inertia, the mass body can be excited to move relative to the base plate
Data Source
Figure 1
Figure 2~4
Figure 5~7
AI summary
Production method for an absorber (20), in which production method a base plate (24) made from plastic and a carrier plate (25) made from plastic are arranged parallel to one another at a spacing, an elastomer is injected for a spring body (21) between the carrier plate (25) and the base plate (24), and a metallic mass element (22) is fastened non-positively and/or positively on a side of the carrier plate (25), which side faces away from the spring body (21).