Fiber-Reinforced Plastic Drive Spring for Hand-Held Fastener
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Solution Overview
Problem
Conventional hand-held tackers using mechanical drive springs face limitations in achieving high driving speeds and setting energies due to significant energy losses from accelerating the spring mass, making them inadequate for applications like driving nails into steel or concrete, where higher energies are required.
Innovation Solution
A drive spring element made from fiber-reinforced plastic material, comprising multiple spring segments connected by gluing or welding, reduces the spring mass while maintaining comparable spring force, increasing rigidity and modulus of elasticity, allowing for higher driving speeds and setting energies, up to 30-35 m/s, and efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a mechanical drive spring is used, then the device can be manufactured inexpensively, but the driving speed is limited due to energy losses from accelerating spring mass
Solution Approach 1:
The patent applies composite materials by replacing conventional metal coil springs with springs made from fiber-reinforced plastic materials. This composite material approach reduces the spring mass significantly while maintaining the necessary spring force and structural integrity, thereby resolving the contradiction between manufacturing cost and driving speed by enabling higher speeds without prohibitively increasing costs.
Solution Approach 2:
The patent changes the physical parameters of the spring by using fiber-reinforced plastic materials with different density and elastic modulus characteristics compared to metal. This parameter change reduces the spring mass and allows for higher driving speeds while maintaining acceptable manufacturing costs through alternative material processing methods.
2Force
If a stronger spring is provided to increase impact speed, then the spring force increases, but the spring mass increases which increases energy loss
Solution Approach 1:
The patent uses fiber-reinforced plastic composite materials to create springs that achieve the required spring force with significantly reduced mass compared to metal springs. The composite structure allows for high strength-to-weight ratio, enabling the spring to deliver necessary force while minimizing the mass that would otherwise be accelerated and cause energy loss.
Solution Approach 2:
The patent applies local quality by strategically orienting and distributing fibers within the spring structure to optimize strength where needed while minimizing mass. The fiber reinforcement is concentrated in areas requiring high strength to achieve the necessary spring force, while other areas use less material, thereby reducing overall spring mass and energy loss.
3Loss of energy
If the spring mass is reduced to decrease energy loss, then energy efficiency improves, but the spring force and rigidity may decrease
Solution Approach 1:
The patent employs fiber-reinforced plastic composite materials that provide high strength and rigidity with low density. The composite structure delivers the necessary spring force and rigidity while maintaining reduced mass, thereby simultaneously improving energy efficiency and preserving mechanical performance.
Solution Approach 2:
The patent segments the spring into multiple individual spring segments that are connected together. This segmentation allows for optimized design of each segment to achieve the required force characteristics while keeping individual segment masses low, reducing overall energy loss while maintaining necessary spring force.
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 solution significantly reduces energy losses and achieves higher driving speeds and setting energies compared to conventional metal coil springs, enabling effective fastening in demanding applications while maintaining a compact and efficient design.
Implementation Method 1
the drive spring element is formed from a fiber-reinforced plastic material
Implementation Method 2
A mechanical drive spring, which can be tensioned via a tensioning mechanism, serves as the drive source for the driving ram
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The device has a drive arrangement (30) for a driving tappet (13) that is displaceably supported at a guide (12). The tappet has a main spring unit (31) stretchable over a tensioning unit (70) for the driving tappet. The main spring unit is formed of a fiber-reinforced plastic material such as epoxy resin. The plastic material consists of fibers selected from a group such as glass fibers, carbon fibers and steel fibers. The main spring unit consists of a set of spring segments.