Nailing Machine Unequal-Pitch Spring Durability
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Solution Overview
Problem
Conventional nailing machines suffer from spring deterioration due to excessive stress at the ends of the nailing spring, leading to reduced durability and increased size, as the spring is uniformly stressed and compressed, resulting in a short lifespan and loss of workability.
Innovation Solution
A nailing machine utilizing an unequal-pitch coil spring with a smaller spring constant at the ends and a higher spring constant at the center, allowing for efficient energy accumulation and absorption of impact, reducing the machine's size while maintaining hitting power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the strength of the nailing spring is enhanced by enlarging the nailing spring, then the durability of the spring is improved, but the nailing machine increases in size and the hitting power becomes too strong
Solution Approach 1:
The spring is designed with non-uniform wire diameter where the central portion has a larger diameter than the end portions. This local quality variation allows the central portion to accumulate elastic energy effectively while the thinner end portions reduce overall spring size and mass, resolving the contradiction between durability and size.
Solution Approach 2:
The wire diameter parameter is changed along the length of the spring, creating a gradient structure. The central portion has increased diameter for strength and energy storage, while end portions have reduced diameter for size reduction, achieving both durability and compactness.
2Device complexity
If the nailing spring is uniformly compressed and stressed, then the structure is simple, but the ends of the spring suffer from greatest impact and are deteriorated
Solution Approach 1:
The spring incorporates varying wire diameter along its length, creating local quality differences. The central portion has larger diameter for strength while end portions have smaller diameter, which reduces impact stress concentration at the ends and improves durability without requiring complex multi-component structures.
3Force
If a large spring is used to enhance spring constant, then the hitting power is sufficient, but the nailing machine size increases
Solution Approach 1:
By concentrating the wire diameter increase in the central portion where elastic energy accumulation is most effective, the spring achieves high spring constant and hitting power without proportionally increasing overall size. The thinner end portions prevent linear scaling of dimensions.
Solution Approach 2:
The spring functions as a composite structure with varying cross-sections, combining regions of different wire diameters to optimize both force output and size, achieving high hitting power in a compact form factor.
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 unequal-pitch coil spring design enhances the durability of the nailing machine by absorbing impact at the ends and accumulating energy at the center, reducing the machine's size and extending its lifespan without compromising hitting performance.
Implementation Method 1
a spring that is expanded or compressed by the motor to accumulate elastic energy and that accelerates the plunger by opening the elastic energy
Data Source
AI summary
According to an aspect of the present invention, there is provided a nailing machine including: a housing; a motor that is accommodated in the housing; a plunger that plunges a nailing member; and a spring that is expanded or compressed by the motor to store an elastic energy therein and that accelerates the plunger by releasing the elastic energy, wherein a spring constant of the spring at one end of the spring in an expanding/compressing direction is set smaller than that of the spring at a center in the expanding/compressing direction.