Lightweight Golf Shaft Composite Design for Swing Stability
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Solution Overview
Problem
Conventional golf club shafts made of fiber-reinforced plastic face challenges in achieving high swing stability and consistent ball flight patterns, especially for golfers with faster head speeds, due to reduced thickness of fiber-reinforced plastic layers and compromised moment of inertia.
Innovation Solution
A golf club shaft design featuring multiple fiber-reinforced plastic layers with specific orientation angles (-5 to +5 degrees for straight layers and -20 to -75 and +20 to +75 degrees for bias layers, along with a smaller-diameter tip end and larger-diameter butt end, optimized to balance weight and bending stiffness, ensuring formulas 1 through 9 are satisfied for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of fiber-reinforced plastic layers is reduced to make the shaft lightweight, then swing speed increases, but swing stability and ball flight consistency deteriorate
Solution Approach 1:
The patent employs a composite structure with multiple fiber-reinforced plastic layers having different fiber orientations (straight layers at 0 degrees, bias layers at ±45 degrees, and hoop layers at 90 degrees). This multi-layer composite design allows the shaft to achieve both lightweight properties and high swing stability by distributing structural functions across different layer types, where each layer contributes differently to overall performance characteristics.
Solution Approach 2:
The patent applies local quality by varying the thickness and orientation of different layers at different positions along the shaft length. Straight layers are positioned in specific regions to control flex characteristics, while bias and hoop layers are distributed to provide circumferential strength and torsional stability. This localized optimization allows the shaft to be lightweight overall while maintaining stability in critical areas.
2Weight of moving object
If the number of straight layers is reduced to decrease weight, then swing speed improves, but flex becomes too soft and swing stability at impact decreases
Solution Approach 1:
The patent compensates for reduced straight layer quantity by incorporating bias layers and hoop layers that work synergistically to maintain impact strength. The bias layers at ±45 degrees provide diagonal reinforcement that enhances torsional rigidity, while hoop layers at 90 degrees provide circumferential strength. This composite approach allows fewer straight layers while maintaining overall impact resistance.
Solution Approach 2:
The bias and hoop layers serve multiple functions: they provide structural reinforcement, control shaft flex characteristics, and maintain torsional stability. These layers compensate for the reduced number of straight layers by performing multiple structural roles, thereby maintaining impact strength without requiring proportional increases in straight layer quantity.
Data Source
AI summary
Provided is a fiber-reinforced golf club shaft with small cantilever bending displacement despite its light weight, and provided to exhibit a longer carry distance while showing excellent ball flight patterns regardless of the skills of a golfer. The golf club shaft configured to have a plurality of fiber-reinforced plastic layers made of resin and a fiber material, comprising: wherein formula (1) below is satisfied when the length of the golf club shaft is set as “L” (mm), the weight as “W” (g), and the displacement as “D” (mm) that is observed when a cantilever bending test is conducted by exerting a predetermined load in the vicinity of the tip end while supporting the butt end to measure the displacement at the tip end.455≤D+7.5×W×(1168/L)≤515 (1)