Golf Club Shaft Local Reinforcement for Weight and Rigidity
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Solution Overview
Problem
Golf club shafts with reduced weight for average golfers face challenges in maintaining strength and flexibility, as reinforcement to prevent bending deformation leads to high flexural rigidity, making the shaft difficult to swing and affecting the bending feel.
Innovation Solution
A golf club shaft formed by multiple fiber-reinforced resin layers with specific configurations, including straight, bias, and hoop layers, where the flexural rigidity is controlled in different regions to maintain strength while preventing excessive rigidity, using a specific butt hoop layer with a thickness of at least 0.05 mm in the second region to enhance reinforcement without increasing flexural rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the shaft wall thickness is reduced to decrease weight, then the weight is reduced, but the strength in the deformation region becomes insufficient
Solution Approach 1:
The patent applies local quality by creating a specific butt hoop layer with thickness of 0.03mm to 0.10mm only in the second region (800mm to 900mm from tip end), while maintaining thinner wall thickness in other regions. This localized reinforcement provides necessary strength in the deformation region without increasing overall shaft weight, resolving the contradiction between weight reduction and strength maintenance.
2Strength
If reinforcement is added to the deformation region to increase strength, then the strength is improved, but the flexural rigidity becomes excessively high
Solution Approach 1:
The patent implements local quality by providing reinforcement only in the second region (800mm to 900mm from tip end) through the specific butt hoop layer, while keeping the first region (200mm to 300mm from tip end) with lower EI/t ratio (10 to 40). This selective reinforcement maintains strength where needed while preserving flexibility and proper bending feel in the deformation region, avoiding excessive flexural rigidity that would hinder swing ease.
Solution Approach 2:
The patent segments the shaft into different regions with different structural characteristics: the first region with EI/t of 10 to 40 for flexibility, the second region with EI/t of 45 to 80 for strength, and intermediate regions transitioning between them. This segmentation allows each region to perform its specific function, resolving the contradiction between strength and ease of operation.
3Weight of moving object
If the shaft wall thickness is uniformly reduced, then the weight is reduced, but the shaft becomes difficult to manufacture with proper strength distribution
Solution Approach 1:
The patent applies local quality by specifying a particular hoop layer thickness range (0.03mm to 0.10mm) for the specific butt hoop layer in the second region, while allowing different thicknesses in other regions. This approach simplifies manufacturing by providing clear local specifications rather than requiring complex variable thickness control throughout the entire shaft, while still achieving optimal weight and strength distribution.
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 solution results in a lightweight shaft that is easy to swing and provides a proper bending feel for average golfers, maintaining sufficient strength and flexibility by controlling flexural rigidity in the second region, thus improving the overall golfing experience.
Implementation Method 1
The shaft is formed by a plurality of fiber reinforced resin layers
Implementation Method 2
The shaft is hollow
Implementation Method 3
The shaft has a flexural rigidity EI (N·m2) and a shaft wall thickness t (mm) at each position in an axial direction of the shaft
Data Source
AI summary
Provided is a hollow shaft including a hoop layer. The shaft weight is 50 g or less. The shaft has a flexural rigidity EI (N·m2) and a shaft wall thickness t (mm). In a first region having a distance of 200 mm to 300 mm from the tip end, EI/t is 10 or greater and 40 or less. In a second region having a distance of 800 mm to 900 mm from the tip end, EI/t is 45 or greater and 80 or less. The hoop layer includes a partial hoop layer disposed in a part of an entire length of the shaft. The partial hoop layer includes a specific butt hoop layer that is not present in the first region and that is disposed over an entirety of the second region. The specific butt hoop layer has a thickness of 0.05 mm or greater.