Racket Frame Tubular Member with Release Layer for Stiffness Control

Solution Overview

Problem

Conventional racket frames made of fiber-reinforced plastic struggle to balance strength and stiffness, making it difficult to design optimal repulsive performance while maintaining sufficient strength.

Innovation Solution

A racket frame design featuring a tubular member with an inner and outer tubular part and a release layer sandwiched between them, where the release layer is strategically positioned to reduce stiffness in specific areas while maintaining strength, allowing for adjustable repulsive and vibration performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the stiffness of the racket frame is increased to secure the required strength, then the strength is improved, but the repulsive performance cannot be appropriately designed

Engineering Contradiction:

Improvestrength of racket frameVSAvoidrepulsive performance

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The racket frame is divided into multiple tubular members with different stiffness characteristics. Some tubular members include release layers to create localized flexibility, while others maintain high stiffness. This segmentation allows different parts of the racket frame to have different mechanical properties, enabling both strength and appropriate repulsive performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Release layers are strategically positioned in specific tubular members at specific locations of the racket frame where flexibility is needed. This local modification allows the racket frame to maintain high strength in critical areas while providing controlled flexibility and improved repulsive performance in specific regions through the release layers.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If the stiffness of the racket frame is reduced to improve repulsive performance, then the repulsive performance is improved, but the strength may become insufficient

Engineering Contradiction:

Improverepulsive performanceVSAvoidstrength of racket frame

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The racket frame is divided into multiple tubular members with different stiffness characteristics. Some tubular members include release layers to create localized flexibility, while others maintain high stiffness. This segmentation allows different parts of the racket frame to have different mechanical properties, enabling both strength and appropriate repulsive performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The tubular members are constructed as composite structures with inner and outer layers, and some include release layers. This composite construction allows the racket frame to combine materials and structures with different mechanical properties, achieving both high strength and controlled flexibility for improved repulsive performance.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS20240033583A1Racket Frame and Racket

Publication Date: 2024.02.01 MIZUNO CORPORATION

AI summary

A racket frame includes a face portion having an annular shape in planar view, a grip portion, and a shaft portion connecting the face portion and the grip portion. At least a part of the face portion, the grip portion, and the shaft portion includes a first tubular member. The first tubular member has an inner tubular part, an outer tubular part surrounding the inner tubular part, and a release layer sandwiched between the inner tubular part and the outer tubular part.