Racket Frame Reinforcing Layer Modulus Control

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Solution Overview

Problem

Existing tennis racket frames are not resilient enough when a ball is hit away from the sweet spot, leading to reduced swing efficiency and control over the ball-hitting face.

Innovation Solution

A racket frame with a reinforcing layer for the gut groove formed from prepregs with carbon fibers and a matrix resin, where the compressive elastic modulus of the prepreg is equal to or less than 100 GPa, providing enhanced deformability and resilience when hitting the ball away from the sweet spot.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional reinforcing layer with high compressive elastic modulus is used, then the frame strength is improved, but the resilience when hitting away from sweet spot deteriorates

Engineering Contradiction:
Improveframe strengthVSAvoidresilience when hitting away from sweet spot
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies parameter changes by specifying a compressive elastic modulus range (10-100 GPa) for the prepreg material in the reinforcing layer. This controlled parameter adjustment optimizes the balance between frame strength and resilience, allowing the frame to deform appropriately during off-center hits while maintaining structural integrity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by forming the reinforcing layer from prepregs that combine carbon fibers with matrix resin. This composite structure provides both the necessary strength and controlled deformability, enabling the frame to exhibit resilient behavior when hit away from the sweet spot while preventing breakage.

Inventive Principle:
Principle #40Composite materials

2Strength

If the reinforcing layer is made rigid, then breakage prevention is improved, but swing completeness deteriorates

Engineering Contradiction:
Improvebreakage resistanceVSAvoidswing completeness
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent changes the rigidity parameter of the reinforcing layer by controlling the compressive elastic modulus within 10-100 GPa. This allows the frame to be flexible enough for complete swings while remaining strong enough to prevent breakage during impact.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the reinforcing layer is made rigid, then breakage prevention is improved, but ball-hitting face direction control deteriorates

Engineering Contradiction:
Improvebreakage resistanceVSAvoidball-hitting face direction control
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent optimizes the compressive elastic modulus parameter to enable the ball-hitting face to deform and return effectively during off-center hits. This parameter control ensures directionality is maintained while preventing frame breakage.

Inventive Principle:
Principle #35Parameter changes

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 racket frame maintains high resilience and operability when hitting the ball away from the sweet spot, allowing for complete swing and direction control, with the deformable reinforcing layer absorbing impact and returning to its original shape for high-speed ball launch.

Implementation Method 1

A compressive elastic modulus of the prepreg is equal to or less than 100 GPa and greater than 10 GPa... the deformable reinforcing layer absorbing impact and returning to its original shape

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2762205B1Racket frame
Publication Date: 2016.09.07 DUNLOP SPORTS CO LTD
  • EP2762205B1 patent drawingFigure 1
  • EP2762205B1 patent drawingFigure 2
  • EP2762205B1 patent drawingFigure 3

AI summary

A head 4 of a racket frame has a gut groove 20. The head 4 includes side reinforcing layers 18. Each side reinforcing layer 18 is formed from a prepreg including carbon fibers and a matrix resin. The compressive elastic modulus of the prepreg is equal to or less than 100 GPa. The tensile elastic modulus of the prepreg is equal to or less than 100 GPa. The tensile elastic modulus of the carbon fibers is equal to or less than 160 GPa. Preferably, the prepreg includes amorphous carbon fibers.