Tennis Racket Frame Projections for Aerodynamic Drag Reduction

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Solution Overview

Problem

Tennis rackets with large curvature at the leading end experience increased air resistance due to airflow separation, and attempts to enhance rigidity at this site often result in weight gain.

Innovation Solution

A tennis racket design featuring projections on the outer peripheral face in the range of maximum curvature, with a wider central thickness and narrower end thickness, and a grommet with recesses and protrusions to fit with these projections, reducing air resistance while maintaining rigidity without increasing weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the frame has large curvature at the leading end, then the racket achieves a streamlined shape, but airflow separation occurs during swing causing increased air resistance

Engineering Contradiction:
Improveframe curvatureVSAvoidair resistance
Core Design Contradiction:
ShapeVSObject-affected harmful factors

Solution Approach 1:

The invention applies different surface characteristics to different parts of the frame. Specifically, the outer peripheral face is made smooth in regions where airflow separation is likely to occur, while other parts of the frame can have different surface properties. This localized optimization prevents airflow separation at critical areas without compromising the overall streamlined shape of the frame.

Inventive Principle:
Principle #3Local quality

2Strength

If a member is added to increase rigidity at the leading end, then the frame rigidity is improved, but the racket weight increases

Engineering Contradiction:
Improveframe rigidityVSAvoidracket weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The invention implements rigidity enhancement only at specific locations where it is most needed - the leading end of the frame with large curvature. By concentrating reinforcement measures at this critical area rather than uniformly throughout the entire frame, the invention achieves the necessary rigidity improvement while minimizing the overall weight increase.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The frame is divided into different functional zones with different structural characteristics. The leading end portion with large curvature receives special structural treatment (such as increased thickness or internal reinforcement) to enhance rigidity, while other parts of the frame maintain their original design. This segmentation allows rigidity enhancement where needed without adding unnecessary weight elsewhere.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If the outer peripheral face has smooth curvature, then the racket achieves aerodynamic performance, but structural rigidity at the leading end is reduced

Engineering Contradiction:
Improveair resistanceVSAvoidframe rigidity
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The invention creates a dual-natured surface structure where the outer peripheral face maintains smooth curvature for aerodynamic performance, while the inner structure or specific regions provide the necessary rigidity. This is achieved by making the smooth surface characteristic localized to the outer face, while the underlying structure can have different properties to ensure structural integrity.

Inventive Principle:
Principle #3Local quality

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 design effectively reduces air resistance and improves swing speed by preventing airflow separation and maintaining structural integrity without adding weight.

Implementation Method 1

an airflow (flow of air) along an outer peripheral face thereof is prone to separating during a swing, which may induce greater air resistance

Methodology Applied
Scientific EffectAirflow separation: Flow Separation

Data Source

PatentEP3466499B1Racket and grommet
Publication Date: 2020.10.28 YONEX CO LTD
  • EP3466499B1 patent drawingFigure 1A~1B
  • EP3466499B1 patent drawingFigure 2A~2D
  • EP3466499B1 patent drawingFigure 3A~3B

AI summary

A racket includes: a grip; an annular frame; and a shaft coupling the grip and the frame together; wherein a projection is provided to an outer peripheral face on a leading end half of the frame in a predetermined range including a location of maximum curvature in a peripheral direction.