Thermoplastic Racquet Frame with Integrated String Support

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Solution Overview

Problem

Current sports racquets made from aluminum and fiber composite materials face challenges such as increasing costs, supply shortages, and high production costs, while thermoplastic racquets have reliability and durability issues and undesirable performance characteristics.

Innovation Solution

A sports racquet frame formed from a thermoplastic material, including a thermoplastic resin and fiber segments, with a design featuring first and second hoop regions and handle regions, where projections and bores engage to support the racquet string, providing a cost-effective and reliable solution with enhanced design flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If aluminum or fiber composite materials are used for racquet frames, then strength and durability are improved, but manufacturing cost and production complexity increase

Engineering Contradiction:
Improveracquet frame strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies composite materials by combining thermoplastic resin with fiber segments (such as carbon, graphite, glass, or aramid fibers) to create a racquet frame that achieves the strength and durability of traditional aluminum or fiber composite racquets while enabling more economical injection molding production. The fiber segments are dispersed throughout the thermoplastic matrix to provide reinforcement.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameter from thermoset composites to thermoplastic composites, allowing the use of injection molding technology. This parameter change enables automated production, reduces manufacturing cost, and improves production efficiency while maintaining the structural integrity and strength requirements through the fiber-reinforced composite formulation.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If fiber composite materials are used for racquet frames, then design flexibility is improved, but production time and complexity increase

Engineering Contradiction:
Improvedesign flexibilityVSAvoidproduction time
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent changes the material state from uncured fiber composite layers to injection-moldable thermoplastic composite material. This allows complex racquet designs with integrated features (such as the projection and bore configurations for string support) to be produced in a single automated injection molding process, dramatically reducing production time while maintaining design flexibility.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent merges multiple production steps into a single injection molding operation. The racquet frame is formed directly in the mold with all structural features, including the head portion, handle portion, throat portion, and the projection-bore string support system, eliminating the need for separate assembly operations required by traditional fiber composite construction.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If thermoplastic material is used for racquet frames, then manufacturing cost is reduced, but reliability and durability deteriorate

Engineering Contradiction:
Improvemanufacturing costVSAvoidracquet frame reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent uses fiber-reinforced thermoplastic composite material to overcome the weaknesses of pure thermoplastic. The fiber segments (carbon, graphite, glass, or aramid) dispersed in the thermoplastic matrix provide enhanced strength, stiffness, and durability, achieving reliability comparable to or exceeding traditional aluminum and fiber composite racquets while maintaining the manufacturing advantages of thermoplastic injection molding.

Inventive Principle:
Principle #40Composite materials

4Productivity

If thermoplastic material is used for racquet frames, then production speed is improved, but performance characteristics deteriorate

Engineering Contradiction:
Improveproduction speedVSAvoidracquet performance
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The fiber-reinforced thermoplastic composite material provides the necessary performance characteristics for racquet playability. The fiber segments contribute to the frame's stiffness, power, and control properties, while the thermoplastic matrix provides toughness and impact resistance. This composite formulation achieves performance parity with traditional materials while enabling faster injection molding production.

Inventive Principle:
Principle #40Composite materials

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 thermoplastic racquet offers exceptional performance, reliability, and durability, allowing for quick and cost-effective production without compromising feel or playability, while maintaining a traditional design aesthetic.

Implementation Method 1

a frame formed of a thermoplastic material including a thermoplastic resin and a plurality of fiber segments

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Data Source

PatentEP2735346B1Optimised thermoplastic racquet
Publication Date: 2016.04.06 WILSON SPORTING GOODS CO(US)
  • EP2735346B1 patent drawingFigure 1
  • EP2735346B1 patent drawingFigure 2
  • EP2735346B1 patent drawingFigure 3

AI summary

A sports racquet extends along an axis and is configured for use with a quantity of racquet string forming a string bed about a string plane. The racquet includes a frame formed of a thermoplastic material, and including first and second halves including first and second spaced apart hoop regions, and first and second handle regions, respectively. The hoop regions includes projections extending from hoop regions in a direction orthogonal to the string plane. At least one of the hoop regions defines a set of bores. The projections are configured to matably engage the bores. The projections extend through the string plane and define curved bearing surfaces configured for engaging and supporting the racquet string. The projections include first and second projections having first and second radii of curvature, respectively. The first radius of curvature being at least 0.5 mm greater than the second radius of curvature.