Bat Barrel Restriction Member for ABI Test Stability

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Solution Overview

Problem

Conventional baseball and softball bats face challenges in maintaining a coefficient of restitution close to the limit value after the delamination of FRP, which can lead to increased rigidity and failure to pass the ABI test, requiring initial design adjustments to reduce the coefficient of restitution.

Innovation Solution

The bat features a ring-shaped restriction member inside the ball hitting portion, made of materials like metal or FRP, positioned to suppress deformation and stress concentration, combined with a core member for enhanced durability and stability, ensuring the coefficient of restitution remains within acceptable limits even after FRP delamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coefficient of restitution is initially reduced to ensure ABI test passage, then the bat can pass the ABI test, but the restitution performance is below the limit value

Engineering Contradiction:

ImproveABI test passageVSAvoidcoefficient of restitution

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The restriction member is installed in advance within the hollow cylindrical structure to pre-establish the deformation constraint mechanism. This preliminary action ensures that when the bat undergoes ABI testing or repeated impacts, the coefficient of restitution remains stable and close to the limit value without requiring initial reduction, thus resolving the contradiction between ABI test passage and maintaining high restitution performance.

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If the bat structure allows high coefficient of restitution, then the restitution performance is close to the limit value, but the FRP delaminates and rigidity increases after repeated impacts

Engineering Contradiction:

Improvecoefficient of restitutionVSAvoidFRP delamination resistance

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The restriction member acts as a protective element installed beforehand within the hollow cylindrical structure. It provides prior cushioning by limiting the deformation amount of the cylinder during repeated impacts, preventing excessive stress concentration that would cause FRP delamination. This allows the bat to maintain high coefficient of restitution close to the limit value while preventing rigidity increase and delamination.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If the hollow cylindrical structure is made more rigid to prevent delamination, then durability improves, but the coefficient of restitution decreases

Engineering Contradiction:

ImprovedurabilityVSAvoidcoefficient of restitution

Core Design Contradiction:

StrengthVSUse of energy by moving object

Solution Approach 1:

Instead of making the entire hollow cylindrical structure more rigid, the restriction member is strategically placed at specific locations where stress concentration occurs during impacts. This local reinforcement approach maintains the overall flexibility and high coefficient of restitution of the bat while providing localized strength to prevent FRP delamination and improve durability.

Inventive Principle:

Principle #3Local quality

4Strength

If the restriction member limits deformation significantly, then FRP delamination is prevented, but the coefficient of restitution drops below acceptable levels

Engineering Contradiction:

Improvedelamination preventionVSAvoidcoefficient of restitution

Core Design Contradiction:

StrengthVSUse of energy by moving object

Solution Approach 1:

The restriction member is designed with specific geometric parameters (dimensions, shape, material properties) that are optimized to limit deformation within an acceptable range rather than completely restricting it. By carefully adjusting these parameters, the bat achieves both delamination prevention and maintains coefficient of restitution close to the limit value, resolving the contradiction between strength and energy performance.

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 design effectively maintains a stable coefficient of restitution close to the limit value after FRP delamination, satisfying the ABI test requirements without initial reduction, while improving durability by preventing stress concentration and maintaining performance throughout repeated impacts.

Implementation Method 1

Deformation of the barrel is limited by the barrel coming into contact with the restriction member

Methodology Applied

Scientific EffectDeformation limitation: Deformation

Implementation Method 2

The restriction member is positioned to suppress deformation and stress concentration

Methodology Applied

Scientific EffectStress distribution: Stress Relaxation

Data Source

PatentUS10507368B2Baseball or softball bat

Publication Date: 2019.12.17 MIZUNO CORPORATION

AI summary

A bat according to the present disclosure includes a ball hitting portion, a grip portion, a tapered portion that connects the ball hitting portion and the grip portion together, and a restriction member. The ball hitting portion is internally hollowed. The restriction member is disposed inside the ball hitting portion. The restriction member is in the form of a ring. The restriction member is disposed such that a radial direction thereof is transverse to a longitudinal direction of the ball hitting portion.