Thick Elastomeric Tennis Ball Core for Rebound Retention
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Solution Overview
Problem
Tennis balls lose rebound and bounce performance over time due to pressure loss during play, necessitating frequent replacement and leading to waste and inconsistent performance in large collections.
Innovation Solution
A tennis ball design featuring a spherical hollow elastomeric core with a specific gravity less than 1 and a thickness of at least 4.5 mm, covered by a textile layer, maintains internal pressure below 34.5 kPa (5 psi), using ethylene copolymers and rubbers to ensure longevity and performance consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tennis balls are pressurized to enhance rebound performance, then rebound performance is improved, but pressure loss during play causes performance degradation over time
Solution Approach 1:
The patent changes the fundamental parameter of the core from pressurized to pressureless, eliminating the pressure loss issue while maintaining rebound performance through the elastic properties of the rubber composition containing polyethylene and polybutadiene
Solution Approach 2:
The patent uses a composite rubber composition combining polyethylene (5-60 parts per 100 parts rubber) and polybutadiene (30-100 parts per 100 parts rubber) to achieve both low density and high elastic recovery, enabling pressureless operation with sustained rebound performance
2Reliability
If tennis balls are packaged in pressurized containers to maintain performance, then performance characteristics are maintained, but packaging complexity and cost increase
Solution Approach 1:
The patent extracts the pressurization requirement from the tennis ball system, making the ball itself self-sufficient for maintaining performance without external pressurized packaging, thereby simplifying packaging to standard non-pressurized containers
3Reliability
If tennis balls are replaced frequently due to performance loss, then consistent performance is maintained, but waste and cost increase
Solution Approach 1:
The patent uses excessive action by incorporating 5-60 parts of polyethylene per 100 parts rubber, which provides such high elastic recovery and resistance to permanent deformation that the ball maintains performance far beyond typical usage periods, dramatically reducing replacement frequency and waste
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 maintains rebound performance within 4% of initial levels after four months, reducing waste and ensuring consistent playability, meeting competitive standards and allowing packaging in lower pressure or non-pressurized containers.
Implementation Method 1
a spherical hollow elastomeric core having a specific gravity of less than 1 and a thickness of at least 4.5 mm
Implementation Method 2
maintains rebound performance within 4% of initial levels after four months
Implementation Method 3
a spherical hollow elastomeric core having a specific gravity of less than 1
Data Source
Figure 1~3
Figure 4
AI summary
A tennis ball (10) comprising a spherical hollow elastomeric core (14) having a specific gravity of less than 1 and a thickness of at least 4.5 mm. The hollow spherical core having an initial pressure of no greater than 34.5 kPa (5 psi), and a textile covering (12). The tennis ball has a first tennis ball coefficient of restitution value of at least 0.53 when measured from an initial velocity of 27.4 m/s (90 feet/second) within 1 hour of the tennis ball first being removed from its packaging and being unused, and a second tennis ball coefficient of restitution value measured from an initial velocity of 27.4m/s (90 feet/second) after the tennis ball is exposed to atmospheric pressure for four months following the tennis ball being first removed from its packaging and is unused. The second coefficient of restitution value is at least 95 percent of the first coefficient value.