String for use in racket
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Solution Overview
Problem
Existing racket strings, particularly those made of synthetic resin, lack an optimal balance between hitting feeling and durability, with polyester strings being too hard and nylon strings still not replicating the softness of natural gut, while natural gut is expensive and less durable.
Innovation Solution
Irradiate untreated strings made of thermoplastic resin, preferably polyester or nylon, with gamma rays in the range of 250 to 2000 kGy to enhance elongation rates and improve hitting feeling without compromising durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If natural gut is used as the string, then excellent hitting feeling is achieved, but durability is inferior and cost is high
Solution Approach 1:
The patent applies gamma ray irradiation to change the physical and chemical parameters of synthetic resin strings, specifically increasing elongation rate and modifying molecular structure to achieve softer hitting feeling while maintaining durability
Solution Approach 2:
The patent uses composite material approach by combining synthetic resin base materials (polyester or nylon) with gamma irradiation treatment to create a string that combines the durability of synthetic materials with the softness traditionally associated with natural gut
2Reliability
If polyester string is used, then durability is excellent, but hitting feeling becomes hard
Solution Approach 1:
The patent changes the physical parameters of polyester strings through gamma irradiation, specifically increasing elongation rate from typical low values to 9.25-18.6% at 217 MPa stress, which softens the hitting feeling while preserving the inherent durability of polyester material
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 irradiated strings achieve a balance of excellent hitting feeling and durability, approaching the softness of natural gut while maintaining structural integrity, suitable for various sports like tennis, squash, and badminton.
Implementation Method 1
irradiating the untreated string with gamma rays in an irradiation amount of greater than or equal to 250 kGy but less than or equal to 2000 kGy
Data Source
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AI summary
A method of manufacturing a string 10 for use in a racket includes: (A) preparing an untreated string; and (B) irradiating the untreated string with radioactive rays. Preferably, the untreated string is irradiated with gamma rays. A preferable irradiation amount of the radioactive rays is greater than or equal to 250 kGy but less than or equal to 2000 kGy. Preferably, a material of the untreated string is polyester. Alternatively, the material of the untreated string may be nylon.