Strings for racquets

Abstract

Novel racquet strings and methods for making the same. A polymer cover combined with a low temperature adhesive is provided to the strings. The string of the present invention may employ a conventional string, such as a string having a center core comprising gut or synthetic material such as nylon, and a polymer cover impregnated with low temperature adhesive. The polymer cover covers the string along at least a portion of the length of the string.

Description

BACKGROUND [0001] The present invention relates to strings for sporting applications, and particularly to strings for racquets such as tennis racquets, badminton racquets, squash racquets, racquetball racquets and the like. [0002] Racquet strings must satisfy competing requirements. In a tennis racquet, for example, the principal requirements are playability and durability and it is difficult to satisfy both requirements in a single racquet string type. String construction and material selection has heretofore required a compromise between acceptable playability and durability. [0003] During play, particularly in tennis, the ball is usually hit with some degree of spin. To generate spin, the strings are brushed against the ball to impart a tangential force to it. This brushing action causes the individual strings to slide over one another and wear against each other. The rubbing action of one string against another as well as the impact of the ball creates notches in the strings at ...

AI Technical Summary

Benefits of technology

The present invention provides improved strings for racquets and methods for making them. The string includes a conventional string with a polymer cover that has at least some porosity and an adhesive disposed within the porosity. The adhesive may be a low temperature adhesive that can be processed at room temperature. The string may also have a composite covering at least a portion of the string, where the composite includes a polymer cover with at least some porosity filled with adhesive. The adhesive can be a low temperature adhesive or a pressure-sensitive adhesive that can be cured through exposure to ultraviolet light or an electron beam. The string may be made of monofiliment construction or multifilament construction, with the filaments of substantially the same diameter. The invention also provides an adhesive that includes at least one filler material, such as ceramics, metals, or polymers. The string has a dynamic modulus of less than about -30 kN / m and a durability of at least about (500 and 800, depending on its diameter.

Problems solved by technology

In a tennis racquet, for example, the principal requirements are playability and durability and it is difficult to satisfy both requirements in a single racquet string type.

This brushing action causes the individual strings to slide over one another and wear against each other.

These notches are the primary reason for string breakage; as the notching becomes more severe, the tensile strength of the string weakens and eventually it breaks.

The friction between the ball and the string during contact with the string surface also causes some string wear.

Unfortunately, gut strings have a short life due to notching and wear.

Few recreational players use gut strings because they are expensive and wear quickly.

Such synthetics generally are more durable than gut, but are not as playable.

Nylon strings demonstrate improved durability over gut, but even nylon strings are subject to frequent breakage by certain players, particularly power hitters and those who hit the ball with a lot of spin.

Such coatings have generally failed because they are inelastic and do not adhere well to the nylon surface as the string stretches in use.

However, the addition of stiff aramid fibers to a string matrix dramatically reduces the playability of the strings.

Nomex, which has better elastic properties than other aramids, has been added to the core of nylon strings with some success with regards to durability, but with a significant tradeoff with regard to playability.

The resultant friction between strings causes energy loss.

This energy loss may also affect playability.

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