The present invention relates to a string structure for sport rackets and the strings include a hollow center core and a plurality of periderm wires spirally wrapped around the center core.
The conventional sport rackets generally include a frame with a netted portion and a handle connected to the handle. The netted portion is composed of strings which can be Nylon strings, synthetic gut strings, or nature gut strings. The Nylon strings are durable but have less flexibility and are affected by changes of temperature. The nature gut intestine strings have better flexibility but are less stronger than the Nylon strings and synthetic gut strings. The conventional sport rackets are focused on the area of sweet spot which is an area on the netted portion and the players can ideally respond the balls that hit the sweet spot.
A conventional string structure is composed of periderm wires and a metal wire of predetermined length. The periderm wires and the metal wire are wrapped together along an axial direction. There is no center core for the string. Another conventional string includes a center core with periderm wires and the metal wire is wrapped along the center core. The periderm wires and the metal wire have different physical properties such as coefficient of extension. They provide flexibility and the metal wire reinforces the structural strength of the strings. However, these two conventional strings need to be improved in flexibility, durability, aid energy return coefficient.
The present invention provides a string structure that includes a hollow center core and periderm wires wrapped about a center core.
The present invention relates to a string for sport rackets and the string comprises a center core having at least one hollow portion extending in an axial direction of the center core. An outer layer comprising of a plurality of first periderm wires is provided around the center core.
A primary object of the present invention is to provide a string for sport rackets which absorbs shock effectively and provide better flexibility in response to a balls hitting a strung portion of the sport rackets.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
Referring to
As disclosed in
Referring to
As shown in
The first and second hollow portions 11, 12 of the center cores 10 provide sport rackets with more flexibility by virtue of the air in the hollow portions 11, 12. Consequently, excessive shock may be absorbed by deformation of the center cores 10. The first and second hollow portions 11, 12 of the center cores 10 reduce the energy transferred to players' hands so as to protect the muscles and wrists of the players from injury. Furthermore, the embodiment disclosed in
As shown in
While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.
Number | Name | Date | Kind |
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3745061 | Champaneria et al. | Jul 1973 | A |
4297835 | Shimizu | Nov 1981 | A |
4344279 | Ohara | Aug 1982 | A |
4499144 | van Rijswijk | Feb 1985 | A |
5327714 | Stevens et al. | Jul 1994 | A |
6062014 | Yeh | May 2000 | A |
6327841 | Bertini et al. | Dec 2001 | B1 |
Number | Date | Country | |
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20070028584 A1 | Feb 2007 | US |