The present invention relates to a sporting racket using strings in a hitting area in tennis, badminton, etc. More particularly, the present invention relates to a racket that allows the tension of stretched strings to be changed (or adjusted) in an appropriate and easy manner.
Rackets for tennis, badminton, etc do not provide satisfactory tension of the strings stretched therein depending on the rigidity of the frame, the size of the face (size of the hitting area), the repulsive force of the strings, the preference of a player, etc. In such a case, the user must put up with the unsatisfactory tension or must stretch the strings again until a desired tension is obtained.
Current users of such rackets also face a situation in which the strings cannot be always maintained to have a desired tension due to the initial elongation of the string itself and the change by the repeated use.
The present invention has been made in view of the above and has an objective of providing a racket capable of easily adjusting the tension of the strings in a simple structure.
According to a first aspect of the present invention, there is provided a racket including a loop-shaped frame body having an inner surrounded region in which strings are stretched in a net shape to provide a hitting area; and a shaft section having a grip section gripped by a player, at a tip end section thereof, the racket comprising: a plurality of string holes provided in the frame body to allow the strings to be folded back therethrough; and a string tension adjustment member provided between the string holes positioned to be adjacent to each other to form a string folding portion and configured to allow the string to be folded in a desired position, wherein the string tension adjustment member includes columnar member having a string-contact face on a peripheral face thereof, and a distance from a rotation center of the string tension adjustment member to the string-contact face is variable.
In accordance with the racket structured as described above, the string tension adjust member can be operated to allow the string to be easily adjusted to have a desired tension.
In the racket, when the string-contact face is provided in a tapered helical manner on a peripheral face of the columnar member, the tension can be continuously changed to become a desired one. In this case, this columnar member may be made of a resin, metals such as aluminum, wood, or ceramics.
When the string-contact face in the racket is formed by a screw groove, a structure which is simple and that has a high reliability is achieved.
According to a second aspect of the present invention, there is provided a sporting racket including a loop-shaped frame body having an inner surrounded region in which strings are stretched in a net shape to provide a hitting area; and a shaft section having a grip section gripped by a player, at a tip end section thereof, the racket comprising: a plurality of string holes provided in the frame body to allow the strings to be folded back therethrough; and a string tension adjustment member provided between the string holes positioned to be adjacent to each other to form a string folding portion and configured to allow the string to be folded at a desired position, wherein the string tension adjustment member has a screw mechanism configured to change a position at which the string is folded.
Thus, according to the racket having the structure as described above, the string tension adjustment member functioning as the screw mechanism can be operated to easily adjust the strings of the racket to have a desired tension.
The racket as described above is superior to the racket according to the first invention in that the wedge action by the screw (force doubling action) can be used to easily change the force of the string.
When any of the rackets has a yoke section and the string tension adjustment member is disposed at the yoke section, a structure preferable from the viewpoint of practicality is obtained.
FIGS. 3(a), 3(b), and 3(c) are views showing the structure of a string tension adjustment member provided in the yoke section of
FIGS. 4(a) and 4(b) are partially enlarged perspective views of the string tension adjustment member with the string tension adjustment member shown in FIGS. 3(a), 3(b), and 3(c) provided in the yoke section of the racket, in which
FIGS. 6(a) and 6(b) are views showing a structure of the string tension adjustment member different from that of FIGS. 3(a), 3(b), and 3(c) in which a columnar member is formed by a tapered columnar member, in which
FIGS. 7(a) and 7(b) are views showing another embodiment illustrating the structure of the string tension adjustment member using a screw mechanism in which the string tension adjustment member is attached to the yoke section, in which
Hereinafter, embodiments of a sporting racket according to the present invention will be described with reference to the drawings, and herein, a tennis racket will be described as an example of the sporting racket.
As shown in
The periphery of the frame body 3 has string holes 8 that penetrate the frame body 3 from an inner peripheral face 3a to an outer peripheral face 3b so that the strings 2 are inserted back and forth therethrough. These string holes 8 (see
As shown in
As schematically shown in a enlarged view of
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As shown in
In this embodiment, the string tension adjustment member 9 itself is fixed to the frame body 3 of the racket 1 by the tension by the string 2.
When a player desires to change the tension of the string 2 of the racket 1 having the structure as described above (e.g., when the player desires to slightly increase the tension), the tension can be increased by inserting a commercially-available hexagonal wrench (not shown) into a hexagonal wrench hole 9B provided at a top face 9A of the string tension adjustment member 9 to rotate the string tension adjustment member 9 in a counterclockwise direction in
Specifically, when the string tension adjustment member 9 is rotated so that the difference in distance from the string-contact face of this string tension adjustment member 9 which is in contact with the string 2 to the outer peripheral face of the frame body 3 becomes 2 mm, the tension of the string 2 can be changed by about 5.7 lb (2.6 kgf). When the difference in the distance becomes 3 mm, the tension of the string 2 can be changed by about 8.5 lb (3.8 kgf). The difference in the distance of about 2 mm to 3 mm is sufficient for practical use.
In this embodiment, only the strings 2 in the longitudinal direction in the sweet spot area of the racket 1 among the string 2 can be adjusted to have a different tension. Alternatively, as necessary only the strings 2 in the lateral direction in the sweet spot area also may be appropriately adjusted to have a different tension. In a further alternative, the strings 2 both in the longitudinal and lateral directions may be adjusted to have a different tension.
Nonetheless, only the change in the tension of the strings 2 in the longitudinal direction in the sweet spot area can effectively adjust the tension of the strings 2 of the racket.
As shown in
In the case of the racket 1 according to Embodiment 2, all of the string tension adjustment member 9 and the folded parts of the string 2 are stored in the storage hole member 20 as shown in
The string tension adjustment member 9 also may be structured such that, a tapered columnar body the head of which is cut off as shown in FIGS. 6(a) and 6(b), has, at a peripheral face thereof, a screw groove 10 that functions as a string-contact face around which the string 2 is wound. In these drawings, the reference numeral 24 denotes a grommet provided between the string tension adjustment member 9 and the yoke section 5. This grommet 24 may be made of synthetic resin such as nylon or made of rubber.
In another embodiment in
In another structure in
In another structure shown in
Although the above embodiments have been described in terms of a racket having a yoke section, the present invention also can be applied to a racket having a yoke section or a racket having no yoke section. When the present invention is applied to a racket having no yoke section, the string hole provided in the yoke section is replaced by a string hole provided in a corresponding part of the frame body.
The above description has mainly been directed to a tennis racket. However, the present invention also can be applied to various rackets in which strings in the hitting area are stretched in a net shape, including badminton, squash, etc.
The present invention is carried out in the manner as described above. According to the racket of the present invention, a simple structure can be used to change the tension of the strings in accordance with the preference of a player and in a simple and quick manner.
Furthermore, the racket according to the present invention does not cause a substantial increase in the weight or an unbalanced appearance.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP02/07151 | 7/15/2002 | WO | 6/30/2005 |