Games using tangible projectile – Player held and powered – nonmechanical projector – per se,... – With sound-deadening – vibration-damping – or shock-absorbing...
Reexamination Certificate
1999-11-30
2001-09-25
Chiu, Raleigh W. (Department: 3711)
Games using tangible projectile
Player held and powered, nonmechanical projector, per se,...
With sound-deadening, vibration-damping, or shock-absorbing...
C473S524000
Reexamination Certificate
active
06293878
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a tennis racket. More particularly, the present invention relates to a tennis racket having improved impact absorbing performance and vibration damping performance so that when a player hits a tennis ball with the tennis racket, an impact is applied to the player's elbow to a lesser extent in order to reduce generation of tennis elbow. The present invention relates also to a tennis racket which rotates on its grip to in a lesser extent to allow a player suffering from the tennis elbow to use it more easily.
DESCRIPTION OF THE RELATED ART
To reduce and soften a impact and a vibration of a tennis racket which is generated when a player hits a tennis ball therewith, vibration damping members are proposed as disclosed in Examined Patent Publication No. 52-13455 and Patent Application Laid-Open Nos. 52-156031 and 4-263876. In these proposals, a tennis racket is provided with a vibration damping member having a cantilever type damper to which a load material is fixed through an elastic material. The vibration of the tennis racket is damped by the vibration damping member which resonates with the vibration of the tennis racket. More specifically, in Examined Patent Publication No. 52-13455, as shown in
FIG. 13
, the cantilever type damper
6
formed of an elastic material is installed on the end of the grip
5
. The rear end of the steel wire
6
b
having the weight
6
a
installed at the front end thereof is embedded in the frame. In Patent Application Laid-Open No. 52-156031, as shown in
FIG. 14
, the base part
3
a
of the damper is fixed to the throat part
4
of a tennis racket, and the body part
3
c
thereof is connected with the base part
3
a
through the neck part
3
b
to vibrate the body part
3
c
. In Patent Application Laid-Open No. 4-263876, as shown in
FIG. 15
, the loading member
4
b
is fixed to the grip end of a tennis racket through the elastic member
4
a.
In the above-described conventional tennis rackets, the shape of the vibration damping member and the fixing position thereof are set to damp a primary vibration in an out-of-plane direction of the tennis racket (direction perpendicular to the gut-stretched plane of tennis racket, namely, thickness direction thereof). That is, the load material is fixed to the front end of one elastic material whose one end is fixed to the racket frame. In this construction, the elastic material and the load material vibrate in the out-of-plane direction before the racket frame vibrates, thus consuming vibration energy. That is, the elastic material and the load material suppress and damp the vibration and impact of the racket frame rapidly.
However, a player also feels vibrations in an in-plane direction (direction parallel with gut-stretched plane and widthwise direction of racket frame) as well as the out-of-plane direction vibration. When the player hits a ball with the tennis racket at a point thereof other than the axis of the racket frame, an impact generated by a rotation of the grip thereof makes the player feel very uncomfortable.
As shown in FIG.
16
(A), in the out-of-plane direction vibration of the entire racket frame, a large mountain M
1
is generated over the whole length of the tennis racket in its lengthwise direction. The apex (position of maximum amplitude) of the mountain M
1
is located at approximately the center P
1
of the tennis racket in its lengthwise direction. Supposing that a face part S is regarded as a clock and its top is 12 o'clock, the center P
1
is located a region from five o'clock of a gut-installing part
1
surrounding the face part S to a throat part. The gut-installing part
1
of the racket frame surrounding the face part S is deformed lengthwise and widthwise by the in-plane direction vibration, as shown in FIG.
16
(B). In the vibration, a maximum vibration occurs at the position of 12 o'clock (top position) and three o'clock of the gut-installing part
1
.
The position of a maximum amplitude of the out-of-plane primary vibration is located in the region from the position of five o'clock of the gut-installing part
1
to the throat part. The position of a maximum amplitude of the out-of-plane secondary vibration is located at the position of three o'clock of the gut-installing part
1
and a region of the grip in the vicinity of the throat part.
The in-plane direction vibration of the tennis racket has not been considered much hitherto. The in-plane direction vibration of the gut-installing part is generated by deformation of the gut strings with which a ball collides and has a great influence on a player's feeling, namely, on whether or not the player feels comfortable when the player hits a tennis ball. For example, a so-called large racket developed flight performance, having a large area in its face (gut) generates uncomfortable vibrations, more so than a tennis racket having a small face area. This is because the large face area thereof to gut strings and head portion of the former causes the be easily flexed in the in-plane direction. More specifically, the head portion former vibrates in the in-plane direction to a high extent. Accordingly, in the so-called large racket and a so-called thick racket developed flight performance, it is important to suppress vibrations in the in-plane direction as well as in the out-of-plane direction.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-described problem. Thus, it is an object of the present invention to suppress vibrations of a tennis racket in an in-plane direction thereof as well as in an out-of-plane direction thereof to allow impacts to be applied to a tennis player's arm to a lesser extent when the tennis player hits a ball therewith and allow the tennis player to feel comfortable throughout the hand and arm holding the racket.
In order to achieve these objects, there is provided a tennis racket having a vibration damping member provided in the vicinity of a position of a racket frame at which a large amplitude is generated when the tennis racket hits a tennis ball. The vibration damping member includes a mass adding part having a portion extending in a widthwise direction of the tennis racket an in-plane direction and a portion extending in a thickness direction thereof out-of-plane direction such that the both portions are integral with each other. Or a mass adding part having a portion extending in a widthwise direction of the tennis racket and a portion extending in a thickness direction thereof such that the both portions are unintegral with each other may also be provided. An elastic connecting part such as a viscoelastic material, a spring; or/and a damper each for connecting the mass adding part to the racket frame is provided. Each of the viscoelastic material, the spring, or/and the damper has a widthwise connection portion for connecting the widthwise portion of the mass adding part and the racket frame with each other and a thickness direction connection portion for connecting both sides of the thickness direction portion of the mass adding part and the racket frame with each other. The vibration damping member absorbs a vibration in the widthwise direction (in plane vibrations) of the racket frame, a vibration in the thickness direction thereof (out-of-plane vibrations), a vibration and an impact generated by a linear movement of a grip and a rotation thereof.
As described above, the vibration damping member to be installed on the racket frame consumes the vibration energy of the tennis racket increasingly as the amplitude thereof becomes greater. Thus, the mass adding part is combined with the viscoelastic material, the spring, or/and the damper. The mass adding part has the widthwise portion and the thickness direction portion. As described above, the widthwise portion and the thickness direction portion are installed on the racket frame through the elastic connecting part such as viscoelastic material and the like. That is, the widthwise connection portion and the thickn
Iwatsubo Takuzo
Kanemitsu Yumi
Chiu Raleigh W.
Sumitomo Rubber Industries Ltd.
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