WO2003018143A1

WO2003018143A1 - Racket being improved elastic and repellent force

Info

Publication number: WO2003018143A1
Application number: PCT/KR2002/001626
Authority: WO
Inventors: Sun-Kyum Kim
Original assignee: Sun-Kyum Kim
Priority date: 2001-08-30
Filing date: 2002-08-29
Publication date: 2003-03-06
Also published as: CN1549735A; CN1246054C; US20040209715A1

Abstract

The present invention relates to a racket being improved elastic and repellent force including an elliptical head frame, a net unit installed along the inner surface of the head frame, a neck unit formed in the long axis direction of the head frame, a handle unit extended from the neck unit, and oblique grooves being consecutively formed along the \outer circumference of the head frame so that strings extended from the net unit can be wound on the head frame. Because the tension is improved in string, the strings crossing each other in the net unit can maintain a predetermined interval to improve the elastic and repellent force, and users can enjoy ball games without correcting the strings. Moreover, the present invention provides the racket having the excellent elastic and repellent force and impact absorption force without considering a material of the racket or strings or using a special device, and thus provides the simple and excellent racket which can be applied to various ball games with a low price.

Description

RACKET BEING IMPROVED ELASTIC AND REPELLENT FORCE

TECHNICAL FIELD

The present invention relates to a racket being improved elastic and

repellent force, and more particularly to, a racket being improved elastic

and repellent force which includes an elliptical head frame, a net unit

installed along the inner surface of the head frame, a neck unit formed in

the long axis direction of the head frame, and a handle unit extended from

the neck unit, oblique grooves being consecutively formed along the outer

circumference of the head frame so that strings extended from the net unit

can be wound on the head frame.

BACKGROUND ART

In general, as shown in Fig. 1, a racket 100 includes an elliptical

head frame 200, a net unit 300 installed along the inner surface of the head

frame 200 to pass through the head frame 200, a neck unit 400 formed in

the long axis direction of the head frame 200, a handle unit 500 extended

from the neck unit 400, and a lower end unit 600 formed at the end of the

handle unit 500.

Rackets are manufactured in a suitable thickness and size for ball games such as tennis, badminton and squash tennis. Especially, researches

have been made to improve a strength, an elastic and repellent force and

an impact adsorption force of the racket. There have been a lot of attempts

to improve the strength, elastic and repellent force and impact adsorption

force of the racket by improving a material thereof, which fails to suggest

the most suitable material for the racket.

In addition, the racket price is considerably changed according to

the material. Therefore, to provide the optimal racket by improving the

material results in the high price of the racket. Even if the racket is made of

a high quality material, it cannot completely solve the foregoing problems.

Accordingly, researches have recently been made to improve the property

of the racket by using a special component, less concentrated on the

improvement of the high-priced material.

For example, there has been suggested an invention which intends

to improve an impact adsorption force and an elastic and repellent force of

a racket by inserting a high elastic sponge piece into a net unit. However,

this invention fails to achieve the aforementioned objects because the

sponge piece is easily separated from the net unit due to an impact by a ball

in a tennis game.

As disclosed in the Korea Patent Official Gazette 2000-36629, there has been taught an invention which intends to improve an elastic and

repellent force and an impact adsorption force of a racket by mounting a

thrust device which can move in the up/down direction on the racket to

increase power of the racket.

However, the aforementioned invention using the thrust device

which can move in the up/down direction can only be applied to the tennis

racket due to structural problems. Moreover, the thrust device complicates

the structure of the racket, increases the production price of the racket,

and incurs the maintenance and repair expenses due to its partial damage.

Thus, this invention fails to provide the racket having high industrial

applicability.

The US Patent 6,062,994 as shown in Figs. 2 and 3 mounts a support

member 114 on the outer circumference of a head frame 124 to improve a

strength and an elastic and repellent force of the head frame 124.

However, the support member 114 for reinforcement increases a

weight of a racket 110. Therefore, when the racket 110 maintains a

constant weight, the head frame 124 is weakened.

In addition, fins 116 are protruded from the support member 114 to

the frame 124 to fix strings 123, to relatively increase air resistance. It

reduces racket performance compared with weight. Furthermore, a hitting surface is reduced as large as the protrusion width of the fins 116. In order

to obtain the sufficient hitting surface, a size of the head frame 124 is

increased, to increase the unit cost and weight of the racket 110. Because

the strings 132 are inserted into string holes 134, the strings 132 are

seriously bent in front of and behind the string holes 134 to reduce the

elastic and repellent force, and easily cut to reduce the life span. It is also

difficult to align the strings 132 in the up/down direction.

The formation process of the support member 114 including the fins

116 is complicated, and an additional process for punching the string holes

134 is necessary, to reduce productivity and increase defects. It results in

great production cost.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a racket being

improved elastic and repellent force which shows the same performance in

a variety of ball games including tennis without considering a property of a

material and installing a special device.

In order to achieve the above-described object of the invention,

there is provided a racket being improved elastic and repellent force

comprising an elliptical head frame, a net unit installed along the inner surface of the head frame, a neck unit formed in the long axis direction of

the head frame, a handle unit extended from the neck unit, and oblique

grooves being consecutively formed along the outer circumference of the

head frame so that strings extended from the net unit can be wound on the

head frame. In addition, the oblique grooves can be consecutively formed

in a part of the head frame.

Gas is filled in a space unit formed by the head frame, the neck unit

and the handle unit.

Preferably, the oblique grooves are rounded in the width direction of

the head frame. Differently from the general racket structure which cannot

easily control tension in string because the strings extended from the net

unit are passed through the insertion holes of the head frame and wound in

a "τ= " shape, the strings extended from the net unit are easily strung by

the rounded surface of the oblique grooves of the head frame.

In addition, high elastic tapes are adhered to the outer surfaces of

the oblique grooves, to improve tension in string.

On the other hand, the above-described object of the invention can

be achieved by forming the grooves on the outer circumference of the head

frame in the longitudinal direction, and adhering the high elastic tapes to

the outer circumference of the grooves. According to another aspect of the invention, the strings extended

from the net unit are coated by high elastic tubes in the oblique grooves,

thereby preventing the strings of the head frame from being abraded when

the racket collides with the ground in tennis and badminton.

In accordance with the present invention, the tension of the tennis

strings is improved without using a special component such as a general

support member. Therefore, the strings crossing each other in the net unit

can maintain a predetermined interval to improve the elastic and repellent

force, and users can enjoy ball games without correcting the strings.

Because the excellent elastic and repellent force and impact absorption

force are obtained without using a special device, the weight or size of the

racket or resistance is not increased. As a result, the whole weight of the

racket can be maintained 240g, which is smaller than the general racket

(270g) by 12% and the racket of Fig. 2 (300g) by 25%.

Especially, the racket of the invention does not need the support

member having the string holes, and thus prevents the elastic and repellent

force and the life span from being reduced because the tennis strings are

seriously bent in front of and behind the string holes. Moreover, it is not

necessary to consider which material is suitable for the racket or strings. A

defect rate and a number of processes are decreased by omitting a complicated formation process of the support member, which results in

improved productivity of the racket.

In addition, the elastic and repellent force, impact absorption force

and strength of the racket can be improved by incorporating the frame, the

neck unit and the handle unit, and filling various gases such as helium gas

and compression air in the space unit thereof, without considering the

material of the racket or strings and using a special device. In the case that

the entire elasticity of the racket is remarkably varied according to the

elastic and repellent force of the shaft itself, such as the badminton racket

or squash tennis racket, performance of the racket is sufficiently improved

to increase the entire strength of the racket. That is, the same strength of

the racket can be obtained with a small amount of material, to reduce the

weight of the racket. As a result, the high performance racket can be

manufactured easily with a low price.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view illustrating one example of a

conventional tennis racket;

Fig. 2 is a plan view illustrating another example of the conventional

tennis racket; Fig. 3 is a partial perspective view illustrating the tennis racket of

Fig. 2;

Fig. 4 is a perspective view illustrating a racket in accordance with a

first embodiment of the present invention;

Fig. 5 is an enlarged view illustrating part A of Fig. 4;

Fig. 6 is a perspective view illustrating a racket in accordance with a

second embodiment of the present invention;

Fig. 7 is an enlarged view illustrating part B of Fig. 6;

Fig. 8 is an enlarged view illustrating major parts of a racket in

accordance with a third embodiment of the present invention;

Fig. 9 is a perspective view illustrating a racket in accordance with a

fourth embodiment of the present invention; and

Fig. 10 is a cross-sectional view illustrating the racket of Fig. 9.

BEST MODE FOR CARRYING OUT THE INVENTION

A racket being improved elastic and repellent force in accordance

with the present invention will now be described in detail with reference to

the accompanying drawings.

Figs. 4 and 5 respectively illustrate a racket in accordance with a

first embodiment of the present invention, including an elliptical head frame, a net unit installed along the inner surface of the head frame, a neck

unit formed in the long axis direction of the head frame, and a handle unit

extended from the neck unit. Here, oblique grooves 13 are consecutively

rounded in the width direction of the head frame 3 along the outer

circumference of the head frame 3 so that strings 15 extended from the net

unit 5 can be wound on the head frame 3, and the strings 15 extended from

the net unit 5 are coated by high elastic tubes 19 in the oblique grooves 13.

The present invention provides the racket having the excellent

elastic and repellent force by increasing tension in string, and constantly

maintains the interval of the strings 13 crossing each other in the net unit 5

so that users do not have to adjust the interval of the strings 13 during the

ball game such as tennis.

Figs. 6 and 7 respectively illustrate a racket in accordance with a

second embodiment of the present invention, including an elliptical head

frame, a net unit installed along the inner surface of the head frame, a neck

unit formed in the long axis direction of the head frame, and a handle unit

extended from the neck unit. Here, oblique grooves 13 are consecutively

rounded in the width direction of the head frame 3 along the outer

circumference of the head frame 3 so that strings 15 extended from the net

unit 5 can be wound on the head frame 3, grooves 21 are formed on the outer circumference of the head frame 3 in the longitudinal direction, high

elastic tapes 16 are adhered to the outer surfaces of the grooves 21, and

the strings 15 extended from the net unit 5 are coated by high elastic tubes

19 in the oblique grooves 13.

That is, the present invention increases the tension in string by

forming the grooves 21 on the outer circumference of the head frame 3 in

the longitudinal direction, and adhering the high elastic tapes 17 to the

outer surfaces of the grooves 21. As shown in Fig. 8, oblique grooves 13-1

can be formed at the center portions of oblique protruding units 14

protruded from the outer circumference of the head frame 3 in the same

direction. Accordingly, the grooves 13-1 are prevented from being caved

into the head frame 3 not to reduce the strength of the head frame 3 like

the grooves 13 of Fig. 5.

Referring to Figs. 9 and 10, gas 18 is filled in a space unit formed by

a head frame 3, a neck unit 7 and a handle unit 9, and a lower end unit 11

having a lower end groove formed to be incorporated with a gas injection

unit 16 is formed at the end of the handle unit 9. Here, the gas injection unit

16 is installed on the inwardly-caved surface of the lower end unit 11 not

to be exposed to the outside environment. As illustrated in Fig. 11, a high

elastic tube 23 is adhered to the whole inner surface of the incorporated structure of a head frame 3, a neck unit 7 and a handle unit 9, to increase

elasticity of a racket 1, Even if cracks are generated in the racket 1 due to

poor formation and long time use, internal filling gas is prevented from

being leaked, to maintain elasticity of the racket.

Claims

WHAT IS CLAIMED IS:

^• 1. A racket being improved elastic and repellent force comprising:

an elliptical head frame;

a net unit installed along the inner surface of the head frame;

a neck unit formed in the long axis direction of the head frame;

a handle unit extended from the neck unit; and

oblique grooves being consecutively rounded along the outer

circumference of the head frame in the width direction of the head frame so

that strings extended from the net unit can be wound on the head frame.

2. The racket of claim 1, wherein protruding units are formed on the

outer circumference of the head frame, and oblique grooves are formed at

the center portions of the protruding units.

3. The racket of claim 1 or 2, wherein high elastic tapes are adhered

to the outer surfaces of the oblique grooves.

4. The racket of claim 1 or 2, wherein grooves are formed on the

outer circumference of the head frame in the longitudinal direction, and high elastic tapes are adhered to the outer surfaces of the grooves.

5. The racket of claim 1 or 2, wherein the strings extended from the

net unit are coated by high elastic tubes in the oblique grooves to prevent

abrasion.

6. The racket of claim 3, wherein the strings extended from the net

unit are coated by high elastic tubes in the oblique grooves to prevent

abrasion.

7. The racket of claim 4, wherein the strings extended from the net

unit are coated by high elastic tubes in the oblique grooves to prevent

abrasion.

8. The racket of claim 1, wherein the oblique grooves are formed in

a part of the outer circumference of the head frame.

9. The racket of claim 1, wherein gas is filled in a space unit formed

by the head frame, the neck unit and the handle unit.

10. The racket of claim 9, wherein a high elastic tube is installed in

the space unit, and the gas is filed through the high elastic tube.

11. The racket of claim 9 or 10, wherein the gas filled in the space

unit is helium gas.

12. The racket of claim 9 or 10, wherein the gas filled in the space

unit is compression air.

13. The racket of claim 9 or 10, wherein a lower end unit

incorporated with a gas injection unit is hermetically sealed to the end of

the handle unit.

14. The racket of claim 13, wherein the gas injection unit is a valve

device.