GB2198959A

GB2198959A - Racket with improved shaft

Info

Publication number: GB2198959A
Application number: GB08630493A
Authority: GB
Inventors: Jin-San Hong
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-12-20
Filing date: 1986-12-20
Publication date: 1988-06-29
Also published as: FR2608443B1; IT1222948B; FR2608443A1; IT8722337A0; DE3700072C1; CA1286332C; GB8630493D0

Abstract

A racket, particularly for badminton, comprises a head 12 and a handle shaft 14 and includes a waved zone 16 at a predetermined location in the handle shaft, whereby the bottom of said waved zone 16 acts as an inflection point of oscillation and such point being easily recognizable from its appearance. The waved zone 16 can store more potential energy than that of a convention design because of stress concentration, and release of the potential energy will provide additional impact force. Furthermore, upon hitting, there is a strain at the waved zone 16 greater than that in a conventional design, and thus the degree of oscillation is increased, duration of impact between incoming ball and strung surface of the racket is prolonged, and control on the ball is hence easier. <IMAGE>

Description

"Racket with Improved Shaft" The present invention relates to a racket, particularly a badminton racket with means on its shaft to enable a player to recognize its inflection point, to provide greater kinetic energy when hitting, and to provide better ball control.

The action offorces upon hitting, results in racket oscillations. The degree of oscillation depends on the location of the inflection point of the racket shaft. Thus, the closer the inflection point to the grip, the greater the degree of oscillation, and the closer the inflection point to the racket head, the smaller the degree of oscillation. The degree of oscillation has a definite effect on ball control and on the impact force on hitting. Recognition of the inflection point which suits a player's capacity is very important. Conventional rackets use straight shafts of constant cross section and it is impossible to recognize their individual inflection points.

Therefore, it is hard to make a decision when purchasing a racket.

Another defect of the straight shaft design in the conventional racket is that it cannot absorb large impulses and such impulses have to be absorbed by the players arm. Consequentially, the player's elbow may be injured by vibration, and it is not possible to apply a reaction force to increase the impact force of hitting. Furthermore, the limited duration of impact between an incoming ball and the strung surface of the racket due to a limited degree of oscillation, makes control of the ball difficult.

The main object of the present invention is to provide a racket in which the inflection point can be recognized easily from its appearance, to facilitate choice at purchase.

Another object of the present invention is to provide a racket which can absorb large impulses and store more potential energy in order to reduce vibration at the player's arm during hitting and to increase impact force from the release of the stored potential energy.

Another object of the present invention is to provide a racket which can prolong duration of impact between the incoming ball and strung surface of the racket, in order to improve control of the ball.

A racket according to the present invention comprises a frame having a head connected to a handle shaft and characterised by a continuous waved zone at a predetermined location in the handle shaft whereby the bottom of said waved zone acts as an inflection point for oscillation.

Such waved zone enables the inflection point of oscillation to be easily recongizable from its appearance. The waved zone can store more potential energy than that stored by conventional designs because of stress concentration, and the release of the potential energy will provide additional impact force. Furthermore, upon hitting, there is a strain at the waved zone greater than that in the conventional design, and thus the degree of oscillation is increased, the duration of impact between an incoming ball and the strung surface of the racket is prolonged, and control of the ball is hence easier.

A badminton racket according to the present invention may comprise a frame having a head connected to a handle shaft so as to have an overall length of 24 to 27.5 inches (61 to 70 cms) and a weight of 2.8 to 3.9 ounces (79 to 110 g). The head has a strung surface of 48 to 60 square inches (309 to 387 square centimetres), and the shaft has a waved zone with a radius of curvature from 0.2 to 0.6 inches (0.5 to 1.5 cms), and a pitch of 0.4 to 1.2 inches (1.0 to 3.0 cms).

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a perspective view of an embodiment according to the present invention, Figure 2A illustrates oscillation of the embodiment according to the present invention after hitting, Figure 2B illustrates oscillation of a conventional racket after hitting, Figure 3A is a partial elevation view of one alternative embodiment of the shaft of a racket according to the present invention, Figure 3B is a partial elevation view of another alternative embodiment of the shaft of the racket according to the present invention, Figure 3C is a partial elevation view of another alternative embodiment of the shaft of the racket according to the present invention, Figure 3D is a partial elevation view of another alternative embodiment of the shaft of the racket according to the present invention, and Figure 3E is a partial elevation view of another alternative embodiment of the shaft of the racket according to the present invention.

A badminton racket 10 shown in Figure 1 has an overall length of 24 to 27.5 inches (61 to 70 cms).

The weight of the racket 10 is in the range of 2.8 to 3.9 ounces (79 to 110 g). The strung surface of the racket head 12 is in the range 48 to 60 square inches (309 to 387 square centimetres). The shaft 14 of the racket 10 has a continuous waved zone 16 in which the radius of curvature is in the range 0.2 to 0.6 inches (0.5 to 1.5 cms) and the pitch of the waved zone is in the range 0.4 to 1.2 inches (1.0 to 3.0 cms).

Referring to Figure 2A, whenever the racket 10 is hitting a ball and swinging backward by the action of an external force F, the waved zone 16 is the inflection point about which oscillation occurs.

Therefore, the bottom of said waved zone 16 represents the inflection point of the racket 16, and can easily be recognized from the appearance of the racket 16.

Such a feature enables a player to select a racket of his own choice. Whenever a ball is giving an impulse to the strung surface of the racket head (12), a strain occurs at the waved zone of the shaft (14) and potential energy is stored therein, and thus vibration transmitted to a player's arm can be reduced. After the external force has left the racket 10, the potential energy is released from the racket 10, the racket swings forward to its original position and the potential energy is turned into kinetic energy, which can act on an outgoing ball so that there is an additional impact force on the ball.

Upon application of an external force, there is considerable strain at the waved zone 16 of the shaft 14.

Referring to Figures 2A and 2B, these show a comparison, upon the same external force from an incoming ball, of the degree of oscillation of the racket 10 with a waved zone 16 in the shaft 14 and with a straight shaft. This shows that oscillation is greater with the waved zoned shaft 14 than with the conventional racket 20 with straight shaft. In other words, duration of impact on the strung surface of racket is prolonged and hence ball control is efficiently improved.

To meet different requirements of different players, the racket shafts shown in Figures 3A, 3B, 3C, 3D and 3E illustrate different types of badminton racket shafts that may be used. As shown in Figures 3B, 3C and 3D, a preferred badminton racket is 25.5 to 26.5 inches (64.8 to 67.3 cms) in length, 3.2 to 3.5 ounces (91 to 99 g) in weight, and 52 to 56 square inches (335 to 361 square centimetres)in strung area. Therefore the radius of curvature of the waved zone in the shaft of such racket is designed at 0.3 to 0.5 inches (0.7 to 1.3 cms) and its pitch is at 0.6 to 1.0 inches (1.5 to 2.5 cms) in order to acquire optimum physical capacities. As shown in Figure 3E, for children, the preferred badminton racket is 24 inches (61 cms) in length, 2.8 ounces (79 g) weight, and 48 square inches (309 square centimetres) in strung area, and thus its radius of curvature of the waved zone in the shaft is increased to 0.6 inches (1.5 cms), and its maximum pitch is not more than 1.2 inches (3.0 cms). As shown in Figure 3A, for a player with special requirements, the preferred badminton racket can be 27.5 inches (70 cms) in length, 3.9 ounces (110 g) in weight, and 60 square inches (387 square centimetres) in strung area, therefore, its radius of curvature of the waved zone in the racket shaft is reduced to 0.2 inches (0.5 cms) and the maximum pitch is not less than 0.4 inches (1.0 cms).

Claims

CLAINS

1. A racket comprising a frame having a head connected to a handle shaft and characterised by a continuous waved zone at a predetermined location in the handle shaft whereby the bottom of said waved zone acts as an inflection point for oscillation.

2. A racket according to Claim 1 wherein the overall length is 24 to 27.5 inches (61 to 70 cms) and the weight is 2.8 to 3.9 ounces (79 to 110 g), said head having a strung surface of 48 to 60 square inches (309 to 387 square centimetres), and the waved zone located in the shaft of the racket having a radius of curvature of 0.2 to 0.6 inches (0.5 to 1.5 cms) and a pitch of 0.4 to 1.2 inches (1.0 to 3.0 cms).

3. A racket substantially as hereinbefore described with reference to and as shown in Figure 1, 2A or 3A to E of the accompanying drawings.