GB2157181A - A string tension adjusting device for tennis rackets - Google Patents

Abstract

A device for adjusting the tension of the strings of a tennis racket, comprises a movable adjustment bar 22 provided in the racket throat. The bar has multiple string holes 221 with the string 222 going through them. Preferably a screw nut 23 is inserted at each end of the adjustment bar, each screw nut engaging a screw bolt 24 which is hinged on a bolt seat 25 which in turn is mounted on the racket frame. By using a wrench to turn the screw bolt, the screw nut can be moved up or down, which in turn will move the adjustment bar up or down, consequently the string on the adjustment bar will be extended longer or shorter, which results in the increase or decrease of string tension. Alternatively the position of the adjustment bar is controlled by a single threaded bolt and nut arrangement, or by a rack and pinion device. <IMAGE>

Description

SPECIFICATION A string tension adjusting device for tennis racket This invention relates to a tennis racket, particularly, a string tension adjusting device for tennis racket.

In the conventional rackets now appear in the market place, the string tension is fixed once the string is mounted on the racket frame by means of the string machine. In high string tension situation, the contact area between ball and racket is small.

The ball rebounds faster after hitting racket. Usually player can get more responsice strike, but is relatively more difficult to get the control and amneuverability of the ball. The high string tension is usually applied by the intermediate and advanced players.

In the low string tension situation, the contact area between ball and racket is larger, as ball sinks deeper into racket string after hitting racket. The control and maneuverability at the ball is better, also can render more effective spin, or slicing. Usually it is applied by the beginner to intermediate players to compensate the players short in skill.

As the players gain more experience and practice, they usually want to change the string tension to get the best fit power and control. In the present available racket, the only way they can do to achieve this is to cut off the old string and buy a new string and use the string machine to restring again. Or buy another racket. It costs money and time. Besides, once the string be mounted and fixed, there is no way to change the string tension. It means the players have to adjust themselves to suit the racket.

It takes players time and lots of trial and error to get used to a fixed-string-tension racket.

In addition, there are lots of other occasions and reasons when the players want to change and adjust the string tension, e.g. to apply different tactics more effectively between games (say straight drive or spin or slicing), at different courts (clay, cement, grass, synthetics courts, where the rebound speed of ball is different), different physical and body strength conditions of player (say vigorous at early games, but subdued at late games), to serving or to receiving, different types of rival, etc. But there is no way to fine-tune the string tension to meet those different needs by using the present available rackets. It is a once and for all.

This invention is to provide an improvement to remedy the aforementioned shortcoming. To give the racket the adjustment flexibility and capability so that the players can obtain the most balancing of power and control in the racket to suit them at different environments and situations.

The objective of this invention is to provide a built-in string adjustment feature on the racket which enable the players to increase or decrease racket string tension on-spot to suit their needs, and can do this in short period of time (usually by seconds) and by using simple and handy tool (such as T Hex Wrench).

The main feature of this invention to achieve the aforesaid objective is by providing a movable bar in the groove of the racket throat juncture, the bar is horizontally positioned vs the vertical axis of racket handle and grip, there are multiple string holes on the bar with string goes through them, and there is a screw nut inserting at each end of the movable bar, each nut gets a matched bolt goes through it, and the bolt head is hinged on the racket frame. By using wrench to turn the bolt head, the screw nut will be moved up or down, which in turn will move the bar up or down, and consequently extend string on the movable bar, thereby, increase or decrease the tension of the string.

Base on this principle, a number of different embodiments can be employed to achieve the same result. The section of Detailed Description will give more description of these embodiments.

An embodiment of this invention is described by means of example, with reference to the drawings in which: Figure 1 is a perspective view of the present invention. (Embodiment No. 1) Figure 2 is a knock down view of embodiment No.

1 and No. 2 of the present invention.

Figure 3 is an another embodiment of the present invention. (Embodiment No. 3).

Figure 4 is a further another embodiment of the present invention. (Embodiment No. 4) Figure 5 is a fragmental sectional view of Figure 4.

(Embodiment No. 4) Figure 6 is another fragmental sectional view of Figure 4. (Embodiment No. 4) Figure 7 is a knock down view of still another embodiment of the present invention. (Embodiment No. 5) Photographs No. 1 to 5 show the prototypes of the various embodiments of the present invention.

Referring to Figure 1,there is shown a perspective view of the present invention, wherein the racket frame 1 is same as that of the conventional one; racket shoulder 11 is the frame which approach the racket throat 2 and racket handle 3. Between the racket shoulder 11 and the racket throad 2, there is furnished a throad connecting juncture 29, in which there is a U-shaped groove 21 wherein inserting a horizontally positioned adjustment bar 22 which can be moved up or down. On the throat connecting juncture 29 surface, there are provided the extension scales 28 that can indicate the up or down distance of the bar position mark 225 which is on the outside surface of bar 22 as shown in Figure 1. The adjustment bar 22 be suggested a groove bar (e.g.U section bar made of light and rigid material such as aluminium alloy or carbon synthetic fiber); on the top of the adjustment bar 22, there are furnished a multiple numbers of string holes 221 with string 222 goes through them. There is a screw nut 23 inserting at each end of the adjustment bar 22, as shown in Figure 2. And a screw bolt 24 goes through and match nut 23. Bolt head 241 is inserting on the bolt seat 25 which is mounted on the racket frame 1 on the throat portion 2, as shown in Figure 1. Whereby by inserting a wrench 242 into the screw bolt head 241 to turn the bolt 24, screw nut 23 can be moved up or down, which consequently will move the adjustment bar 22 up or down, thereby the tension of the string 222 which goes through bar 22 will be adjusted to increase or decrease.In order to absorb the strong impact from the coming ball, a reinforced frame 26 is provided to clamp over the outside of the U-shaped groove 21, and with both ends fixed on the racket shoulder 11 as shown in Figure 1.

Referring to Figure 2, there is shown another embodiment of the present invention, in which a screw bolt pad 27 is furnished at both ends of the reinforced frame 26 corresponding to the positions of the nuts 23; in this embodiment, no screw bolt seat 25 is needed. The screw bolt 24 upon passing through the nut 23 will directly contact against the screw bolt 27. For making adjustment, use a wrench 242 to turn the screw bolt 241, the screw nut 23 will be moved up or down, which will move adjustment bar 23 up or down at the same time, and the tension of string 222 will be decreased or increased accordingly.

Referring to Figure 3, there is shown a further another embodiment of the present invention, in which a cross-section or f-section adjustment bar 22' is mounted in U-shaped groove 21 of the racket throat juncture portion 29; the top of the adjustment bar 22' is provided with a multiple numbers of string holes 221. The bottom edge of the adjustment bar 22' is connected to a control bar 31, which is extended downwards through racket handle 3. The bottom end 312 of the control bar 31 entends through the inner hollow space of the grip 4 and insert into a U-shaped groove 412 of a cross-shaped sliding block 41, and connected with the sliding block 41 by a connecting pin 413. The other end of the sliding block 41 is furnished with a screw hole 414 and engaged with a screw 415 which has a hex head cap 416.The cap 416 is held by a washer 417 which in turn is held by the racket frame at the end of the grip 418. By using a wrench 420 to turn hex head cap 416, sliding block 41 will be moved up or down, which in turn will move control bar 31 up or down, which at the same time will move adjustment bar 22 up or down; therefore, the tension of string 222 can be adjusted to increase or decrease. On the throat connecting juncture 29, there is an extension scales 28 to indicate the change of extension length of the string 222 or the corresponding of string tension. On the control bar 31, there is also furnished with bar position mark 225 be pointing to the extension scale 28 to show the up or down position of the adjust ment bar 22.

Referring to Figure 4, there is shown a perspective view of a still another embodiment of the present invention, wherein two fragmental sectional views are shown in Figure 5 and 6 respectively. Refer to Figure 4, on the top of a reverse U-shaped adjust ment bar 22", there are multiple numbers of T shaped string holes 221 '. Under each hole 221' there is a string pin 223 and is fixed at both ends of the adjustment bar 22". The adjustment bar 22" is connected to the control bar 31 by means of connecting pins 313. The upper flange of control bar 31 which is inserted into the adjustment bar 22 is furnished with multiple numbers of smooth curved string guiding groove 224, each groove 224 housed a pair of string pins 223.Upon a string 222 passing through one T-shaped string hole 221', the string will slide along the guiding groove 224 and will be wound around two string pins 223 before going out of another T-shaped string hole 221', thereby the string 222 will hold tightly around the string pins 223. The string tension adjustment is indicated by means of a rotary pointer 316 attached to a pinion 315, which is engaged with a gear rack 314 on the side of the control bar 31. When the control 31 being moved up or down, gear rack 314 will move pinion 315 which in turn will rotate pointer 316. The change of string tension can be measured and indicated by the rotation angle of pointer of 316.

Referring to Figure 7, there is shown a knock down view of again another embodiment of the present invention, in which the top of the throat connecting juncture 29 is furnished with a U-shaped groove 21 with multiple numbers of extruded rails 211 on the inside wall to hold and clamp adjustment bar 22"'; the adjustment bar 22"' is furnished with multiple numbers of string holes 221 with the string goes through them. A reinforced frame 26 is furnished to clamp the throat connecting juncture 29 over the outside of groove 21 to absorb the impact of the coming ball. When the control bar 31 is moved up or down, each pair of the string holes 221 with strings passing through will also be moved up or down in the concave portion 212 of the groove 21 thereby the tension of the strings can be adjusted as required.

The aforesaid embodiments should not be construed as the limit of the present invention. Any disclosure of the similar kind with minor modification which can be applied in tennis racket, squash racket and racquet ball racket should be included in the scope of the present invention claimed.

Claims (7)

1. A string tension adjusting device for tennis racket or squash racket or racquet ball racket comprising: an adjustment bar, which includes position mark on the surface, and multiple numbers of string holes on its top for winding strings, and with a screw nut inserted at each end; and the throat connecting juncture, which includes a groove for holding the adjustment bar, and the tension scale to indicate the tension change of the string; reinforced frame, which is mounted over the throat connecting juncture outside the groove with two ends fixed on the racket frame; and screw bolt, which matches the screw nut on the adjustment bar, and is hinged on a bolt seat which is mounted on the racket frame; and upon turning said screw bolt by a wrench, the adjustment bar can be moved up or down to increase or decrease the tension of strings.

2. A string tension adjusting device for tennis racket as claimed in claim 1, wherein a screw bolt pad is provided at the corresponding position of the screw nut at each end of the reinforced frame; and the screw bolt passing through said screw nut, and directly contact against said screw bolt pad without the bolt seat on the racket frame to hinge the screw bolt.

3. A string tension adjusting device for tennis racket as claimed in claim 1, wherein the adjustment bar may be in "cross" or "f" cross section; and the lower part of the said adjustment bar is connected to a control bar with its bottom end extends through the racket handle and inner hollow space of the grip and inserting into the U-shaped groove of a crossshaped sliding block, and connected to it; and the other end of said sliding block is furnished a screw hole which is engaged by a screw bolt which is held by a washer and said washer is held by the racket frame at the grip end. Through turning said screw bolt by the head, said sliding block will be moved up or down, thereby said control bar and adjustment bar will be moved up or down, consequently the tension of the string on adjustment bar can be increased or decreased.

4. A string tension adjusting device for tennis racket as claimed in claim 3, wherein the adjustment bar may be formed by a reverse "U" shape groove bar, of which the top is furnished with multiple numbers of T-shaped string holes, and under said string holes, there are furnished with string pins. Top flange of said control bar is inserted into and connected to said adjustment bar, and on said top flange of control bar, there is a smooth curved string guiding groove to house a pair of string pins, string can be wound around string pin by passing through T-shaped string holes and slide over said guiding groove. The up or down movement of said control bar will increase or decrease the string tension wound around said string pins.

5. Astring tension adjusting devicefortennis racket as claimed in claim 3, wherein a gear rack is provided on one side of the control bar; and on one side of the throad connecting juncture, there is furnished with a pinion engaged with said gear rack, and said pinion is attached a pointer. The movement of control bar will turn the pinion which rotates said pointer to different angles, thereby to indicate the net increase or decrease of the string tension.

6. Astring tension adjusting device for tennis racket as claimed in claim 3, wherein the control bar is furnished with position mark and on the throat connecting juncture, an extension scale is furnished so as to indicate the increase or decrease of the string tension by the moving position of said position mark on the control bar against said extension scale.

7. A string tension adjusting devicefortennis racket as claimed in claim 3, wherein the throat connecting juncture is furnished with a U-shaped groove with multiple numbers of rails on its inside wall to hold said adjustment bar and with reinforced frame clamp the throat connecting juncture over said groove to absorb impact from the coming ball.