GB2406059A

GB2406059A - A method of stringing a racquet

Info

Publication number: GB2406059A
Application number: GB0323015A
Authority: GB
Inventors: Jonathan William Bennett
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-09-16
Filing date: 2003-10-02
Publication date: 2005-03-23
Also published as: GB0323015D0; GB0321657D0

Abstract

A method of stringing a racquet in which three sets of strings are interwoven and tensioned to form the string grid. The angle between the strings and spacing may be varied. The method may be used for racquets for a variety of games.

Description

TRI-DIRECTIONAL RACQUET STRINGING

This invention relates to a method of stringing racquets, as used in various racquet sports, including lawn tennis.

Racquet sports comprise a large variety of different games, including badminton, squash, rackets, real tennis, and lawn tennis. The following descriptions are based on the lawn tennis racquet, but the method could be applied to any stringed racquet used for playing sports.

The construction of a tennis racquet consists of a handle, a hoop, and strings. Over the last hundred years, it has evolved in terms of design and materials to the point where today's racquets are embodiments of the latest technology, developed for speed, power and accuracy. There are still, however, areas of performance that leave room for further improvement. The area of performance that this method addresses is to do with the quantity, pattern, tension and useful life of the strings.

In a modern racquet, the strings are set out as a grid of vertical and horizontal components, sometimes of different materials, and often more densely arranged in the middle of the racquet hoop. During the action of hitting the ball, especially when serving or imparting spin, the vertical and horizontal components can become displaced, impairing the performance of the racquet, and shortening the life of the strings due to friction. A player will often be seen to adjust their strings between game points, or even to add "string-savers", small discs inserted at the overlap of two strings to minimise friction.

Another factor which is partially governed by the stringing is the "sweet spot", an area in the centre of the hoop where the action of hitting the ball shows the best ability of the racquet. As the size of the sweet spot is dependent on the size of the hoop, hoops have been getting larger over the years, to the point where the authorities have imposed maximum hoop dimensions at tournaments.

The tension at which the strings are strung is a matter of a player's individual choice, and at the highest level of the professional game, players will have their racquets strung not only to suit their own game, but also the court surface that they are playing on. It is generally understood that a lower tension will give greater power, while a higher tension increases control.

According to the proposed method, the strings are set out in a tridirectional formation, with each set of strings lying at an average of 60 degrees to the others, as opposed to the 90 degree formation of conventional racquets. The design of the hoop and handle of the racquet remains similar to conventional racquets, apart from the drilling pattern of the hoop, which has to accommodate the new string formation. The new string formation is seen as a pattern of hexagons, interspersed with triangles.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows an isometric close-up of the strings of a conventional racquet; Figure 2 shows an isometric close-up of the strings of a proposed racquet; Figure 3 shows a possible stringing sequence for the racquet shown in figure 4.

Figure 4 shows an example of the strung hoop of the proposed racquet with all the string sets at 60 degrees to one another; Figure 5 shows an example of an alternative stringing pattern of the proposed racquet shown in Figure 4, with the string sets arranged at 90 degrees to those in Figure 4; Figure 6 shows an example of the strung hoop where the lateral sets of strings are strung at a greater angle than the example shown in figure 4; Figure 7 shows an example of the strung hoop as shown in Figure 6, but with the strung area radially offset by 20 degrees.

The proposed racquet shown in figure 3 demonstrates that although it is more complicated to string than a conventional racquet, it is by no means impossible. When stringing a racquet by this method, it is important that any string is strung over all the cross-strings in one direction, and under all the cross-strings in the other, resulting in a multiplication of the even weave shown in figure 2.

For the purposes of this description, it is necessary to catalogue the required performance criteria for the strings of any racquet.

a./ The strings should form a grid, best capable of controlling the amplitude of the direction and spin of the kinetic energy of the projectile in play.

b./ The grid should be as stable as possible, distorting as little as possible during play, and, if possible, returning to the undistorted optimum state after a shot.

c./ The grid should be as durable as possible, lessening the likelihood of string breakages during play.

d./ The grid should be aerodynamically efficient, to enable a high racquet head speed to be achieved.

A modern conventional racquet relies largely on high string tension and non-uniform string spacing to achieve the best combination of the performance criteria detailed above.

In a conventional racquet, any projectile hitting the string grid will impose pressure on the hoop in four areas, which are centred at both ends of the strings which cross nearest to the point of contact of the projectile. The more evenly these areas are spaced around the hoop, the greater the "sweetness" of the resulting shot. This characteristic gives rise to the nominal "sweet spot" of a racquet. However, in the proposed racquet, there are six such pressure areas spaced around the hoop, and consequently, a greater proportion of the area of the stringing within the hoop is able to achieve a "sweet" resulting shot, and therefore the sweet spot is enlarged.

In a conventional racquet, the resistance to displacement of any string is firstly dependent on the inherent tension held in the string, and secondly dependent on frictional interaction with the cross-strings at right angles to it. Should the string be displaced sideways, as happens when imparting spin to the projectile, the inherent string tension will tend to re-straighten the string, but the friction of the cross-strings may prevent its full return to the optimum position. In the proposed racquet, the resistance to displacement of any string is still dependent on the tension held in the string, but the two sets of cross-strings exert tensional, as well as frictional, forces on it. When the string is in its straight, and optimum, position, these tensional forces are balanced out along the length of the string, but the more the string is displaced, the more the tensional forces exerted by the two sets of cross- strings become increasingly unbalanced, and act to force the string back to its original and optimum position. A much more stable grid is thereby achieved.

When a string in a conventional racquet is displaced during play, each point of contact with the cross-strings is moved directly along the crossstring, leading to the frictional erosion of a weak spot in the string's formation, which will eventually result in a string breakage. In the proposed racquet, a similar string displacement results in the points of contact with the cross-strings travelling up or down both the displaced string and the cross-string, with the result that the frictional erosion described above is spread over an elongated area of the string and the cross-strings, rather than a point, thereby greatly increasing the useful life of the strings.

When a player wishes to impart spin to the projectile, they do so by moving the racquet head across the intended line of the stroke as they hit it. A frictional interface between the projectile and the grid of strings is created, and depending on the amount of sideways movement and the efficiency of the frictional interface, a degree of projectile spin can be achieved. In gauging the efficiency of the frictional interface of a racquet, it is useful to think in terms of the roughness of the grid surface presented to the projectile. A modern conventional racquet, strung with 16 vertical and 18 horizontal strings, has 288 string crossing points, or nodes, per side. The example of the proposed racquet shown in figure 4 has 229 nodes per side. It can be argued that the proposed racquet has fewer nodes, and therefore a rougher surface, and that, like coarse sandpaper as compared to fine, it would create a more efficient frictional interface with the projectile to be spun, with greater results.

In a similar way, the proposed racquet shown in figure 4 is strung with a total of 30 strings, as compared with 34 in the typical modern racquet. This would mean that the proposed racquet would be more aerodynamically efficient, and would enable the player to achieve a greater racquet head speed during services or strokes.

If the proposed racquet strings are set at approximately 60 degrees to each other, as they are in figures 4&5, it follows that the spacing of the strings in each set will be uniform, otherwise the regular weave shown in Figure 2 is unattainable. If it is desired that the vertical set of strings be spaced more densely, then the angle of the lateral sets of strings to each other can be enlarged, resulting in a strung hoop as is represented in figure 6. Conversely, if it is desired that the vertical set of strings be spaced less densely, then the angle of the lateral sets of strings to each other can be diminished.

For the purpose of completing this description there could also exist a variation of the stringing arrangements already described, whereby a racquet that is strung using a weave having linear, but not rotational symmetry, as in Figure 6, could also be strung using a rotational bias, as in Figure 7. This would have the effect of changing the action of the racquet if the head were reversed, and would only be valid should it be found that a tangible benefit to performance was observed, as effectively this racquet would have designated "forehand" and "backhand" faces. 5.

Claims

CLAIMS(1) 1./ A method of stringing a racquet using three interwoven sets

of strings.
2./ A method of stringing a racquet, as claimed in claim 1, whereby each set of strings lies at 60 degrees to each of the others.
3./A method of stringing a racquet, as claimed in claim 1, whereby one set of strings lies at 60 degrees to one of the others.
4./ A method of stringing a racquet, as claimed in claim l, whereby no set of strings lies at 60 degrees to any of the others.
5./ A method of stringing a racquet, as claimed in claims 1 - 4, having any number of strings in any directional set of strings.
6./ A method of stringing a racquet, as claimed in claims I - 5, where the spacing of all the strings in all three directional sets of strings is the same.
7./ A method of stringing a racquet, as claimed in claims I - 5, where the spacing of all the strings in two of the three directional sets of strings is the same.
8./ A method of stringing a racquet, as claimed in claims l - 5, where the spacing of the strings in the three directional sets of strings is not the same.
9./ A method of stringing a racquet, as claimed in claims I - 8, where any stringing sequence is used to string the racquet.
I O / A method of stringing a racquet, as claimed in claims I - 9, where the same string is used in all the sets of strings
11./ A method of stringing a racquet, as claimed in claims I - 9, where different string is used in the sets of strings.
12./ A method of stringing a racquet, as claimed in claims I - 1 1, wherein the method is adapted for use in a racquet intended for use in playing lawn tennis.
13./ A method of stringing a racquet, as claimed in claims I - 11, wherein the method is adapted for use in a racquet intended for use in playing real tennis.
14./ A method of stringing a racquet, as claimed in claims I - 11, wherein the method is adapted for use in a racquet intended for use in playing squash.
15./ A method of stringing a racquet, as claimed in claims I - I 1, wherein the method is adapted for use in a racquet intended for use in playing badminton. 6.

CLAIMS (2)
16./ A method of stringing a racquet, as claimed in claims 1 1 1, wherein the method is adapted for use in a racquet intended for use in playing rackets.
17./ A method of stringing a racquet, as claimed in claims 1 - 11, wherein the method is adapted for use in a racquet intended for use in playing any racquet sport not specified in claims 12 to 16.
18./ A method of stringing a racquet, as claimed in claims I - I 1, wherein the method is adapted for use in a racquet intended for use in playing more than one racquet sport.
19./ A method of stringing a racquet, as claimed in claims I - 18, wherein the ratio of the area of the sweet spot of the racquet to the area of the hoop is greater than found on a conventional racquet.
20./ A method of stringing a racquet, as claimed in claims I - 19, wherein the strings are displaced less than those of a conventional racquet during play.
21./ A method of stringing a racquet, as claimed in claims 1 - 20, wherein the strings, when displaced during play, are more likely to return to their original positions than those of a conventional racquet.
22./ A method of stringing a racquet, as claimed in claims 1 - 21, wherein the strings, when displaced during play, rub along each other, as opposed to across, as do those of a conventional racquet.
23./ A method of stringing a racquet, as claimed in claims 1 - 22, wherein less string breakages occur than are found in a conventional racquet.
24./ A method of stringing a racquet, as claimed in claims 1 - 23, wherein greater and/or more controllable spin may be imparted to the projectile than is achievable when using a conventional racquet.
25./ A method of stringing a racquet, as claimed in claims 1 - 24, wherein the aerodynamic characteristics of the strings enable greater racquet-head speeds to be achieved than when using a conventional racquet.