EP0570307B1 - Tennisracket or the like - Google Patents

Abstract

Tennis racket or the like, consisting of a shaft (1) aligned in the median longitudinal axis (I, I') of a plane head, this head comprising a frame (5) intended to receive strings in order to form the stringing, connected to the shaft (1) by two branches (3, 4) in the form of a V defining a throat (wedge) (8), the throat (8) comprising at least two bridges connecting the two branches (3, 4) of the V, respectively a main bridge (10) arranged at the connections (11, 12) of each of the two branches (3, 4) of the V with the bottom (10) of the frame (5), and at least one intermediate bridge arranged between the main bridge (10) and the meeting point of the branches, characterised: - in that the intermediate bridge (15) is inclined with respect to the perpendicular to the median longitudinal axis (I-I'); - and in that the attachment points (16, 17) of this intermediate bridge (15) on each of the two branches (3, 4) are asymmetrical. <IMAGE>

Description

The invention relates to a new improved tennis racket or the like, for example for the practice of squash, badmington, etc.

As is known, in general, a tennis racket comprises a handle aligned in the median longitudinal axis of a flat basket, this basket comprising a frame intended to receive the sieve, connected to the handle by two V-shaped branches defining an open core, delimited by the two branches of the V and by a bridge arranged at the connection of the branches and the bottom of the frame. Such a racket is described, for example, in document US-A-4,082,274.

In document US-A-4 983 242, the core comprises several successive bridges, respectively a main bridge arranged at the connection of the branches and the bottom of the frame, and several parallel intermediate bridges, arranged between the main bridge and the end of the handle. These intermediate bridges are intended to strengthen the handle at the branches to limit bending.

In document US-A-5,005,834, a racket has been proposed, the heart of which has two pairs of intermediate crossed bridges, the attachment points of which on the branches are symmetrical with respect to the median longitudinal axis of the racket. These intermediate bridges are intended to stiffen the core and the frame. However, this arrangement has the same drawbacks as above.

In document DE-A-3 731 529, a tennis racket has been described, the single deck of which is inclined relative to the median longitudinal axis. In this way, the sieve has an asymmetrical shape giving the longitudinal strings called "uprights" different lengths between the part located to the left of the longitudinal axis passing through the handle and the part located to the right of this axis. This arrangement essentially aims to increase and offset the percussion zone (sweet spot) on one side of the racket. If the increase in the "sweet spot" improves the tolerance of the racket, this shift can be a handicap for the player.

The invention relates to a racket of the type in question with an intermediate bridge which has a better effect of damping vibrations upon impact.

This improved tennis racket or the like, consisting of a handle aligned in the median longitudinal axis of a flat basket, this basket comprising a frame intended to receive strings to form the sieve, connected to the handle by two branches in V defining a core, this core comprising at least two bridges, respectively a main bridge disposed at the connections of each of the two branches with the bottom of the frame, and at least one intermediate bridge disposed between the main bridge and the meeting point of the two branches of the V , is characterized in that the intermediate bridge is inclined relative to the perpendicular to the median longitudinal axis, and in that the attachment points of this intermediate bridge on each of the two branches are asymmetrical.

In other words, the invention consists in providing the intermediate bridge of the open heart, no longer parallel to the main bridge, but inclined with respect to the latter and with respect to the perpendicular to the median longitudinal axis, so as to that the position of the attachment points of this intermediate bridge with each of the branches forming the heart is asymmetrical relative to this median longitudinal axis of the racket. In this way, the vibratory waves which propagate in each of the branches, are damped by phase shift when they arrive at the handle of the handle. This results in better comfort and therefore less fatigue for the sportsman.

• le pont intermédiaire est incliné de 15 à 60 degrés, et de préférence au voisinage de 20 degrés, par rapport à la perpendiculaire à l'axe longitudinal médian ;
• le pont intermédiaire est disposé au milieu et est perpendiculaire à une des branches formant le coeur ;
• une extrémité de ce pont intermédiaire est située au milieu d'une des branches formant le coeur alors que l'autre extrémité vient prendre appui au point de raccordement du pont principal avec l'autre branche formant ce coeur ;
• la section du pont intermédiaire est constante ;
• la section du pont intermédiaire est la même que celle du pont principal et/ou des branches ;
• le pont intermédiaire est plus large et/ou plus épais que le pont principal et/ou des branches ;
• le pont intermédiaire est réalisé au moins pour partie dans un matériau ayant des propriétés viscoélastiques, tels que par exemple en un polyether bloc amide, ou un polyamide ou un polyuréthane thermoplastique ;
• le pont intermédiaire est rectiligne ou courbe ;
• la section du pont intermédiaire varie le long de sa longueur ;
• une des extrémités du pont intermédiaire vient se raccrocher au pont principal.

Advantageously, in practice:

• the intermediate bridge is inclined from 15 to 60 degrees, and preferably in the vicinity of 20 degrees, relative to the perpendicular to the median longitudinal axis;
• the intermediate bridge is arranged in the middle and is perpendicular to one of the branches forming the heart;
• one end of this intermediate bridge is located in the middle of one of the branches forming the heart while the other end comes to bear at the point of connection of the main bridge with the other branch forming this heart;
• the section of the intermediate bridge is constant;
• the section of the intermediate bridge is the same as that of the main bridge and / or the branches;
• the intermediate bridge is wider and / or thicker than the main bridge and / or branches;
• the intermediate bridge is made at least in part from a material having viscoelastic properties, such as for example a polyether amide block, or a polyamide or a thermoplastic polyurethane;
• the intermediate bridge is straight or curved;
• the section of the intermediate bridge varies along its length;
• one end of the intermediate bridge clings to the main bridge.

The manner in which the invention can be implemented and the advantages which ensue therefrom will emerge more clearly from the embodiment which follows, supported by the appended figures.

FIG. 1 is a summary schematic perspective representation of a first embodiment of a racket according to the invention, the characteristic core of which is shown in detail in FIG. 2.

Figure 3 is a detailed representation of another embodiment of the invention.

Figures 4 to 7 are schematic representations of other embodiments of the invention.

Referring to FIG. 1, the tennis racket according to the invention comprises a handle comprising a handle (1), shown here naked, the upper end (2) of which is connected by two V-shaped branches respectively (3) and (4) connected to the basket (5), intended to receive the screen, not shown. The median longitudinal axis (I, I ') of the racket, which passes through the handle (1) defines two half-baskets, respectively right (6) and left (7). The basket (5) is connected to the branches (3,4) forming the heart (8) at the ends (11) and (12) of the main deck (10).

According to the invention, the heart (8) substantially comprises in its middle another intermediate bridge (15) inclined at an angle alpha of twenty degrees relative to the perpendicular to the median longitudinal axis (I-I '). The connection point (16) of this intermediate bridge (15) on the branch (4) is closer to the end (12) of the main bridge (10) than is the connection (17) on the branch opposite (3) (see Figure 2).

In the embodiment shown in FIG. 3, the heart (8) comprises an intermediate bridge also designated by the reference (15), but one of the ends (17) of which is situated substantially in the middle of the branch (3) of the heart , while the other end (16) merges with the point of intersection (12) of the main bridge (10) and the other branch (4) of the heart.

Thus, during the striking of the ball, the vibratory waves generated by the impact propagate first in the half-baskets (6,7), then from there in the branches (3,4) until the connection (16,17) with the characteristic intermediate bridge (15). Part of the waves then continues to progress in the branches (3,4) and another part borrows the intermediate bridge (15) thus causing a phase shift of these waves. In addition, the attachment points (16,17) of the intermediate bridge (15), (forming a fulcrum) on the branches (3,4) of the heart no longer being symmetrical, the rigidity is then different on each of these two branches, which in turn leads to a reduction in amplitudes, therefore a damping of the resonance at the level of the handle (2), which improves the comfort of the user.

• le pont intermédiaire (20) (figure 4) est courbe et rejoint le pont principal (10) en (12) ;
• le pont intermédiaire (21), (figure 5), présente une section variable qui va décroissant de la branche gauche (3) à la branche droite (4) ;
• le pont intermédiaire (22) (voir figure 6) relie en courbe le milieu de la branche gauche au milieu du pont principal (10) ;
• le pont intermédiaire (23) relie comme précédemment (voir figure 7) le milieu de la branche gauche (3) au milieu du pont (10), mais est rectiligne (figure 7).

FIGS. 4 to 7 illustrate other embodiments of the invention, in which respectively:

• the intermediate bridge (20) (FIG. 4) is curved and joins the main bridge (10) at (12);
• the intermediate bridge (21), (Figure 5), has a variable section which decreases from the left branch (3) to the right branch (4);
• the intermediate bridge (22) (see FIG. 6) connects in a curve the middle of the left branch to the middle of the main bridge (10);
• the intermediate bridge (23) connects as before (see FIG. 7) the middle of the left branch (3) to the middle of the bridge (10), but is rectilinear (FIG. 7).

Although the embodiment has been described in relation to a tennis racket, it goes without saying that this racket can be used for other ball games, such as squash, badmington or the like.

Claims (10)

1. Racket for tennis or the like, consisting of a shaft (1) aligned in the median longitudinal axis (I,I') of a flat head, this head comprising a frame (5) intended to receive strings for forming the stringing, connected to the shaft (1) by two branches (3,4) in a V, defining a neck (8), the neck (8) comprising at least two lies, respectively a main tie (10) located at the junctions (11,12) of each of the two branches (3,4) of the V with the bottom (10) of the frame (5), and at least one intermediate tie located between the main tie (10) and the meeting point (2) of the two branches (3,4) in a V, characterised:

   - in that the intermediate tie (15) is inclined with respect to the perpendicular to the median longitudinal axis (I-I');

   - and in that the points (16,17) of attachment of this intermediate tie (15) on each of the two branches (3,4) are asymmetric.
2. Racket according to Claim 1, characterised in that the inclined intermediate tie (15) is located substantially in the middle, and is perpendicular to one of the branches forming the neck (8).
3. Racket according to Claim 1, characterised in that the intermediate tie (15) is inclined at 15 to 60 degrees with respect to the perpendicular to the median longitudinal axis I-I'.
4. Racket according to one of Claims 1 to 3, characterised in that one of the ends (17) of the intermediate tie (15) is situated in the middle of one of the branches (3) forming the neck, whereas the other end (16) bears on and merges with the point of connection (12) of the main tie(10) with the other branch (4) forming this neck.
5. Racket according to one of Claims 1 to 4, characterised in that, essentially, the cross-section of the intermediate tie (15) is the same as that of the main tie (10).
6. Racket according to one of Claims 1 to 4, characterised in that the intermediate tie (15) is wider and/or thicker than the main tie (10).
7. Racket according to one of Claims 1 to 6, characterised in that the intermediate tie (15) is made of a material having viscoelastic properties.
8. Racket according to one of Claims 1 to 7, characterised in that the intermediate tie (15,20,22) is curved.
9. Racket according to one of Claims 1 to 7, characterised in that the intermediate tie (21) has a cross- section which varies from one branch (3) to the other (4).
10. Racket according to Claim 1, characterised in that the intermediate tie (22,23) links one of the branches (3) of the neck (8) to the main tie (10).

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