EP1557203B1 - Racquet for ball sports and method for its manufacture - Google Patents

Abstract

Racket (2) comprises a racket head (6) and a frame (4) with a connected grip section (10). The racket head defines a tensioned surface and the frame profile has an opening (12) extending through the frame profile and running vertically to the tensioned surface of the racket.

Description

The present invention relates to a racket for ball games, in particular a tennis, squash, badminton, racquetball or paddle tennis racket with excellent handling characteristics, as well as a manufacturing method for such a racket.

Such clubs typically include a frame that forms a club head and a handle portion connected thereto. Typically, a so-called heart region is formed in the transition region between the club head and the grip section. Usually, the frame is formed of a frame profile or hollow profile, which is often made of a carbon fiber reinforced plastic material in a molding press. The club head of the racket defines a clothing plane in which the clothing of the racket is placed. To accommodate the strings of the covering lying through holes are provided on the frame in the stringing level for the performance of stringed strings.

US-A-3,917,267 discloses a tennis racket formed from a frame having a substantially square club head and a handle portion projecting therefrom. The racket is covered such that each string length spanning the club head is perpendicular to the side members of the square club head to provide a ball striking surface in which the strings are each of equal length and tension. To reduce weight and to reduce the wind resistance may be provided in the corners of the club head openings in the frame.

DE-A-39 10 890 describes a racquet with a frame body having a head, a neck and a shaft. A gap between two opposing legs of the frame body is spanned by a neck bridge, which encloses a clothing surface together with the head. The neck bridge has an upper bridge portion and a lower bridge portion which extend substantially transverse to the longitudinal axis of the racquet and are spaced apart longitudinally of the racquet so as to define a slot therebetween. Between the two bridge parts, a damping body of vibration-absorbing material is arranged.

FR-A-821 471 and US-A-3,647,211 disclose a racket with a club head and a handle portion connected thereto in which recesses are provided.

US 5,188,360 discloses a racket with a club head carrying the clothing and a racket handle. The frame section forming the club head has at least one opening which runs perpendicular to the clothing plane. At least one elastic counterweight may be releasably fixed in the opening to affect the weight distribution of the racket. The counterweight has a plurality of through holes to receive the strings of the string.

The present invention has for its object to improve a racket of the type mentioned in terms of its handling characteristics, in particular its ball guide, while allowing a lightweight construction is possible. This object is achieved with a racket having the features of independent claim 1. In the dependent claims preferred embodiments of the racket according to the invention are described. The independent method claim 12 relates to a manufacturing method for such a racket. The dependent claims relate to advantageous embodiments of the method according to the invention.

The racquet for ball games according to the invention has a frame formed from a frame or hollow profile, which has a club head and a preferably connected thereto via a heart region grip portion. The clubhead defines a stringing plane. The frame profile has at least one opening which extends through the frame profile and which extends substantially perpendicular to the clothing plane of the racket. In other words, the opening extends in the frame profile of the racket according to the invention substantially perpendicular to the frame profile usually provided through holes for the implementation of stringed strings. The opening may be arranged such that it is arranged in the region between two adjacent passage holes for the strings. However, it may also be advantageous to provide the opening in the region of a passage hole for the string, as this, for example, a cover of the opening by the string and / or an eyelet ("Grommet") can be fixed for the string.

The head shape of the racket is largely arbitrary and may for example be oval, egg-shaped, teardrop-shaped, rectangular with rounded corners. To define the respective positions of the openings along the circumference of the club head, a dial of a watch is usually used, the 12 o'clock position being located at the extreme or free end of the club head (cf. Fig. 1a ). Accordingly, the 3 o'clock or 9 o'clock position is approximately in the middle of the total length of the club head.

Preferably, the openings are provided in pairs substantially symmetrical to the longitudinal axis of the racket, ie, two, four, six or more openings may be provided symmetrically to the longitudinal axis of the racket. The at least one opening is in the range between 2 o'clock and 4 o'clock and / or between 8 o'clock and 10 o'clock Clock on the clubhead. Particularly preferred is the paired arrangement of openings in this area. More preferably, at least one pair of apertures are provided at about 3 o'clock and 9 o'clock respectively at the club head. Furthermore, it may be advantageous to provide a plurality of openings on each side. For example, a plurality of openings could be arranged symmetrically about the 3 o'clock or 9 o'clock position or, starting from 3 o'clock or 9 o'clock towards the gripping portion or starting from 3 o'clock or 9 o'clock toward the free end of the clubhead.

According to the invention, the opening provided perpendicular to the clothing plane extends completely through the frame profile, i. in the case of a hollow profile, a first hole is provided on a first racket side and in alignment therewith a second hole is provided on the opposite second racket side, which together form the opening.

The opening is preferably formed after the forming of the racket in the molding press subsequently to the frame, but it can also be made during the molding process, for example by inserting a core into the mold. The subsequent formation of the mold is preferably carried out by drilling, milling or sawing.

The cross section of the opening is circularly cylindrical. The circular opening preferably has a diameter in the range between about 2 mm and 8 mm, more preferably between 3 mm and 6 mm. In an opening formed by milling or sawing usually the two opposite holes are generated in the frame profile independently of each other, each of the holes is preferably formed in the direction of bow parallel to the clothing plane substantially arcuate or trough-shaped. However, any other shape for the holes is possible. The depth of each hole is at least the wall thickness of the frame profile.

The dimensions of the hole, in particular its width and depth, should be chosen so that the hole does not reach to a provided in the frame groove for receiving a headband.

In order to prevent the ingress of dirt and / or moisture into the frame profile, it is preferred to provide the opening with a substantially tubular insert, so that the frame profile is closed inwards. This tubular insert is usually made of an elastic material (e.g., rubber) so that the beneficial effects of providing the apertures are minimally affected. It is also possible to cover each of the openings forming the opening with a separate cover made of an elastic material, whereby the same effect is achieved.

It may also be preferable to reinforce the frame profile in the area around the at least one opening by the provision of reinforcing layers. In particular reinforcing layers of carbon fiber, glass or aramid fabric and / or a unidirectional prepreg are suitable, which are arranged at an angle of ± 45 ° to the longitudinal extent of the frame profile (i.e., helically in the wall of the frame profile).

The effect of the apertures perpendicular to the clothing plane is, in particular, that during a stroke, the bat has a relatively stiff characteristic at the moment of batting, whereby the ball can be given excellent acceleration, while after the ball has left the bat, the bat is more likely to do so soft or damped characteristic has. The effect according to the invention can be further enhanced by providing the frame profile in the region of the opening, preferably on both sides, with a trough-shaped indentation, the depth of which extends parallel to the opening.

A further advantage of the racket according to the invention lies in the fact that vibrations caused by the impact of the ball in the racket are conducted much less strongly to the handle than in the case of known rackets, which leads in particular to improved ball guidance during play and to improved damping of the racket. As a result, phenomena such as e.g. "Tennis elbow", minimized or prevented.

Fig. 1a

eine schematische Vorderansicht einer ersten Ausführungsform eines erfindungsgemäßen Schlägers;

Fig. 1b

eine schematische Vorderansicht einer zweiten Ausführungsform eines erfindungsgemäßen Schlägers;

Fig. 2a

eine vergrößerte Darstellung in perspektivischer Ansicht eines Bereichs des Rahmens eines erfindungsgemäßen Schlägers gemäß Fig. 1a mit einer kreiszylindrischen Öffnung und muldenförmiger Einbuchtung;

Fig. 2b

eine vergrößerte Darstellung in perspektivischer Ansicht eines Bereichs des Rahmens eines Schlägers gemäß Fig. 1b mit einer Öffnung, die durch zwei gegenüberliegende, separate Löcher gebildet ist, von denen eines sichtbar ist;

Fig. 2c

eine vergrößerte Darstellung in perspektivischer Ansicht eines Bereichs des Rahmens ähnlich Fig. 2b, wobei das Loch kürzer ist als bei der in Fig. 2b dargestellten Ausführungsform;

Fig. 2d

eine perspektivische Teilansicht eines Bereichs des Rahmens einer anderen Ausführungsform des Schlägers, wobei die gegenüberliegenden Löcher eine im wesentlichen rechteckige Querschnittsform haben;

Fig. 3a

eine schematische Querschnittsansicht des Rahmenprofils eines erfindungsgemäßen Schlägers gemäß der in Fig. 2a dargestellten Ausführungsform, jedoch ohne eine muldenförmige Einbuchtung;

Fig. 3b

eine schematische Querschnittsansicht des Rahmenprofils eines erfindungsgemäßen Schlägers ähnlich Fig. 3a, jedoch ohne einen rohrförmigen Einsatz; und

Fig. 3c

eine schematische Querschnittsansicht des Rahmenprofils eines Schlägers gemäß der in Fig. 2d dargestellten Ausführungsform.

The racket according to the invention will now be described by way of example with reference to preferred embodiments with reference to the drawings. Show it:

Fig. 1a

a schematic front view of a first embodiment of a racket according to the invention;

Fig. 1b

a schematic front view of a second embodiment of a racket according to the invention;

Fig. 2a

an enlarged view in perspective view of a portion of the frame of a racket according to the invention Fig. 1a with a circular cylindrical opening and trough-shaped indentation;

Fig. 2b

an enlarged view in perspective view of a portion of the frame of a racket according to Fig. 1b with an opening formed by two opposed, separate holes, one of which is visible;

Fig. 2c

an enlarged view in perspective view of a portion of the frame similar Fig. 2b , where the hole is shorter than in the Fig. 2b illustrated embodiment;

Fig. 2d

a partial perspective view of a portion of the frame of another embodiment of the racket, wherein the opposite holes have a substantially rectangular cross-sectional shape;

Fig. 3a

a schematic cross-sectional view of the frame profile of a racket according to the invention according to the in Fig. 2a illustrated embodiment, but without a trough-shaped recess;

Fig. 3b

a schematic cross-sectional view of the frame profile of a racket invention similar Fig. 3a but without a tubular insert; and

Fig. 3c

a schematic cross-sectional view of the frame profile of a racket according to the in Fig. 2d illustrated embodiment.

In the Fig. 1a shown schematic representation of the racket 2 according to the invention includes for better understanding a Ziffemblatt corresponding to a normal clock, wherein the 12 o'clock position (XII) is provided at the extreme, free end of the racket.

The racket according to the invention has a frame 4 which forms a racket head 6 and a handle section 10 preferably connected thereto via a heart area 8. The frame 4 is formed from a frame or hollow profile (see Figures 2d and 3a-3c ). The club head defines a clothing plane of the racket. To accommodate the clothing, the frame 4 in the region of the club head 6 has a plurality of substantially in the clothing plane through holes (not shown) for the implementation of stringed strings 7, of which in cross-section Fig. 3a a schematic can be seen.

On the frame profile is in accordance with the in Fig. 1a illustrated embodiment at 3 o'clock or 9 o'clock each one extending through the frame profile extending opening 12 which extends substantially perpendicular to the clothing plane or to the through holes for the stringed strings. This opening is as in Fig. 2a shown closer, formed in the form of a substantially circular cylindrical through hole. The bore extends through the two opposite walls of the frame profile and thereby forms the opening 12 extending through the frame profile. The circular opening 12 preferably has a diameter D in the range between about 2 mm and 8 mm, more preferably between 3 mm and 6 mm, up.

To avoid the ingress of dirt and / or moisture into the interior of the frame profile, an insert 14 is preferably provided in the opening 12, which terminates the frame profile to the interior of the opening 12. The insert 14 is preferably tubular, ie formed with a through hole 16. However, it can also be designed as a "lid" or as a solid profile. The insert 14 is typically made of a soft material so that it does not significantly affect the properties of the racquet in this area. Preferably, a transparent plastic (eg rubber) is used for this purpose. The tubular insert 14 preferably has a small wall thickness of, for example, about 0.5 to 1.5 mm, preferably about 0.5 to 1 mm. In Fig. 3b is a cross section of the racket according to the invention without an insert shown.

As in Fig. 2a shown, the bat according to the invention in the region of the opening 12 may have a trough-shaped recess 18. Preferably, the frame has on the two opposite sides of the frame 4 each such indentation 18, that is, the frame height is reduced in this area by twice the amount of each trough-shaped indentation 18. More preferably, the racket according to the invention has four such trough-shaped recesses 18, ie two opposite each opening 12. The opening 12 and optionally the associated indentation (s) 18 are in the range between 2 o'clock and 4 o'clock or between 8 o'clock and 10 o'clock on the racket. Particularly preferably, each opening 12 is provided at about 3 o'clock and 9 o'clock on the frame 4. In this case, it is preferable to provide a trough-shaped indentation 18 each at 3 o'clock or 9 o'clock respectively at the front and the back of the racket.

The trough-shaped indentation is preferably formed during molding of the racket frame in the frame profile, for example by providing a corresponding bulge in the mold. Furthermore, it may be preferable, in the region of the opening 12 - regardless of whether or not there is a recess 18 - provide one or more reinforcement layers in the material forming the frame profile. For example, carbon fiber material, glass or aramid fabric and / or a unidirectional prepreg at an angle of ± 45 ° to the longitudinal frame extension of the frame profile (ie helically in the wall of the frame profile) are incorporated into the racket frame forming frame profile. This is preferably done by superimposing the different layers of frame material and reinforcing material and then rolling the superimposed materials into a "tube", which is then inserted into the molding press and pressed under the action of temperature and pressure to the frame.

Another possibility to provide the opening 12 in the frame 4 of the racket 2 according to the invention consists, according to the in Fig. 2b and 2c illustrated embodiments, instead of a through hole through the frame profile at the front and back of the frame each provide individual holes 12a. In the Fig. 2b and 2c For example, only one such hole 12a can be seen, while a corresponding hole provided on the opposite frame side is not shown. Two opposite holes 12a together form an opening extending through the frame profile.

As in the FIGS. 2b and 2c shown, the holes 12a have a substantially arcuate or trough-shaped in the viewing direction parallel to the clothing plane. This can be realized for example by milling or sawing. In the embodiment according to Fig. 2c For example, the length L of the holes 12a along the frame is preferably in the range between 1 mm and 10 mm, more preferably between 3 mm and 7 mm. The largest depth T of a hole 12a corresponds at least to the wall thickness of the frame profile, so that the frame profile is at least partially completely removed to expose an opening in the interior of the frame profile. The maximum depth of the hole 12a is preferably the depth up to a groove 20 (FIG. Fig. 3c ) to accommodate the headband of the racket practicable. The width B of the hole 12a is preferably in the range between 3 mm and 7 mm. Although in the Fig. 2b and 2c not shown, it is also preferred in these embodiments to provide the opening with a (preferably substantially tubular) insert or cover, the shape of which may be adapted to the shape of the hole or trough so that neither dirt nor moisture in the interior of the frame profile can get.

In Fig. 2d and 3c Another racket is shown similar to the one in the Fig. 2 b and 2c illustrated embodiments. The opposite holes 12a, which together form the opening, here have a substantially rectangular cross-section when viewed parallel to the clothing plane.

In addition to the embodiments shown in the figures, it is of course also possible to provide a plurality of openings 12 along the frame, each extending substantially perpendicular to the clothing plane of the racket. For example, several openings could be arranged symmetrically at 3 o'clock or 9 o'clock or, starting from 3 o'clock or 9 o'clock towards the handle section or starting from 3 o'clock or 9 o'clock toward the free end of the club head.

The racket according to the invention is particularly advantageous in terms of its improved ball guidance. In addition, vibrations that occur when hitting the ball, derived less to the handle than known rackets. At the same time, however, the acceleration capacity that can be transferred to the ball with the racket according to the invention is improved. The advantageous properties of the racket according to the invention are presumably due to the fact that the outermost wall of the frame profile, i. the part of the wall of the frame profile furthest from the clothing plane, is weakened by the opening in the range between 2 o'clock and 4 o'clock or between 8 o'clock and 10 o'clock, so that here the bending resistance moment of the frame profile is considerably lower than in the Areas without opening. Such a weakening of the frame profile has hitherto been considered unrealizable, since it was assumed that thereby the frame would inevitably break at the loads occurring through the games. According to the invention, however, has shown that not only a particularly good ball control is possible through these openings but at the same time the required stability of the racket remains guaranteed.

By means of the opening (s) provided on the frame, in particular in the case of two openings provided symmetrically to the longitudinal axis of the racket, a kind of "control point" is created in the area of the openings. the racket can be particularly flexible, whereby the particularly advantageous effects are achieved.

Claims (16)

1. A racket for ball games including a frame (4) having a racket head (6) and a handle portion (10) connected thereto and being formed of a hollow frame profile, wherein the racket head (6) defines a stringing plane and the frame profile comprises at least one opening (12) extending through the frame profile and essentially perpendicular with respect to the stringing plane of the racket (2), wherein the at least one opening (12) is provided in the area between two o'clock and four o'clock and/or between eight o'clock and ten o'clock on the racket head (6), characterized in that the at least one opening (12) is formed by two opposite holes (12a) as circular cylindrical through hole in the hollow frame profile and that the diameter (D) of the through hole ranges between 2 mm and 8 mm.
2. The racket according to claim 1, wherein the frame (4) comprises a plurality of through holes lying essentially in the stringing plane for passing through them the individual strings of the stringing.
3. The racket according to claim 1 or 2, wherein at least two openings (12) are provided essentially symmetrical with respect to the longitudinal axis of the racket (2).
4. The racket according to any one of claims 1 to 3, wherein the at least one opening (12) is provided at about three o'clock and/or about nine o'clock on the racket head (6).
5. The racket according to any one of claims 1 to 4, wherein the diameter (D) of the through hole ranges between 3 mm and 6 mm.
6. The racket according to any one of claims 1 to 5, wherein each of the holes (12a) is essentially trough-shaped when being viewed in the direction of the stringing plane.
7. The racket according to any one of claims 1 to 6, wherein the at least one opening (12) comprises an essentially tubular insert (14) in order to close the frame profile towards the interior.
8. The racket according to any one of claims 1 to 7, wherein the frame profile comprises one or more strengthening layer(s) in the area around the at least one opening (12).
9. The racket according to claim 8, wherein the strengthening layer comprises woven materials made of carbon fiber, glass or aramid and/or a unidirectional prepreg, and is arranged at an angle of ± 45° with respect to the direction of the frame.
10. The racket according to any one of claims 1 to 9, wherein in the area of the opening (12) a trough-shaped depression (18) is formed in the frame profile.
11. The racket according to claim 10, wherein two opposite trough-shaped depressions (18) are formed at each opening (12).
12. A process for producing a racket, in particular according to any one of claims 1 to 11, comprising the following steps:

    (a) forming a frame (4) consisting of a hollow frame profile and comprising a racket head (6) and a handle portion (10) connected thereto; and

    (b) providing at least one opening (12) extending through the frame profile essentially perpendicular with respect to a stringing plane formed by the racket head (6), wherein the at least one opening (12) is provided in the area between two o'clock and four o'clock and/or between eight o'clock and ten o'clock on the racket head (6) and wherein the at least one opening (12) is formed by two opposite holes (12a) as circular cylindrical through hole in the hollow frame profile, wherein the diameter (D) of the through hole ranges between 2 mm and 8 mm.
13. The process according to claim 12, wherein at least two openings (12) are provided essentially symmetrical with respect to the longitudinal axis of the racket (2).
14. The process according to claim 12 or 13, wherein the at least one opening (12) is drilled, milled or sawed into the frame profile.
15. The process according to any one of claims 12 to 14, wherein an essentially tubular insert (14) is introduced in the at least one opening (12) in order to close the frame profile towards the interior.
16. The process according to any one of claims 12 to 15, wherein one or more strengthening layer(s) is/are provided in the area around the at least one opening (12) when the frame profile is formed.

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