DE9016980U1 - Rackets for ball games - Google Patents

Description

PATENT ATTORNEY KALDENKIRCHENER STRASSE 35a

DIPL-ING. M. BONSMANN **< ., D-4050 Mönchengladbach &igr;

EUROPEAN PATENT ATTORNEY! ₌ " . - ^ TEL. 0 2161/12114 ■ TELEX 852 873

File: 90 212

Hans-Werner KORTE-JUNGERMANN
Kleinkollenburgstr. 58, 4156 Willich 2

Rackets for ball games

The invention relates to a racket for ball games, in particular tennis racket, with an oval or round frame connected to a handle with a stringing having longitudinal strings and cross strings, wherein the longitudinal strings and the cross strings of the stringing are designed as individual strings each separately fastened under pre-tension (tensile tension) in the string end area.

It is known that the longitudinal strings and the cross strings of a racket string of the type mentioned above should each have the same pre-tension. This means that the elasticity of the string is greater in the middle of the string than in the edge areas of the string.

The invention is based on the object of proposing a racket of the type mentioned at the beginning, in which the elasticity of the stringing is essentially the same over the entire stringing area.

This object is achieved according to the invention in that the pre-tension or pre-tensions of the "longest" individual strings are greater than the "shortest" individual strings of the longitudinal strings and/or the cross strings by such an amount that a force applied transversely to the stringing plane

both the "longest" and the "shortest" single string cause an approximately equal deflection.

The advantage here is that the different pre-tensioning according to the invention means that the deflection - in relation to the middle of the respective individual string - is essentially the same, regardless of whether it is a "short" or a "long" individual string. This results in an increase in the meeting point (so-called "sweet point") in the stringing area. The requirement for "short" or "long" individual strings arises from the fact that the frame is either oval or round. The invention is based on the idea that with a pre-tensioned individual string, a force applied in the middle of the string transverse to the longitudinal direction of the string causes a certain deflection, and that with the same force and the same pre-tensioning of the string, the deflection is greater the longer the string is. Accordingly, starting from a certain pre-tension of the "shortest" longitudinal string or cross string, the pre-tension of the "longer" individual string is increased to such an extent that the deflection is always the same for the same force applied in the middle of the string.

In a further embodiment of the invention, it can be provided that the string pre-tension gradually increases, starting from the "shortest" single string to the "longest" single string.

A practical embodiment of the invention consists in that several longitudinal strings and cross strings lying next to one another form a string group, and that the pretension of the strings in a string group is always the same.

The invention ensures that the stringing of the racket has a substantially uniform elasticity when a ball hits it, regardless of whether the

Ball hits the racket in the middle of the strings or outside the middle of the strings.

The invention is explained in more detail below using the embodiment shown schematically in the drawing.

The single figure shows a schematic plan view of the frame of a tennis racket, which has a stringing consisting of single strings.

The individual strings are not shown in the drawing. The middle cross indicates the position of the cross strings (horizontal) and the position of the long sides (vertical). The position of the cross strings and some long sides is indicated schematically in the edge of the racket. The numbers on them indicate the pre-tension to be applied to the individual strings when they are attached. A middle group of six long sides each receive a pre-tension of 25 kp, while the "shorter" long sides adjoining them on both sides receive a pre-tension of 24 or 23 or twice 22 kp.

The same applies to the pre-tension of the horizontal cross string. A middle group of six cross strings each has a pre-tension of 24 kp, while the "shorter" cross strings on either side of this group have a pre-tension of 23.5, 23, 22.5 or twice 22 kp.

Claims (3)

Protection claims 1. Racket for ball games, in particular tennis rackets, with an oval or round frame connected to a handle with a stringing having longitudinal strings and cross strings, whereby the longitudinal strings and the cross strings of the stringing are designed as individual strings each separately fastened under pre-tension (tensile tension) in the string end area, characterized in that the pre-tension or pre-tensions of the "longest" individual strings are greater than the "shortest" individual strings of the longitudinal strings and/or the cross strings by such an amount that a force applied transverse to the stringing plane causes an approximately equal deflection in both the "longest" and the "shortest" individual string. 2. Racket according to claim 1, characterized in that the string pre-tension gradually increases from the "shortest" single string to the "longest" single string. 3. Racket according to claim 2, characterized in that several longitudinal strings and cross strings lying next to one another form a group of strings, and that the pretension of the strings of a group of strings is always the same.