DE19851918A1 - Elastic device for protecting racket strings comprises spring steel, set at intersection of strings to deform and absorb tension - Google Patents

Abstract

The device, e.g. a ring, is made at least in part of a material with a high modulus of elasticity such as spring steel. Preferred Features: When hitting a ball the bending tensions and/or torsion strains appear in the device so that the material of the device is deformed in the elastic area.

Description

When stringing tennis rackets, strings are usually made of plastic or natural gut used. An important property of the strings is the elastic stretch. To make the ball effective when struck To accelerate, the strings must stretch elastically when hitting the ball. After one if possible In a short reaction time, the strings contract again, which accelerates the ball. So for the player has good controllability of the ball, the ball should be as short as possible touch. So the covering should have a short reaction time. That means that when the Ball's stored kinetic energy should be returned to the ball as quickly as possible. To achieve this, the strings are pretensioned with high tensile force. However, then the covering does not accelerate the ball as much as with a softer covering.

Strings from z. B. Steel would be due to the high elastic modulus and the expected short Response time desirable. But because of the low elastic stretch, steel strings are unsuitable. It no appreciable amounts of stretch are achieved and the ball cannot accelerate sufficiently become.

In order to achieve larger amounts of elongation, according to DE 196 03 068 A1 there are resilient devices known that are attached to the frame when stringing the racket. Since these devices on the outside Exceeding the frame increases the risk of injury. Protruding devices are therefore not allowed according to tennis rules. If the devices should not survive, there are special rackets required.

To protect the string covering plastic parts or parts made of soft materials are known, which on the Crossing points of the strings are used. These parts are intended to reduce the slipping of the strings and the Protect strings. After inserting the parts, the tension of the strings increases because of the way of each one String is extended. This can be desirable. However, due to the plastic deformation of the parts string tension lost again. This has a particularly negative effect on strings with low elasticity. This affects particularly inexpensive strings.

If parts made of a hard plastic are inserted into the covering, there are no plastic ones Deformations, however, this solution is also unsatisfactory, especially for strings with low elasticity. When struck, the tension of the strings increases because the ball deflects the tension. For strings with less This increase in tension is particularly high in elasticity. These load peaks contribute to the wear of the Covering at. Devices are therefore required which reduce the load peaks that occur.

The invention specified in protection claim 1 is based on the problem of stringing with To protect devices that can be used in the covering. The ones that occur during the blow Load peaks of the strings should be reduced without causing plastic deformation of the devices Allow the tension to decrease. The slipping of the strings should also be reduced.  

This problem is solved with elastic devices with features listed in protection claim 1.

With the invention it is achieved that in addition to the elastic stretching of the string a further spring travel Available. When struck, the devices deform elastically. Then the devices go back to the initial state. The devices are at least partially made of one material high elastic modulus. The elastic deformation is caused by bending or by torsion of the Material reached. The material is e.g. B. spring steel. So it is possible to use strings that are relative have low elastic self-expansion. These can be steel cables or strings that are particularly inexpensive or are particularly durable. The frictional engagement or the positive engagement between the Devices and the strings can be improved. This can e.g. B. with a suitable groove or a coating a material with a high coefficient of friction. This ensures that the strings move less. Moreover the devices used cannot fall out so easily.

In an advantageous embodiment, the device is a ring made of spring steel ( 2 ), which is coated on both sides with a rubber-like material. The devices are installed at the crossing points of the strings ( 1 ). The coating prevents the strings from slipping. Several devices of this type are installed in the fabric. In addition to the spring action, increasing the contact surface of the strings reduces the surface pressure acting on the strings. This protects the string. When struck, the ring-shaped devices are subjected to bending, which reduces stress peaks. Since the devices deform only in the elastic range, they return to their original state after the impact. The tension of the strings remains.

Claims (6)

1. Elastic devices for protecting string strings in rackets of ball games, characterized in that the devices at least partially consist of a material with a high modulus of elasticity, in particular spring steel. 2. According to claim 1, characterized in that the impact at least bending stresses and / or Torsional stresses occur in the devices, whereby the material of the devices in the deformed elastic area. 3. According to claim 1, characterized in that the use of strings with low elasticity, for. B. steel cables, is positively influenced. 4. According to claim 1, characterized in that the devices recesses or the like for a better Have a positive fit with the strings. 5. According to claim 1, characterized in that the devices have a rough surface and / or a Coating with a high coefficient of friction for better frictional engagement with the strings. 6. According to claim 1, characterized in that the covering with the built-in devices with a Adhesive is treated.