EP3241590A1 - Racket with magnesium bridge - Google Patents

Abstract

The invention relates to a frame for a ball game racket with a handle portion and a head portion with a bridge, wherein a part of the head portion and / or the handle portion has / have a carbon fiber composite material and wherein the bridge has magnesium and is integrally formed.

Description

The present application relates to a frame for a ball game racket, which has sections of different materials and in particular has a magnesium-containing bridge.

For the scope of a ball game racket, especially a tennis racket, are so far, after initial models of wood, primarily aluminum or carbon fiber composites in use. Furthermore, the use of magnesium or magnesium alloys in ball game racket frame is known, for example from the US Pat. No. 3,874,667 , the German utility model DE 1 757 527 U and the DE 10 2013 011 174 A1 ,

A disadvantage of previous frame models lies in a limitation of the shape and thus in a limitation of the mechanical properties. Many of these limitations arise from the manufacturing process and / or the need to pick up the string bed or to redirect the strings. This applies in particular to a bridge of a ball game racket frame. For example, filigree structures when using the Schlauchblasverfahrens are extremely expensive or impossible to produce. Also, the joining of several components, as in the DE 10 2013 011 174 A1 discloses extremely difficult, especially if, for example, filigree and / or particularly thin-walled structures are provided.

The present invention therefore has for its object to provide a frame for a ball game racket, which at least partially solves the above-mentioned problems, can be produced easily and is particularly stable especially in the area of the bridge.

This object is achieved by a frame for a ball game racket according to claim 1. The frame according to the invention can in principle be used for any known type of ball game rackets, in particular for tennis rackets, squash rackets and badminton rackets.

The frame according to the invention has a handle portion and a head portion with bridge, wherein the bridge can form together with two frame spars in a conventional manner a heart portion. The frame defines a substantially two-dimensional stringbed in the stringbed plane for receiving a string.

A portion of the head portion and / or the handle portion has a carbon fiber composite. The bridge has magnesium and is integrally formed. Preferably, substantially the entire bridge is made of a magnesium-containing material or a magnesium alloy. It is further preferred that the entire remaining frame is made of carbon fiber composite material.

In the context of the present invention, the integrity of the bridge means the integrity of the bridge structure, the bridge being in particular in spite of one or more complementary components such as a damper, eyelet, weight or weight band, and the like / or a coating in the form of a primer, a lacquer, a plastic layer and / or the like, as seen in one piece. In particular, the bridge is not zusammengestzt from two halves or sections, such as in the DE 10 2013 011 174 A1 disclosed. Furthermore, in particular, the magnesium-containing part of the bridge is made of a single piece and does not consist of several interconnected sections. For example, the bridge may be a single casting.

Such an integrally formed bridge has the advantage that on the one hand it can be produced particularly simply, for example by a single casting step, and on the other hand it is particularly stable. In particular, it has been found that bridges composed of several parts are susceptible to breakage and / or deformation at the connecting lines. Magnesium-containing alloys have proven to be particularly advantageous in this context, since on the one hand they are relatively light and, on the other hand, extremely stable. Since particularly great forces occur in the bridge area during play of the racket, the playability of a racket according to the invention can be substantially improved and at the same time improve the stability of the racket. The racket according to the invention is also rackets made entirely of a light metal, e.g. Aluminum, far superior, since the frame sections of the usual carbon fiber composite material have significantly better stiffness-to-weight ratios and correspondingly positive damping properties.

In a preferred embodiment, the bridge is essentially made of a uniform material, for example of a uniform magnesium alloy. Fluctuations in material composition and / or mixing known to the materials and / or methods of manufacture are within the tolerance of the present invention.

In a preferred embodiment, the bridge has at least 50% by weight, preferably at least 80% by weight, preferably at least 90% by weight, preferably at least 95% by weight of magnesium. Particularly preferably, the bridge has a magnesium alloy. The magnesium alloy is preferably, for example, AM60 or a fiber-reinforced or particle-reinforced alloy, particularly preferably SAE SiC / AZ91.

The bridge can be produced, for example, in a diecasting process or an injection molding process, preferably in the so-called thixotropic process. The bridge, together with prepreg layers, which after completion form part of the head section and / or the handle section, can be inserted into a tubular blow mold and pressed. Alternatively or additionally, the bridge may be otherwise connected to the rest of the frame, e.g. by gluing, pressing, curing, welding, riveting and / or screwing.

Preferably, the bridge is completely or at least partially executed as a solid profile or solid. In particular, the bridge does not form - at least in sections - a hollow profile / hose-like structure. As a result, in contrast to the use of hollow profiles, particularly filigree structures can be produced. This allows, for example, to guide the power flow in the area of the bridge and in particular in the transition areas between the bridge and the rest of the frame. In the context of conventional methods, this was possible, for example, only to a limited extent with the aid of different orientation of the prepreg layers or by varying the wall thickness of hollow bodies. On the other hand, the combination of particularly stable magnesium alloys with massive structures enables the formation of perfectly placed stabilizing bars or truss-like structures, which can be very filigree and correspondingly lightweight.

The term solid profile is to be understood in the context of this application, a profile in which substantially no cavities are present, in particular no closed cavities, which are accessible only via string openings. In the context of the present invention, string opening is to be understood as meaning an opening in the ball game racket framework which serves to pass one or more strings through the frame and whose diameter exceeds a string diameter only insofar as a smooth string passage is possible, and in particular if additionally one Eyelet or similar component is installed in the string opening. Full profiles can therefore definitely have notches or recesses and the like. However, a cross section through a solid profile has no area in which a cavity from a closed and / or apart from string openings closed material envelope is surrounded. In particular, a cross-section of a bridge section with a solid profile can have exactly one or more full profiles lying next to one another. In the context of the present invention, a section perpendicular to the guide curve, also referred to as direct line, of the frame section is designated by the cross section. In the context of the present invention, the guide curve of a frame section is understood to be a channel surface guide curve, that is to say that line which, essentially following the frame contour, runs centrally through a frame section.

In a preferred embodiment, the bridge has at least four, preferably at least six webs. In a further embodiment, the bridge has at least eight webs. Under a web or arm is an elongated, relatively thin structure understood, the length of which is many times greater than the minimum cross-sectional dimension. Preferably, the ratio of length to minimum cross-sectional dimension is 5: 1, more preferably 10: 1, and most preferably 15: 1. Such a web has a cross-sectional area which is significantly smaller than the maximum cross-sectional area of the bridge. A web preferably has in cross section a solid profile, particularly preferably a convex solid profile, for example a convex polygonal, oval or round solid profile, and / or a substantially U- and / or V-shaped solid profile and / or another concave polygonal solid profile. A corner of a profile can be pointed or rounded. However, the web cross-section may also partially have a hollow profile.

The webs may each have, at least in sections, a cross-sectional area of up to 100 mm ² , preferably up to 50 mm ² , more preferably up to 30 mm ² , particularly preferably up to 25 mm ² . In particular, webs may each at least partially have a cross-sectional area of 1 mm ² to 100 mm ² , but preferably each have a cross-sectional area of 1 mm ² to 50 mm ² , preferably 2 mm ² to 30 mm ² , more preferably 2 mm ² to 25 mm ² on. The cross-sectional area of the webs can vary along the web-guide curve. In particular, the area of the web cross-section can increase continuously from a bridge section located closer to the middle of the bridge to a web section located at a lower center.

Ridges may be sectioned, preferably over at least 5 mm, more preferably over at least 10 mm, more preferably over at least 15 mm, more preferably over at least 20 mm, more preferably over at least 30 mm, more preferably over at least 40 mm, more preferably over at least 50 mm, more preferably over at least 60 mm, each preferably measured along the frame profile, be separated from each other. In places and / or sections webs may be connected in pairs and / or with several other webs. In particular, webs of a magnesium-containing material can be connected via intermediate pieces, which may be made of a different material. For example, one or more damping elements can be attached between two or more webs.

Two adjacent webs, which may also be referred to as a web pair, preferably have, at least in sections, a surface spacing of 1 mm or more, more preferably 3 mm or more, particularly preferably 5 mm, measured perpendicular to the string bed plane and between their surfaces more. Two adjacent webs preferably have, at least in sections, a surface pitch measured perpendicular to the string bed plane of 30 mm or less, more preferably 20 mm or less, more preferably 15 mm or less, most preferably 10 mm or less. In particular, two adjacent webs preferably have, at least in sections, a surface distance of 1 mm to 30 mm, preferably 1 mm to 20 mm, more preferably 3 mm to 15 mm, particularly preferably 5 mm to 10 mm, measured perpendicular to the string bed plane. The measured perpendicular to the string bed plane surface distance between two adjacent webs can vary along the guide curve of the webs. Likewise, the surface distance between two webs of a first web-pair may differ from the surface distance between two webs of a second web-pair.

Two adjacent webs preferably have, at least in sections, a surface spacing of 1 mm or more, more preferably 3 mm or more, particularly preferably 5 mm or more, measured parallel to the string bed plane. Two adjacent webs preferably have, at least in sections, a surface spacing measured parallel to the string bed plane of 30 mm or less, more preferably 20 mm or less, more preferably 15 mm or less, particularly preferably 10 mm or less. In particular, two adjacent webs preferably have, at least in sections, a surface spacing of 1 mm to 30 mm, preferably 1 mm to 20 mm, preferably 3 mm to 20 mm, preferably 3 mm to 15 mm, preferably 5, measured parallel to the string bed plane mm to 10 mm. The surface distance of two adjacent webs measured parallel to the string bed plane can vary along the guide curve of the webs. Likewise, the surface distance between two webs of a first web-pair may differ from the surface distance between two webs of a second web-pair.

The webs preferably have a length LS along the web-guide curve. The length LS is preferably greater than or equal to 1 mm, more preferably greater than or equal to 5 mm, more preferably greater than or equal to 10 mm, more preferably greater than or equal to 15 mm, particularly preferably greater than or equal to 20 mm. The length LS is preferably less than or equal to 120 mm, more preferably less than or equal to 100 mm, more preferably less than or equal to 80 mm, more preferably less than or equal to 50 mm, particularly preferably less than or equal to 30 mm. In particular, the webs preferably have a length LS along the web-guide curve of 1 mm to 120 mm, preferably from 5 mm to 120 mm, preferably from 10 mm to 100 mm, preferably from 15 mm to 80 mm, preferably from 20 mm to 50 mm, more preferably from 20 mm to 30 mm.

A preferred embodiment of the bridge according to the invention has at least one attachment tab which serves to connect the bridge to at least one further frame section. The tie bar not only guarantees a stable connection between the bridge and the rest of the frame, but also allows for a large-scale transfer of forces occurring in the bridge in the rest of the frame. Preferably, the bridge has two connection tabs. The attachment tabs are preferably disposed substantially at opposite ends of the bridge. Embodiments with one, four, six or more attachment straps are also possible. In particular, embodiments are possible in which each web opens into its own connection tab into which no other web opens, and / or in which two webs open into a common connection tab into which no other web opens, and / or in which three webs in lead to a common connection tab into which no other bridge opens. In particular, there is an embodiment in which three out of a total of six webs open into a first connecting link and the further three out of a total of six webs open into a second connecting link. In an alternative embodiment, a first and a second of six webs lead into a first attachment tab, a third and a fourth of the six webs into a second attachment tab, a fifth web into a third attachment tab and a sixth web into a fourth attachment tab. In an alternative embodiment, six of a total of six webs open into one each of a total of six connecting straps. The webs can open directly into the connection straps and / or open into another bridge section and / or frame section, which is located between webs and connection straps.

Preferably, the central portion of the bridge is formed as a solid profile with a groove. The gutter is preferably open to the string bed and may otherwise be closed. The gutter-shaped central portion can thus be in the form of an open channel and / or the shape have a pot. Alternatively or additionally, the middle section of the bridge may have a truss structure. In a further embodiment, the middle section has a solid profile without a groove.

Preferably, the bridge of a frame according to the invention has a contiguous bridge length of 5 mm or more, preferably 10 mm or more, more preferably 15 mm or more, more preferably 20 mm or more, most preferably 30 mm or more along the bridges -Leitkurve a contiguous cross-sectional profile and / or over a contiguous bridge length of 5 mm or more, preferably of 10 mm or more, more preferably 15 mm or more, more preferably 20 mm or more, particularly preferably 30 mm or more along the bridge-Leitkurve a discontinuous cross-sectional profile. Preferably, the bridge of a frame according to the present invention has a contiguous cross-sectional profile along a contiguous bridge length of 100 mm or less, preferably 80 mm or less, more preferably 60 mm or less, along the frame contour and / or over a contiguous bridge length of 100 mm or less , preferably of 80 mm or less, more preferably 60 mm or less along the frame contour, has a discontinuous cross-sectional profile. Preferably, the bridge of a frame according to the invention has a continuous cross-sectional profile along a contiguous bridge length of between 10 mm and 100 mm, preferably between 30 mm and 80 mm, along the frame contour and / or over a contiguous bridge length of between 5 mm and 100 mm of between 10 mm and 60 mm along the frame contour on a discontinuous cross-sectional profile.
An inventive frame is provided for receiving a fabric. The covering preferably consists of longitudinal and transverse strings, wherein the longitudinal strings are arranged substantially parallel to the frame longitudinal axis and substantially perpendicular to the transverse strings. Alternatively or additionally, strings may be arranged at an angle substantially different from 0 ° and / or 90 ° to the frame longitudinal axis. For example, the longitudinal strings may be substantially fan-shaped and the transverse strings may be substantially perpendicular to the frame longitudinal axis. As is common in the art, in the context of this application each string section extending between two frame points is referred to as a string. However, it is understood by those skilled in the art that the entire fabric may consist of a single, two or more pieces of string. If the string consists of fewer pieces of string than strings, the one or more pieces of string are deflected on the frame to form the individual strings.

Preferably, at least one attachment tab has at least one string opening, as specified above in the application, for the passage of at least one longitudinal and / or transverse string. Two attachment straps particularly preferably have string openings for the passage of at least one longitudinal and / or transverse string. Alternatively, none of the attachment tabs has a string opening.

In a preferred embodiment, two webs of the bridge each have at least one string opening, as specified above in the application, for the passage of at least one longitudinal and / or transverse string. Preferably, two webs each have two string openings. In an alternative embodiment, two bars each have one, two, three, four and / or more string openings. In one embodiment, four or six webs each have at least one string opening. However, there are also embodiments in which none of the webs has a string opening.

Preferably, the middle section has at least one string opening, as specified above in the application, for the passage of at least one longitudinal string. Preferably, the middle section has a plurality of string openings. However, the middle section can also have no string openings, for example in an embodiment in which the middle section has a particularly short extension along the bridge guide curve.

The channel-shaped central portion may, in addition to the one-piece supporting basic structure of the bridge, a damper, which is provided for the mitigation of vibrations included. The damper preferably comprises rubbery or elastic or viscoelastic materials such as TPU or TPE or general materials from the class of thermoelastomers or thermoplastic elastomers. The damper can completely and / or completely completely fill the channel in the channel-shaped middle section of the bridge, with the exception of the string openings. Preferably, however, it has recesses that do not serve the performance of strings on. The damper may be formed in several pieces, but preferably it is integrally formed. The damper may be fixed to the bridge, for example by gluing, vulcanizing, pressing and / or other known methods. Preferably, however, the damper can be removed at least from the bridge. In this case, a sufficient fixation of the damper during beating is preferably ensured by the fact that the damper at least Sectionally has the negative shape of the channel-shaped central portion. This creates a stiction between damper and bridge, which prevents unwanted slippage of the damper. Alternatively or additionally, the damper, as usual for known dampers in tennis, be clamped between at least two strings. In a particularly preferred embodiment, however, the damper has openings for the passage of strings, preferably of at least 2 strings, more preferably of at least 4 strings. According to the invention, such a damper with string openings is introduced into the channel-shaped middle section of the bridge of an uncovered ball game racket frame. The string openings in the damper are positioned in extension of corresponding string openings of the channel-shaped central portion of the bridge. When stringing the ball game racket frame, the strings, which are intended to be attached to the channel-shaped central portion of the bridge to be guided by the respectively provided string opening of the channel-shaped central portion of the bridge and through the respective corresponding string opening of the damper. As a result, it is particularly excluded that the damper jumps out of the ball game racket by the force of a blow and cumbersome sought and reused, as is often the case with the commercial dampers that are clamped between two longitudinal strings, the case.

In a preferred embodiment, the bridge according to the invention and / or the ball game racket frame according to the invention is symmetrical with respect to the racket longitudinal axis and / or symmetrically with respect to the string bed plane.

A preferred embodiment of a bridge according to the invention has an area moment of inertia Iy and an area moment of inertia Iz, where Iy and Iz are defined as follows: Iy and Iz respectively refer to bridge sections that are perpendicular to the fixed x-axis (ie in a yz-plane) wherein the right-handed Cartesian coordinate system is defined such that the y-axis is congruent with the frame longitudinal axis, the origin lies in the centroid of the bridge center plane and the y-axis points from the handle towards the head section. The bridge center plane is the cross section of the bridge, which is formed by the center and perpendicular to the guide curve. That is, a commonly shaped beater has negative y values in the handle portion and positive y values in a substantial portion of the head portion. It should be noted that the bridge sections perpendicular to the x-axis are not necessarily cross-sections within the meaning of the definition of the present application, as bridge cross sections are defined as perpendicular to the bridge guide curve. For better distinction, the sections perpendicular to the x-axis are therefore referred to below as yz sections because they lie in yz planes. Iy and Iz can vary with position on the x-axis, ie, Iy (x) and Iz (x), for example, when the shape of the yz-section changes along the x-axis. Iy is the area moment of inertia for a bend about the y-axis, ie a force acting on the bridge acts in this case in the z-direction. Iz is the area moment of inertia for a bend about the z-axis, ie a force acting on the bridge acts in this case in the y-direction. Expressed mathematically, the area moment of inertia for a yz intersection is Iy = ∬ z ² dydz and Iz = ∬ y ² dydz. Thus, Iz is the area moment of inertia which is relevant to the y-direction force transmitted to the bridge during ball contact by the longitudinal strings.

In the following, the properties of Iz (x) and Iy (x) are discussed in more detail. In particular, Iz (x) and Iy (x) are compared with each other. It is understood for the entire present application that a comparison of Iz (x) with Iy (x) always means the comparison at the same x-values.

In a preferred embodiment of the bridge, its area moment of inertia Iz (x) along the x-axis is at least partially greater than the area moment of inertia Iy (x). Alternatively or additionally, Iy (x) may be greater than Iz (x) at least in sections. The difference Iz (x) -Iy (x) and / or the quotient Iz (x) / Iy (x) and / or the values of Iy (x) and Iz (x) may vary with the x-value, respectively for x greater than or equal to zero and / or x less than zero.

In a preferred embodiment, the value of Iz (x) is at least in sections, preferably in sections in a web section of the bridge, 2500 mm ⁴ or more, preferably 3000 mm ⁴ or more, more preferably 3500 mm ⁴ or more, more preferably 4000 mm ⁴ or more, more preferably 4500 mm ⁴ or more. Alternatively or additionally, the value of Iz (x) may be at least in sections, preferably in sections in a web section of the bridge, 6500 mm ⁴ or less, preferably 6000 mm ⁴ or less, more preferably 5500 mm ⁴ or less, more preferably 5000 mm ⁴ or less. Preferably, the value of Iz (x) is at least in sections, preferably in sections in a web section of the bridge, in a range of 2500 mm ⁴ - 6500 mm ⁴ , preferably 3000 mm ⁴ - 6000 mm ⁴ , more preferably 3500 mm ⁴ - 5500 mm ⁴ , more preferably 4000 mm ⁴ - 5500 mm ⁴ , more preferably 4500 mm ⁴ - 5000 mm ⁴ . Alternatively or additionally, the value of Iz (x) may be at least in sections, preferably in sections in the middle section of the bridge, 3500 mm ⁴ or less, preferably 3000 mm ⁴ or less, more preferably 2500 mm ⁴ or less, more preferably 2000 mm ⁴ or less, More preferably, 1750 mm is ⁴ or less, more preferably 1500 mm is ⁴ or less. Alternatively or additionally, the value of Iz (x) may be at least in sections, preferably in sections in the middle section of the bridge, 100 mm ⁴ or more, preferably 250 mm ⁴ or more, more preferably 500 mm ⁴ or more, more preferably 750 mm ⁴ or more, more preferably 1000 mm ⁴ or more, more preferably 1250 mm ⁴ or more. Preferably, the value of Iz (x) is at least in sections, preferably in sections in the middle section of the bridge, in a range of 100 mm ⁴ - 3500 mm ⁴ , preferably 250 mm ⁴ - 3000 mm ⁴ , more preferably 500 mm ⁴ - 2500 mm ⁴ , more preferably 750 mm ⁴ - 2000 mm ⁴ , more preferably 1000 mm ⁴ - 1750 mm ⁴ , particularly preferably 1250 mm ⁴ - 1500 mm ⁴ .

Alternatively or additionally, the value of Iy (x) may be at least in sections, preferably in sections in a web section and / or in the transition region from a web section to the middle section of the bridge, 100 mm ⁴ or more, preferably 250 mm ⁴ or more, more preferably 500 mm ⁴ or more, more preferably 1000 mm ⁴ or more, more preferably 1500 mm ⁴ or more, more preferably 2000 mm ⁴ or more, particularly preferably 2300 mm ⁴ or more. Alternatively or additionally, the value of Iy (x) may be at least in sections, preferably in sections in a web section and / or in the transition region from a web section to the middle section of the bridge, 4000 mm ⁴ or less, preferably 3500 mm ⁴ or less, more preferably 3000 mm ⁴ or less , more preferably 2500 mm ⁴ or less. The value of Iy (x) is preferably at least in sections, preferably in sections in a web section and / or in the transition region from a web section to the middle section of the bridge, in a range of 100 mm ⁴ - 4000 mm ⁴ , preferably 500 mm ⁴ - 3500 mm ⁴ , more preferably 1000 mm ⁴ - 3000 mm ⁴ , more preferably 1500 mm ⁴ - 2500 mm ⁴ , more preferably 2300 mm ⁴ - 2500 mm ⁴ . Alternatively or additionally, the value of Iy (x) may be at least in sections, preferably in sections in the middle section of the bridge, 100 mm ⁴ or more, preferably 250 mm ⁴ or more, more preferably 500 mm ⁴ or more, more preferably 750 mm ⁴ or more. Alternatively or additionally, the value of Iy (x) may be at least in sections, preferably in sections in the middle section of the bridge, 2500 mm ⁴ or less, preferably 2000 mm ⁴ or less, more preferably 1500 mm ⁴ or less, particularly preferably 1000 mm ⁴ or less , Preferably, the value of Iy (x) is at least in sections, preferably in sections in the middle section of the bridge, in a range of 100 mm ⁴ - 2500 mm ⁴ , preferably 250 mm ⁴ - 2000 mm ⁴ , more preferably 500 mm ⁴ - 1500 mm ⁴ , more preferably 750 mm ⁴ - 1000 mm ⁴ .

In a preferred embodiment of the bridge, Iz (x) differs from Iy (x) at least in sections by 2000 mm ⁴ or less, preferably 1500 mm ⁴ or less, more preferably 1000 mm ⁴ or less, respectively for x ≥ 0 and / or x <0. Alternatively or additionally, Iz (x) differs from Iy (x) along the x-axis at least in sections by 1500 mm ⁴ or more, preferably 2000 mm ⁴ or more, more preferably 2500 mm ⁴ or more and each for x ≥ 0 and / or x <0.

In a preferred embodiment of the bridge there is at least one value pair d1 and d2 of the same sign, for which Iz (x) is greater at the location x = d1 than at the location x = d2 and Iy (x) at the location x = d1 smaller than at the point x = d2. D1 may be larger than d2. Alternatively or additionally, there may be a pair of values d1 and d2 in which d2 is greater than d1.

In a preferred embodiment, the bridge has at least a portion A1 in which Iz (x) increases with increasing amount of x and in which Iy (x) decreases with increasing amount of x. Such a section A1 may have one or more bridge sections with bridge bridges. Particularly preferably, the bridge has at least two sections A1, but the bridge may also have at least three, at least four or even more sections A1. The one or more sections A1 preferably each have an extension in the x-direction of 1 mm or more, preferably 5 mm or more.

Furthermore, a bridge according to the invention may have one or more sections A2, wherein Iy (x) and Iz (x) within a section A2 have substantially the same absolute change. At least one of the sections A2 preferably has the center plane of the bridge. Alternatively, none of the sections A2 may have the center plane of the bridge. Preferably, the one or more sections A2 each extend over at least 5 mm, more preferably at least 10 mm, more preferably at least 15 mm, more preferably at least 20 mm, more preferably at least 25 mm, more preferably at least 30 mm, more preferably at least 35 mm, more preferably at least 40 mm, more preferably at least 45 mm, particularly preferably at least 50 mm in the x-direction. More preferably, the center of at least one of the sections A2 has an x-coordinate value of zero. In particular, a bridge according to the invention can have a section A2 around the origin of the coordinate system and two sections A1, with one section A1 in the positive x and one section A1 in the negative x-axis area.

In a preferred embodiment of the bridge, the value of Iz (x) and / or the value of Iy (x) has a variation over an x value range A3 of 15 mm or less, preferably 10 mm or less, more preferably 5 mm or less of at least 100% of its smallest value in the considered x value range.

In the above-described ranges or sections A1-A3, it should be noted that the characteristics of Iy and Iz described for these ranges should be understood in terms of global properties, respectively. That is, the behavior of the moment of inertia of area is considered in the overview or also broadly, whereas individual outliers for the consideration remain unconsidered. In particular, area moments of inertia of yz sections with string openings are to be classified as outliers.

In a preferred embodiment, Iz (x) has at least one minimum. Alternatively or additionally, Iy (x) preferably has a maximum. The maxima and minima also relate to the behavior of the moments of inertia on the whole and not to outliers.

Furthermore, the present invention relates to a method for producing a frame or frame portion for a ball game racket. Preferably, the frame or frame portion produced by the method according to the invention has the properties described above.

According to the method of manufacturing a frame according to the invention, a bridge is cast from a material comprising magnesium. This is preferably done in the so-called Thixoverfahren.

Furthermore, the manufacturing method comprises providing a carbon-containing frame portion. The carbon-containing frame portion may include a head portion and / or a handle portion.

Furthermore, the manufacturing method according to the invention comprises the connection of the bridge with the carbon-containing frame section. For this purpose, the bridge with the frame portion, for example glued, pressed, welded, cured together, riveted and / or bolted.

The carbon-containing frame section may be a finished or unfinished frame section. The step of connecting the bridge to the carbon-containing frame portion and the step of completion and / or the permanent shaping of the carbon-containing frame portion can generally take place in one method step.

In particular, the unfinished carbon-containing frame section can be prepreg layers which are provided for the production of the carbon-containing frame section in the tubular blowing process.
Preferably, the bridge is inserted together with prepreg layers, which form the carbon-containing frame portion after completion, in a Schlauchblasform and pressed and cured.

1. 1 Eine Brücke für einen Ballspielschläger, die Magnesium aufweist.
2. 2 Brücke gemäß dem vorstehenden Aspekt, wobei die Brücke ein Hohlprofil aufweist.
3. 3 Brücke gemäß einem der vorstehenden Aspekte, wobei die Wandstärke der Brücke entlang eines Querschnitts durch das Rahmenprofil variiert.
4. 4 Brücke gemäß einem der vorstehenden Aspekte, wobei die Brücke ein Vollprofil aufweist.
5. 5 Brücke nach einem der vorstehenden Aspekte, wobei die Brücke einen Mittelabschnitt und zwei Randabschnitte aufweist, die dazu vorgesehen sind, mit dem Rahmen eines Ballspielschlägers verbunden zu werden, wobei sich von dem Mittelabschnitt beidseitig jeweils ein unterer Steg und zwei obere Stege zu den beiden Randabschnitten erstrecken, wobei der Mittelabschnitt erste Durchgangsöffnungen zur Aufnahme von Längssaiten aufweist und wobei mindestens zwei weitere zweite Durchgangsöffnungen zur Aufnahme von Längssaiten derart angeordnet sind, dass die von ihnen aufzunehmenden Längssaiten jeweils zwischen den entsprechenden zwei oberen Stegen hindurch verlaufen.
6. 6 Brücke nach einem der vorstehenden Aspekte, wobei die von den mindestens zwei zweiten Durchgangsöffnungen aufzunehmenden Längssaiten jeweils berührungslos zwischen den entsprechenden zwei oberen Stegen hindurch verlaufen.
7. 7 Brücke nach einem der vorstehenden Aspekte, wobei jeweils der untere Steg zwischen dem Mittelabschnitt und dem entsprechenden Randabschnitt mit keinem der beiden oberen Stege verbunden ist.
8. 8 Brücke nach einem der vorstehenden Aspekte, wobei jeweils die beiden oberen Stege zwischen dem Mittelabschnitt und dem entsprechenden Randabschnitt nicht miteinander verbunden sind.
9. 9 Brücke nach einem der vorstehenden Aspekte, wobei jeweils der Oberflächen-Abstand zwischen den beiden oberen Stegen vom Mittelabschnitt zum entsprechenden Randabschnitt hin zunimmt.
10. 10 Brücke nach einem der vorstehenden Aspekte, wobei jeweils zwischen den beiden oberen Stegen und dem unteren Steg eine Durchgangsöffnung senkrecht zu einer durch die Bespannung definierten Ebene gebildet wird, deren parallel zur durch die Bespannung definierten Ebene ausgerichtete Schnittfläche bevorzugt mindestens 1,5 cm², stärker bevorzugt mindestens 2 cm² und besonders bevorzugt mindestens 2,5 cm² beträgt.
11. 11 Brücke nach einem der vorstehenden Aspekte, wobei an den beiden Randabschnitten jeweils Anbindungslaschen vorgesehen sind, die dazu geeignet sind, die Brücke an einem mittels Schlauchblasverfahren herzustellenden Schlägerrahmen anzubinden.
12. 12 Brücke nach Aspekt 11, wobei die Anbindungslaschen jeweils wenigstens abschnittsweise eine konkave Außenfläche aufweisen, die bevorzugt mindestens 10 cm², stärker bevorzugt mindestens 15 cm² und besonders bevorzugt mindestens 20 cm² beträgt.
13. 13 Brücke nach Aspekt 11 oder 12, wobei jeweils mindestens eine der zweiten Durchgangsöffnungen in jeweils einer der Anbindungslaschen angeordnet ist
14. 14 Brücke nach Aspekt 11, 12 oder 13, wobei die Anbindungslaschen jeweils mindestens eine, bevorzugt zwei dritte Durchgangsöffnung(en) zur Aufnahme von Längs- und/oder Quersaiten aufweisen.
15. 15 Brücke nach einem der vorstehenden Aspekte, wobei der Mittelabschnitt rinnenförmig ausgebildet ist und wobei die Seiten der Rinne jeweils als durchgehende Seitenwand oder als Fachwerkstruktur ausgebildet sind.
16. 16 Brücke nach Aspekt 15, wobei die Rinne gegenüberliegende Ränder aufweist, von denen sich die Stege zu den Randabschnitten erstrecken, und wobei die Rinne an diesen gegenüberliegenden Rändern jeweils mittels einer Stirnwand verschlossen ist.
17. 17 Brücke nach Aspekt 15 oder 16, wobei der Boden der Rinne mindestens zwei, bevorzugt mindestens drei, bevorzugt mindestens vier Durchgangsöffnungen zur Aufnahme von Längssaiten aufweist.
18. 18 Brücke nach einem der vorstehenden Aspekte, wobei mindestens einige, bevorzugt alle Durchgangsöffnungen zur Aufnahme jeweils einer einzelnen Saite ausgebildet sind.
19. 19 Brücke nach einem der vorstehenden Aspekte, wobei jeweils mindestens eine der zweiten Durchgangsöffnungen in jeweils einem der unteren Stege angeordnet ist.
20. 20 Brücke nach einem der vorstehenden Aspekte, wobei sich von dem Mittelabschnitt beidseitig jeweils zwei untere Stege zu den beiden Randabschnitten erstrecken.
21. 21 Brücke nach Aspekt 20, wobei die von den zweiten Durchgangsöffnungen aufzunehmenden Längssaiten jeweils zwischen den entsprechenden zwei unteren Stegen hindurch verlaufen.
22. 22 Brücke nach einem der vorstehenden Aspekte, wobei die Brücke als Metall-Gussteil, bevorzugt als Metall-Spritzgussteil ausgebildet ist.
23. 23 Brücke nach einem der vorstehenden Aspekte, wobei die Brücke ein Flächenträgheitsmoment Iz und ein Flächenträgheitsmoment Iy aufweist.
24. 24 Brücke nach Aspekt 23, wobei Iz(x) entlang der x-Achse mindestens abschnittsweise größer als Iy(x) ist.
25. 25 Brücke für einen Ballspielschläger nach einem der Aspekte 23-24, wobei der Wert von Iz(x) entlang der x-Achse mindestens abschnittsweise 2500 mm⁴ oder mehr, bevorzugt 3000 mm⁴ oder mehr, stärker bevorzugt 3500 mm⁴ oder mehr, stärker bevorzugt 4000 mm⁴ oder mehr, besonders bevorzugt 4500 mm⁴ oder mehr beträgt.
26. 26 Brücke für einen Ballspielschläger nach einem der Aspekte 23-25, wobei es mindestens ein Wertepaar d1 und d2 mit gleichem Vorzeichen gibt, für die Iz(x) an der Stelle x=d1 größer als an der Stelle x=d2 ist und Iy(x) an der Stelle x=d1 kleiner als an der Stelle x=d2 ist.
27. 27 Brücke für einen Ballspielschläger nach einem der Aspekte 23-26, wobei die Brücke mindestens einen, bevorzugt mindestens zwei Abschnitte A1 aufweist, in dem oder in denen Iz(x) mit zunehmendem Betrag von x ansteigt und in dem oder in denen Iy(x) mit zunehmendem Betrag von x abfällt, wobei der oder die Abschnitte A1 bevorzugt jeweils eine Ausdehnung in x-Richtung von 1 mm oder mehr, bevorzugt 5 mm oder mehr, stärker bevorzugt 10 mm oder mehr, besonders bevorzugt 15 mm oder mehr aufweisen.
28. 28 Brücke für einen Ballspielschläger nach einem der Aspekte 23-27, wobei sich Iz(x) von Iy(x) entlang der x-Achse wenigstens abschnittsweise um 2000 mm⁴ oder weniger, bevorzugt 1500 mm⁴ oder weniger, besonders bevorzugt 1000 mm⁴ oder weniger unterscheidet und/oder sich Iz(x) von Iy(x) entlang der x-Achse wenigstens abschnittsweise um 1500 mm⁴ oder mehr, bevorzugt 2000 mm⁴ oder mehr, stärker bevorzugt 2500 mm⁴ oder mehr unterscheidet.
29. 29 Brücke für einen Ballspielschläger nach einem der Aspekte 23-28, wobei die Brücke einen oder mehrere Abschnitte A2 aufweist, wobei Iy(x) und Iz(x) innerhalb der jeweiligen Abschnitte A2 jeweils im Wesentlichen die gleiche absolute Veränderung aufweisen.
30. 30 Brücke für einen Ballspielschläger nach einem der Aspekte 23-29, wobei Iz ein Maximum und Iy ein Minimum aufweist.
31. 31 Brücke für einen Ballspielschläger nach einem der Aspekte 23-30, wobei der Wert von Iz(x) und/oder der Wert von Iy(x) über einen Achsenabschnitt A3 von 15 mm oder weniger, bevorzugt 10 mm oder weniger, besonders bevorzugt 5 mm oder weniger eine Variation von 100% ihres kleinsten Wertes oder mehr aufweisen.
32. 32 Brücke nach einem der Aspekte 23-31, wobei Iy(x) mindestens abschnittsweise größer als Iz(x) ist.
33. 33 Brücke für einen Ballspielschläger nach einem der Aspekte 23-32, wobei der Wert von Iz(x) mindestens abschnittsweise 6500 mm⁴ oder weniger, bevorzugt 6000mm⁴ oder weniger, stärker bevorzugt 5500mm⁴ oder weniger, besonders bevorzugt 5000 mm⁴ oder weniger beträgt.
34. 34 Brücke für einen Ballspielschläger nach einem der Aspekte 23-33, wobei der Wert von Iy(x) mindestens abschnittsweise in einem Bereich von 100 mm⁴ - 4000 mm⁴, bevorzugt 500 mm⁴ - 3500 mm⁴, stärker bevorzugt 1000 mm⁴ - 3000 mm⁴, stärker bevorzugt 1500 mm⁴ - 2500 mm⁴, besonders bevorzugt 2300 mm⁴ - 2500 mm⁴ und/oder mindestens abschnittsweise in einem Bereich von 100 mm⁴ - 2500 mm⁴, bevorzugt 250 mm⁴ - 2000 mm⁴, stärker bevorzugt 500 mm⁴ - 1500 mm⁴, besonders bevorzugt 750 mm⁴ - 1000 mm⁴ liegt.
35. 35 Ballspielschläger mit einem Schlägerrahmen, der einen Griffabschnitt, einen Schlägerkopf und einen dazwischen angeordneten Herzbereich aufweist, wobei der Herzbereich durch eine Brücke nach einem der vorstehenden Aspekte und zwei sich vom Griffabschnitt erstreckende Rahmenholme gebildet wird.
36. 36 Ballspielschläger nach Aspekt 35, ferner mit einer durch Längs- und Quersaiten gebildeten Bespannung, wobei mindestens eine erste Längssaite durch eine Durchgangsöffnung im Mittelabschnitt der Brücke und jeweils mindestens eine zweite Längssaite durch jeweils eine Durchgangsöffnung zweier unterer Stege der Brücke geführt ist und wobei die beiden zweiten Längssaiten jeweils zwischen zwei entsprechenden oberen Stegen der Brücke hindurch verlaufen.
37. 37 Ballspielschläger nach Aspekt 35 oder 36, wobei der Schlägerrahmen als Kohlefaser-Hohlprofil ausgebildet und an die Brücke angeformt ist.
38. 38 Ballspielschläger mit einem Schlägerrahmen, der einen Griffabschnitt, einen Schlägerkopf und einen dazwischen angeordneten Herzbereich aufweist, wobei der Herzbereich durch zwei sich vom Griffabschnitt erstreckende Rahmenholme und eine Brücke gebildet wird, wobei die Brücke einen Mittelabschnitt und zwei Randabschnitte aufweist, die dazu vorgesehen sind, mit dem Rahmen eines Ballspielschlägers verbunden zu werden, wobei sich von dem Mittelabschnitt beidseitig jeweils ein unterer Steg und zwei obere Stege zu den beiden Randabschnitten erstrecken, wobei der Mittelabschnitt erste Durchgangsöffnungen zur Aufnahme von Längssaiten aufweist und wobei mindestens zwei weitere zweite Durchgangsöffnungen in den beiden Rahmenholmen zur Aufnahme von Längssaiten derart angeordnet sind, dass die von ihnen aufzunehmenden Längssaiten jeweils zwischen den entsprechenden zwei oberen Stegen hindurch verlaufen.
39. 39 Rahmen für einen Ballspielschläger mit einer Brücke, jeweils nach einem der vorstehenden Aspekte, wobei der Rahmen ein Hohlprofil aufweist.
40. 40 Rahmen für einen Ballspielschläger nach einem der vorstehenden Aspekte mit einer Brücke nach einem der vorstehenden Aspekte, wobei der Rahmen ein Vollprofil aufweist.
41. 41 Rahmen für einen Ballspielschläger nach einem der vorstehenden Aspekte mit einer Brücke nach einem der vorstehenden Aspekte, wobei der Rahmen Karbon aufweist.
42. 42 Rahmen für einen Ballspielschläger nach einem der vorstehenden Aspekte mit einer Brücke nach einem der vorstehenden Aspekte, wobei der Rahmen einen Kohlefaser-Verbundwerkstoff aufweist.
43. 43 Rahmen für einen Ballspielschläger nach einem der vorstehenden Aspekte mit einer Brücke nach einem der vorstehenden Aspekte, wobei der Rahmen einen Prepregschlauch aufweist.
44. 44 Ballspielschläger mit einer Bespannung und einem Schlägerrahmen nach einem der vorstehenden Aspekte, der einen Griffabschnitt, einen Schlägerkopf und einen dazwischen angeordneten Herzbereich aufweist, wobei der Herzbereich durch zwei sich vom Griffabschnitt erstreckende Rahmenholme und eine Brücke nach einem der vorstehenden Aspekte gebildet wird, wobei die Brücke zwei Randabschnitte aufweist, die dazu vorgesehen sind, mit dem Rahmen eines Ballspielschlägers verbunden zu werden.

The present invention particularly relates to the following aspects:

1. 1 A bridge for a ball game racket that has magnesium.
2. 2 bridge according to the preceding aspect, wherein the bridge has a hollow profile.
3. A bridge according to any preceding aspect, wherein the wall thickness of the bridge varies along a cross-section through the frame profile.
4. 4 bridge according to one of the preceding aspects, wherein the bridge has a solid profile.
5. 5 bridge according to one of the preceding aspects, wherein the bridge has a central portion and two edge portions, which are intended to be connected to the frame of a ball game racket, wherein on both sides in each case a lower web and two upper webs to the two edge portions of the central portion extend, wherein the central portion has first passage openings for receiving longitudinal strings and wherein at least two further second passage openings for receiving longitudinal strings are arranged such that the longitudinal strings to be accommodated by each extend between the corresponding two upper webs.
6. 6. Bridge according to one of the preceding aspects, wherein the longitudinal strings to be received by the at least two second through openings each extend without contact between the corresponding two upper webs.
7. 7 bridge according to one of the preceding aspects, wherein in each case the lower web between the central portion and the corresponding edge portion is connected to neither of the two upper webs.
8. 8 bridge according to one of the preceding aspects, wherein in each case the two upper webs between the central portion and the corresponding edge portion are not connected to each other.
9. 9 bridge according to one of the preceding aspects, wherein in each case the surface distance between the two upper webs increases from the central portion to the corresponding edge portion.
10. 10 bridge according to one of the preceding aspects, wherein in each case between the two upper webs and the lower web a passage opening is formed perpendicular to a plane defined by the clothing whose parallel to the plane defined by the clothing plane aligned cut surface preferably at least 1.5 cm ² , more preferably at least 2 cm ² and more preferably at least 2.5 cm ² .
11. 11 bridge according to one of the preceding aspects, wherein at the two edge portions respectively connecting tabs are provided which are adapted to connect the bridge to a manufactured by means of tubular blowing racket frame.
12. 12 bridge according to aspect 11, wherein the connection tabs in each case at least partially have a concave outer surface, which is preferably at least 10 cm ² , more preferably at least 15 cm ² and particularly preferably at least 20 cm ² .
13. 13 bridge according to aspect 11 or 12, wherein in each case at least one of the second passage openings in each case one of the connection tabs is arranged
14. 14 bridge according to aspect 11, 12 or 13, wherein the attachment tabs each have at least one, preferably two third passage opening (s) for receiving longitudinal and / or transverse strings.
15. 15 bridge according to one of the preceding aspects, wherein the central portion is channel-shaped and wherein the sides of the channel are each formed as a continuous side wall or as a truss structure.
16. 16. A bridge according to aspect 15, wherein the channel has opposite edges, from which the webs extend to the edge portions, and wherein the Gutter is closed at these opposite edges in each case by means of an end wall.
17. 17 bridge according to aspect 15 or 16, wherein the bottom of the channel has at least two, preferably at least three, preferably at least four through holes for receiving longitudinal strings.
18. 18 bridge according to one of the preceding aspects, wherein at least some, preferably all passage openings for receiving a single string are formed.
19. 19 bridge according to one of the preceding aspects, wherein in each case at least one of the second passage openings in each case one of the lower webs is arranged.
20. 20 bridge according to one of the preceding aspects, wherein extending from the central portion on both sides in each case two lower webs to the two edge portions.
21. 21. A bridge according to aspect 20, wherein the longitudinal strings to be received by the second passage openings each extend between the respective two lower lands.
22. 22 bridge according to one of the preceding aspects, wherein the bridge is formed as a metal casting, preferably as a metal injection molded part.
23. 23 Bridge according to one of the preceding aspects, wherein the bridge has an area moment of inertia Iz and an area moment of inertia Iy.
24. 24 Bridge according to aspect 23, wherein Iz (x) along the x-axis at least in sections is greater than Iy (x).
25. A bridge for a ball game racket according to any one of aspects 23-24, wherein the value of Iz (x) along the x-axis is at least partially 2500 mm ⁴ or more, preferably 3000 mm ⁴ or more, more preferably 3500 mm ⁴ or more, More preferably, 4000 mm is ⁴ or more, more preferably 4500 mm is ⁴ or more.
26. 26. A bridge for a ball game racket according to any of aspects 23-25, wherein there is at least one value pair d1 and d2 of the same sign, for which Iz (x) is greater at the location x = d1 than at the location x = d2, and Iy ( x) is smaller at the point x = d1 than at the point x = d2.
27. Bridge for a ball game racket according to one of the aspects 23-26, wherein the bridge has at least one, preferably at least two sections A1, in which or in which Iz (x) increases with increasing amount of x and in which or in which Iy (x ) decreases with increasing amount of x, wherein the section or sections A1 preferably each have an extension in the x-direction of 1 mm or more, preferably 5 mm or more, more preferably 10 mm or more, particularly preferably 15 mm or more.
28. 28 bridge for a ball game racket according to one of the aspects 23-27, wherein Iz (x) of Iy (x) along the x-axis at least in sections by 2000 mm ⁴ or less, preferably 1500 mm ⁴ or less, more preferably 1000 mm ⁴ or less, and / or Iz (x) differs from Iy (x) along the x-axis at least in sections by 1500 mm ⁴ or more, preferably 2000 mm ⁴ or more, more preferably 2500 mm ⁴ or more.
29. 29. A bridge for a ball game racket according to any one of aspects 23-28, wherein the bridge has one or more sections A2, where Iy (x) and Iz (x) within the respective sections A2 each have substantially the same absolute variation.
30. A bridge for a ball game racket according to any one of aspects 23-29, wherein Iz has a maximum and Iy a minimum.
31. 31. A bridge for a ball game racket according to any one of aspects 23-30, wherein the value of Iz (x) and / or the value of Iy (x) over an axis section A3 is 15 mm or less, preferably 10 mm or less, more preferably 5 mm or less have a variation of 100% of their smallest value or more.
32. 32 Bridge according to any of aspects 23-31, wherein Iy (x) is at least partially greater than Iz (x).
33. 33 bridge for a ball game racket according to any of aspects 23-32, wherein the value of Iz (x) at least in sections 6500 mm ⁴ or less, preferably 6000mm ⁴ or less, more preferably 5500mm ⁴ or less, more preferably 5000 mm ⁴ or less ,
34. 34 bridge for a ball game racket according to any of aspects 23-33, wherein the value of Iy (x) at least in sections in a range of 100 mm ⁴ - 4000 mm ⁴ , preferably 500 mm ⁴ - 3500 mm ⁴ , more preferably 1000 mm ⁴ - 3000 mm ⁴ , more preferably 1500 mm ⁴ - 2500 mm ⁴ , more preferably 2300 mm ⁴ - 2500 mm ⁴ and / or at least partially in a range of 100 mm ⁴ - 2500 mm ⁴ , preferably 250 mm ⁴ - 2000 mm ⁴ , stronger preferably 500 mm ⁴ - 1500 mm ⁴ , more preferably 750 mm ⁴ - 1000 mm ⁴ is located.
35. 35 ball game racket with a racket frame having a handle portion, a club head and a heart area disposed therebetween, wherein the heart area is formed by a bridge according to one of the above aspects and two frame spars extending from the handle portion.
36. 36 ball game racket according to aspect 35, further comprising a string formed by longitudinal and transverse strings, wherein at least a first longitudinal string through a through hole in the central portion of the bridge and at least one second Längssaite is guided through a respective through hole of two lower webs of the bridge and wherein the two second longitudinal strings each extending between two corresponding upper webs of the bridge.
37. 37 ball game rackets according to aspect 35 or 36, wherein the racket frame is formed as a carbon fiber hollow profile and formed on the bridge.
38. 38 ball game racket comprising a racket frame having a handle portion, a club head and a heart portion disposed therebetween, the heart portion being formed by two frame spars extending from the handle portion and a bridge, the bridge having a central portion and two edge portions provided therewith; to be connected to the frame of a ball game racket, wherein extending from the central portion on both sides in each case a lower web and two upper webs to the two edge portions, wherein the central portion has first passage openings for receiving longitudinal strings and wherein at least two further second through holes in the two frame spars are arranged for receiving longitudinal strings such that the longitudinal strings to be picked up by them each extend between the corresponding two upper webs.
39. Frame for a ball game racket with a bridge, each according to one of the preceding aspects, wherein the frame has a hollow profile.
40. A frame for a ball game racket according to any one of the preceding aspects, comprising a bridge according to any one of the preceding aspects, wherein the frame has a solid profile.
41. A frame for a ball game racket according to any preceding aspect, comprising a bridge according to any one of the preceding aspects, wherein the frame comprises carbon.
42. 42. A ball game racket frame according to any preceding aspect, comprising a bridge according to any one of the preceding aspects, wherein the frame comprises a carbon fiber composite.
43. A frame for a ball game racket according to any preceding aspect, comprising a bridge according to any one of the preceding aspects, wherein the frame comprises a prepreg tube.
44. 44 ball game racket with a string and a racket frame according to one of the preceding aspects, a handle portion, a club head and a the heart region being formed by two frame spars extending from the handle portion and a bridge according to any one of the preceding aspects, the bridge having two edge portions intended to be connected to the frame of a ball game racket.

• Fig. 1 eine schematische frontale Ansicht eines erfindungsgemäßen Rahmens;
• Fig. 2A eine schematische perspektivische Ansicht einer erfindungsgemäßen Brücke;
• Fig. 2B eine schematische Ansicht eines Querschnitts der Brücke aus Fig. 2A durch die Linie A-B gemäß Fig. 1;
• Fig. 2C eine schematische Ansicht eines Querschnitts der Brücke aus Fig. 2A durch die Linie C-D gemäß Fig. 1;
• Fig. 3A eine schematische perspektivische Ansicht einer weiteren erfindungsgemäßen Brücke;
• Fig. 3B eine schematische Ansicht eines Querschnitts der Brücke aus Fig. 3A durch die Linie A-B gemäß Fig. 1;
• Fig. 3C eine schematische Ansicht eines Querschnitts der Brücke aus Fig. 3A durch die Linie C-D gemäß Fig. 1;
• Fig. 4 eine schematische perspektivische Ansicht eines erfindungsgemäßen Rahmens von frontal schräg oben;
• Fig. 5A-5D je eine schematische frontale Ansicht einer erfindungsgemäßen Brücke;
• Fig. 6A eine schematische perspektivische Teilansicht einer erfindungsgemäßen Brücke;
• Fig. 6B eine schematische Ansicht eines Querschnitts der Brücke aus Fig. 6A durch die Linie A-B gemäß Fig. 1;
• Fig. 6C eine schematische Ansicht eines Querschnitts der Brücke aus Fig. 6A durch die Linie C-D gemäß Fig. 1.
• Fig. 6D eine schematische frontale Ansicht eines Abschnitts eines erfindungsgemäßen Rahmens mit der Brücke aus Fig. 6A.
• Fig. 6E einen vergrößerten Ausschnitt der Fig. 6D.
• Fig. 7A die yz-Schnitte einer Brücke eines herkömmlichen Ballspielschlägerrahmens;
• Fig. 7B ein Diagramm berechneter Flächenträgheitsmomente der yz-Schnitte aus Fig. 7A;
• Fig. 7C die yz-Schnitte einer Brücke eines erfindungsgemäßen Ballspielschlägerrahmens;
• Fig. 7D ein Diagramm berechneter Flächenträgheitsmomente der yz-Schnitte aus Fig. 7C.

In the following, preferred embodiments of the frame according to the invention are described in more detail with reference to FIGS. Show it:

• Fig. 1 a schematic frontal view of a frame according to the invention;
• Fig. 2A a schematic perspective view of a bridge according to the invention;
• Fig. 2B a schematic view of a cross section of the bridge Fig. 2A according to the line AB Fig. 1 ;
• Fig. 2C a schematic view of a cross section of the bridge Fig. 2A through the line CD according to Fig. 1 ;
• Fig. 3A a schematic perspective view of another bridge according to the invention;
• Fig. 3B a schematic view of a cross section of the bridge Fig. 3A according to the line AB Fig. 1 ;
• Fig. 3C a schematic view of a cross section of the bridge Fig. 3A through the line CD according to Fig. 1 ;
• Fig. 4 a schematic perspective view of a frame according to the invention from the front obliquely above;
• Figs. 5A-5D in each case a schematic frontal view of a bridge according to the invention;
• Fig. 6A a schematic perspective partial view of a bridge according to the invention;
• Fig. 6B a schematic view of a cross section of the bridge Fig. 6A according to the line AB Fig. 1 ;
• Fig. 6C a schematic view of a cross section of the bridge Fig. 6A through the line CD according to Fig. 1 ,
• Fig. 6D a schematic frontal view of a portion of a frame according to the invention with the bridge Fig. 6A ,
• Fig. 6E an enlarged section of the Fig. 6D ,
• Fig. 7A the yz sections of a bridge of a conventional ball game racket frame;
• Fig. 7B a diagram of calculated area moments of inertia of the yz sections Fig. 7A ;
• Fig. 7C the yz sections of a bridge of a ball game racket frame according to the invention;
• Fig. 7D a diagram of calculated area moments of inertia of the yz sections Fig. 7C ,

Fig. 1 shows a schematic frontal view of a frame 2 for a ball game racket according to the present invention. The frame 2 has a head section 4 with a bridge section or a bridge 6. The head section 4 with the bridge 6 defines a string bed 8 for receiving a fabric, not shown. Furthermore, the frame 2 has a handle portion 10 whose central axis coincides with the longitudinal axis 14 of the frame 2.

In the preferred embodiment of the frame 2 of Fig. 1 For example, the bridge has a magnesium alloy and the frame has a carbon fiber composite. Furthermore, the bridge is integrally formed. In the illustrated preferred embodiment, the bridge is made substantially entirely of a unitary material.

A preferred embodiment of a bridge section or bridge 6 according to the invention is shown in a perspective view in FIG Fig. 2A shown. The bridge 6, in its preferred embodiment of the Fig. 2A two connection tabs 16a, 16b, which serve to connect the bridge with at least one further frame section. The attachment tabs 16a, 16b define the illustrated bridge 6 at both ends of its guideway. Centered between the two attachment tabs 16, the bridge 6 has a central portion 18 which on two sides, which are associated with the indices a and b over each two upper webs 22a and 22b and a respective lower web 24a and 24b is connected to the two connecting straps 16a and 16b.

The bridge 6 is in the illustrated preferred embodiment of Fig. 2A designed as a one-piece casting with solid profile and has a uniform magnesium alloy. Fig. 2B represents a cross section of the bridge Fig. 2A according to the line AB Fig. 1 represents. Fig. 2B thus represents a cross section through the central portion 18 of the bridge Fig. 2A as in Fig. 2B can be seen, the bridge has a central portion 18 with exclusively convex cross-section, which is designed here by way of example substantially rectangular. Fig. 2C represents a cross section of the bridge Fig. 2A through the line CD according to Fig. 1 represents. Fig. 2C thus represents a cross section through the web portion of the bridge Fig. 2A as in Fig. 2C it can be seen, the webs 22 and 24 of the bridge also each have a convex cross-sectional profile, also executed by way of example substantially rectangular.

It should be emphasized that the arrangement of the webs relative to one another as well as the surfaces of the individual web cross sections are only to be understood schematically and by way of example. Thus, in particular, the surface spacings of two adjacent webs are not fixed to the illustrated land surface distances h, w1 and w2, where h represents a surface distance between two adjacent webs perpendicular to the string bed plane and w1 and w2 each have a surface distance of two represent adjacent webs parallel to the stringbed level. Alternative embodiments with other web configurations, profile shapes, cross-sectional areas and / or surface distances are possible. In particular, oval, round, convex or concave polygonal and / or irregular web cross-sections are possible. Cross-sectional areas and shapes of lands of the same embodiment may generally differ. The values of web arrangements, lengths, profile shapes, cross-sectional areas and / or surface distances as well as bridge lengths, profile shapes and / or cross-sectional areas are preferably in the value ranges already described above.

Like from the FIGS. 2A and 2C As can be seen, the use of a one-piece solid profile of a magnesium alloy allows the formation of extremely filigree structures such as the upper webs 22a, 22b, the minimum extent along a cross-sectional area may be, for example, less than 3 mm. Thus, web cross-sectional areas in the range of 5 mm ² to 10 mm ^{2 can be} achieved without substantially increasing the risk of breakage of the bridge.

Fig. 3A shows a further embodiment of a bridge 6 of a frame 2 according to the invention, in which also the central portion 18 is formed more filigree than in the case of Fig. 2A , The bridge 6 off Fig. 3A has a uniform magnesium alloy and is designed as a one-piece casting with solid profile. In the middle between the two attachment tabs 16, the bridge 6 has a central portion 18 which on two sides, which are again associated with the indices a and b, via two upper webs 22a and 22b and one lower web 24a and 24b with the two connection tabs 16a and 16b is connected. Fig. 3B represents a cross section of the bridge Fig. 3A according to the line AB Fig. 1 represents. Fig. 3B thus represents a cross section through the central portion 18 of the bridge Fig. 3A as in Fig. 3B can be seen, the bridge points out Fig. 3A a groove-shaped recess 26 in the central portion 18. The groove-shaped recess 26 has an open side to the string bed, but is completed on both sides a and b, and thus may be referred to as cup-shaped. Further shows Fig. 3C a cross section of the bridge Fig. 3A through the line CD according to Fig. 1 , Fig. 3C thus represents a cross section through the web portion of the bridge Fig. 3A dar. The bridge 6 off Fig. 3A has webs 22 and 24 with convex cross-sectional profiles, for example, shown substantially rectangular in shape. Also, this cup-shaped central portion 18 of the bridge in Fig. 3A is formed as a solid profile or solid, ie the cup-shaped central portion has no voids and in particular does not consist of opposite wall portions which would enclose a cavity.

It should be emphasized that the arrangement of the webs relative to one another as well as the surfaces of the individual web cross sections are only to be understood schematically and by way of example. Thus, in particular, the surface spacings of two adjacent webs are not fixed to the illustrated land surface distances h, w1 and w2, where h represents a surface distance between two adjacent webs perpendicular to the string bed plane and w1 and w2 each have a surface distance of two represent adjacent webs parallel to the stringbed level. Alternative embodiments with other web configurations, profile shapes, cross-sectional areas and / or surface distances are possible. In particular, oval, round, convex or concave polygonal and / or irregular web cross-sections are possible. Cross-sectional areas and shapes of webs of the same embodiment may generally differ. The values of web arrangements, lengths, profile shapes, cross-sectional areas and / or surface distances as well as bridge lengths, profile shapes and / or cross-sectional areas are preferably in the value ranges already described.

FIG. 4 shows a schematic perspective view of a frame according to the invention with the bridge according to Fig. 3 , The frame comprises a handle portion 10 and head portion 4 with bridge 6 in a view from the front obliquely above. The middle section 18 is located in the middle in the bridge 6. Each two upper webs 22a and 22b grown from the central portion 18 and extend to the nearest connection tab, which is not visible here, since the connection tabs in the finished racket frame preferably in the carbon fiber composite material of the club head are incorporated. The central portion 18 has a groove-shaped recess 26 which is open to the string bed 8. The facing in the direction of the sides a and b end faces and the direction handle portion 10 facing side (bottom) of the channel are closed, so that the central portion 18 may be referred to as cup-shaped. The bottom of the cup-shaped channel 26 has a string opening 28, as previously specified, for passing through a string of the string. In the bottom of the cup-shaped channel 26 is at least one string opening 28. In the preferred embodiment of Fig. 4 the bottom of the channel 26 has four string openings 28.

In the FIGS. 5A-D By way of example, four further embodiments of the bridge are shown schematically in frontal view. The embodiments correspond to the embodiments of Fig. 2 or the Figures 3 and / or 4, however, in addition to those already associated with the Figures 2 . 3 and / or 4 described features a framework structure 30 in the central portion 18. The truss structure depends on the mutually dependent forms of the struts 32 and the spaces 34 and their number.

The number of spaces or through holes 34 in the FIGS. 5A and 5B is five each. In alternative embodiments, the number of spaces 34 may take other values. For example, the embodiment of the FIG. 5C each three spaces 34, while the embodiment of the Fig. 5D has nine spaces 34. However, the number of spaces 34 is preferably at least 2.

The spaces in between can generally take many forms. For example, the spaces 34 may be oval, triangular, quadrangular, convex, or concave polygonal and / or of irregular shape, with corners may be pointed or rounded.

In the Fig. 5A illustrated embodiment of a bridge 6 according to the invention has in the front view five round spaces 34. In the Fig. 5B illustrated alternative Embodiment of a bridge 6 according to the invention has in the front view five largely triangular gaps 34 which have a tip alternately direction club head 4 and direction handle portion 10 (wherein the orientation of the triangular spaces 34 could also be inverted). The gap triangles may have rounded corners and may be oblique, isosceles, and / or equilateral. In the illustrated embodiment, the middle and the two outer inter-space triangles have the tips of the head section 4 and the remaining two triangles the direction of the handle section 10. In alternative embodiments, the directions in which the tips of the triangles face are just reversed. Alternatively, the triangles may also point in other directions.

A truss structure according to the invention may have similarly shaped gaps 34 and / or similarly shaped struts 32 and additionally or alternatively have non-similarly shaped gaps 34 and / or non-similarly shaped struts. The areas of the gap shapes may remain the same within one embodiment, as shown in FIGS FIGS. 5A and 5B is shown, or vary between the space shapes, as shown in the Fig. 5D is shown.

The different in the FIGS. 5A to 5D shown truss structures are to be understood as exemplary only and are intended to illustrate that can be produced using a one-piece bridge of a magnesium alloy very complex and delicate structures. The use of magnesium ensures the necessary stability and lightweight construction, while the one-piece design ensures, among other things, that the figures shown can be produced with the corresponding precision without fractures occurring at joints. Preferably, the illustrated structures can be produced in a casting, particularly preferably injection molding process, so that the finished bridge consists of a single cast or injection-molded part.

FIG. 6A schematically shows a perspective section of another preferred embodiment of a bridge 6 according to the invention. The bridge 6 is in the illustrated preferred embodiment of Fig. 6A designed as a one-piece casting with solid profile and has a uniform magnesium alloy. A part of the frame portion, to which the bridge is connected via the connection tab, is indicated by dashed lines. The illustrated bridge section of the bridge 6 of Fig. 6A has a connection tab 16 and a part of the middle section 18. The middle section 18 is cut off graphically beyond the longitudinal axis 14. In this embodiment, the bridge 6 four webs per side a and b, two upper webs 22 and two lower webs 24th Fig. 6B represents a cross section of the bridge Fig. 6A according to the line AB Fig. 1 represents. Fig. 6B thus represents a cross section through the central portion 18 of the bridge Fig. 6A as in Fig. 6B it can be seen, the bridge 6 has a central portion 18 with exclusively convex cross section, which is designed here by way of example substantially rectangular. Fig. 6C represents a cross section of the bridge 6 Fig. 6A through the line CD according to Fig. 1 represents. Fig. 6C thus represents a cross section through the web portion of the bridge 6 Fig. 6A as in Fig. 6C it can be seen, the webs 22 and 24 of the bridge 6 also each have a convex cross-sectional profile, also executed by way of example substantially rectangular. It should be emphasized that the arrangement of the webs relative to one another as well as the surfaces of the individual web cross sections are only to be understood schematically and by way of example. Thus, in particular, the surface spacings of two adjacent webs are not fixed to the illustrated land surface distances h1, h2, w1 and w2, where h1 and h2 each represent a surface distance of two adjacent webs perpendicular to the string bed plane and w1 and w2 each represent a surface distance between two adjacent webs parallel to the string bed plane. Alternative embodiments with other web arrangements, profile shapes, cross-sectional areas and / or surface distances are possible. In particular, oval, round, convex or concave polygonal and / or irregular web cross-sections are possible. Cross-sectional areas and shapes of webs of the same embodiment may generally differ. The values of web arrangements, lengths, profile shapes, cross-sectional areas and / or surface distances as well as bridge lengths, profile shapes and / or cross-sectional areas are preferably in the value ranges already described.

The embodiment of Fig. 6A is in the Fig. 6D shown in a frontal view, so that the string guide of the fabric is easily visible. In the embodiment of the FIGS. 6A-E none of the webs has a string opening 28. Instead, the longitudinal strings 36 and 37 each run without contact between the two upper webs 22 of the corresponding side a and b and between the two lower webs 24 of the corresponding side a and b, respectively. The longitudinal strings 36 and 37 engage in a respective string opening 28 in the connection tab 16 of the corresponding side a and b, respectively. This is especially clear Fig. 6E can be seen, an enlargement of the frame area to the side of the bridge 6 a Fig. 6D shows. In the Figures 6D and 6E the boundary curves between the connection tabs 16 and the adjoining, carbon-containing frame section are schematically marked by dashed lines. Alternatively or additionally, a string 36 and / or 37 can also engage in the frame outside of the attachment tabs and outside the bridge.

The Figures 7A-7D refer to calculated area moments of inertia at various locations on a bridge of a preferred embodiment of a ball game racket frame according to the present invention as compared to a conventional, also known as conventional or conventional, bridge of an ordinary ball game racket frame.

FIG. 7A shows yz sections of a bridge of a conventional ball game racket frame at various points along the x-axis, the x-axis satisfying the definition already described. The conventional ball game racket frame used in the calculation is a ball racket frame having a substantially tube-shaped bridge symmetrical with respect to the center plane. The yz cuts are, as already defined, cuts perpendicular to the x-axis. The x-axis locations where the yz sections shown are spaced 2.5 mm apart on the x-axis, starting at the midplane of the bridge (x = 0), up to a maximum value of x = 35 mm. In mathematical terms, yz cuts are shown for all x with the property that x is from the set {0 mm, 2.5 mm, 5.0 mm, ..., 35.0 mm}. The yz intercept at x = 0 is named AA, the yz intercept at x = 2.5 mm with BB, etc., to OO for the yz intercept at x = 35 mm. FIG. 7A also shows the y and z directions for better orientation. The yz cuts for the corresponding locations in the negative x-axis area are due to the symmetry of the FIGS. 7A and 7B The bridge is identical to the respective yz-section at the positive x-value with the same amount | x |.

FIG. 7B shows the calculated area moments of inertia for the in Fig. 7A shown yz sections of a conventional ball game racket frame. The graph shows the position on the racket x axis as the abscissa and the area moment of inertia as the ordinate. The calculated Iz values are plotted as squares, the calculated Iy values as diamonds. Both area moments of inertia show a moderate increase with increasing amount of x. In this case, the Iz and Iy values are essentially parallel, ie the respective absolute increase from a first x value x _m to a second x value x _n is essentially the same for Iz and Iy. In this case, for all calculated values x _i , Iz (x = x _i ) is smaller than Iy (x = x _i ). Iz of the ordinary ball game racket frame ranges from about 500 mm ⁴ to about 1600 mm ⁴ . Iy of the ordinary ball game racket frame ranges from about 1900 mm ⁴ to about 2800 mm ⁴ . A maximum and / or minimum does not occur.

FIG. 7C shows yz sections of a bridge of a ball game racket frame according to the invention. The yz-sections are just as positioned in the racket coordinate system and oriented as the yz-sections of the Fig. 7A , Also, the bridge of the embodiment of Fig. 7C is symmetrical with respect to the center plane, so that the yz sections shown are not only valid for the respective positive x values, as shown, but also for the respective negative x values with the same magnitude | x |.

Figure 7D shows the calculated area moments of inertia for the in Fig. 7C shown yz sections of a ball game racket frame according to the invention. Again, the abscissa shows the x-values, the ordinate the area moment of inertia and the calculated Iz values are plotted as squares, the calculated Iy values as diamonds. The graph shows clear differences from the usual ball game racket frame. Thus, the calculated area moments of inertia Iz (x = x _i ) for the bridge of an embodiment according to the invention are greater than the corresponding values of Iy (x = x _i ). Furthermore, the course of the values differs with increasing x. In the embodiment of the present invention, there is a first portion or region A2-1, such as from x = 0 mm to x = 15 mm, in which Iz and Iy are substantially parallel to each other and also show only a small decrease with increasing x. In a second section A2-2, Iz and Iy are also substantially parallel to each other, but increase significantly as x increases. A2-2 includes the range of about 20 mm to 25 mm on the x-axis. In a third region A1, approximately from x = 25 mm to x = 35 mm, Iz increases steeply with increasing x, while Iy moderately decreases with increasing x. As already mentioned, the consideration of the area moment of inertia with regard to a division into areas A1-A3 relates to the global behavior. The value Iz (x = 27.5 mm) for the yz-section LL is therefore to be classified as an outlier, because this yz-section has a reduced area due to a string opening. Iz has for all calculated x _i a significantly higher value than the usual ball game racket frame from the FIGS. 7A and 7B , In addition, the area moment of inertia Iz in the edge regions of the bridge according to the invention is particularly high in comparison to the Iz values of a conventional, ie conventional, ball game racket frame.

The bridge of a ball game racket according to the invention has with the increased Iz (compared to a conventional racket frame) a significantly higher rigidity in the bending about the z-axis (z-axis is perpendicular to string plane or string bed), in which the forces along the Long strings work. This is advantageous in terms of the energy balance during a blow. During a normal strike, a ball hits the string, the strings of a stringed ball racket frame. The Energy of the ball, in particular the kinetic energy of the ball relative to the racket, is transmitted in the form of vibrations, potential energy and friction to the ball itself, the strings and the ball game racket frame. It is well known that in this process, the fabric absorbs the smallest amount and the ball absorbs most of the transferred energy. The proportion of energy absorbed by the ball game racket frame is in between. The increased rigidity of the ball game racket frame according to the invention helps to absorb and dissipate less energy from the frame, and instead absorb more energy from the strings. As a result, more energy for the acceleration of the ball can be provided and the playability of the ball game racket improves.

The basis of the Figures 1A-7D described embodiments are - by no means exhaustive - examples of one-piece bridges with filigree sections or for ball game racket frame with such bridges, as they satisfy claim 1. The fine structures shown in the examples in the form of webs or arms and / or in the form of the truss structure can not be produced with previously known prior art or only with extremely high technical complexity. For example, the bridges presented by means of the figures would not be able to be produced with adequate stability in the tubular blowing process. However, as a result of the production or use of a bridge formed as a one-piece casting presented in this application, it is also possible to manufacture such and other filigree structures which are not explicitly described.

The in the Figures 1A-7D listed embodiments are exemplary and in no way conclusive. All figures are to be seen as a schematic representation, on the basis of which special features are to be explained. Therefore, in illustrations of embodiments, features may have been omitted for clarity. For example, in the FIGS. 2A-C . 3A-C . 4 and 6A-D completely or partially dispensed with the representation of string openings 28. This means that features from different representations can be combined, unless this has been explicitly excluded.

Claims (15)

Frame for a ball game racket with a handle portion and a head portion with a bridge, wherein a part of the head portion and / or the handle portion / has a carbon fiber composite material, and wherein the bridge has magnesium and is formed in one piece. The frame for a ball game racket according to claim 1, wherein the bridge consists essentially of a unitary material. Frame for a ball game racket according to claim 1, wherein the bridging material comprises at least 50 wt .-%, preferably at least 80 wt .-%, preferably at least 90 wt .-%, particularly preferably at least 95 wt .-% magnesium. Frame for a ball game rackets according to one of the preceding claims, wherein the bridge is at least partially, preferably completely formed as a solid profile. Frame for a ball game racket according to one of the preceding claims, wherein the bridge has at least four, preferably at least six webs, preferably at least eight webs. Frame for a ball game rackets according to claim 5, wherein the webs at least in sections, preferably over a length of at least 5 mm, preferably of at least 15 mm, more preferably at least 30 mm along the frame profile, separated from each other Frame for a ball game rackets according to claim 5 or 6, wherein two adjacent webs at least in sections have a measured parallel to the string bed plane distance of 1 mm to 30 mm, preferably from 3 mm to 20 mm, particularly preferably from 5 mm to 10 mm. Frame for a ball game racket according to one of claims 5-7, wherein two adjacent webs at least in sections have a measured perpendicular to the string bed plane distance of 1 mm to 20 mm, preferably from 3 mm to 15 mm, particularly preferably from 5 mm to 10 mm. Frame for a ball game racket according to any one of claims 5-8, wherein the webs have a cross-section with solid profile. Frame for a ball game racket according to any one of claims 5-9, wherein at least two webs have string openings. Frame for a ball game racket according to any one of claims 5-10, wherein the webs each at least partially a cross-sectional area of 1 mm ² to 100 mm ² , preferably from 1 mm ² to 50 mm ² , more preferably from 2 mm ² to 30 mm ² , more preferably from 2 mm ² to 25 mm ² and / or
wherein the webs has a length LS along the web guide curve of 1 mm to 120 mm, preferably from 10 mm to 100 mm, preferably from 15 mm to 80 mm, more preferably from 20 mm to 50 mm, particularly preferably from 20 mm to 30 mm have. Frame for a ball game racket according to one of the preceding claims, wherein the bridge has at least two attachment tabs, wherein the attachment tabs are used to connect the bridge with at least one second frame portion. A ball game racket frame according to any one of the preceding claims, wherein a cross-section through the bridge has a continuous cross-sectional profile over a continuous bridge length of between 10mm and 100mm, preferably between 30mm and 80mm along the frame contour and over a contiguous bridge length of between 5 mm and 100 mm, preferably between 10 mm and 60 mm along the frame contour has a discontinuous cross-sectional profile. Method for producing a frame for a ball game racket, in particular a frame according to one of the preceding claims, the method comprising the following steps: Casting a bridge of a material comprising magnesium, preferably in thixotropy; Providing a frame portion having a handle portion and a head portion, a portion of the head portion and / or the handle portion comprising a carbon fiber composite material; Connecting the bridge to the frame section to form a frame. The method of claim 14, wherein providing the frame portion includes providing a prepreg tube, wherein bonding the bridge to the frame portion preferably occurs in a process step of curing the prepreg tube.

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