Abstract
The invention relates to a bridge for a ball game racket as well as to a frame for a ball game racket comprising a bridge.
Claims
1. A bridge for a ball game racket, wherein the bridge comprises a central region and two edge regions which are intended for being connected to the frame of a ball game racket, wherein from both sides of the central region a lower web and two upper webs respectively extend to the two edge regions, wherein the central region comprises first through openings for receiving longitudinal strings and wherein at least two further second through openings are arranged for receiving longitudinal strings in such a manner that the longitudinal strings to be received therein each extend between the corresponding two upper webs.
2. The bridge according to claim 1, wherein the longitudinal strings to be received by the at least two second through openings each extend in a contactless manner between the corresponding two upper webs.
3. The bridge according to claim 1, wherein the respective lower web is not connected to any of the two upper webs between the central region and the corresponding edge region.
4. The bridge according to claim 1, wherein the respective two upper webs are not connected with each other between the central region and the corresponding edge region.
5. The bridge according to claim 1, wherein the respective distance between the two upper webs increases from the central region towards the corresponding edge region.
6. The bridge according to claim 1, wherein a through opening is respectively formed between the two upper webs and the lower web perpendicularly with respect to a plane defined by the stringing.
7. The bridge according to claim 6, wherein the cross-sectional area of said plane is at least 1.5 cm.sup.2.
8. The bridge according to claim 6, wherein the cross-sectional area of said plane is at least 2 cm.sup.2.
9. The bridge according to claim 6, wherein the cross-sectional area of said plane is at least 2.5 cm.sup.2.
10. The bridge according to claim 1, wherein the two edge regions each comprise brackets which are suitable for connecting the bridge to a racket frame to be made by using the blow tube molding.
11. The bridge according to claim 10, wherein the brackets each have a concave outer surface which is at least 10 cm.sup.2.
12. The bridge according to claim 10, wherein the brackets each have a concave outer surface which is at least 15 cm.sup.2.
13. The bridge according to claim 10, wherein the brackets each have a concave outer surface which is at least 20 cm.sup.2.
14. The bridge according to claim 10, wherein at least one of the second through openings is respectively arranged in a corresponding one of the brackets.
15. The bridge according to claim 10, wherein the brackets each have at least one third through opening for receiving longitudinal and/or transverse strings.
16. The bridge according to claim 1, wherein the central region is groove-shaped and wherein the sides of the groove are each configured as continuous side wall or as a lattice structure.
17. The bridge according to claim 16, wherein the groove has opposing edges from which the webs extend to the edge regions, and wherein the groove is closed at said opposing edges by means of a respective end wall.
18. The bridge according to claim 16, wherein the bottom of the groove comprises at least two through openings for receiving longitudinal strings.
19. The bridge according to claim 1, wherein at least one of the second through openings is respectively arranged in a corresponding one of the lower webs.
20. The bridge according to claim 1, wherein from both sides of the central region two lower webs respectively extend to the two edge regions.
21. The bridge according to claim 20, wherein the longitudinal strings to be received by the second through openings each extend between the corresponding two lower webs.
22. A ball game racket having a racket frame which comprises a handle region, a racket head and a heart region arranged therebetween, the heart region being formed by two frame bars extending from the handle and a bridge according to claim 1.
23. A ball game racket having a racket frame which comprises a handle region, a racket head and a heart region arranged therebetween, the heart region being formed by two frame bars extending from the handle region and a bridge, wherein the bridge has a central region and two edge regions being connected to the frame of the ball game racket, wherein from both sides of the central region a lower web and at least two upper webs respectively extend to the two edge regions, wherein the central region has first through openings for receiving longitudinal strings and wherein at least two further second through openings are arranged in the two frame bars for receiving longitudinal strings in such a manner that the longitudinal strings to be received therein each extend between the corresponding two upper webs.
Description
[0066] In the following, preferred embodiments of the bridge according to the invention and the frame according to the invention are described in more detail on the basis of the Figures in which
[0067] FIG. 1 shows a schematic front view of a frame according to the invention in accordance with a preferred embodiment;
[0068] FIG. 2A shows a schematic perspective view of a bridge according to the invention in accordance with a preferred embodiment;
[0069] FIG. 2B shows a schematic view of a cross-section of the bridge of FIG. 2A through the line A-B according to FIG. 1;
[0070] FIG. 2C shows a schematic view of a cross-section of the bridge of FIG. 2A through the line C-D according to FIG. 1;
[0071] FIG. 3A shows a schematic perspective view of a bridge according to the invention in accordance with a further preferred embodiment;
[0072] FIG. 3B shows a schematic view of a cross-section of the bridge of FIG. 3A through the line A-B according to FIG. 1;
[0073] FIG. 3C shows a schematic view of a cross-section of the bridge of FIG. 3A through the line C-D according to FIG. 1;
[0074] FIG. 4 shows a schematic perspective view of a frame according to the invention in accordance with a further preferred embodiment in a front view seen in an inclined manner from the top;
[0075] FIGS. 5A-5D each show a schematic front view of a bridge according to the invention in accordance with further preferred embodiments;
[0076] FIG. 6A shows a schematic perspective partial view of a bridge according to the invention in accordance with a further preferred embodiment;
[0077] FIG. 6B shows a schematic view of a cross-section of the bridge of FIG. 6A through the line A-B according to FIG. 1;
[0078] FIG. 6C shows a schematic view of a cross-section of the bridge of FIG. 6A through the line C-D according to FIG. 1;
[0079] FIG. 6D shows a schematic front view of a section of a frame according to the invention in accordance with a further preferred embodiment with the bridge of FIG. 6A; and
[0080] FIG. 6E shows an enlarged section of FIG. 6D.
[0081] FIG. 1 shows a schematic front view of a frame 2 for a ball game racket according to the present invention. The frame 2 comprises a head region or racket head 4 for receiving a stringing (not shown) and a handle region 10, the central axis of which coincides with the longitudinal axis 14 of the frame 2. A heart region 3 is arranged between the racket head 4 and the handle region 10, said heart region being formed by two frame bars 5a, 5b extending from the handle region 10 and a bridge 6. The dimensions and the shape of the frame 2 are of course understood to be exemplary. The schematic frame 2 shown in FIG. 1 can have any bridges according to the invention, for example the preferred embodiments of bridges according to the invention described in detail below.
[0082] A preferred embodiment of a bridge 6 is shown in a perspective view in FIG. 2A. The bridge is suitable for any ball game racket, for example the ball game racket according to FIG. 1. The bridge has a central region 18 and two edge regions 16a, 16b, which are intended for being connected to the frame of a ball game racket. In the shown preferred embodiment of FIG. 2A, the two edge regions are formed by two brackets 16a, 16b, which serve for connecting the bridge 6 to the frame bar 5a, 5b and/or a part of the head region 4. The brackets 16a, 16b limit the shown bridge 6 at both ends of its directrix and preferably have concave outer surfaces, which can engage with the correspondingly shaped convex regions of the frame or can be connected thereto in a positive-locking manner.
[0083] From both sides of the central region 18 of the bridge a lower web 24a, 24b and two upper webs 22a, 22b respectively extend to the two edge regions or brackets 16a, 16b. The central region 18 has (in this case four) first through openings 28 for receiving longitudinal strings, wherein at least two further second through openings (not shown) are arranged for receiving longitudinal strings in such a manner that the longitudinal strings to be received therein each extend between the corresponding two upper webs 22a, 22b. Preferably, at least some of these second through openings are respectively provided in the lower webs 24a, 24b. Alternatively or additionally, at least some of these second through openings can be provided in brackets 16a, 16b (see also the discussion of FIGS. 6D and 6E).
[0084] FIG. 2B shows a cross-section of the bridge of FIG. 2A through the line A-B of FIG. 1. FIG. 2B also shows a cross-section through the central region 18 of the bridge of FIG. 2A (at a region without through opening or string opening 28). As shown in FIG. 2B, in the shown preferred embodiment the bridge comprises a central region 18 with exclusively convex cross-section, which is exemplarily shown here to be substantially rectangular. Alternatively, the cross-section can also have rounded corners or be round, elliptical or multiangular or have any other cross-sectional shape. FIG. 2C shows a cross-section of the bridge of FIG. 2A through the line C-D according to FIG. 1. FIG. 2C thus shows a cross-section through the web region of the bridge of FIG. 2A. As shown in FIG. 2C, the webs 22 and 24 of the bridge of the shown preferred embodiment also each have a convex cross-sectional profile, exemplarily also being substantially rectangular. Alternatively, the cross-section can also have rounded corners, be round, elliptical or multiangular or have any other cross-sectional shape.
[0085] As evident from the different cross-sectional shapes shown in FIGS. 2B and 2C, which are meant to be exemplary only, an aspect of the invention relates to the idea of providing a central region 18 for receiving the longitudinal strings, said central region 18 being as stable as possible, and to connect it by means of relatively filigree webs 22 and 24 (optionally by means of brackets 16a and 16b) to the remaining racket frame. As schematically shown in FIG. 1, this web structure allows the bridge to be attached relatively close to the top of the racket head 4 by means of the upper webs 22a and 22b, without disadvantageously reducing the length of the longitudinal strings, because the longitudinal strings extend between the opposing upper webs 22a and 22b. Moreover the web structure reduces the overall weight of the bridge advantageously. This advantage can also be achieved by cross-sectional profiles different from that according to FIGS. 2B and 2C. For example, it is preferred that the cross-sectional area of the lower web 24 is larger than the cross-sectional area of an upper web 22, as schematically shown in FIG. 2C. However, in a direction perpendicular with respect to the stringing plane, the lower web 24 does not have to extend as far as the two upper webs 22 (as also shown in FIG. 2C). The two upper webs 22 have a respective distance w1 and w2 from the lower web 24 and a distance h from each other. These distances are in each case preferably at least 5 mm, more preferably at least 10 mm and particularly preferably at least 15 mm, wherein the distance can vary along the directrix of the webs and preferably increases from the central region 18 in the direction towards the edge regions 16a and 16b.
[0086] FIG. 3A shows a further preferred embodiment of a bridge 6 for a frame 2 according to the invention, in which also the central region 18 is groove-shaped. FIG. 3B shows a cross-section of the bridge of FIG. 3A through the line A-B according to FIG. 1. Thus, the bridge of FIG. 3A has a groove-shaped recess 26 in the central region 18, which has a side that is open towards the string bed but is closed on both sides by means of end walls 26b. Together with the two side walls 26a of the groove-shaped central region 18, these end walls 26b form a pot-shaped structure. The bottom of the grove preferably has at least two through openings or string openings (not shown).
[0087] In view of the cross-sectional profile of the bridge of FIG. 3A through the line C-D according to FIG. 1 as shown in FIG. 3C, the above statements as to FIG. 2C apply analogously.
[0088] The extension D of the central region in the longitudinal direction of the racket frame (see FIG. 3B) is, at least in sections, preferably at least 10 mm, more preferably at least 12 mm. The groove depth d is preferably at least 8 mm, more preferably at least 10 mm. It is of course not necessary that the groove-shaped recess 26 has a square cross-section, as indicated in FIG. 3B, but can also be, e.g., rectangular or U-shaped.
[0089] 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 region 10 and a head region 4 with bridge 6 in a front view seen in an inclined manner from the top. The central region 18 is in the center of the bridge 6. Two upper webs 22a, 22b extend from the central region 18 and extend towards the closest bracket, which is not shown here because in the finished racket frame the brackets are preferably incorporated in the carbon fiber composite material of the racket head. The central region 18 has a groove-shaped recess 26 which is open towards the string bed 8. The end sides facing in the direction of sides a and b, as well as the bottom of the groove facing in the direction of the handle region 10, however, are closed, so that the central region 18 can be called pot-shaped. The bottom of the pot-shaped groove 26 has four string openings 28, as specified above, through which corresponding longitudinal strings of the stringing are passed. Instead of four string openings 28, also more (e.g., six or eight) or less (e.g., two or three) string openings can be provided in the bottom of the pot-shaped groove 26.
[0090] FIGS. 5A to 5D exemplarily show four further embodiments of the bridge 6 in a schematic front view. The basic structures of the embodiments (i.e., for example, in view of the arrangement of the upper and lower webs 22, 24) correspond to the embodiments of FIG. 2 or 3, but in addition to the features already described in connection with FIGS. 2 and 3, they have a lattice structure 30 in the central region 18. The lattice structure 30 is formed by the mutually dependent shapes of the struts 32 and the gaps 34 and depends, i.a., on the number thereof.
[0091] The number of gaps or through openings 34 in FIGS. 5A and 5B is five. In alternative embodiments, the number of gaps 34 can have other values. For example, the embodiment of FIG. 5C shows three gaps 34, while the embodiment of FIG. 5D shows nine gaps 34. However, the number of gaps 34 is preferably at least 2.
[0092] In general, the gaps can have many shapes. For example, the gaps 34 can be oval, triangular, quadrangular, convexly or concavely polygonal and/or have an irregular shape, wherein corners can be pointed or rounded.
[0093] In a front view, the preferred embodiment of a bridge 6 according to the invention as shown in FIG. 5A has five round gaps 34. The alternative preferred embodiment of a bridge 6 according to the invention as shown in FIG. 5B has, in a front view, five mostly triangular gaps 34, the apexes of which point alternatingly towards the racket head 4 and towards the handle region 10. The gap-triangles can have rounded corners and be oblique, equal-sided and/or equilateral. In the shown embodiment, the apexes of the middle and the two outer gap-triangles point towards the head region 4 and the apexes of the remaining two triangles towards the handle region 10. In alternative embodiments, the directions into which the apexes of the triangles point are the other way round. Alternatively, the triangles can also point in other directions.
[0094] A lattice structure according to the invention can have similarly shaped gaps 34 and/or similarly shaped struts 32 and additionally or alternatively non-similarly shaped gaps 34 and/or non-similarly shaped struts. The areas of the gap shapes can remain the same within one embodiment, as shown in FIGS. 5A and 5B, or vary between the gap shapes, as shown in FIG. 5D.
[0095] The different lattice structures shown in FIGS. 5A to 5D are only meant to be exemplary and should clarify that the weight of the bridge can be minimized by means of a lattice structure according to the invention in different ways, without affecting the mechanical stability of the bridge. Preferably, accordingly complex and delicate structures can be made from a magnesium alloy in the case the bridge is formed as one part. The use of magnesium provides for the required stability and light-weight construction, whereas the one-part form i.a. guarantees that the shown structures can be made with the required precision without fractures possibly occurring at the joints. Preferably, the shown structures can be made in a casting, particularly preferably injection molding process, so that the finished bridge is made as one single cast or injection molded part.
[0096] FIG. 6A schematically shows a perspective section of a further preferred embodiment of a bridge 6 according to the invention. A part of the frame region, with which the bridge is connected by way of the bracket 16, is indicated in dashed lines. The shown bridge section of the bridge 6 of FIG. 6A comprises a bracket 16 and a part of the central region 18. The central region 18 is cut off in the drawing after the longitudinal axis 14. In this embodiment, the bridge 6 has four struts per side a or b, two upper struts 22 and two lower struts 24. FIG. 6B shows a cross-section of the bridge of FIG. 6A through the line A-B according to FIG. 1. FIG. 6B thus shows a cross-section through the central region 18 of the bridge of FIG. 6A. FIG. 6C shows a cross-section of the bridge 6 of FIG. 6A through the line C-D according to FIG. 1. FIG. 6C thus shows a cross-section through the web region of the bridge 6 of FIG. 6A.
[0097] The embodiment of FIG. 6A is shown in a front view in FIG. 6D, so that the extension of the strings of the stringing is easily visible. In the embodiment of FIGS. 6A to 6E, none of the webs has a string opening 28. Instead, the longitudinal strings 36 and 37 each extend in a contactless manner between the two upper webs 22 of the corresponding side a or b and between the two lower webs 24 of the corresponding side a or b. The longitudinal strings 36 and 37 each engage with a string opening 28 in the bracket 16 of the corresponding side a or b. This is particularly clearly visible in FIG. 6E which shows an enlarged view of the frame area around side a of the bridge 6 of FIG. 6D. In FIGS. 6D and 6E, the boundaries between the brackets 16 and the adjoining, e.g. carbon-containing frame region are schematically marked by dashed lines. Alternatively or additionally, a string 36 and/or 37 can engage with the frame also outside the brackets and outside the bridge.
[0098] FIGS. 6D and 6E show an advantage of the web structure according to the invention: Although the upper webs 22a, 22b are connected to the racket head 4 by means of the brackets 16a and 16b relatively close to the top of the racket head 4 and, therefore, provide for a good force transmission from the bridge into the racket head, the length of the longitudinal strings 36 and 37 is not affected disadvantageously by the course of the webs 22a and 22b because the strings 36 and 37 extend between the upper webs 22a and 22b and are passed through corresponding string openings 28 in the brackets 16a and 16b or the remaining racket frame. This is also applicable in the embodiments of FIGS. 1 to 4, in which only one lower web 24a is provided and, e.g., the string 37a (see FIG. 6E) is passed through a string opening in this single lower web 24a.
[0099] The embodiments shown in FIGS. 1A to 6E are exemplary and by no means final. All Figures are considered to be schematic illustrations by means of which specific preferred features are to be discussed. Therefore, it is possible that features have been omitted in illustrations of embodiments for reasons of clarity. For example, in FIGS. 2A to 2C, 3A to 3C, 4 and 6A to 6D, the string openings 28 have been omitted completely or partly. This means that features from different illustrations can be combined as far as this is not explicitly excluded.
