BALL GAME RACKET FRAME, BALL GAME RACKET, AND METHOD FOR MANUFACTURING A BALL GAME RACKET FRAME

Abstract

A ball game racket frame includes a head portion, a grip portion and a shaft portion which connects the grip portion and the head portion. The ball game racket frame is at least partially made of at least one layer of a plurality of fibers which are randomly orientated and intertwined within the layer. According to further aspects, a ball game racket includes the ball game racket frame according to any of the embodiments described herein and a string bed plane comprising a plurality of strings which are attached to at least a portion of the head portion of the ball game racket frame. The string bed plane provides at least one striking surface for striking a game ball. According to yet further aspects, a method for manufacturing a ball game racket frame is disclosed.

Claims

1. A ball game racket frame including a head portion, a grip portion and a shaft portion which connects the grip portion and the head portion, wherein the ball game racket frame is at least partially made of at least one layer of a plurality of fibers configured as a fiber veil formed of a non-woven fabric material, wherein the fibers are randomly orientated and intertwined within the at least one layer, wherein the at least one layer is embedded between layers of prepregs of a composite material, and wherein the fiber veil is at least partially transparent or at least partially translucent before incorporation into the ball game racket frame.

2. (canceled)

3. (canceled)

4. The ball game racket frame according to claim 1, wherein the layer(s) of fibers which are randomly orientated and intertwined, including any bonding material which may be provided in the layer(s) to bond the fibers together, account for at least 20 vol % of a total volume of the ball game racket frame in at least one cross-section of the ball game racket frame.

5. The ball game racket frame according to claim 1, wherein the fibers, which are randomly orientated and intertwined, have an average length of no more than 30 mm.

6. The ball game racket frame according to claim 1, wherein each fiber of the fibers, which are randomly orientated and intertwined, has a length of no more than 30 mm.

7. The ball game racket frame according to claim 1, wherein the ball game racket frame is at least partially made of at least one layer of a plurality of substantially unidirectionally orientated fibers in at least one or more sections of the ball game racket frame.

8. (canceled)

9. The ball game racket frame according to claim 1, wherein the ball game racket frame is at least partially made of: a plurality of fibers which are braided; and/or a plurality of fibers which are woven.

10. The ball game racket frame according to claim 1, wherein the layer of fibers, which are randomly orientated and intertwined, has a ratio of a strength or a stiffness of the layer of fibers in a first direction to a strength or a stiffness of the layer of fibers in a second direction of no more than 12, the first direction extending substantially perpendicularly to the second direction.

11. The ball game racket frame according to claim 1, wherein the layer of fibers, which are randomly orientated and intertwined, has a ratio of a strength or a stiffness of the layer of fibers in a first direction to a strength or a stiffness of the layer of fibers in a second direction from 1.4 to 12, the first direction extending substantially perpendicularly to the second direction.

12. The ball game racket frame according to claim 1, wherein the ball game racket frame includes a plurality of layers of the at least one layer of fibers, which are randomly orientated and intertwined, and a plurality of layers of fiber-reinforced prepregs, wherein the plurality of layers of fibers, which are randomly orientated and intertwined, and the plurality of layers of fiber-reinforced prepregs are stacked intermittently in at least a section of the ball game racket frame.

13. The ball game racket frame according to claim 1, wherein the layer of fibers which are randomly orientated and intertwined, including any bonding material which may be provided to bond the fibers together, has an area weight of 20 to 150 g/m2.

14. The ball game racket frame according to claim 1, wherein at least one cross-section of the ball game racket frame includes at least two layers of the fibers which are randomly orientated and intertwined, wherein a first layer of the at least two layers, which is arranged further from a center of the cross-section than a second layer of the at least two layers, has a greater thickness than the second layer.

15. The ball game racket frame according to claim 1, wherein, at least in a section of the ball game racket frame, the layer of fibers, which are randomly orientated and intertwined, has an average ratio of a length of the fibers in a fiber extension direction to a total length of the layer of fibers in the fiber extension direction of no more than 0.5.

16. The ball game racket frame according to claim 1, wherein the fibers which are randomly orientated and intertwined account for at least 20 wt % of a total weight of at least a segment of the ball game racket frame.

17. The ball game racket frame according to claim 1, wherein the fibers which are randomly orientated and intertwined account for at least 20 vol % of a total volume of the ball game racket frame in at least one cross-section of the ball game racket frame.

18. The ball game racket frame according to claim 1, wherein a proportion of the fibers which are randomly orientated and intertwined and which have a length of no more than 30 mm account for at least 20 wt % of a total weight of at least a segment of the ball game racket frame.

19. A ball game racket including the ball game racket frame according to claim 1 and at least one striking surface for striking a game ball.

20. A method for manufacturing a ball game racket frame, including the following steps: a) providing at least one layer of a plurality of fibers configured as a fiber veil formed of a non-woven fabric material, where the fibers are randomly orientated and intertwined within the at least one layer, wherein the at least one layer is embedded between layers of prepregs of a composite material, and wherein the fiber veil is at least partially transparent or at least partially translucent before incorporation into the ball game racket frame; b) forming the ball game racket frame at least partially from the at least one layer of fibers.

21. The method of claim 20, further including: c) providing at least one layer of a fiber-reinforced prepreg; wherein the ball game racket frame is formed at least partially from the at least one layer of fiber-reinforced prepreg.

22. A ball game racket frame including a head portion, a grip portion and a shaft portion which connects the grip portion and the head portion, wherein the ball game racket frame is at least partially made of at least one layer of a plurality of fibers configured as a fiber veil formed of a non-woven fabric material, wherein the fibers are randomly orientated and intertwined within the at least one layer, wherein the at least one layer is embedded between layers of prepregs of a composite material, and wherein the fiber veil is at least partially transparent or at least partially translucent.

23. The ball game racket frame of claim 22, wherein the layer(s) of fibers which are randomly orientated and intertwined, including any bonding material which may be provided in the layer(s) to bond the fibers together, account for at least 20 vol % of a total volume of the ball game racket frame in at least one cross-section of the ball game racket frame.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0101] Preferred embodiments of the present invention are further elucidated below with reference to the figures. The described embodiments do not limit the present invention.

[0102] FIG. 1 shows, in a schematic front view, a ball game racket frame according to an embodiment of the invention;

[0103] FIG. 2 shows, in a schematic enlarged cross-sectional view, a configuration of a cross-section of the ball game racket shown in FIG. 1 according to an embodiment of the invention;

[0104] FIG. 3 shows, in a schematic enlarged cross-sectional view, a configuration of a cross-section of the ball game racket shown in FIG. 1 according to an embodiment of the invention;

[0105] FIG. 4 shows, in a schematic front view, a layer of fibers which are randomly orientated and intertwined within the layer before the layer is applied to a ball game racket frame;

[0106] FIG. 5 shows, in a schematic front view, a ball game racket including a ball game racket frame according to a further embodiment of the invention;

[0107] FIG. 6 shows, in a schematic cross-sectional view, the ball game racket shown in FIG. 5 according to an embodiment of the invention;

DETAILED DESCRIPTION OF EMBODIMENTS

[0108] FIG. 1 shows a ball game racket 10. In mere exemplary manner, the ball game racket 10 is illustrated as a tennis racket. However, the ball game racket 10 may also be any other ball game racket used for striking a ball or other object, such as a shuttlecock, in a leisure activity and/or a sports activity. For instance, the ball game racket 10 may be a badminton racket, a squash racket, or a paddle, such as for use in paddle ball, as shown in exemplary manner in FIGS. 5 and 6, or table tennis, or any other racket used in any other known racket sport.

[0109] The ball game racket 10 includes a ball game racket frame 12 having a head portion 14, a shaft portion 18 and a grip portion 20. As illustrated in FIG. 1, the ball game racket frame 12 may also include a throat portion 16 extending from the shaft portion 18 to the head portion 14.

[0110] The throat portion 16 may be open, in which case the throat portion 16 includes an opening 22, as illustrated in FIG. 1. Alternatively, the throat portion 16 may be closed, in which case the throat portion 16 does not include an opening. The throat portion 16 essentially serves the purpose of splitting the shaft portion 18 into two sections to extend around a circumference of the head portion 14. The throat portion 16 may also be omitted. In this case, the shaft portion 14 may be attached directly to the head portion 14.

[0111] The grip portion 20 may be configured to be gripped by a user, preferably by a user's hand, either by one hand or both hands of the user. For this purpose, the grip portion 20 may include features which may facilitate gripping thereof, such as suitable dimensions and/or a suitable shape and/or features which may increase the friction between the user's body, e.g., the user's palm, and the grip portion 20. The grip portion 20 may include a soft material, e.g., softer than the material of the shaft portion 18 and/or the head portion 14, to provide a comfortable grip for the user. The grip portion 20 extends along a longitudinal axis to the shaft portion 18.

[0112] The head portion 14 may comprise an opening 24 defined by a peripheral section 26 of the head portion 14, as shown in FIG. 1. The peripheral section 26 may be configured in a substantially oval shape, as shown in FIG. 1. Alternatively, the peripheral section 26 may be formed in any other shape, e.g., circular, rectangular, triangular, etc.

[0113] A string bed plane comprising a plurality of strings may be provided (not shown) and attached to at least a portion of the peripheral section 26 and extending across at least a portion of the opening 24. Such a string bed plane may provide a striking surface for striking a ball during use in a ball game sport and/or leisure activity.

[0114] Alternatively, the opening 24 may be omitted in the head portion 14. In this case, the head portion 14 may have a solid surface, which is preferably continuous and uninterrupted at least section-wise, instead of a string bed plane, which may provide the striking surface for striking a ball during use in a ball game sport and/or activity, as shown in FIG. 5. In such a configuration, the ball game racket 10 may be referred to as a paddle. Such a striking surface may also have at least one opening formed therein, the opening preferably being smaller than the size of the ball to be struck during use of the corresponding ball game racket in a respective ball game sport and/or activity (see FIG. 5 and the corresponding description further below).

[0115] The ball game racket frame 12 may be at least partially made of at least one layer of a plurality of fibers which are randomly orientated and intertwined within the layer. In particular, the layer of fibers, which are randomly orientated and intertwined within the layer, may be configured as a fiber veil, preferably a carbon fiber veil and/or a glass fiber veil.

[0116] Providing the ball game racket frame 12 with one or more layers of fibers which are randomly orientated and intertwined within the layer may improve the degree of dampening and/or the shock absorption properties of the ball game racket frame 12, in particular compared with ball game rackets which only include one or more layers of unidirectionally orientated fibers.

[0117] Furthermore, the randomly orientated and intertwined fibers may also improve the deformability and/or the handleability of the material, i.e., the at least one layer of a plurality of randomly orientated and intertwined fibers, e.g., the drapability of the material, during manufacturing and/or prior to manufacturing the ball game racket frame 12. For instance, improving the drapability of the material may allow to achieve smaller radii in at least sections of the ball game racket frame 12 and/or may facilitate providing smaller radii in at least sections of the ball game racket frame 12.

[0118] Moreover, providing at least one layer of a plurality of fibers which are randomly orientated and intertwined within the layer may reduce and/or limit a degree of orthotropy of the layer of fibers, more specifically of the ball game racket frame 12, and/or may increase a degree of isotropy of the layer of fibers, more specifically of the ball game racket frame 12, in at least a section of thereof. This may provide a more balanced ball game racket, e.g., compared with ball game rackets which only include layers of composite material having unidirectionally orientated fibers.

[0119] As shown in FIG. 1, a portion of the peripheral section 26 of the head portion 14 is cut along a cutting line 29, which is substantially perpendicular to the direction in which the peripheral section 26 extends around the opening 24. The cutting line 29 is illustrated as a dashed line to show an imaginary cut along said cutting line 29.

[0120] Based on the resulting cross-section 28 across a portion of the peripheral section 26 of the ball game racket frame 12 along line 29, a proportion, i.e., a percentage, e.g., a wt % and/or a vol %, of the fibers which are randomly orientated and intertwined, optionally including any bonding material which may be provided to bond the fibers together, of a total weight and/or a total volume, respectively, of at least a segment of the ball game racket frame, in particular at the respective cross-section 28, may be determined at the cross-section 28.

[0121] A plurality of cross-sections 28a, 28b, 28c, 28d, and 28e along several portions of the ball game racket frame 12 along a plurality of respective lines 29a, 29b, 29c, 29d, and 29e may be made to determine the proportion, i.e., a percentage, e.g., a wt % and/or a vol %, of the fibers which are randomly orientated and intertwined, optionally including any bonding material which may be provided to bond the fibers together, with respect to a total weight and/or a total volume, respectively, of at least a segment of the ball game racket frame, in particular at the respective cross-section 28, along the respective cross-section 28.

[0122] Thus, at least one cross-section, preferably a plurality of cross-sections, may be made in each of the head portion 14 and/or the shaft portion 18 and/or grip portion 20. For instance, a cross-section 28b, 28c, 28d, 28e along a portion of the grip portion 20 and/or the shaft portion 18, respectively, may have a first proportion, i.e., percentage, of fibers which are randomly orientated and intertwined, optionally including any bonding material which may be provided to bond the fibers together, with respect to a total weight and/or a total volume in the grip portion 20 and/or the shaft portion 18, respectively.

[0123] The shapes of the cross-sections 28, 28a, 28b, 28c, 28d, and 28e shown in FIG. 1 are for exemplary illustrative purposes only and do not necessarily reflect the actual cross-sections of the ball game racket frame 12 at the respective cross-section 28, 28a, 28b, 28c, 28d, and 28e. In fact, the ball game racket frame 12 may have any cross-sectional shape, e.g., circular, rectangular, or polygonal.

[0124] Preferably, the head portion 14, the shaft portion 18 and/or the grip portion 20 include(s) at least one layer of the at least one layer of a plurality of fibers which are randomly orientated and intertwined. This may provide an increased degree of dampening and/or shock absorption of the ball game racket frame in the respective portion(s) of the ball game racket frame 12 by improving a distribution of forces and/or moments and/or by at least partially interrupting a transfer of forces and/or moments in the head portion 14, the shaft portion 18 and/or the grip portion 20. Selectively providing the layer(s) of fibers which are randomly orientated and intertwined in one or more certain portions of the ball game racket frame 12 may allow the ball game racket frame 12 to be fine-tuned and/or tailored to the respective user's desires and/or needs, e.g., to the respective user's style of play and/or experience.

[0125] For instance, providing at least one layer of the of at least one layer of a plurality of fibers which are randomly orientated and intertwined at least in the head portion 14 may be advantageous to the impact characteristics of the ball game racket. In particular, as discussed above, a string bed plane comprising a plurality of strings may be attached to at least a portion of the peripheral section 26 of the head portion 14. Such a string bed plane may provide a striking surface for striking a ball during use in a ball game sport and/or leisure activity. Thus, providing at least one layer of fibers which are randomly orientated and intertwined at least in the head portion 14 may be an efficient and/or effective means for absorbing at least a portion of forces and/or moments which may be exerted to the ball game racket via the string bed plane.

[0126] Exemplary cross-sections 28 are shown in FIGS. 2 and 3. In particular, FIGS. 2 and 3 show configurations of the cross-section 28a of the head portion 14.

[0127] As shown in FIGS. 2 and 3, the ball game racket frame 12 may include a tube 30, sometimes also referred to as a bladder, in particular with respect to tennis rackets. The tube 30 includes a hollow space 32 arranged within the tube 30. The tube 30 may be covered in one or more layers 34 of a plurality of fibers which are randomly orientated and intertwined within the respective layer 34. As mentioned above, the cross-sections of the ball game racket frame 12, e.g., the cross-section 28a of the head portion 14 shown in FIGS. 2 and 3, may have any cross-sectional shape, e.g., circular, rectangular, or polygonal. The cross-sectional shape of the cross-section 28a shown in FIGS. 2 and 3 is thus only exemplary and does not limit the cross-sections of the ball game racket frame 12 to such a shape. The same applies to the cross-sectional shape of the tube 30. In fact, the tube 30 may have any cross-sectional shape and is thus not limited to the cross-sectional shape shown in FIGS. 2 and 3.

[0128] As shown in FIG. 3, the tube 30 may be covered in one or more layers 34 of fibers which are randomly orientated and intertwined within the layer 34, and optionally one or more layers 36 of prepregs of a composite material, e.g., prepregs which include unidirectionally orientated fibers in each layer thereof. As shown in FIG. 3, the one or more layers 36 of prepreg may be arranged between the tube 30 and the one or more layers 34 of fibers which are randomly orientated and intertwined within the respective layer 34. Alternatively, the one or more layers 34 of fibers which are randomly orientated and intertwined within the layer 34 may be arranged between the tube 30 and the one or more layers 36 of prepreg. Further alternatively, the one or more layers of fibers, which are randomly orientated and intertwined, and the one or more layers of fiber-reinforced prepregs, e.g., prepregs which include unidirectionally orientated fibers in each layer thereof, may be stacked intermittently in at least a section of the ball game racket frame 12. Alternatively, or additionally, at least one layer of fibers, which are randomly orientated and intertwined, may be embedded between layers of prepregs of composite material which preferably include unidirectionally orientated fibers in each layer thereof.

[0129] FIG. 4 shows, in an exemplary manner, a layer 50 of fibers 52 which are randomly orientated and intertwined within the layer 50, such as the layer(s) 34 shown in FIGS. 2 and 3, before the layer 50 is applied to the ball game racket frame 12. The layer 50 may be configured as a fiber veil, preferably a carbon fiber veil and/or a glass fiber veil. Alternatively, the layer 50 may be configured as a non-woven fabric material.

[0130] The fibers 52 may be at least partially bonded together by at least one bonding material 54, preferably a thermoplastic material, e.g., a resin and/or a thermosetting material.

[0131] At least some of the fibers 52, which are randomly orientated and intertwined within the layer 50, may be looped, preferably randomly looped, in the layer 50 of fibers 52, as indicated, for instance, at 52a in FIG. 4.

[0132] FIG. 5 shows an exemplary embodiment of a ball game racket 110 which also includes a ball game racket frame 112 having a head portion 114, a shaft portion 118 and a grip portion 120. The head portion 114 defines at least one striking surface 121, which is preferably substantially planar surface, for striking a ball during use in a ball game sport and/or leisure activity. The striking surface 121 does not have to be substantially planar. Instead, the striking surface 121 may be curved and/or angled in sections thereof. Preferably, the ball game racket 110 has two striking surfaces 121 which are arranged on opposite sides of the ball game racket 110, as shown in FIG. 6.

[0133] As shown in FIG. 5, the striking surface 121 may be at least partially defined by a solid structure, which is preferably continuous and uninterrupted at least section-wise. The solid structure may be at least partially defined by a core (see FIG. 6 and the corresponding description below).

[0134] The solid structure may have one or more openings 124 formed therein, preferably one or more through-holes which extend completely through the head portion 114, preferably substantially perpendicular to at least one of the striking surfaces 121. Alternatively, or additionally, a string bed plane comprising a plurality of strings, which are attachable to at least a portion of the head portion 114, may be provided to define the striking surface(s). In particular, the ball game racket frame 10 shown in FIG. 1 may be suitable for having such a string bed plane comprising a plurality of strings which may provide at least one striking surface for striking a ball during use in a ball game sport and/or leisure activity, as discussed above.

[0135] The ball game racket 110 shown in FIG. 5 is a padel tennis racket. However, the configuration of the ball game racket 110 as a padel tennis racket is only an exemplary embodiment. The ball game racket 110 may be any ball game racket which has a striking surface 121 which is defined by a substantially solid structure, which is preferably continuous and uninterrupted at least section-wise, and optionally having one or more openings 124, as shown in FIG. 5, and which is used for striking a ball or other object in a leisure activity and/or a sports activity. Such a ball game racket 110, i.e., as shown in FIG. 5, may be referred to as a paddle.

[0136] The ball game racket 110 may further include an opening 126 provided in the shaft portion 118, the opening 126 preferably extending completely through the ball game racket 110, preferably substantially perpendicularly to the at least one of the striking surfaces 121.

[0137] FIG. 6 shows a cross-sectional view of the ball game racket 110 shown in FIG. 5 along the cutting along A-A which extends through a section of the head portion 114. As shown in FIG. 6, the ball game racket 110 may include a core 129 and one or more layers 130 of a plurality of fibers which are randomly orientated and intertwined within the layer 130, such as one or more of the layer 50 shown in FIG. 4. One or more layers 130 of a plurality of fibers which are randomly orientated and intertwined within the layer 130 may be attached on one side or each side of the ball game racket 110, as shown in FIG. 6. An outer layer of the one or more layers 130 may at least partially define at least one of the striking surfaces 121, as shown in FIG. 6. Alternatively, one or more coatings, e.g., one or more coatings made of polyamide (PA), polylactides (PLA), and Polyethylene terephthalate (PET), and/or a powder, and/or one or more further layers of material, such as one or more layers of a further composite material, which preferably include unidirectionally orientated fibers, may be arranged on an outer surface of the layer(s) 130 and may thus at least partially define the striking surface(s) 121.

[0138] The core 129 may be made of a solid material, e.g., foam. Alternatively, the core 129 may be omitted. For instance, the core 129 may be replaced by a composite material, e.g., one or more layers of a composite material which includes a plurality of fibers, e.g., the one or more layers 130 and/or one or more layers of a composite material which includes unidirectionally orientated fibers.

[0139] Alternatively, or additionally, to the layers 130 provided in the head portion 114, as shown in FIG. 6, the shaft portion 118 and/or the grip portion 120 may be provided with one or more of the layers 130 shown in FIG. 6.

[0140] Optionally, the ball game racket 110 may include one or more layers of prepregs of a composite material, e.g., prepregs which include unidirectionally orientated fibers in each layer thereof. The one or more layers of prepreg, which preferably include unidirectionally orientated fibers, may be arranged between the core 129 and the layers 130 of fibers which are randomly orientated and intertwined, respectively. Alternatively, the one or more layers of prepreg, which preferably include unidirectionally orientated fibers, may be arranged on a side of the layers 130 which is opposite of the core 129. of fibers which are randomly orientated and intertwined, respectively. Further alternatively, the one or more layers of fibers 130, which are randomly orientated and intertwined, and the one or more layers of fiber-reinforced prepregs, e.g., prepregs which include unidirectionally orientated fibers in each layer thereof, may be stacked intermittently in at least a section of the ball game racket 110.