• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a racket (1) for a game of balls, in particular tennis, comprising a frame (2) with a head delimiting a striking surface for the ball, for example a strung surface forming a sieve (4), and a handle (5) mounted in the extension of the head outside the hitting surface of the ball. The frame (2) comprises: - a core comprising at least two layers of wood, preferably at least seven layers of wood; and - at least one layer of composite material arranged around said core, for example wound around said core. The present invention also relates to a method of manufacturing such a racket (1).
    公开号:BE1023759B1
    申请号:E2015/5580
    申请日:2015-09-17
    公开日:2017-07-13
    发明作者:Antoine Chastan；Guillaume Lenclen；Bozec Yvan Le
    申请人:Decathlon；
    IPC主号:
    专利说明:

    RACKET FOR BALL SETS AND CORRESPONDING METHOD Background of the invention
    The present invention relates to a racket for ball game, and more particularly to a tennis racket.
    The first rackets, especially tennis, were made of wood. In the 1930s, new glues for wood made glulam strips with several different types of wood, such as ash, walnut, beech or maple, to obtain better mechanical properties. and a better balance between power and ball control. The appearance of synthetic fibers in the 1980s made it possible to replace wood and make snowshoes that were both light and resistant. In particular, the frame of rackets made from composite materials, such as carbon or glass fibers impregnated with a matrix, are designed around an inflated bladder to apply to composite materials adequate pressure during the crosslinking of the matrix. Such snowshoes and have a hollow frame.
    However, snowshoes composite materials are not completely satisfactory in terms of vibration, and more particularly in terms of vibration absorption, which can lead to a lack of comfort for the user, or even pain.
    The document FR 2 974 307 describes a tennis racket comprising a wooden frame. In particular, the frame comprises a glulam of different wood species to obtain, in section, a center of mass distinct from the geometric center.
    However, such a racket remains difficult to manufacture, and therefore is more expensive than traditional rackets made of composite materials. Moreover, such a racket loses the benefit of the mechanical properties of rackets made of composite materials.
    Object and summary of the invention
    The present invention aims to solve the various technical problems mentioned above. In particular, the present invention aims to provide a racket that can be easily manufactured and to obtain improved mechanical performance, especially in the absorption of vibration.
    Thus, in one aspect, there is provided a racket for a game of balls, including tennis, comprising a frame with a head defining a striking surface of the ball, for example a roped surface forming a sieve, and a handle mounted in the extension of the head on the outside of the ball striking surface. The frame comprises: - a core comprising at least two wooden layers, preferably at least seven layers of wood, bent or molded to the frame shape, the wood of the layers having a density less than or equal to 400kg / m3; and at least one layer of composite material wound around said core before or after bending, or else wound around said core after molding to the shape of the frame.
    The layer of composite material forms in particular a sheath for the wooden core. The composite material layer corresponds to the frame of the composite material snowshoes of the prior art, except that it is applied to a core comprising wood, and not on a bladder. The layer of composite material therefore has the same shape as the frame of the racket. The use of a wooden core avoids the use of a bladder for the manufacture of the racket. Indeed, the racket obtained according to the invention, although having a sheath of composite materials of the glass fiber or carbon type impregnated with a polymeric matrix, comprises a "full" core (as opposed to bladders currently used in rackets made of composite materials) with layers of wood. Thus, thanks to its soul, the vibrations appearing during the strikes are absorbed by the wooden soul, which improves the comfort of the racket for the user and limits the risk of pain. In addition, the sheath made of composite materials makes it possible to preserve the mechanical properties of the current rackets.
    The wood of the layers may have a density less than or equal to 200 kg / m3, and more preferably less than or equal to 150 kg / m3. The preferred wood species for snowshoeing are light wood species, which provide a suitable vibration absorption and also facilitate the manufacture of the racket. In addition, the use of light wood allows not to change the distribution of the masses along the racket.
    Preferentially, the wood of the layers is chosen from: balsa, samba, poplar and kiri. Balsa, samba, poplar and kiri are examples of wood species with a relatively low density and mechanical properties suitable for use in a racket. In particular, the balsa has flexural and compressive properties which make its use within the racket according to the invention advantageous.
    Preferably, the core comprises at least one layer of composite material disposed between the wooden layers. The composite materials are not only arranged around the wooden core, but can also be arranged within the wooden core, for example to strengthen some light wood layers. It is thus possible to modulate the behavior of the wooden soul, without necessarily having recourse to very particular wood species, and while preserving the desired properties of absorption of the vibrations.
    Preferably, the soul of the handle is formed by extending the soul of the head. This gives a uniform structure, with vibration absorption properties distributed throughout the frame of the racket. It also improves the strength of the racket, while simplifying its manufacture, as described below.
    Preferably, the composite material comprises fibers, for example carbon or glass fibers, impregnated with a thermosetting resin or an epoxy resin. The composite material is chosen from those used for the manufacture of current tennis rackets. We can thus benefit from the materials developed specifically for snowshoes, while adding the properties of the wooden core.
    Preferably, the wooden layers are glued together. In particular, the wooden core can be a glulam laminated with wooden layers. The glulam provides additional mechanical properties, while allowing a method of making the racquet simplified, as described below.
    Alternatively, the wooden layers can be laminated, with a foaming element between them. For example, the wooden core may comprise two wooden layers with a foaming element disposed between the two.
    Preferably, the core has at least one section in which the wood fibers are not homogeneously compressed on the surface of said section, and in which the most compressed wood fibers are located at the periphery of said section, by example at a peripheral groove of the section. In such an embodiment, the wooden core is obtained by compression, for example by molding, in order to directly obtain the desired final shape, without requiring additional machining operations of the core. In particular, it is possible to compress the wooden core locally in order to form the circumferential grooves present around the sieve of the racket, for the passage of the rope. In this case, the portion of the wooden core located in the immediate vicinity of the groove, may have fibers that are more compressed than in the rest of the wooden core.
    The wooden layers may have a thickness less than or equal to 2 mm, preferably less than or equal to 1 mm, or even 0.5 mm. The choice of the thicknesses of the wooden layers makes it possible to modulate the number of layers of the soul, and its mechanical properties.
    Preferably, the layer of composite material also comprises at least one through opening revealing the core of the frame. The soul of the racket being full, it is possible to have openings in the sheath of composite material, especially in regions with little mechanical stress.
    Preferably, at least two wooden layers of the soul form a laminate.
    Preferably, the core also comprises a layer of foaming material between two wooden layers. The layer of foaming material makes it possible to adjust the thickness of the frame of the racket, without modifying the number or the thickness of the wooden layers forming the core of the frame.
    Preferably, the wood fibers of at least one of the layers of the core are arranged in the longitudinal direction of said layer.
    According to another aspect, the invention also relates to a method of manufacturing a racket for a game of balls, in particular tennis balls, comprising a frame with a head delimiting a striking surface of the ball, for example a strung surface forming a sieve , and a handle mounted in the extension of the head, outside the surface of, strikes the -balle, the method comprises the following steps: a) at least two wooden layers are combined, preferably at least seven wooden layers, for forming a core, the wood of layers having a density less than or equal to 400kg / m3; and b) the soul is disposed in a mold to obtain, by compression, the shape of the core of the frame, for example when hot, and then c) at least one layer of preimpregnated fibers is wound with a thermosetting resin , around the soul.
    Thus, by means of a hot molding step, it becomes possible to form the core of the racket, with its final shape, without requiring expensive additional steps. Indeed, by compression of the wooden core, it is possible to directly form the grooves and other desired shapes during a single manufacturing step. Step c) is performed after step b) and the method may also comprise a step d) during which the frame is placed in a mold to crosslink the preimpregnated fiber layer. In this embodiment, the steps of compression of the wooden core and crosslinking of the sheath of composite material are carried out separately and successively.
    Preferentially, step a) comprises the application between the wood layers, an adhesive, a thermosetting resin, for example an epoxy resin, a foaming element, for example a foaming adhesive, or a foam expansive, for example EVA. The use of a foaming element between the wooden layers makes it possible, during the subsequent hot molding steps, to obtain the desired pressure in the mold, while adjusting the size of the frame to the size of the mold.
    Preferably, step a) comprises disposing a layer of fibers pre-impregnated with a thermosetting resin between the wooden layers. The process remains totally compatible with the incorporation of composite material in the core of the racket: it is therefore easy to modify the properties of the core by modifying the materials composing it, especially in the case where the core is a laminate -glue.
    BRIEF DESCRIPTION OF THE DRAWINGS The invention and its advantages will be better understood on reading the detailed description of two particular embodiments, taken as non-limiting examples and illustrated by the appended drawings, in which: FIG. tennis racket ; - Figure 2 shows a cross section of a first embodiment of a racket frame according to Figure 1, along the line A-A; - Figure 3 shows a cross section of a second embodiment of a racket frame according to Figure 1, along the line B-B; and - Figure 4 shows the wooden core of the racket of Figure 1, during the process of making the racket.
    Detailed description of the invention
    Figure 1 schematically illustrates a racket 1 according to the invention.
    In a conventional manner, the racket 1 comprises a frame 2 with a head delimiting a roped surface forming a sieve 4, and a handle 5. The handle 5 comprises a handle 6 and two connecting branches 8, 10 mounted in the extension of the head and defining a hollow space 12 allowing the passage of air.
    According to a variant not shown, the handle 6 can be connected to the head of the frame 2 by a single central branch.
    According to the invention, the frame 2 of the racket comprises a wooden core surrounded by a layer of composite material.
    Figure 2 illustrates a first embodiment of the frame 2, and shows the cross section along the line A-A of a racket according to the first embodiment.
    As can be seen, the frame 2 of the racket 1 comprises a core 14 and a sheath 16. The core 14 comprises several layers, or plies, 18 of wood and possibly of composite material. The layers 18 may have a thickness of between 0.5 mm and 2 mm, depending on the nature of the wood used and the number of plies forming the core. In Figure 2, the core 14 thus comprises eight layers 18 of wood which are laminated-glued.
    According to this first embodiment, the layers 18 are of light wood, for example balsa, and are bonded together, for example with an epoxy adhesive, vinyl or polyurethane, before being shaped by bending in a template. In order to facilitate the bending, the wood fibers of the core are arranged in the longitudinal direction of the glulam. The bent laminated core then has the general shape of a racket, with the handle mounted in the extension of the frame (see Figure 4), which is machined to get the final shape of the racket. Thus, grooves and chamfers are made on the bent laminated core, for example the groove 20 visible in FIG. 2 and intended to receive the rope along the periphery of the frame 2.
    When the glued-laminated core is finished, strips of composite material, for example glass fibers and / or carbon pre-impregnated with a thermosetting resin such as an epoxy resin, are disposed over all around. . Furthermore, the frame 2 extending to form the handle 5, it is also added a frame portion between the two arms 8, 10 to close the sieve 4 on the side of the handle 5. The assembly is then placed in a mold , especially hot, to achieve the crosslinking of composite material strips and thus obtain the final frame of the racket before decoration.
    FIG. 3 illustrates a second embodiment of the frame 2, and represents the cross section along the line B-B of a racket according to the second embodiment.
    As can be seen, the frame 2 of the racket 1 also comprises a core 22 and a sheath 16. The core 22 comprises a plurality of layers, or plies, 18 of wood and a layer 24 of composite material. The layers 18 of wood, and possibly the layer 24 of composite material, may have a thickness of between 0.5mm and 2mm, depending on the nature of the wood used and the number of folds forming the core. In Figure 3, the core 14 thus comprises six layers 18 of wood and a layer 24 of composite material, which are laminated.
    According to this second embodiment, the layers 18 are of light wood, for example balsa, and are bonded together and with the layer 24 of composite material before being shaped in a mold. More particularly, in order to best fit the inner shape of the mold, some wood layers 18 of the core 22 are glued together with a foaming glue 26, for example EVA, which will take volume during the step of shaping the glulam in the mold.
    Thus, FIG. 3 represents a frame section in which a foaming glue has been used twice to bond layers 18 of wood to one another: these foaming layers 26 are particularly particularly visible after shaping of the glulam due to their increase in volume to obtain, on the final racket, the desired shape.
    The shaping of the glulam is obtained by molding, especially hot. The molding step provides a frame having, in addition to the general shape of the racket, the finishes made by machining in the first embodiment. In fact, by localized compression of the wood layers 18, the chamfered shapes and the desired grooves of the final racket are obtained, for example the peripheral groove intended to receive the rope.
    Furthermore, with hot molding, it is possible, at the same time as giving the final form to the glulam, to crosslink the glue used between the wood layers 18 and / or between the layers 18 and 24. The crosslinking layers of foaming glue 26 also makes it possible to obtain a frame section having a variable surface along the racket, from a uniform glulam: according to the space available in the mold, the foaming glue goes to expand to fit the inner shape of the mold. Thus, near the branches 8, 10, the section of the frame 2 may have a surface greater than that of the racquet head section. The molded glulam core then has the general shape of a racket, with the handle mounted in the extension of the frame (see Figure 4).
    Next, strips of composite material, for example glass and / or carbon fibers pre-impregnated with a thermosetting resin such as an epoxy resin, are then placed over all around. Furthermore, the frame 2 extending to form the handle 5, it is also added a frame portion between the two arms 8, 10 to close the sieve 4 on the side of the handle 5. The assembly is then placed in a mold , especially hot, to achieve the crosslinking of the strips of composite materials and thus obtain the final frame of the racket before decoration.
    Alternatively, it is possible to arrange the strips of composite materials around the glue-laminated core before shaping the laminate. In this case, the core is shaped, glued and surrounded by a layer of composite material in one and the same heat molding step, instead of two.
    FIG. 4 represents an example of glulam formed according to a process of the invention, before application of the strips of corfiposite material. The core of the frame 2 is extended in particular to form the connecting legs 8, 10 and the handle 6 of the racket. This gives mechanical properties, including vibration absorption, uniform along the racket, and therefore more efficient.
    Thus, thanks to the invention, it is possible to obtain, with a simplified manufacturing process, a racket combining the mechanical properties of rackets made of composite materials, and improved vibration absorption.
    权利要求:
    Claims (15)
    [1]
    1. Racket (1) for a game of balls, especially tennis balls, comprising a frame (2) with a head delimiting a striking surface of the bafle, for example a roped surface forming a sieve (4), and a handle (5). ) mounted in the extension of the head outside the striking surface of the ball, characterized in that the frame (2) comprises: - a core (14, 22) comprising at least two wooden layers (18) preferably at least seven layers of wood, bent or molded to the frame shape, the wood of the layers (18) having a density of less than or equal to 400kg / m3; and - at least one layer (16) of composite material wound around said core before or after bending, or wound around said core after molding to the shape of the frame.
    [2]
    2. The racket (1) according to claim 1, wherein the wood layers (18) has a density less than or equal to 200 kg / m3, and more preferably less than or equal to 150 kg / m3.
    [3]
    3. Racket (1) according to claim 1 or 2, wherein the wood of the layers (18) is selected from: balsa, samba, poplar and kiri.
    [4]
    4. Racket (1) according to any one of claims 1 to 3, wherein the web of the handle (5) is formed by extension of the core (14, 22) of the head.
    [5]
    A racket (1) according to any one of claims 1 to 4, wherein the composite material comprises fibers, for example carbon or glass fibers, impregnated with a thermosetting resin or an epoxy resin.
    [6]
    6. racket (1) according to any one of claims 1 to 5, wherein the core comprises at least one layer (24) of composite material disposed between the wooden layers (18).
    [7]
    The racket (1) according to any one of claims 1 to 5, in. .. which <layers> (18) .Æn> wood are glued together.
    [8]
    Racket (1) according to any one of claims 1 to 7, wherein the core (22) has at least one section in which the wood fibers are not homogeneously compressed on the surface of said section, and in which the most compressed wood fibers are located on the periphery of said section, for example at a circumferential groove of the section.
    [9]
    9. Racket (1) according to any one of claims 1 to 8, wherein the layers (18) of wood have a thickness less than or equal to 2mm, preferably less than or equal to 1mm.
    [10]
    10. Racket (1) according to any one of claims 1 to 9, wherein the layer (16) of composite material also comprises at least one through opening revealing the core (14, 22) of the frame (2).
    [11]
    11. Racket (1) according to any one of claims 1 to 10, wherein at least two layers (18) made of wood of the core form a laminate.
    [12]
    12. A method of manufacturing a racket (1) for a game of balls, including tennis, comprising a frame (2) with a head defining a striking surface of the ball, for example a roped surface forming a sieve, and a handle (5) mounted in the extension of the head outside the striking surface of the bale, comprising the following steps: a) at least two layers (18) of wood are combined, preferably at least seven layers of wood, to form a core (14, 22), the wood of the layers (18) having a density less than or equal to 400kg / m3; b) the soul is placed in a mold to obtain, by compression, the shape of the core of the frame, for example when hot; and then c) at least one layer of fibers pre-impregnated with a thermosetting resin is wound around the core.
    [13]
    13. The method of claim 12, wherein the method further comprises a step d) during which the frame is disposed in a cell to crosslink the prepreg fiber layer.
    [14]
    14. A method according to any one of claims 12 to 13, wherein step a) comprises the application between the layers (18) of wood, an adhesive, a thermosetting resin, for example an epoxy resin , a foaming element, for example a foaming adhesive, or an expansive foam, for example EVA.
    [15]
    A method according to any one of claims 12 to 14, wherein step a) comprises disposing a layer (24) of fibers pre-impregnated with a thermosetting resin between the layers (18) of wood.
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    同族专利:
    公开号 | 公开日
    BE1023759A1|2017-07-13|
    FR3026015B1|2018-03-23|
    ES2564208A1|2016-03-18|
    FR3026015A1|2016-03-25|
    ES2564208B1|2016-11-16|
    CN205073617U|2016-03-09|
    ITUB20153723A1|2017-03-18|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US2878020A|1949-12-16|1959-03-17|Roy H Robinson|Racket for batting games|
    GB1295704A|1969-08-08|1972-11-08|
    FR2258874A1|1974-01-24|1975-08-22|Exxon Research Engineering Co|
    EP0046204A2|1980-08-14|1982-02-24|Friedrich Dr. Esper|Laminated composite section|
    EP0132993A1|1983-07-28|1985-02-13|Robert John Seymour|A racquet|
    FR2974307A1|2011-04-20|2012-10-26|Lacoste|NEW GENERATION WOODEN RACKET|
    GB794869A|1956-04-30|1958-05-14|Tokichi Oka|Improvements in racket frames for tennis, badminton and the like|
    FR2195163A5|1972-08-02|1974-03-01|Martel Rene|
    ES236396Y|1978-05-31|1979-01-16|PERFECTED RACKET FOR THE GAME OF TENNIS|
    FR2495477B1|1980-12-04|1984-08-10|Ireb|
    IT1137039B|1981-05-29|1986-09-03|You Chin San|REINFORCED FRAME FOR RACKET AND METHOD FOR ITS PRODUCTION|
    EP0077134A1|1981-10-09|1983-04-20|Kun Nan Lo|Method for making fiber sheet reinforced wood racket|
    TW469848U|2000-10-13|2001-12-21|Yuan Min An Entpr Co Ltd|Racket frame|CN106730688A|2017-01-10|2017-05-31|桐乡波力科技复材用品有限公司|Reeded wall ball racket of inside casing band and preparation method thereof|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    FR1458819A|FR3026015B1|2014-09-18|2014-09-18|RACKET FOR BALL SETS AND CORRESPONDING METHOD|
    FR1458819|2014-09-18|
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