Manufacturing method and structure of composite racket frame

Abstract

The invention mainly provides a manufacturing method and a structure of a composite racket frame. The manufacturing method comprises the following steps: (a) resin impregnation: impregnating a composite into resin; (b) a core mold is wound with the composite material, wherein the core mold in a racket shape is made of polymethacrylimide (PMI) or polypropylene foaming particles (EPP); winding and coating the composite material outside the core mold to form a composite material layer, wherein the composite material layers and the core mold which are wound mutually form a semi-finished product; (c) heating and pressurizing: putting the semi-finished product into a mold with a mold cavity, heating the mold to a preset temperature in a matched manner, and forming internal pressure in the semi-finished product due to thermal expansion of the core mold after heating; (d) cooling and curing: stopping heating, and cooling until the semi-finished product is in a cured state; (e) forming a finished product; taking out a racket frame finished product from the mold; according to the composite material racket frame, the core mold, the composite material layer and the like are sequentially formed from inside to outside to jointly form the integrated racket frame, the racket is light in weight and can maintain considerable strength and rigidity, the plate-shaped racket face has hitting elasticity, meanwhile, the damping effect can be achieved, and the manufacturing cost is effectively reduced.

Description

Technical Field

[0001] The present invention relates to a manufacturing method and structure of a racket frame, particularly to a racket frame applied to various rackets such as net-woven or non-net-woven rackets, which is lightweight, has good controllability, and has a shock-absorbing effect. Background Art

[0002] Common ball games can generally be divided into "using striking tools" and "not using striking tools". Among them, ball games that "do not use striking tools" refer to directly using the hands, feet, or body to contact the ball for attacking, receiving, or passing actions, such as basketball, volleyball, handball, football, American football, water polo, dodge ball, bowling, etc.; while ball games that "use striking tools" refer to using striking tools to contact the ball for attacking, receiving, or passing actions, including baseball, tennis, badminton, hockey, pickleball, golf, croquet, table tennis, billiards, etc.

[0003] Generally common striking tools, such as rackets, baseball bats, pool cues, mallets, etc., are generally in the shape of a racket, a bat, or a rod. According to the relevant requirements of various sports actions and game rules, their shapes and structures are different, and they must comply with the game regulations. In particular, most ball games are listed as Olympic competition sports, and each sports equipment must comply with the relevant Olympic regulations to be used.

[0004] Further analyzing the striking tools of racket type, that is, the striking tools used in tennis, badminton, table tennis, ping pong, etc., their structures must have a racket face and a handle. When using, hold the handle with the hand and hit the ball with the racket face, so the racket face is the striking part; and the racket face part can be further divided into a "plate structure" and a "net-woven structure". For example, the racket faces of tennis rackets and badminton rackets belong to the "net-woven structure", which is surrounded by a hollow frame to form a net-woven area, and a net surface is formed by threading lines in the net-woven area as the hitting surface. While the racket faces of table tennis and pickleball rackets belong to the "plate structure", which uses a plate-shaped part as the hitting surface.

[0005] For the rackets with a market plate structure, most of them use carbon fiber material for the outer layer of the racket and plastic material for the inner layer of the racket; and then according to various different requirements, such as frame strength, shock absorption, racket face resilience, racket face support, etc., there are further different technical applications and changes in the racket structure, material, and process.

[0006] For example, if the face of a pike racket or a table tennis racket has a better shock absorption effect, the impact force on the ball will be absorbed by the face, the rebound force will be smaller, the rebound sensitivity will be lower, the face strength and hardness will be lower, the hand feeling will be heavier when swinging, and the ball control will be lower; on the contrary, if the face of a board racket has a worse shock absorption effect, the impact force on the ball will be less absorbed by the face, the rebound force will be larger, the rebound sensitivity will be higher, the face strength and hardness will be higher, the hand feeling will be lighter when swinging, and the ball control will be higher. Therefore, the face structure and material of a racket affect many physical factors, and also create racket frames of various structures and materials, each with different characteristics, and each suitable for the user's preferences and physical conditions.

[0007] In the prior art, there is a plate body racket face structure, such as the "a shock-absorbing pickle ball racket" disclosed in Patent No. CN114569990A; another prior art pickle ball racket frame structure of the plate body racket face, such as the "a pickle ball racket" disclosed in Patent No. CN115155026A; and there is another prior art pickle ball racket frame structure of the plate body racket face, such as the "multi-layer composite pickle ball racket" disclosed in Patent No. CN112870660A. The racket-related technologies of the plate body racket face in the aforementioned prior art, among which the first case is the process of the pickle racket, and the second and third cases are the structural technologies of the pickle racket. Further analysis shows that the first and second cases are mainly technical contents developed for strengthening the shock absorption or shock absorption function, with a shock-absorbing layer of rubber material, and a structure with multiple layers stacked on the racket face; the racket faces of the second and third cases are both honeycomb structures. In addition to maintaining the rigidity of the racket face, the honeycomb structure also has good durability and environmental resistance.

[0008] The prior art of the above three cases all focus on the multi-layer inner core structure to buffer the impact force of the pickle ball and achieve a better shock absorption effect. However, because the impact force of the pickle ball is consumed more, the hitter (user) needs to use more force to make the pickle ball fly to the same distance. When the pickle ball contacts the racket face, the racket face is deeply concave, resulting in large friction, making it more difficult to control the rebound direction of the ball. Moreover, the honeycomb structure is prone to produce different rebound forces due to hitting different positions on the honeycomb frame or honeycomb holes. On the other hand, a large number of buffer core layers will also increase the weight of the entire racket, causing a burden on the hitter's hands. Moreover, for children and the elderly (elderly) who have less swinging power, pickle rackets with enhanced shock absorption effects are not suitable. In addition, the production cost of the honeycomb core layer in the prior art is quite high, and the process is also relatively complicated.

[0009] For a racket with a net-woven hitting surface, since its racket frame needs to provide for rope weaving, and at the same time withstand the tension of the ropes and the impact force during hitting, the frame has relatively high requirements for support and rigidity to avoid racket breakage. To achieve better frame support, existing technologies such as multi-layer structures, or metal tube layers, or wooden inner tubes, or the use of expanding agents are used inside the racket frame.

[0010] In the prior art, for the racket technology with a net-woven hitting surface, such as the "Racket Manufacturing Method Combining Metal Tube and Fiber Material" disclosed in Taiwan Patent No. 090101386 of China, its outer layer is a composite material layer and its inner layer is a racket structure with a hollow metal frame; another racket structure with a net-woven hitting surface in the prior art, such as the "Racket Molding Method and Racket" disclosed in Taiwan Patent No. 100116656 of China, its outer layer is a composite material layer and its inner layer is a racket structure with a nylon inner tube and an expanding agent; yet another racket structure with a net-woven hitting surface in the prior art, the "Improved Structure of Racket Frame" disclosed in Taiwan Patent No. 090211041 of China, its outer layer is a composite material layer and its inner layer is a racket structure with a wooden inner layer and a fiber composite inner tube.

[0011] On the other hand, for the related technologies of rackets with net-woven hitting surfaces in the aforementioned prior art, in addition to mostly using carbon fiber materials for the outer layer, in order to maintain the support and rigidity of the racket frame, technical means such as multi-layer structures, or metal tube layers, or wooden inner tubes, or the use of expanding agents are adopted for the inner layer; however, the more layers the racket frame has, the more complex the manufacturing process becomes, and the manufacturing costs of materials, equipment, molds, labor, etc. to be used are higher. In addition, the more layers there are, the heavier the overall racket will be, it will consume more physical strength of the player when swinging the racket, and it is more difficult to control the ball. Summary of the Invention

[0012] In view of the above, the manufacturing method and structure of the composite material racket frame disclosed in the present invention include the following steps: (a) Impregnating resin: impregnating a composite material with resin; (b) Wrapping the core mold with the composite material: on a core mold in the shape of a racket, made of polymethacrylimide (PMI) or polypropylene foam particles (EPP); then winding and covering the composite material outside the core mold to form a composite material layer, and the mutually wound composite material layers and the core mold together form a semi-finished product; (c) Heating and pressurizing: placing the semi-finished product into a mold with a cavity, heating the mold to a preset temperature, and after heating, the core mold expands due to heat and generates internal pressure inside the semi-finished product; (d) Cooling and curing: stopping heating and cooling to make the semi-finished product in a cured state; (e) Finished product forming: taking out a finished racket frame from the mold; the composite material racket frame thus manufactured forms an integrated racket frame jointly formed by a core mold and a composite material layer in sequence from the inside to the outside, which has a light racket weight, can maintain considerable strength and rigidity, the plate-shaped racket face has striking elasticity, can achieve a shock-absorbing effect, effectively reduce the manufacturing cost, and improve the handling feel.

[0013] Comparing with the efficacy of the prior art, the main object of the present invention is to provide a manufacturing method and structure of a composite material racket frame, the core mold of which is made of polymethacrylimide (PMI) or polypropylene foam particles (EPP), expands due to heat during the heating step, and simultaneously generates internal pressure to completely fill the cavity space of the semi-finished product, so that any pressurizing device can be dispensed with, effectively reducing the manufacturing cost, and the process is applicable to the forming of plate rackets and net-woven rackets.

[0014] The secondary object of the present invention is to provide a manufacturing method and structure of a composite material racket frame, the core mold of which eliminates the honeycomb structure, so there is no need to carry out the processing flow of forming the honeycomb structure of the core mold, and the process is effectively simplified due to the simple structure, thereby saving the manufacturing cost.

[0015] Another object of the present invention is to provide a manufacturing method and structure of a composite material racket frame, the core mold of which replaces the elastic layer with the honeycomb structure in the prior art with polymethacrylimide (PMI) or polypropylene foam particles (EPP), which can improve the support of the striking part, has higher hardness and rigidity, the racket face has better return elasticity, improves the handling feel of the hitting direction, but still has a shock-absorbing effect.

[0016] A further object of the present invention is to provide a manufacturing method and structure of a composite racket frame, which uses a core mold made of polymethacrylimide (PMI) or expanded polypropylene (EPP) particles as the matrix. Compared with the inner layer structures in the prior art, such as multi-layer, or multi-elastic layer, or metal inner layer, or wood inner layer, or filled with an expanding agent, the overall weight of the racket is lighter, effectively reducing the burden during swinging, and is suitable for children or the elderly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a manufacturing flow chart of a preferred embodiment of the present invention; Figure 2 is a schematic diagram of covering the core mold in step (b) of a preferred embodiment of the present invention; Figure 3 is a schematic diagram of the mold and heating device of a preferred embodiment of the present invention; Figure 4 is a three-dimensional external view schematic diagram of a racket frame of a preferred embodiment of the present invention; Figure 5 is a schematic diagram of a plane cross-section of a finished racket frame of a preferred embodiment of the present invention; Figure 6 is a schematic diagram of covering the core mold in step (b) of the second embodiment of the present invention; Figure 7 is a schematic diagram of a plane cross-section of a finished racket frame of the second embodiment of the present invention; Figure 8 is a schematic diagram of covering the core mold in step (b) of the third embodiment of the present invention; Figure 9 is a schematic diagram of a plane cross-section of a finished racket frame of the third embodiment of the present invention; Figure 10 is a schematic diagram of a plane cross-section of a finished racket frame of the fourth embodiment of the present invention.

[0018] DESCRIPTION OF THE REFERENCE NUMERALS Core mold 10; Striking part 11; Grip part 12; Elastomer 20; Elastomer layer 20'; Composite material 30; Composite material layer 30'; Mold 40; Cavity 41; Heating devices 42, 43; Finished racket frame 60. DETAILED DESCRIPTION OF THE INVENTION

[0019] First, please refer to Figures 1 to 4, the manufacturing method of a composite racket frame provided by the present invention will be described first in the implementation state of a tennis racket with a net - woven racket, and it includes the following steps: (a) Impregnating resin: Impregnate a composite material 30 with resin; the composite material 30 can be one of carbon fiber, glass fiber, graphene, etc.

[0020] (b) Wrapping the core mold with the composite material: On a core mold 10 in the shape of a racket, which is made of polymethacrylimide (PMI) or expanded polypropylene beads (EPP); then wind and wrap the composite material 30 around the outside of the core mold 10 to form a composite material layer 30', and the mutually wound composite material layers 30' and the core mold 10 together form a semi - finished product; the core mold 10 has a striking part 11 and a handle part 12; the core mold 10 is in one of the states of hollow, solid, or partially hollow, etc. In the net - woven racket frame of this embodiment, the core mold 10 is in a solid state; the striking part 11 is in one of the states of a frame with a hollow middle or a solid plate, etc. In the net - woven racket frame of this embodiment, the striking part 11 is a frame with a hollow middle.

[0021] (c) Heating and pressurizing: Place the semi - finished product into a mold 40 with a cavity 41, and heat the mold 40 to a preset temperature. After heating, the core mold 10 expands due to heat and forms an internal pressure inside the semi - finished product; two heating devices 42, 43 can be further used.

[0022] (43) Are arranged on both sides of the mold 40 for heating; the heating temperature exceeds the melting point temperature of the composite material 30; the heating temperature value ranges from 120°C to 180°C.

[0023] (d) Cooling and curing: Stop heating and cool to make the semi - finished product in a cured state.

[0024] (e) Finished product forming; Take out a racket frame finished product 60 from the mold 40.

[0025] According to the manufacturing method described above, the racket frame finished product 60 is made. Please refer to Figures 4 to 5 Its structure includes: A core mold 10, which is made of polymethacrylimide (PMI) or expanded polypropylene beads (EPP), and has a striking part 11 and a handle part 12 formed integrally. The striking part 11 and the handle part 12 can be integrally formed; the core mold 10 is in one of the states of hollow, solid, or partially hollow, etc. In the net - woven racket frame of this embodiment, the core mold 10 is a frame with a hollow middle; the striking part 11 is in one of the states of a frame with a hollow middle or a solid plate, etc. In the net - woven racket frame of this embodiment, the striking part 11 is a frame with a hollow middle.

[0026] A composite material layer 30' simultaneously coats the core mold 10 and forms an integrated racket frame for each striking part and the handle part; the composite material layer 30' can be made of one of materials such as carbon fiber, glass fiber, or graphene.

[0027] For the composite material racket frame structure manufactured by the above manufacturing method, the core mold 10 is made of polymethacrylimide (PMI) or polypropylene foam particles (EPP), and then the composite material 30 is completely coated in a winding manner. The integrated racket frame formed thereby has a polymethacrylimide (PMI) material inside the striking part 11, which has relatively high strength and rigidity, the racket face has better return elasticity, the overall racket is light in weight, the handling feel is improved, and the manufacturing cost can be reduced. Therefore, it has high economic benefits and practicability.

[0028] To further understand the structural features, technical means, and expected effects of the present invention, the usage method of the present invention will be described as follows: Please refer to Figure 1 and Figure 2 , for the manufacturing process of the present invention, first in step (a), the resin impregnation step, a composite material 30 is first impregnated with resin. The composite material 30 can be made of one of materials such as carbon fiber, glass fiber, or graphene. In step (b), the step of winding the composite material around the core mold, a core mold 10 made of polymethacrylimide (PMI) or polypropylene foam particles (EPP) in the shape of a racket is taken, and then the composite material 30 is wound around the outside of each core mold 10 to form a composite material layer 30', that is, each striking part 11 and the handle part 12 are completely wound and coated with the composite material 30 to form a semi-finished product.

[0029] Please refer to Figure 3 , in step (c), heating and pressing, the semi-finished product is placed in the mold cavity 41 of the mold 40. After closing the mold, the mold 40 is heated by the heating devices 42 and 43 provided on both sides of the mold 40. The heating temperature exceeds the melting point temperature of the composite material, about 120°C to 180°C; when heating, the core mold 10 expands due to heat and forms an internal pressure inside the semi-finished product, thereby filling the entire mold cavity 41 with the semi-finished product. When the heating temperature exceeds the melting point temperature of the composite material, the composite material layer 30' softens and melts, and completely coats the outside of the entire semi-finished product.

[0030] In step (d), cooling and curing, after stopping heating, it is first cooled to a preset temperature to gradually cure and form the semi-finished product in the mold. Please refer to Figure 4, in step (e), the finished product is formed, that is, a finished racket frame 60 is taken out from the mold 40.

[0031] For the structure of the finished racket frame 60 of the present invention, please refer to Figure 4 and Figure 5 , in the part of the striking part 11, from the inside to the outside, there are the core molds 10 and the composite material layer 30' in sequence; in the part of the handle part 12, from the inside to the outside, there are also the core molds 10 and the composite material layer 30' in sequence.

[0032] The racket frame structure of the present invention is manufactured through five processes: (a) impregnating resin; (b) winding the core mold with composite materials; (c) heating and pressurizing; (d) cooling and curing; (e) forming the finished product. It is an integrated racket frame formed by a core mold 10 and a composite material layer 30' sequentially from the inside to the outside, and can effectively achieve the following effects: 1. In step (c) of heating and pressurizing, since the core mold 10 is made of polymethacrylimide (PMI) or polypropylene foam particles (EPP) material, it will gradually expand and generate internal pressure when heated, so that the semi-finished product completely fills the space of the mold cavity 41, and no pressurizing or filling related devices and equipment need to be set, thus effectively reducing the manufacturing cost.

[0033] 2. In this embodiment, polymethacrylimide (PMI) or polypropylene foam particles (EPP) material is used as the core mold 10 to replace the inner layer structures such as metal layers, wood layers, or expanders commonly used in existing net-woven rackets. The number of frame layers is small and the manufacturing process is more simplified.

[0034] 3. In this embodiment, polymethacrylimide (PMI) or polypropylene foam particles (EPP) material is used as the core mold 10 to replace the inner layer structures such as metal layers, wood layers, or expanders commonly used in existing net-woven rackets. Due to the simplified process and simple structure, compared with the existing net-woven rackets, the present invention uses less materials, and the manufacturing costs of the equipment, molds, manpower, etc. required for preparation or use are lower.

[0035] 4. The structure of the net-woven racket in this embodiment has fewer internal layers, so it can effectively reduce the overall weight of the racket. Also, using polymethacrylimide (PMI) or polypropylene foam particles (EPP) material can maintain the necessary support and rigidity. When swinging the racket, it is easier and more labor-saving, and can improve the ball control ability.

[0036] V. By using the core mold 10 made of polymethacrylimide (PMI) or polypropylene foam particles (EPP) as the matrix and adopting a structural design that occupies a relatively large volume of the overall racket frame, compared with the inner layer structures such as metal layers, wooden layers, or expanders commonly used in existing net-woven rackets, the overall weight of the racket is lighter, effectively reducing the burden during swinging, and is suitable for children or the elderly.

[0037] VI. The core mold can be pre-formed into each striking part and the handle part in one piece, eliminating the assembly operation of connecting the two, and simplifying the process.

[0038] VII. The manufacturing method of the present invention can be applied to the molding of both plate rackets and net-woven rackets.

[0039] Please refer to Figure 6 and Figure 7 , the second embodiment of the present invention will be described with the implementation form of a plate racket. Its manufacturing process is the same as that of the first embodiment, including (a) impregnating resin; (b) wrapping the core mold with a composite material; (c) heating and pressurizing; (d) cooling and curing; (e) forming the finished product; and other five processes. Among them, when wrapping the core mold with the composite material in step (b), a core mold 10 made of polymethacrylimide (PMI) or polypropylene foam particles (EPP) in the shape of a plate racket is provided with an elastomer 20 on each side surface of the striking part 11 to form an elastomer layer 20'. It can be completely covered or partially covered. The elastomer layer 20' can be one of plastic materials such as TPR (thermoplastic rubber), TPU (thermoplastic polyurethane), or TPE (thermoplastic elastomer). Then, the composite material 30 is wound around and covered outside each core mold and the elastomer layer 20', that is, the striking part 11 or the handle part 12 provided with the elastomer layer 20' is completely wound and covered by the composite material 30 to form a semi-finished product, and then the subsequent operations of (c) heating and pressurizing; (d) cooling and curing; (e) forming the finished product are carried out.

[0040] The structure of the racket frame finished product 60 of this embodiment includes: a core mold 10 made of polymethacrylimide (PMI) or polypropylene foam particles (EPP), which is formed with a striking part 11 and a handle part 12 in one piece; the striking part 11 of the core mold 10 is in a completely solid state.

[0041] An elastomer layer 20' is an application of a plastic material and is attached to the two striking surfaces of the striking part.

[0042] A composite material layer simultaneously covers each core mold and the elastomer layer and forms an integrated racket frame for each striking part and the handle part.

[0043] In this embodiment, for the striking part 11, from the inside to the outside in sequence are the respective core molds 10, the elastomer layer 20', and the composite material layer 30'; for the handle part 12, from the inside to the outside in sequence are also the respective core molds 10, the elastomer layer 20', and the composite material layer 30'.

[0044] In the second embodiment of the present invention, an integrated racket frame is formed by using the core mold 10 made of polymethacrylimide (PMI) or polypropylene foam particles (EPP), combining with the elastomer layer 20' provided on the hitting surface of the striking part 11, and then completely wrapping with the composite material 30 in a winding manner. While the elastomer layer 20' can achieve a shock-absorbing effect, the interior of the striking part 11 made of polymethacrylimide (PMI) or polypropylene foam particles (EPP) and combined with the elastomer layer 20' still maintains the strength and rigidity of the first embodiment.

[0045] The racket frame structure of the present invention is manufactured through five processes: (a) impregnating resin; (b) winding the core mold with a composite material; (c) heating and pressurizing; (d) cooling and curing; (e) forming the finished product. An integrated racket frame is formed by sequentially forming a core mold 10 and a composite material layer 30' from the inside to the outside, which can effectively achieve the following effects: 1. The core mold 10 of the present invention is made of polymethacrylimide (PMI) or polypropylene foam particles (EPP). In the process of step (b) winding the core mold with a composite material in its original physical structure state, there is no need to pre-process the core mold 10 into a honeycomb structure. Compared with the prior art in which a honeycomb elastic layer is used on the plate hitting surface, the present invention can effectively simplify the process flow, and thus save the manufacturing cost of forming the honeycomb structure of the core mold.

[0046] 2. Due to the material characteristics of polymethacrylimide (PMI) or polypropylene foam particles (EPP), compared with other general plastic materials, it has better support and rigidity. Therefore, the present invention uses the core mold 10 made of polymethacrylimide (PMI) or polypropylene foam particles (EPP) to replace the honeycomb structure elastic layer on the plate hitting surface in the prior art. In comparison, the tissue density of the core mold 10 is denser, and the resilience after contact between various parts of the striking part 11 and a Pickleball or a table tennis ball is more consistent, solving the problem that the honeycomb structure is prone to generate different resilience when hitting different positions such as the honeycomb frame or the honeycomb nest.

[0047] 3. The core mold 10 of the present invention replaces the honeycomb structure elastic layer of the racket face in the prior art with polymethacrylimide (PMI) or polypropylene foam particles (EPP). In addition to the shock-absorbing effect of the core mold 10 itself, the support of the striking part can be improved, and the racket face has a higher hardness and rigidity. The racket face has a better return elasticity, which enhances the control feel of the hitting direction, and solves the problems of large friction caused by the enhanced shock-absorbing function in the prior art, and it is more difficult to control the rebound and flying direction of the ball.

[0048] Fourth, the core mold 10 made of polymethacrylimide (PMI) or polypropylene foam particles (EPP) is used as the base, and the structural design occupies a larger volume of the entire racket frame. Compared with the multi-layer elastic layer structure of the racket body in the prior art, the overall racket weight is lighter, which effectively reduces the burden when swinging the racket, and is suitable for children or the elderly.

[0049] The other manufacturing methods, structures, assembly methods, technical applications, actions, usage states and expected effects of this embodiment are exactly the same as those of the first embodiment.

[0050] Please refer to Figure 8 and Figure 9 , which is the third embodiment of the present invention, is an implementation form of a badminton racket with a net-woven racket surface, wherein the striking part 11 of the core mold 10 is in the shape of a frame with a hollow center. Before performing the step (b) of wrapping the core mold with the composite material, an elastomer 20 can be attached to the striking part 11 or the handle part 12 of the core mold 10 in advance, or the elastomer 20 is attached to each striking part 11 and the handle part 12 to form an elastomer layer 20', and then the composite material 30 is wrapped around each core mold 10 and the elastomer layer 20' to form a composite material layer 30'. The composite material layers 30', the core mold 10 and the elastomer layer 20' that are wound together form a semi-finished product, and then the subsequent operations of (c) heating and pressurizing; (d) cooling and curing; (e) finished product molding are performed.

[0051] according to Figure 8 and Figure 9 As shown, this embodiment takes the partial attachment of the elastomer 20 to the handle portion 12 as an example, so that in the hollow frame portion of the striking portion 11, from the inside to the outside, there are the core molds 10 and the composite material layer 30'; in the portion of the handle portion 12, from the inside to the outside, there are the core molds 10, the elastomer layer 20' and the composite material layer 30'.

[0052] In this embodiment, since the grip portion 12 is provided with the elastomer layer 20', when the impact force generated during hitting is transmitted to the grip portion 12, the vibration impact force can be effectively reduced, and thus it has a better buffering effect. Other manufacturing methods, structures, assembly methods, technical applications, operating and usage states, and expected effects of this embodiment are exactly the same as those of the foregoing first embodiment.

[0053] Please refer to Figure 10 , which is the fourth embodiment of the present invention and is an embodiment of a locally hollow core mold. Before processing, the core mold 10 is integrally formed with a solid hitting portion 11 and a hollow grip portion 12 in advance, and then the manufacturing method of the pick racket frame of the present invention is started. For the finished racket frame 60 manufactured, the grip portion 12 is in a closed hollow state.

[0054] In this embodiment, the internal structure of the core mold 10 is mainly changed. The hollow structure can make the overall weight of the racket lighter, and the hollow volume can also be adjusted according to requirements, so as to manufacture racket frames of different weights, and thus has the effect of adjusting the racket weight. On the other hand, for the pressurization operation in step (c), the resin infusion molding (RTM) technology application can be further applied. Other manufacturing methods, structures, assembly methods, technical applications, operating and usage states, and expected effects are exactly the same as those of the foregoing first embodiment.

[0055] To sum up, the "manufacturing method and structure of a composite material racket frame" disclosed in the present invention is a racket frame structure manufactured by five processes including (a) impregnating resin; (b) wrapping the core mold with a composite material; (c) heating and pressurizing; (d) cooling and curing; (e) forming the finished product. It is an integrated racket frame jointly formed by a core mold 10 and a composite material layer 30' formed in sequence from the inside to the outside. The inside of the hitting portion is made of polymethacrylimide (PMI) or polypropylene foam particles (EPP) material, which has relatively high strength and rigidity. The racket face has better return elasticity, the overall racket is light in weight, the handling feel is improved, the manufacturing cost can be reduced, and the elastomer layer can be added to achieve a shock absorption effect for each hitting portion or grip portion, and the internal space size of the core mold 10 can be used to adjust the racket weight, so as to truly have industrial practicability and cost effectiveness as a whole.

[0056] It should be noted that the above are specific embodiments of the present invention and the technical principles applied. If changes are made according to the concept of the present invention and the functions and effects generated still do not exceed the spirit covered by the claims, they should all be within the scope of the present invention.

Claims

1. A manufacturing method of a composite material racket frame, characterized in that, Comprising the following steps: (a) Impregnating with resin: Impregnating a composite material with resin; (b) Wrapping the core mold with the composite material: On a core mold in the shape of a racket, made of polymethacrylimide; then winding and covering the composite material around the core mold to form a composite material layer, and the mutually wound composite material layers and the core mold together form a semi-finished product; (c) Heating and pressurizing: Placing the semi-finished product into a mold with a cavity, and heating the mold to a preset temperature. After heating, the core mold expands due to heat and an internal pressure is formed inside the semi-finished product; (d) Cooling and curing: Stopping heating and cooling until the semi-finished product is in a cured state; (e) Finished product forming: Taking out a finished racket frame from the mold.

2. A manufacturing method of a composite material racket frame, characterized in that, Comprising the following steps: (a) Impregnating with resin: Impregnating a composite material with resin; (b) Wrapping the core mold with the composite material: On a core mold in the shape of a racket, made of polypropylene foam particles; then winding and covering the composite material around the core mold to form a composite material layer, and the mutually wound composite material layers and the core mold together form a semi-finished product; (c) Heating and pressurizing: Placing the semi-finished product into a mold with a cavity, and heating the mold to a preset temperature. After heating, the core mold expands due to heat and an internal pressure is formed inside the semi-finished product; (d) Cooling and curing: Stopping heating and cooling until the semi-finished product is in a cured state; (e) Finished product forming: Taking out a finished racket frame from the mold.

3. The manufacturing method of the composite material racket frame according to claim 1 or 2, characterized in that, The core mold has a striking part and a handle part; the core mold is in one of the states of being hollow, solid, or partially hollow; the striking part is in one of the states of being a frame with a hollow middle or a solid plate.

4. The manufacturing method of the composite material racket frame according to claim 1 or 2, characterized in that, For the heating operation in step (c), two heating devices are arranged on both sides of the mold for heating; the heating temperature in step (c) exceeds the melting point temperature of the composite material; the heating temperature value ranges from 120°C to 180°C.

5. The manufacturing method of the composite material racket frame according to claim 1 or 2, characterized in that For the operation of wrapping the core mold in step (b), first, an elastomer is provided at at least one preset part outside the core mold to form an elastomer layer, and then the composite material is wound and covered outside each core mold and the elastomer layer to form the composite material layer.

6. The manufacturing method of the composite material racket frame according to claim 5, characterized in that, The core mold has a striking part and a handle part; the elastomer is provided on both hitting surfaces of the striking part or the elastomer covers the handle part in one of the cases.

7. The manufacturing method of the composite material racket frame according to claim 5, characterized in that, The elastomer is a plastic material, and the plastic material is one of TPR, TPU, or TPE.

8. The manufacturing method of the composite material racket frame according to claim 1 or 2, characterized in that, The composite material is one of carbon fiber, glass fiber, or graphene for application.

9. The manufacturing method of the composite material racket frame according to claim 1 or 2, characterized in that, For the pressurizing operation in step (c), a resin infusion molding technique is further applied.

10. Structure of a composite material racket frame, characterized in that, Including: A core mold, made of polymethacrylimide material, which integrally forms a striking part and a handle part; A composite material layer that simultaneously covers each core mold and the elastomer layer and forms an integrated racket frame for each striking part and handle part.

11. Structure of a composite material racket frame, characterized in that Including: A core mold, made of polypropylene foam particle material, which integrally forms a striking part and a handle part; A composite material layer that simultaneously covers each core mold and the elastomer layer and forms an integrated racket frame for each striking part and handle part.

12. The structure of the composite racket frame according to claim 10 or 11, characterized in that, The core mold is in one of the states of being hollow, solid, or partially hollow; the striking part is in one of the states of being a frame with a hollow in the middle or a solid plate.

13. The structure of the composite racket frame according to claim 10 or 11, characterized in that, The thickness of the core mold gradually thins in the direction of the handle part at the striking part on the other side of the handle part.

14. The structure of the composite racket frame according to claim 10 or 11, characterized in that, It further has an elastomer layer, which is a plastic material, and is attached to the two hitting surfaces of the striking part, or the elastomer layer is attached to the handle part or the like in one of the cases.

15. The structure of the composite racket frame according to claim 14, characterized in that, Regarding the application of the elastomer layer as a plastic material, the plastic material can be one of the plastic materials such as TPR, TPU, or TPE; the composite material layer can be one of the materials such as carbon fiber, glass fiber, or graphene.

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