Self-locking plug for badminton racket and method for manufacturing badminton racket

Abstract

The present invention provides a self-locking plug for a badminton racket, comprising a first connecting block and a second connecting block, wherein the first connecting block is connected to a racket frame preform, one end of the second connecting block is rotatably connected to the first connecting block, and the other end of the second connecting block is provided with a self-locking structure, which is fixedly connected to a middle tube. A method for manufacturing a badminton racket using the self-locking plug is also provided. The advantages of the present invention are: the combined structure retains the ability of the middle tube to rotate around the central axis while realizing the self-locking function of the plug and the middle tube, which can block the foaming material to form a perfect enclosed space, and at the same time facilitate the adjustment of the position of the middle tube, which is beneficial to the selection of the rigidity of the middle tube and improves the consistency of the hitting feeling of the processed racket; the self-locking method between the plug and the middle tube does not require the use of adhesive, which avoids the risk of abnormal sound caused by debonding at the connection between the middle tube of the processed racket and the plug.

Description

Technical Field

[0001] The invention relates to the field of sports equipment, in particular to a self-locking plug for a badminton racket and a manufacturing method of the badminton racket. Background Art

[0002] With the improvement of living standards, badminton, a whole-body sport with controllable intensity, has become a sport that many people participate in. Designing and producing a racket that suits the market has become the direction of most manufacturers.

[0003] Because badminton balls are fast and the reaction time is short, athletes need to swing the rackets quickly during exercise. In order to reduce exercise consumption, the market needs lightweight rackets with shock-absorbing functions.

[0004] Carbon fiber composite materials have high specific modulus and specific strength, and are a very excellent structural material. They are widely used in defense, industry, construction and other industries. They are very suitable for the weight, strength and torsion resistance requirements of badminton. Due to the incomparable advantages of carbon fiber composite materials, they have been widely used in badminton racket products.

[0005] Badminton rackets are generally composed of a racket frame, a middle tube, and a handle. The middle tube of a commonly used badminton racket is a hollow tubular object. When the racket frame is processed using foaming molding technology, a carbon fiber composite material prepreg containing epoxy resin is generally rolled into a tubular racket frame preform, and the foaming material is placed in the middle of the racket frame preform. Before the epoxy resin hardening process, the flowing epoxy resin is easy to enter the hollow middle tube under the extrusion of the foaming material, which creates several hidden dangers: First, the expansion pressure of the foaming material is reduced, which is easy to cause the interlayer bonding of the carbon fiber composite material substrate of the racket frame to be loose, and there is a hidden danger of low strength of the racket frame; second, the foaming material and the flowing epoxy resin are easy to enter the interior of the middle tube, and the produced racket has a certain probability of falling off when playing, generating noise, and forming a hidden danger of abnormal sound.

[0006] The common method for solving the above problem is to block one end of the middle tube close to the tubular preform by using a gluing process, which generally includes the following steps:

[0007] 1. The plug is generally made by plastic injection molding. The plug adopts a "T"-shaped layout, with the lower part of the "T"-shaped plug connected to the inner cavity of the middle tube, and the two ends of the upper part connected to the racket frame;

[0008] 2. Apply glue on the "T"-shaped plug and glue the plug to the middle tube and racket frame.

[0009] 3. Let it stand and wait for the glue to harden.

[0010] Although the gluing process is simple to operate, it also has some disadvantages. For example, since the main deformation location during racket processing is on the middle tube, the stiffness control of the middle tube is the key technical control point of the racket molding process. Generally, the stiffness of the middle tube is selected and marked, and the mark is placed on the front of the racket. However, with the gluing process, if an abnormality occurs after the bonding glue hardens, it is not easy to adjust the position of the middle tube, and the overall operational tolerance is low. In the subsequent epoxy resin hardening process, since the temperature in the mold is around 150°C, the bonding glue is prone to softening, resulting in poor gluing, and there is a risk of debonding and abnormal noise when the racket is in use. Summary of the invention

[0011] In order to solve the technical problems existing in the above-mentioned gluing process, the present invention provides a self-locking plug for a badminton racket and a method for manufacturing the badminton racket.

[0012] The technical solution provided by the present invention is as follows: a self-locking plug for a badminton racket, comprising a first connecting block and a second connecting block, wherein both ends of the first connecting block are connected to a racket frame preform, one end of the second connecting block is rotatably connected to the first connecting block, and a self-locking structure is provided on the other end of the second connecting block, and the self-locking structure is fixedly connected to a middle tube.

[0013] Furthermore, a connecting hole is arranged on the first connecting block, and a rotating block is arranged on the second connecting block, and the rotating block can rotate in the connecting hole.

[0014] Furthermore, the connecting hole includes a snap-in hole and a limiting hole, the snap-in hole is arranged above the limiting hole, the diameter of the snap-in hole is larger than the diameter of the limiting hole, the second connecting block includes a rotating block and an insert, the self-locking structure is arranged on the insert, the rotating block is arranged above the insert, the insert can pass through the snap-in hole and the limiting hole, drive the rotating block to abut against the connection between the snap-in hole and the limiting hole, and the rotating block can rotate in the snap-in hole.

[0015] Furthermore, the self-locking structure includes a protrusion and a side wing, the protrusion is arranged on the side wall of the insert, the side wing includes a free end and a fixed end, the free end is arranged on the outside of the protrusion and faces the rotating block, the fixed end is connected to the side wall of the insert, and when the free end is pressed against the insert, a bulging cavity is formed between the protrusion and the fixed end, and the insert and the cavity as a whole are interference fit with the middle tube.

[0016] Furthermore, the horizontal position of the free end of the wing is located between the horizontal positions of the protrusion and the rotating block.

[0017] Furthermore, the outer diameter of the joint between the free end of the wing and the insert is consistent with the diameter of the limiting hole.

[0018] Furthermore, the distance between the protrusion and the bottom of the rotating block is greater than the axial length of the limiting hole.

[0019] Furthermore, the axial length of the rotating block is consistent with the axial length of the clamping hole.

[0020] Furthermore, the diameter of the limiting hole is the same as the inner diameter of the middle tube.

[0021] The present invention provides a method for manufacturing a badminton racket, using the above-mentioned badminton racket self-locking plug, comprising the following steps:

[0022] S1. Make a preform of the frame with foam material, select the stiffness of the middle tube and mark it;

[0023] S2, the self-locking structures of the two connecting blocks are interference-fitted with the inner wall of the middle tube, and then the two ends of the first connecting block are inserted into the positions of the two ends of the racket frame preform to block the two ends of the racket frame preform;

[0024] S3. Adjust the position of the middle tube so that the mark is on the front side of the frame preform.

[0025] The advantages of the present invention are as follows: the combined structure can retain the ability of the middle tube to rotate around the central axis while realizing the self-locking function of the plug and the middle tube, so that the foaming material can be blocked to form a perfect enclosed space suitable for the subsequent expansion of the foaming material, and at the same time, the position of the middle tube can be adjusted conveniently, which is beneficial to the selection of the stiffness of the middle tube and improves the consistency of the hitting feel of the processed racket; the self-locking method between the plug and the middle tube does not require the use of adhesives, thereby avoiding the risk of abnormal noise caused by debonding at the connection between the middle tube and the plug of the processed racket. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic diagram of the structure of the first connection block;

[0027] Figure 2 is a schematic diagram of the structure of the second connection block;

[0028] Figure 3 It is a schematic diagram of the overall structure of the self-locking plug;

[0029] Figure 4 This is a schematic diagram of the self-locking plug in use. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The self-locking plug structure of the present invention is used in the processing of badminton rackets. It is an improvement on the drawbacks of the prior art when the racket frame preform and the middle tube are bonded by a bonding process. In particular, the main deformation position of the racket during the manufacturing process is on the middle tube, and the stiffness control of the middle tube is a key technical control point in the racket molding process.

[0032] Generally, the center tube is made of carbon fiber composite materials, and the reinforcement material used is a fiber-type material, which is a typical anisotropic material. Although R&D personnel in the industry will achieve consistency in batches of center tube products through the angle and number of layers of the fiber during design, in fact, there are still certain differences in the various positions of the processed center tube.

[0033] In order to ensure the consistency of the hitting feel of the produced rackets, the stiffness of the middle tube will be selected and marked during the racket manufacturing process, and the mark will be located exactly on the front of the racket. This selection of the middle tube can ensure that the actual hitting feel of the processed racket is more easily matched with the designed one. The existing gluing process cannot realize the rotation of the middle tube around the central axis. Especially in the mass production of rackets, the position of the middle tube cannot be adjusted due to the hardening of the glue, so that the mark is located exactly on the front of the racket, resulting in a low fault tolerance rate in the operation of selecting the stiffness of the middle tube. At the same time, the glue is prone to softening in subsequent processing, causing the risk of abnormal noise when the racket is used.

[0034] The self-locking plug of the present invention is a combined structure, including a first connecting block 1 and a second connecting block 2. Both ends of the first connecting block are connected to the racket frame preform, one end of the second connecting block 2 is rotatably connected to the first connecting block 1, and a self-locking structure is provided on the other end. The self-locking structure is fixedly connected to the middle tube 3, replacing the gluing and realizing that the middle tube can rotate around the racket frame preform.

[0035] like Figure 1 As shown, the first connecting block 1 is rod-shaped, and a radial snap-in hole 11 and a limiting hole 12 are integrally provided at the axial middle position of the rod body, which are used to cooperate with the second connecting block 2. The center positions of the two circles are located on the same vertical axis. The snap-in hole 11 is located above the limiting hole 12. The diameter of the snap-in hole 11 is larger than the diameter of the limiting hole 12, which is used to limit the downward sliding of the second connecting block 2 when cooperating with the second connecting block 2; the diameter of the limiting hole 12 is the same as the inner diameter of the middle tube 3, so that the second connecting block 2 can better cooperate with the middle tube 3 through the limiting hole 12.

[0036] like Figure 2 , 3 As shown, the second connecting block 2 is in the shape of a short rod as a whole, and includes a rotating block 21 and an insert 22; the rotating block 21 is located directly above the axial direction of the insert 22, and is integrally arranged with the insert 22. The axial length of the rotating block 21 is consistent with the axial length of the clamping hole 11, ensuring that the rotating block 21 does not protrude when cooperating with the clamping hole 11; the diameter of the rotating block 21 is smaller than the diameter of the clamping hole 11 and larger than the diameter of the limiting hole 12, so that the rotating block 21 can abut between the clamping hole 11 and the limiting hole 12, and a certain gap can be left between the rotating block 21 and the clamping hole 11, so as to realize the rotation of the rotating block 21 in the clamping hole 11; the outer diameter of the insert 22 is smaller than the diameter of the limiting hole 12, so as to better cooperate with the limiting hole 12 and the middle tube 3.

[0037] A self-locking structure is provided on the insert 22 to achieve interference fit between the self-locking structure and the middle tube 3 when it cooperates with the middle tube 3. The self-locking structure includes a protrusion 221 and a flank 222, the protrusion 221 is circumferentially arranged on one side close to the rotating block 21, and the flank 222 is sheet-shaped and symmetrically arranged.

[0038] The side wing 222 includes a fixed end and a free end. The fixed end is located on the side away from the rotating block 21 and is fixedly connected to the insert. The free end faces the rotating block 21 and has a certain elasticity. The free end is located on the outside of the protrusion 221, and the horizontal position is between the horizontal positions of the protrusion 221 and the rotating block 21, so as to ensure that the side wing 222 will not be tripped by the rotating block 21 when it approaches the insert 21; when force is applied along the free end in the direction of the insert 22, the outer diameter of the free end and the insert 22 at the joint is consistent with the diameter of the limiting hole 12, so as to ensure better cooperation with the limiting hole 12; and due to the existence of the protrusion 221, when the free end is close to the insert 22, a bulging cavity 223 is formed between the bottom of the protrusion 221 and the fixed end.

[0039] When the side wing 222 is unfolded, the outer diameter of the free end is larger than the diameter of the limiting hole 12, so as to ensure that when the top of the side wing 222 is pressed toward the insert 22 by the limiting hole 12, the maximum outer diameter of the insert 22 and the cavity 223 as a whole is larger than the inner diameter of the middle tube 3, so that the insert 22 can better form an interference fit when cooperating with the middle tube 3.

[0040] The distance between the protrusion 221 and the bottom of the rotating block 21 is greater than the axial length of the limiting hole 12, ensuring that when the insert 22 cooperates with the limiting hole 12, the protrusion 221 can pass through the limiting hole 12, so that the limiting hole 12 completely abuts the free end of the side wing 222 above the protrusion 221.

[0041] like Figure 3 , 4 As shown, when the self-locking plug is used, the first connecting block 1 and the second connecting block 2 must be matched. Before use, verification can be carried out first. The insert 22 passes through the clamping hole 11 and the limiting hole 12, driving the rotating block 21 to abut against the clamping hole 12 and allowing the second connecting block 2 to rotate around the first connecting block 2. When the rotating block 21 and the clamping hole 11 are abutted, the limiting hole 12 just presses the free end of the side wing 222 tightly on the upper part of the protrusion 221 to form a bulging cavity 223. If the overall outer diameter of the insert 22 and the cavity 223 is larger than the inner diameter of the middle tube 3, the verification is completed. After the verification is completed, the second connecting block 2 can be pulled out from the clamping hole 11.

[0042] When in use, firstly roll the carbon fiber composite material prepreg containing epoxy resin into a tubular racket frame preform, and place the foaming material in the middle of the racket frame preform, and the length of the preform is the same as the circumference of the racket; then take the first connecting block 1, make the limiting hole 111 fit on the top of the middle tube 3, and align the limiting hole 111 with the hollow part of the middle tube 3, and then take the second connecting block 2, and insert the insert 22 of the second connecting block 2 from the clamping hole 11 of the first connecting block 1, and the insert 22 and the cavity 223 as a whole form an interference fit with the hollow part of the middle tube 3, so as to achieve self-locking with the middle tube 3, and at the same time, the middle tube 3 together with the insert 22 can rotate around the first connecting block 1 on the central axis of the middle tube 3, so as to ensure the self-locking plug structure and the middle tube 3 are self-locking while retaining the ability of the middle tube 3 to rotate around the central axis.

[0043] Furthermore, the two ends of the first connecting block 1 are inserted into the positions of the two ends of the racket frame preform with foaming material. Since the rotating block 21 does not protrude when cooperating with the clamping hole 11, it can better block the two ends of the racket frame preform, which is beneficial to the foaming of the foaming material and the curing of the epoxy resin. By adjusting the position of the middle tube 3, the stiffness mark is located on the front of the racket frame preform.

[0044] Furthermore, the racket frame preform with the self-locking plug structure and the middle tube 3 are joined and positioned at the tee, and the tee is wrapped layer by layer with special prepreg cloth to ensure the structural strength after curing; the entire racket frame preform together with the joined middle tube is placed in the corresponding mold, pushed into the molding table, heated to 150±5℃, and the foaming and epoxy resin curing process is carried out. After 30 minutes, the mold is cooled to form a rough blank.

[0045] Finally, the surface of the rough blank is drilled and polished, the handle is assembled, and it is painted and decorated. A racket is produced by combining the back cover, handle leather, single nails and other ingredients.

[0046] An example with specific parameters is now provided to further illustrate the structure of the self-locking plug.

[0047] Example 1

[0048] The inner diameter of the middle tube 3 is 5.0 mm, the diameter of the limiting hole 12 is 5.0 mm, the diameter of the free ends of the side wings 222 on the insert 22 when unfolded is 5.4 mm, and the outer diameter of the free ends of the side wings 222 at the fitting point after being fitted with the insert 22 is 5.0 mm. The overall outer diameter of the insert 22 and the cavity 223 can reach 5.2 mm.

[0049] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A self-locking plug for a badminton racket, characterized in that: It comprises a first connecting block and a second connecting block, wherein the first connecting block is connected to the racket frame preform, one end of the second connecting block is rotatably connected to the first connecting block, and the other end of the second connecting block is provided with a self-locking structure, which is fixedly connected to the middle tube; The two ends of the first connecting block are used to insert the two ends of the racket frame preform with the foaming material, blocking the two ends of the racket frame preform, which is conducive to the foaming of the foaming material and the curing of the epoxy resin; A connecting hole is provided on the first connecting block, and a rotating block is provided on the second connecting block, and the rotating block can rotate in the connecting hole; the connecting hole includes a clamping hole and a limiting hole, the clamping hole is provided above the limiting hole, and the diameter of the clamping hole is larger than the diameter of the limiting hole; the second connecting block includes a rotating block and an insert, a self-locking structure is provided on the insert, and the rotating block is provided above the insert, and the insert can pass through the clamping hole and the limiting hole, driving the rotating block to abut against the connection between the clamping hole and the limiting hole, and the rotating block can rotate in the clamping hole; The self-locking structure includes a protrusion and a side wing. The protrusion is arranged on the side wall of the insert. The side wing includes a free end and a fixed end. The free end is arranged on the outside of the protrusion and faces the rotating block. The fixed end is connected to the side wall of the insert. When the free end is pressed against the insert, a bulging cavity is formed between the protrusion and the fixed end. The insert and the cavity as a whole have an interference fit with the middle tube, thereby realizing self-locking of the second connecting block and the middle tube. At the same time, the middle tube together with the insert can rotate circumferentially around the first connecting block on the central axis of the middle tube, thereby ensuring that the self-locking plug structure is self-locking with the middle tube while retaining the ability of the middle tube to rotate around the central axis.

2. The self-locking plug for badminton racket as claimed in claim 1, characterized in that: The horizontal position of the free end of the wing is located between the horizontal positions of the protrusion and the rotating block.

3. The self-locking plug for badminton racket as claimed in claim 1, characterized in that: The outer diameter of the joint between the free end of the wing and the insert is consistent with the diameter of the limiting hole.

4. The self-locking plug for badminton racket as claimed in claim 1, characterized in that: The distance between the protrusion and the bottom of the rotating block is greater than the axial length of the limiting hole.

5. The self-locking plug for badminton racket as claimed in claim 1, characterized in that: The axial length of the rotating block is consistent with the axial length of the clamping hole.

6. The self-locking plug for badminton racket according to any one of claims 2 to 5, characterized in that: The diameter of the limiting hole is the same as the inner diameter of the middle tube.

7. A method for manufacturing a badminton racket, using the badminton racket self-locking plug as claimed in any one of claims 1 to 6, characterized in that: The steps include: S1. Make a preform of the frame with foam material, select the stiffness of the middle tube and mark it; S2, the self-locking structure of the second connecting block is interference-fitted with the inner wall of the middle tube, and then the two ends of the first connecting block are inserted into the positions of the two ends of the racket frame preform to block the two ends of the racket frame preform; S3, by adjusting the position of the middle tube, the mark is located on the front side of the racket frame preform; S4, the racket frame preform with the self-locking plug structure and the middle tube are joined and positioned at the three-way joint, and the three-way joint is wrapped layer by layer with special prepreg cloth to ensure the structural strength after curing; the whole racket frame preform together with the joined middle tube is placed in the corresponding mold, pushed into the molding table, heated to perform the foaming and epoxy resin curing process, and the mold is cooled to form a rough blank; S5. Drill holes on the rough surface, polish it to make it smooth, assemble the handle, and paint it. Combine the back cover, handle leather, and single nail ingredients to produce a racket.

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