Table tennis practice device base, table tennis practice device and manufacturing method thereof

Abstract

The table tennis practice device base provided by the application comprises a plastic base plate, a metal weight plate and a glue layer, the plastic base plate is in the shape of an inverted disc and comprises a circular support plate and an annular enclosing plate, the metal weight plate is coaxial with the circular support plate and is arranged in the cavity, the metal weight plate is bonded to the circular support plate by the glue layer and is not exposed, the safety is good, no groove needs to be formed on the upper surface of the circular support plate, the structure is simple and the sense of high grade is strong; the table tennis practice device comprises a table tennis ball, an elastic soft shaft, a base and a locking bolt, the upper end of the elastic soft shaft is inserted into the table tennis ball, the lower end is fixed to the base by the locking bolt, the base is any one of the table tennis practice device bases, the metal weight plate is not exposed, and the safety is better; the manufacturing method of the table tennis practice device is simple and convenient for manufacturing the base, connecting the elastic soft shaft and fixing the table tennis ball, is suitable for mass production and can be well matched with online sales.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sports goods, in particular to a table tennis practice device base, a table tennis practice device and a manufacturing method thereof. BACKGROUND

[0002] Table tennis is a sport that can be enjoyed by people of all ages and can be widely used for exercise by people of different ages. However, it is difficult for a single person to practice table tennis because two people are required to play on a table tennis table, and it is sometimes difficult to find a suitable partner for practice. Therefore, a table tennis practice device has been developed for single person practice.

[0003] To solve this problem, a table tennis practice device for single person practice has appeared on the market. For example, Chinese patent CN217794400U discloses such a table tennis practice device. The table tennis practice device includes a table tennis ball, an elastic soft shaft, and a base. The base is provided with a groove for setting a counterweight. Since the counterweight is mostly made of metal and the upper surface of the counterweight is the appearance surface of the base, the counterweight is actually exposed. In the event of accidental impact on the metal block, the training personnel will be seriously injured, and there is a safety hazard. The setting of the groove also makes the structure of the base more complex, and the sense of high-grade is not good. In addition, the connection between the elastic soft shaft and the table tennis ball of the table tennis practice device is a clamping connection, which only relies on friction to fix the table tennis ball. When the hitting force is large, the table tennis ball is easily separated from the elastic soft shaft and flies out. The end of the elastic soft shaft without the table tennis ball has sharp corners, which can easily scratch the training personnel, and there is a large safety hazard. The table tennis practice device also involves components such as a fixing piece, a limiting tube, and a support rod. During assembly, the steps are many and the operation is complex, which is not suitable for mass production. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a table tennis practice device base with good safety, simple structure, and strong sense of high-grade, a table tennis practice device with better safety, and a manufacturing method of a table tennis practice device suitable for mass production.

[0005] To achieve the above-mentioned purpose, the product in the technical solution provided by the present application is a table tennis practice device base, which includes:

[0006] The plastic base disc is in the shape of an inverted disc. The plastic base disc includes a circular support plate and an annular surrounding plate extending downward and outward from the periphery of the circular support plate. An inner wall of the annular surrounding plate and a lower surface of the circular support plate form a cavity therebetween.

[0007] The metal counterweight plate extends in the horizontal direction. The projection of the metal counterweight plate in the vertical direction is circular.

[0008] The metal weight plate is arranged in the cavity and coaxial with the circular support plate, the upper surface of the metal weight plate and / or the lower surface of the circular support plate is provided with a sticky layer, and the metal weight plate is bonded to the circular support plate through the sticky layer.

[0009] The table tennis trainer base further comprises a through hole penetrating through the center of the metal weight plate, the center of the sticky layer and the center of the circular support plate.

[0010] Preferably, the side wall of the metal weight plate is fitted and pressed against the inner wall of the annular enclosure.

[0011] Further preferably, the lower surface of the circular support plate is provided with a coaxial and downwardly protruding round cake boss, so that the outer wall of the round cake boss, the upper surface of the metal weight plate, the inner wall of the annular enclosure and the lower surface of the circular support plate form an annular cavity.

[0012] Further preferably, the sticky layer covers the lower surface of the round cake boss, or the sticky layer is composed of at least two double-sided adhesive tapes, which are symmetrically distributed on both sides of the axial line of the round cake boss.

[0013] Further preferably, the height of the round cake boss is 1 to 2 times the thickness of the circular support plate.

[0014] Further preferably, the height of the round cake boss is equal to the thickness of the metal weight plate and the sticky layer.

[0015] Preferably, the plastic base further comprises a skirt connected to the lower end of the enclosure and extending horizontally in all directions, and the width of the skirt is not less than 2mm.

[0016] Preferably, the plastic base is a PPC plastic base, and the metal weight plate is a stainless steel plate.

[0017] To achieve the above-mentioned purpose, the product in the technical scheme provided by the application is a table tennis trainer, which comprises a table tennis ball, an elastic soft shaft, a base and a locking bolt, the upper end of the elastic soft shaft is inserted into the table tennis ball, the lower end of the elastic soft shaft is fixed to the base through the locking bolt, the base is any one of the table tennis trainer bases described above, the center of the lower end surface of the elastic soft shaft is provided with an upwardly extending threaded blind hole, the head of the locking bolt abuts against the lower surface of the metal weight plate, the shank of the locking bolt penetrates through the through hole and extends into the threaded blind hole and is threadedly connected with the threaded blind hole, and the lower end of the elastic soft shaft is coaxially fixed to the upper surface of the circular support plate.

[0018] Preferably, the outer diameter of the elastic soft shaft gradually increases from top to bottom.

[0019] Further preferably, the elastic soft shaft is sleeved with an upper glue sleeve and a lower glue sleeve for connecting the table tennis ball, the upper glue sleeve is inserted into the table tennis ball following the upper end of the elastic soft shaft, the upper end and the middle part of the upper glue sleeve are bonded with the elastic soft shaft, the lower end of the upper glue sleeve is outwardly flared and abuts against the inner wall of the table tennis ball, and the lower glue sleeve is located outside the table tennis ball, the upper end of the lower glue sleeve abuts against and is bonded with the outer wall of the table tennis ball.

[0020] Further preferably, the upper end of the upper glue sleeve is sealed to completely wrap the upper end of the elastic soft shaft.

[0021] Further preferably, the lower end of the lower glue sleeve is bonded with the elastic soft shaft.

[0022] Further preferably, the upper end of the lower glue sleeve is an umbrella-shaped part flared upward and outward, and the inner wall of the umbrella-shaped part abuts against and is bonded with the outer wall of the table tennis ball.

[0023] To achieve the above object, the method in the technical scheme provided by the application is a manufacturing method of the table tennis ball trainer, comprising the following steps:

[0024] S1. A double-sided tape is pasted on the lower surface of the round cake boss, and then the metal weight plate is moved into the cavity from bottom to top and abuts against the inner wall of the annular fence and the lower surface of the round cake boss, so that the metal weight plate is coaxially bonded with the round cake boss;

[0025] S2. The lower end of the elastic soft shaft is placed at the center of the circular support plate, so that the threaded blind hole is aligned with the through hole;

[0026] S3. An elastic washer and a round washer are sequentially sleeved on the screw rod of the locking bolt, then the screw rod is passed through the through hole and screwed into the threaded blind hole and tightened, so that the screw head of the locking bolt abuts against the lower surface of the metal weight plate;

[0027] S4. The lower glue sleeve and the upper glue sleeve are sequentially sleeved on the upper end of the elastic soft shaft;

[0028] When the lower glue sleeve is sleeved, the distance between the lower glue sleeve and the upper end of the elastic soft shaft is 1.5 to 2 times the length of the upper glue sleeve;

[0029] When the upper glue sleeve is sleeved, the lower end of the upper glue sleeve is first folded outward, then glue is applied to the inner wall of the upper end and the middle part of the upper glue sleeve, and then the upper glue sleeve is sleeved on the upper end of the elastic soft shaft, and after being sleeved in place, the lower end of the upper glue sleeve is folded back;

[0030] S5. After the upper end and the middle part of the rubber sleeve are bonded with the elastic soft shaft, the upper end of the elastic soft shaft is inserted into the through hole of the bottom of the table tennis ball, so that the rubber sleeve is completely extruded into the table tennis ball;

[0031] S6. The table tennis ball is held, and the elastic soft shaft is pulled downward by a distance equal to the length of the outwardly folded lower end of the rubber sleeve, so that the lower end of the rubber sleeve abuts against the inner wall of the table tennis ball;

[0032] S7. The lower rubber sleeve is moved upward, and when the distance between the lower rubber sleeve and the table tennis ball is 0.5-1.0 cm, the movement is stopped, and glue is injected into the umbrella-shaped part of the lower rubber sleeve, and the lower end of the lower rubber sleeve is pinched during the injection of glue;

[0033] S8. The lower rubber sleeve is continuously moved upward, and the movement is stopped when the umbrella-shaped part completely abuts against the outer wall of the table tennis ball;

[0034] S9. The glue overflowed from the umbrella-shaped part and the lower end of the lower rubber sleeve is wiped, and the table tennis ball trainer is obtained after the bonding between the umbrella-shaped part and the outer wall of the table tennis ball and the bonding between the lower end of the lower rubber sleeve and the elastic soft shaft are completed.

[0035] Preferably, the elastic soft shaft is rotated while being pulled downward in step S6, so that the lower end of the rubber sleeve is opened outward.

[0036] Thanks to the above technical solution, the present application has the following advantages compared with the prior art:

[0037] The table tennis ball trainer base provided by the present application comprises a plastic base plate, a metal counterweight plate and a glue layer. The plastic base plate is in the shape of an inverted disc and comprises a circular support plate and an annular enclosing plate. The metal counterweight plate is coaxial with the circular support plate and is arranged in the cavity. The metal counterweight plate is bonded to the circular support plate by the glue layer and is not exposed. The safety is good, and the structure is simple and has a strong sense of seniority.

[0038] The table tennis ball trainer provided by the present application comprises a table tennis ball, an elastic soft shaft, a base and a locking bolt. The upper end of the elastic soft shaft is inserted into the table tennis ball, and the lower end is fixed to the base by the locking bolt. The base is any one of the table tennis ball trainer bases described above. The metal counterweight plate is not exposed, and the safety is better.

[0039] The manufacturing method of the table tennis ball trainer provided by the present application is simple and convenient for manufacturing the base, connecting the elastic soft shaft and fixing the table tennis ball, and is suitable for mass production and online sales. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1is the front view schematic diagram of the preferred embodiment of the table tennis practice device in the application.

[0041] Figure 2 is Figure 1 the top view schematic diagram.

[0042] Figure 3 is Figure 2 the sectional view schematic diagram of A-A direction in the application.

[0043] Figure 4 is Figure 3 the local enlarged schematic diagram of B in the application.

[0044] Figure 5 is Figure 3 the local enlarged schematic diagram of C in the application.

[0045] Figure 6 is Figure 3 the local enlarged schematic diagram of D in the application.

[0046] Figure 7 is Figure 3 the state diagram after glue injection of the lower glue sleeve umbrella-shaped part.

[0047] Wherein: 10. Table tennis; 20. Elastic soft shaft; 21. Threaded blind hole; 22. Upper glue sleeve; 23. Lower glue sleeve; 231. Umbrella-shaped part; 24. First glue liquid solidification layer; 25. Second glue liquid solidification layer; 26. Glue liquid; 30. Base; 31. Plastic bottom disc; 311. Circular support plate; 312. Annular fence; 313. Cavity; 314. Round cake boss; 315. Skirt; 32. Metal counterweight plate; 33. Adhesive layer; 34. Through hole; 40. Locking bolt; 41. Screw head; 42. Screw rod; 43. Elastic gasket; 44. Round gasket. DETAILED DESCRIPTION

[0048] The preferred embodiment of the application will be described in detail below with reference to the accompanying drawings.

[0049] As Figures 1 to 7 shown, the table tennis practice device provided by the application includes table tennis 10, elastic soft shaft 20, base 30 and locking bolt 40. The elastic soft shaft 20 extends in the up-down direction, the upper end thereof is inserted into the table tennis 10, and the lower end thereof is fixed on the base 30 through the locking bolt 40.

[0050] The base 30 is a table tennis practice device base, which comprises a plastic base disc 31 and a metal weight plate 32. The plastic base disc 31 is in the shape of an inverted disc, and comprises a circular support plate 311 and an annular surrounding plate 312 extending downward and outward from the periphery of the circular support plate 311. A cavity 313 is formed between the inner wall of the annular surrounding plate 312 and the lower surface of the circular support plate 311. The metal weight plate 32 is a stainless steel plate, which extends in the horizontal direction and has a circular projection in the vertical direction. The metal weight plate 32 is arranged in the cavity 313 coaxially with the circular support plate 311, and the side wall of the metal weight plate 32 is tightly fitted with the inner wall of the annular surrounding plate 312. The lower surface of the circular support plate 311 is provided with an adhesive layer 33, and the metal weight plate 32 is bonded to the circular support plate 311 through the adhesive layer 33. Specifically, the lower surface of the circular support plate 311 is provided with a circular cake boss 314 coaxially and protruding downward, and the adhesive layer 33 covers the lower surface of the circular cake boss 314. In another embodiment, the adhesive layer 33 is composed of at least two double-sided adhesive tapes, which are symmetrically distributed on both sides of the axis of the circular cake boss 314. The base 30 further comprises a through hole 34 penetrating through the center of the metal weight plate 32, the center of the adhesive layer 33, and the center of the circular support plate 311. The metal weight plate 32 of the base 30 is not exposed, which is safe and does not need to open a groove on the upper surface of the circular support plate 311, so that the structure is simpler, and the overall flat structure is easy to color display and not easy to dazzle under light irradiation, so that the base 30 has a stronger senior feel.

[0051] In this embodiment, the height of the circular cake boss 314 is equal to the thickness of the metal weight plate 32 and the adhesive layer 33. Specifically, the height of the circular cake boss 314 is 3 mm, the thickness of the circular support plate 311 is 2 mm, and the height of the circular cake boss 314 is 1.5 times the thickness of the circular support plate 311. To improve the stability of the base 30, the plastic base disc 31 further comprises a skirt 315 connected to the lower end of the annular surrounding plate 312 and extending horizontally in all directions. The width of the skirt 315 is 2.5 mm, and the thickness of the skirt 315 is equal to the thickness of the annular surrounding plate 312, which is equal to the thickness of the circular support plate 311.

[0052] In this embodiment, the plastic base disc 31 is a PPC plastic base disc, the outer diameter of the circular support plate 311 is 170-175 mm, the inclination angle between the annular surrounding plate 312 and the vertical direction is less than 3°, preferably 1.5° to 2°, and the height of the annular surrounding plate 312 is slightly larger than the width of an adult's thumb, preferably 10 mm to 15 mm. In this embodiment, the height is 13 mm.

[0053] In this embodiment, the lower end face of the elastic flexible shaft 20 is provided with an upwardly extending threaded blind hole 21. The screw head 41 of the locking bolt 40 abuts against the lower surface of the metal counterweight plate 32. The screw 42 of the locking bolt 40 passes through the through hole 34 and extends into the threaded blind hole 21 to be threadedly connected with the threaded blind hole 21, thereby coaxially fixing the lower end of the elastic flexible shaft 20 to the upper surface of the circular support plate 311. Due to the presence of the disc boss 314, the compressive strength of the circular support plate 311 is enhanced. When tightening the locking bolt 40, it is not easy to crush the circular support plate 311. At the same time, the outer wall of the disc boss 314, the upper surface of the metal counterweight plate 32, the inner wall of the annular surrounding plate 312, and the lower surface of the circular support plate 311 can form an annular cavity.

[0054] The advantage of this design is that it prevents the metal counterweight plate from being exposed. At the same time, because the metal counterweight plate is located inside the cavity, the center of gravity of the base is lower, thus improving the safety and stability of the table tennis training device during use.

[0055] To facilitate the connection between the flexible shaft 20 and the ping-pong ball 10, in this embodiment, the outer diameter of the flexible shaft 20 gradually increases from top to bottom. Furthermore, an upper rubber sleeve 22 and a lower rubber sleeve 23 for connecting the ping-pong ball 10 are fitted onto the flexible shaft 20. The upper rubber sleeve 22 is inserted into the ping-pong ball 10 following the upper end of the flexible shaft 20. The inner wall of the upper end and middle of the upper rubber sleeve 22 is bonded to the outer wall of the flexible shaft 20. Figure 4 The first adhesive curing layer 24), the lower end of the upper rubber sleeve 22 opens outward and abuts against the inner wall of the ping-pong ball 10, the upper end of the upper rubber sleeve 22 is sealed to completely cover the upper end of the elastic flexible shaft 20 so that it is not exposed, the lower rubber sleeve 23 is located outside the ping-pong ball 10, the upper end of the lower rubber sleeve 23 abuts against and is bonded to the outer wall of the ping-pong ball 10 ( Figure 4 The second adhesive curing layer 25, specifically, the upper end of the lower rubber sleeve 23 is an umbrella-shaped part 231 that opens upward and outward, and the inner wall of the umbrella-shaped part 231 abuts against and adheres to the outer wall of the ping-pong ball 10. Figure 4 The inner wall of the lower end of the lower adhesive sleeve 23 is bonded to the outer wall of the elastic flexible shaft 20.

[0056] The advantage of this design is that the ping-pong ball 10 can be fixed by the contact between the lower end of the upper rubber sleeve 22 and the inner wall of the ping-pong ball 10, and the adhesion between the umbrella-shaped part 231 and the outer wall of the ping-pong ball 10. Combined with the adhesion between the upper end and middle of the upper rubber sleeve 22 and the elastic flexible shaft 20, and the adhesion between the lower end of the lower rubber sleeve 23 and the elastic flexible shaft 20, the ping-pong ball 10 can be better supported. When subjected to greater hitting force, the ping-pong ball 10 is less likely to detach from the elastic flexible shaft 20. Even if it does detach accidentally, since the upper rubber sleeve 22 completely covers the upper end of the elastic flexible shaft 20, the sharp edges of the upper end of the elastic flexible shaft 20 are not exposed, and it is less likely to cause scratches to the trainee, thus improving safety.

[0057] The application also provides a manufacturing method of the table tennis practice device, comprising the following steps:

[0058] S1. Paste double-sided tape on the lower surface of the round cake boss 314, and then move the metal weight plate 32 into the cavity 313 from bottom to top and tightly abut against the inner wall of the ring-shaped surrounding plate 312 and the lower surface of the round cake boss 314, so that the metal weight plate 32 is coaxially bonded with the round cake boss 314;

[0059] S2. Place the lower end of the elastic soft shaft 20 at the center of the circular support plate 311, so that the threaded blind hole 21 is aligned with the through hole 34;

[0060] S3. Set the elastic gasket 43 and the round gasket 44 on the screw rod 42 of the locking bolt 40 in sequence, then pass the screw rod 42 through the through hole 34 and screw into the threaded blind hole 21 and tighten, so that the screw head 41 of the locking bolt 40 tightly abuts against the lower surface of the metal weight plate 32;

[0061] S4. Set the lower glue sleeve 23 and the upper glue sleeve 22 on the upper end of the elastic soft shaft 20 in sequence;

[0062] When setting the lower glue sleeve 23, the distance between the lower glue sleeve 23 and the upper end of the elastic soft shaft 20 is 1.5-2 times the length of the upper glue sleeve 22, so as to facilitate subsequent operation;

[0063] When setting the upper glue sleeve 22, first fold the lower end of the upper glue sleeve 22 outward, then apply glue on the inner wall of the upper end and the middle part of the upper glue sleeve 22, and then set the upper glue sleeve 22 on the upper end of the elastic soft shaft 20, and after setting in place, fold the lower end of the upper glue sleeve 22 back, so as to avoid the lower end of the upper glue sleeve 22 being glued, and ensure that the lower end of the upper glue sleeve 22 can be outwardly opened to abut;

[0064] S5. After the upper end and the middle part of the upper glue sleeve 22 are bonded with the elastic soft shaft 20, insert the upper end of the elastic soft shaft 20 into the through hole at the bottom of the table tennis ball 10, so that the upper glue sleeve 22 is completely squeezed into the table tennis ball 10;

[0065] S6. Hold the table tennis ball 10, and pull out the elastic soft shaft 20 downward by a distance equal to the outward folding length of the lower end of the upper glue sleeve 22, so that the lower end of the upper glue sleeve 22 abuts against the inner wall of the table tennis ball 10;

[0066] S7. Move the lower glue sleeve 23 upward, stop moving when the distance between the lower glue sleeve 23 and the table tennis ball 10 is 0.5-1.0 cm (convenient for glue injection), and inject glue into the umbrella-shaped part 231 of the lower glue sleeve 23, and when injecting glue, pinch the lower end of the lower glue sleeve 23 to avoid glue leakage;

[0067] S8. Continue to move the lower rubber sleeve 23 upward, since the outer diameter of the elastic flexible shaft 20 gradually increases from top to bottom, the more upwardly it is moved, the easier the gap between the inner wall of the lower rubber sleeve 23 and the outer wall of the elastic flexible shaft 20 is generated, thus, in the process of moving upwardly, the glue liquid contained in the umbrella-shaped part 231 can automatically flow into the gap to automatically realize the glue coating operation on the inner wall of the lower end of the lower rubber sleeve 23, and after the umbrella-shaped part 231 is completely contacted with the outer wall of the table tennis ball 10, the moving is stopped;

[0068] S9. Wipe the glue liquid overflowing from the umbrella-shaped part 231 and the lower end of the lower rubber sleeve 23, and after the umbrella-shaped part 231 and the lower end of the lower rubber sleeve 23 are completely bonded with the elastic flexible shaft 20, the table tennis ball trainer is obtained.

[0069] The method is simple and convenient to operate, suitable for mass production, and can be well matched with online sales.

[0070] Preferably, when the elastic flexible shaft 20 is pulled downwardly in step S6, the elastic flexible shaft 20 is rotated while being pulled, so as to as far as possible make the lower end of the upper rubber sleeve 22 completely open outwardly, and improve the contacting effect between the lower end of the upper rubber sleeve 22 and the inner wall of the table tennis ball 10.

[0071] The above embodiments are only for illustrating the technical concept and characteristics of the present application, the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application, any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A table tennis practice device, comprising a table tennis ball, a base, a locking bolt, and a flexible shaft with an upper end inserted into the table tennis ball and a lower end fixed to the base by the locking bolt, the base comprising a plastic base disc in the shape of an inverted saucer, a metal weight plate extending in the horizontal direction, the plastic base disc comprising a circular support plate and an annular wall extending downward and outward from the periphery of the circular support plate, and a skirt connected to the lower end of the annular wall and extending horizontally in all directions, a cavity being formed between the inner wall of the annular wall and the lower surface of the circular support plate, the projection of the metal weight plate in the vertical direction being circular, the metal weight plate being coaxial with the circular support plate and located in the cavity, the upper surface of the metal weight plate and / or the lower surface of the circular support plate being provided with an adhesive layer, and the metal weight plate being bonded to the circular support plate by the adhesive layer. Characterized in that: the metal weight plate is a stainless steel plate, the side wall of which is in close contact with the inner wall of the annular wall and is pressed tightly against it, and the lower surface of the circular support plate is provided with a coaxial and downwardly protruding round cake boss; the outer diameter of the flexible shaft gradually increases from top to bottom, and the center of the lower end surface is provided with a threaded blind hole extending upward, the head of the locking bolt abuts against the lower surface of the metal weight plate, the shank of the locking bolt passes through the through hole passing through the center of the metal weight plate, the center of the adhesive layer, and the center of the circular support plate, and extends into the threaded blind hole and is screwed therein to coaxially fix the lower end of the flexible shaft to the upper surface of the circular support plate; an upper rubber sleeve and a lower rubber sleeve for connecting the table tennis ball are sleeved on the flexible shaft, the upper rubber sleeve is inserted into the table tennis ball along with the upper end of the flexible shaft, the upper end of the upper rubber sleeve is sealed, the upper end and the middle part of the upper rubber sleeve are bonded to the flexible shaft, the lower end of the upper rubber sleeve is outwardly flared and abuts against the inner wall of the table tennis ball, and the lower rubber sleeve is located outside the table tennis ball, the upper end of the lower rubber sleeve abuts against and is bonded to the outer wall of the table tennis ball.

2. The table tennis practice device of claim 1, wherein: The adhesive layer covers the lower surface of the round cake boss, or the adhesive layer is composed of at least two double-sided adhesive tapes, which are symmetrically distributed on both sides of the axial line of the round cake boss.

3. The table tennis practice device of claim 1, wherein: The height of the round cake boss is 1 to 2 times the thickness of the circular support plate.

4. The table tennis practice device of claim 1, wherein: The height of the round cake boss is equal to the sum of the thicknesses of the metal weight plate and the adhesive layer.

5. The table tennis practice device of claim 1, wherein: The width of the skirt is not less than 2 mm.

6. The table tennis practice device of claim 1, wherein: The plastic base disc is a PPC plastic base disc.

7. The table tennis practice device of claim 1, wherein: The lower end of the lower rubber sleeve is bonded to the flexible shaft.

8. The table tennis practice device of claim 1, wherein: The upper end of the lower rubber sleeve is an umbrella-shaped part flared upward and outward, and the inner wall of the umbrella-shaped part abuts against and is bonded to the outer wall of the table tennis ball.

9. A method of manufacturing the table tennis practice device of claim 8, wherein, The method comprises the following steps: S1. Paste double-sided adhesive tape on the lower surface of the round cake boss, and then move the metal weight plate into the cavity from bottom to top and abut against the inner wall of the annular wall and the lower surface of the round cake boss, so that the metal weight plate is coaxially bonded to the round cake boss; S2. Place the lower end of the flexible shaft at the center of the circular support plate, so that the threaded blind hole is aligned with the through hole; S3. Successively sleeve an elastic gasket and a round gasket on the shank of the locking bolt, then pass the shank through the through hole and screw it into the threaded blind hole and tighten it, so that the head of the locking bolt abuts against the lower surface of the metal weight plate. S4. The lower rubber sleeve and the upper rubber sleeve are sequentially sleeved on the upper end of the elastic soft shaft; when sleeving the lower rubber sleeve, the distance between the lower rubber sleeve and the upper end of the elastic soft shaft is 1.5 to 2 times the length of the upper rubber sleeve; when sleeving the upper rubber sleeve, the lower end of the upper rubber sleeve is first folded outward, then glue is applied to the inner walls of the upper end and the middle part of the upper rubber sleeve, and then the upper rubber sleeve is sleeved on the upper end of the elastic soft shaft, after being sleeved in place, the lower end of the upper rubber sleeve is folded back; S5. After the upper end and the middle part of the upper rubber sleeve are bonded with the elastic soft shaft, the upper end of the elastic soft shaft is inserted into the through hole at the bottom of the ping pong ball, so that the upper rubber sleeve is completely squeezed into the ping pong ball; S6. Hold the ping pong ball and pull the elastic soft shaft downward by a distance equal to the length of the lower end of the upper rubber sleeve folded outward, so that the lower end of the upper rubber sleeve abuts against the inner wall of the ping pong ball; S7. Move the lower rubber sleeve upward, stop moving when the distance between the lower rubber sleeve and the ping pong ball is 0.5-1.0 cm, and inject glue into the umbrella-shaped part of the lower rubber sleeve, while pinching the lower end of the lower rubber sleeve when injecting glue; S8. Continue to move the lower rubber sleeve upward, and stop moving when the umbrella-shaped part abuts against the outer wall of the ping pong ball; S9. Wipe the glue overflowed from the umbrella-shaped part and the lower end of the lower rubber sleeve, and obtain the ping pong ball trainer after the umbrella-shaped part and the ping pong ball outer wall and the lower end of the lower rubber sleeve and the elastic soft shaft are bonded.

10. The method of manufacturing according to claim 9, wherein: When pulling the elastic soft shaft downward in step S6, the elastic soft shaft is rotated while being pulled, so that the lower end of the upper rubber sleeve is unfolded outward.

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