An impact-resistant wheel that is easy to replace and a scooter thereof

Abstract

The present invention provides an impact-resistant wheel and a scooter that are easy to replace, and relates to the technical field of wheels, including a wheel assembly, wherein the wheel assembly includes a first fixing frame, a bolt body is fixedly installed on the upper end of the first fixing frame, a second fixing frame is fixedly installed on the lower end of the first fixing frame, a mounting groove is provided at the lower end of the second fixing frame, and arc grooves are provided on the inner walls of the four sides of the mounting groove, and a third fixing frame is provided below the second fixing frame, and a user can rotate the bolt to leave the bolt frame, and at this time the fourth fixing frame can leave the mounting groove provided by the second fixing frame, and at this time the fourth fixing frame and the third fixing frame are completely disassembled as a whole; when the user only needs to replace two wheels, the user rotates and disassembles the two hexagonal nuts to replace the two wheels, and by designing the wheel assembly into a variety of disassembly and replacement methods, it is convenient for the user to quickly replace, and the replacement speed is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of wheels, and more specifically, particularly relates to an impact-resistant wheel which is easy to replace and a scooter thereof. Background Art

[0002] A scooter is a mobile tool for entertainment. Four wheels are arranged under the board body. The wheels are responsible for movement and also need to bear the weight of the user's body. The wheels of existing scooters have the following disadvantages:

[0003] When installing wheels on existing scooters, four threaded holes are opened on the skateboard, and four screws are needed to install the wheels on the scooter. However, this installation method not only has requirements on the installation order of the screws, but also has certain requirements on the fixing degree of the screws, which makes it very troublesome to disassemble and replace the wheels, and it is impossible to achieve the function of quick disassembly and replacement. In addition, since the wheel frame of the existing wheel has no impact-resistant structure, the wheel frame often breaks due to impact force when the wheel is running.

[0004] Therefore, in view of this, the existing structure and defects are studied and improved, and an impact-resistant wheel and a scooter that are easy to replace are provided, in order to achieve the purpose of having more practical value. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides an impact-resistant wheel that is easy to replace and a scooter thereof to solve the above problems.

[0006] A shock-resistant wheel that is easy to replace, includes a wheel assembly, wherein the wheel assembly includes a first fixing frame, a bolt body is fixedly installed on the upper end of the first fixing frame, a second fixing frame is fixedly installed on the lower end of the first fixing frame, a mounting groove is opened at the lower end of the second fixing frame, and arc grooves are opened on the inner walls of the four sides of the mounting groove, a third fixing frame is arranged below the second fixing frame, a rotating shaft is rotatably installed inside the third fixing frame, wheels are respectively installed at both ends of the rotating shaft, a fourth fixing frame is fixedly installed above the third fixing frame, sliding protrusions are slidably installed inside the four ends of the fourth fixing frame, the fourth fixing frame is installed in the mounting groove opened in the second fixing frame, and the end of each sliding protrusion is located in the arc groove, and bolts are installed between the third fixing frame, the fourth fixing frame and the second fixing frame.

[0007] Preferably, a U-shaped frame is fixedly installed on both ends of the first fixing frame, and each of the upper ends of the U-shaped frames is provided with a downward pressing groove, and a U-shaped block is movably installed inside each of the lower pressing grooves, and a first spring is fixedly installed between the lower end of each U-shaped block and the bottom of the lower pressing groove, and a connecting column is fixedly installed on the lower end of each U-shaped block, and each connecting column slides through the outside of the U-shaped frame, and the same connecting frame is fixedly installed under the two U-shaped blocks, and the middle part of the connecting frame is in a downwardly protruding state, and a cross groove is provided on the top of the second fixing frame, and the connecting frame is located in the cross groove, and a bolt frame is fixedly installed on the top of the mounting groove, and the end of the bolt is installed in the bolt frame by threading, and a rotating shaft sleeve and a reinforcement are fixedly installed on the left and right side walls of the third fixing frame, and the end of the reinforcement is close to the front side of the third fixing frame, and the end of the rotating shaft sleeve is close to the rear side of the third fixing frame.

[0008] Preferably, the rotating shaft sleeve is arranged in the third fixing frame and the two rotating shaft sleeves, the left and right ends of the rotating shaft are installed with hexagonal nuts, the two wheels are respectively installed between the two rotating shaft sleeves and the hexagonal nuts, each of the reinforcement members is in a V-shape, and one end of each reinforcement member is fixedly connected to the third fixing frame, the end of each reinforcement member not connected to the third fixing frame is located on the rotating shaft sleeve, and the entire section is fixedly connected to the rotating shaft sleeve, the four side walls of the fourth fixing frame are provided with an inner sliding groove, each of the sliding protrusions are installed in the inner sliding groove, and a second spring is fixedly installed between the side wall of each sliding protrusion and the side wall of the inner sliding groove, the top of the fourth fixing frame is provided with a rectangular groove, the upper and lower ends of the rectangular groove are penetrated with a second threaded groove, and the upper and lower ends of the third fixing frame are penetrated with a first threaded groove, when the fourth fixing frame is located inside the second fixing frame, the bolt frame is inserted into the rectangular groove, and the bolts penetrate the first threaded groove and the second threaded groove and are connected with the bolt frame.

[0009] A scooter comprises a skateboard body, wherein impact-resistant wheels are installed on the front and rear sides of the skateboard body, two thread grooves are penetrated through the upper and lower ends of the skateboard body, and U-shaped grooves are opened on the left and right sides of each thread groove, the two thread grooves are respectively close to the front and rear sides of the skateboard body, and each bolt body is installed in the thread groove by thread.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] In the present invention, by pulling the connecting frame downward, the connecting frame moves and drives the two U-shaped blocks to move downward and leave the U-shaped groove. At this time, the wheel assembly can be rotated, and the rotation of the wheel assembly drives the bolt body to rotate and leave the threaded groove provided in the skateboard body. At this time, the wheel assembly is completely disassembled and can be replaced; when the user does not need to replace the entire wheel assembly, the user can rotate the bolt to leave the bolt frame, and the fourth fixing frame can leave the installation groove provided in the second fixing frame. At this time, the fourth fixing frame and the third fixing frame are completely disassembled as a whole; when the user only needs to replace two wheels, the user rotates and removes the two hexagonal nuts to replace the two wheels. By designing the wheel assembly into a variety of disassembly and replacement methods, it is convenient for the user to quickly replace it, which greatly improves the replacement speed.

[0012] In the present invention, the first spring drives the two U-shaped blocks into the downward pressure groove through elastic force. At this time, the first fixing frame, the bolt body, the threaded groove and the downward pressure groove are fixed. By arranging U-shaped frames and U-shaped blocks on both sides of the first fixing frame, when the bolt body is disassembled, the U-shaped blocks need to be pulled away from the downward pressure groove, thereby ensuring the stability of the connection between the first fixing frame and the skateboard body, and the two U-shaped blocks can prevent the bolt body from rotating when the skateboard body is in use, effectively improving the stability of the bolt body connection, and improving the stability of the wheel assembly when it is impacted.

[0013] In the present invention, when the fourth fixing frame is installed into the second fixing frame, the fourth fixing frame is located in the installation groove, and the ends of the four sliding protrusions are all located in the arc groove opened in the installation groove. Since each sliding protrusion can slide in the inner sliding groove, and each sliding protrusion is supported by the elastic force of the second spring, fourth fixing frames of different sizes can be installed in the second fixing frame, and the end of each sliding protrusion is against the arc groove, so the stability of each fourth fixing frame can be maintained, and the fourth fixing frame can be effectively prevented from rotating in the installation groove when the wheel assembly is subjected to impact force, thereby greatly improving the stability and impact resistance of the fourth fixing frame.

[0014] In the present invention, the second fixing frame and the third fixing frame are designed to be independently detachable as a whole. After removing the two hexagonal nuts, the rotating shaft can be removed from the third fixing frame and the two rotating shaft sleeves, so that a single component can be easily replaced, further improving the convenience of replacement.

[0015] In the present invention, a reinforcing member is used between the third fixing frame and the rotating shaft sleeve for secondary support. The reinforcing member is V-shaped, which can improve the supporting force of the rotating shaft sleeve, and the reinforcing member semi-surrounds the outer wall of the rotating shaft sleeve, thereby further improving the impact resistance of the rotating shaft sleeve and effectively improving the impact resistance of the entire wheel assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1It is a schematic diagram of the structure of the skateboard body of the present invention;

[0017] Figure 2 It is a schematic diagram of the structure of the first fixing frame of the present invention;

[0018] Figure 3 It is a schematic diagram of the thread groove structure of the present invention;

[0019] Figure 4 It is a schematic diagram of the structure of the wheel assembly of the present invention;

[0020] Figure 5 It is a schematic diagram of the bolt body structure of the present invention;

[0021] Figure 6 It is a schematic diagram of the U-shaped block structure of the present invention;

[0022] Figure 7 is a schematic diagram of the structure of the third fixing frame of the present invention;

[0023] Figure 8 is a schematic diagram of the structure of a fourth fixing frame of the present invention;

[0024] Fig. 9 It is a schematic diagram of the reinforcement structure of the present invention.

[0025] In the figure, the correspondence between the component names and the figure numbers is: 1. skateboard body; 12. threaded groove; 13. U-shaped groove; 2. first fixing frame; 21. bolt body; 22. U-shaped frame; 23. downward pressure groove; 24. first spring; 25. U-shaped block; 26. connecting frame; 27. cross groove; 28. connecting column; 3. second fixing frame; 31. mounting groove; 32. arc groove; 33. bolt frame; 34. bolt; 35. third fixing frame; 36. first threaded groove; 37. reinforcement; 38. shaft sleeve; 39. shaft; 4. fourth fixing frame; 41. rectangular groove; 42. second threaded groove; 43. inner slide groove; 44. sliding protrusion; 45. second spring; 46. hexagonal nut; 47. wheel; 5. wheel assembly. DETAILED DESCRIPTION

[0026] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0027] See also Figure 1-Figure 9The present invention provides an impact-resistant wheel that is easy to replace, including a wheel assembly 5, wherein the wheel assembly 5 includes a first fixing frame 2, a bolt body 21 is fixedly installed on the upper end of the first fixing frame 2, a second fixing frame 3 is fixedly installed on the lower end of the first fixing frame 2, a mounting groove 31 is provided at the lower end of the second fixing frame 3, and arc grooves 32 are provided on the inner walls of the four sides of the mounting groove 31, a third fixing frame 35 is provided below the second fixing frame 3, a rotating shaft 39 is rotatably installed inside the third fixing frame 35, wheels 47 are respectively installed at both ends of the rotating shaft 39, and a fourth fixing frame 4 is fixedly installed above the third fixing frame 35, and the wheel assembly 5 rotates to drive the bolt body 21 to rotate away from the threaded groove 12 provided on the skateboard body 1, and the wheel assembly 5 is completely disassembled as a whole. The fourth fixing frame 4 and the third fixing frame 35 are integrally disassembled and can be replaced; when the user does not need to replace the entire wheel assembly 5, the user can rotate the bolt 34 to leave the bolt frame 33, and the fourth fixing frame 4 can leave the mounting groove 31 opened in the second fixing frame 3. At this time, the fourth fixing frame 4 and the third fixing frame 35 are disassembled as a whole; when the user only needs to replace two wheels 47, the user rotates and removes the two hexagonal nuts 46 to replace the two wheels 47. Sliding protrusions 44 are slidably installed inside the four ends of the fourth fixing frame 4, and the fourth fixing frame 4 is installed in the mounting groove 31 opened in the second fixing frame 3, and the end of each sliding protrusion 44 is located in the arc groove 32. Bolts 34 are installed between the third fixing frame 35, the fourth fixing frame 4 and the second fixing frame 3.

[0028] A U-shaped frame 22 is fixedly installed on both ends of the left and right sides of the first fixed frame 2, and a downward pressing groove 23 is opened at the upper end of each U-shaped frame 22, and a U-shaped block 25 is movably installed inside each downward pressing groove 23, and a first spring 24 is fixedly installed between the lower end of each U-shaped block 25 and the bottom of the downward pressing groove 23, and a connecting column 28 is fixedly installed at the lower end of each U-shaped block 25, and each connecting column 28 slides through the outside of the U-shaped frame 22, and the same connecting frame 26 is fixedly installed below the two U-shaped blocks 25, and the middle part of the connecting frame 26 is in a downward protruding state. As the bolt body 21 rotates, the U-shaped blocks 25 on both sides of the first fixed frame 2 gradually contact the bottom of the skateboard body 1, and the first fixed frame 2 continues to rotate, and the two U-shaped blocks 25 are forced to move downward into the downward pressing groove. The two first springs 24 are squeezed in the groove 23 at the same time. When the two U-shaped blocks 25 are facing the two downward pressing grooves 23, the first spring 24 drives the two U-shaped blocks 25 into the downward pressing groove 23 through elastic force. At this time, the first fixing frame 2, the bolt body 21, the threaded groove 12 and the downward pressing groove 23 are fixed. A cross groove 27 is opened on the top of the second fixing frame 3, and the connecting frame 26 is located in the cross groove 27. A bolt frame 33 is fixedly installed on the top of the mounting groove 31. The end of the bolt 34 is installed in the bolt frame 33 through threads. The left and right side walls of the third fixing frame 35 are fixedly installed with a rotating shaft sleeve 38 and a reinforcement member 37. The end of the reinforcement member 37 is close to the front side of the third fixing frame 35, and the end of the rotating shaft sleeve 38 is close to the rear side of the third fixing frame 35.

[0029] The rotating shaft 39 is rotatably sleeved in the third fixing frame 35 and the two rotating shaft sleeves 38. The left and right ends of the rotating shaft 39 are installed with hexagonal nuts 46. The two wheels 47 are respectively installed between the two rotating shaft sleeves 38 and the hexagonal nuts 46. The shape of each reinforcement 37 is V-shaped, and one end of each reinforcement 37 is fixedly connected to the third fixing frame 35. The end of each reinforcement 37 that is not connected to the third fixing frame 35 is located on the rotating shaft sleeve 38, and the entire section is fixedly connected to the rotating shaft sleeve 38. The four side walls of the fourth fixing frame 4 are provided with inner slide grooves 43, and each sliding protrusion 44 is installed in the inner slide groove 43, and the ends of the four sliding protrusions 44 are located in the arc groove 32 opened in the installation groove 31. Since each sliding protrusion 44 can slide in the inner slide groove 43, and each sliding protrusion 44 Supported by the elastic force of the second spring 45, the fourth fixing frame 4 of different sizes can be installed in the second fixing frame 3, and the end of each sliding protrusion 44 is against the arc groove 32, which can maintain the stability of each fourth fixing frame 4, and effectively prevent the wheel assembly 5 from being subjected to impact force. A second spring 45 is fixedly installed between the side wall of each sliding protrusion 44 and the side wall of the inner sliding groove 43, and a rectangular groove 41 is provided on the top of the fourth fixing frame 4, and a second thread groove 42 is penetrated through the upper and lower ends of the rectangular groove 41, and a first thread groove 36 is penetrated through the upper and lower ends of the third fixing frame 35. When the fourth fixing frame 4 is located inside the second fixing frame 3, the bolt frame 33 is inserted into the rectangular groove 41, and the bolt 34 penetrates the first thread groove 36 and the second thread groove 42 to be connected with the bolt frame 33.

[0030] A scooter includes a skateboard body 1, and the front and rear sides of the skateboard body 1 are both equipped with impact-resistant wheels as described above. Two thread grooves 12 are penetrated through the upper and lower ends of the skateboard body 1, and each thread groove 12 is provided with a U-shaped groove 13 on the left and right sides. The two thread grooves 12 are respectively close to the front and rear sides of the skateboard body 1, each bolt body 21 is installed in the thread groove 12 through a thread, and each U-shaped block 25 is located in the U-shaped groove 13.

[0031] Working principle:

[0032] In the first step, when the user replaces the wheel assembly 5, the user inserts a finger into the cross groove 27 provided in the second fixing frame 3, inserts a finger into the groove of the connecting frame 26, pulls the connecting frame 26 downward, and the connecting frame 26 moves to drive the two U-shaped blocks 25 to move downward and leave the U-shaped groove 13. At this time, the wheel assembly 5 can be rotated, and the rotation of the wheel assembly 5 drives the bolt body 21 to rotate and leave the threaded groove 12 provided in the skateboard body 1. At this time, the wheel assembly 5 is completely disassembled and can be replaced; when the user does not need to replace the entire wheel assembly 5, the user can rotate the bolt 34 to leave the bolt frame 33, and the fourth fixing frame 4 can leave the installation groove 31 provided in the second fixing frame 3. At this time, the fourth fixing frame 4 and the third fixing frame 35 are completely disassembled as a whole; when the user only needs to replace two wheels 47, the user rotates and removes the two hexagonal nuts 46, and the two wheels 47 can be replaced. By designing the wheel assembly 5 into a variety of disassembly and replacement methods, it is convenient for the user to quickly replace it, which greatly improves the speed of replacement.

[0033] In the second step, when the user installs the bolt body 21, the user inserts the bolt body 21 into the threaded groove 12 and rotates it. The rotation of the bolt body 21 drives the first fixing frame 2 to rotate. As the bolt body 21 rotates, the U-shaped blocks 25 on both sides of the first fixing frame 2 gradually contact the bottom of the skateboard body 1. The first fixing frame 2 continues to rotate, and the two U-shaped blocks 25 are forced to move downward into the lower pressing groove 23, while squeezing the two first springs 24. When the two U-shaped blocks 25 are facing the two lower pressing grooves 23, the first springs 24 drive the two U-shaped blocks 25 into the lower pressing grooves 23 through elastic force. At this time, the first fixing frame 2, the bolt body 21, the threaded groove 12, and the lower pressing groove 23 are fixed. By arranging U-shaped frames 22 and U-shaped blocks 25 on both sides of the first fixing frame 2, when the bolt body 21 is disassembled, the U-shaped blocks 25 need to be pulled away from the lower pressing groove 23, so that the stability of the connection between the first fixing frame 2 and the skateboard body 1 can be ensured, and the two U-shaped blocks 25 can prevent the bolt body 21 from rotating when the skateboard body 1 is in use, effectively improving the stability of the bolt body 21 connection, and improving the stability of the wheel assembly 5 when it is impacted;

[0034] When the fourth fixing frame 4 is installed in the second fixing frame 3, the fourth fixing frame 4 is located in the installation groove 31, and the ends of the four sliding protrusions 44 are located in the arc groove 32 opened in the installation groove 31. Since each sliding protrusion 44 can slide in the inner slide groove 43, and each sliding protrusion 44 is supported by the elastic force of the second spring 45, fourth fixing frames 4 of different sizes can be installed in the second fixing frame 3, and the end of each sliding protrusion 44 is against the arc groove 32, so that the stability of each fourth fixing frame 4 can be maintained, and the fourth fixing frame 4 can be effectively prevented from rotating in the installation groove 31 when the wheel assembly 5 is subjected to impact force, which greatly improves the stability and impact resistance of the fourth fixing frame 4.

[0035] The second fixing frame 3 and the third fixing frame 35 are designed to be independently detachable. After removing the two hexagonal nuts 46, the rotating shaft 39 can be removed from the third fixing frame 35 and the two rotating shaft sleeves 38, so that the replacement of a single component can be convenient, further improving the convenience of replacement;

[0036] A reinforcing member 37 is used between the third fixing frame 35 and the rotating shaft sleeve 38 for secondary support. The reinforcing member 37 is V-shaped, which can improve the supporting force of the rotating shaft sleeve 38, and the reinforcing member 37 semi-surrounds the outer wall of the rotating shaft sleeve 38, thereby further improving the impact resistance of the rotating shaft sleeve 38, and effectively improving the impact resistance of the overall wheel assembly 5.

[0037] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. An impact-resistant wheel that is easy to replace, comprising a wheel assembly (5), characterized in that: The wheel assembly (5) comprises a first fixing frame (2), a bolt body (21) is fixedly mounted on the upper end of the first fixing frame (2), a second fixing frame (3) is fixedly mounted on the lower end of the first fixing frame (2), a mounting groove (31) is provided at the lower end of the second fixing frame (3), arc grooves (32) are provided on the inner walls of four sides of the mounting groove (31), a third fixing frame (35) is arranged below the second fixing frame (3), a rotating shaft (39) is rotatably mounted inside the third fixing frame (35), and wheels (47) are respectively mounted at both ends of the rotating shaft (39); A fourth fixing frame (4) is fixedly mounted above the third fixing frame (35), and sliding protrusions (44) are slidably mounted inside the four ends of the fourth fixing frame (4), and the fourth fixing frame (4) is mounted in a mounting groove (31) provided in the second fixing frame (3), and the end of each sliding protrusion (44) is located in the arc groove (32), and bolts (34) are installed between the third fixing frame (35), the fourth fixing frame (4) and the second fixing frame (3), and U-shaped frames (22) are fixedly mounted on both left and right ends of the first fixing frame (2), and a lower pressing groove (23) is provided at the upper end of each of the U-shaped frames (22), and a U-shaped block (22) is movably mounted inside each of the lower pressing grooves (23). 5), a first spring (24) is fixedly installed between the lower end of each U-shaped block (25) and the bottom of the lower pressure groove (23), a connecting column (28) is fixedly installed at the lower end of each U-shaped block (25), and each connecting column (28) slides through the outside of the U-shaped frame (22), a same connecting frame (26) is fixedly installed below the two U-shaped blocks (25), and the middle part of the connecting frame (26) is in a downwardly protruding state, a cross groove (27) is opened at the top of the second fixing frame (3), and the connecting frame (26) is located in the cross groove (27), a bolt frame (33) is fixedly installed at the top of the installation groove (31), and the end of the bolt (34) is installed in the bolt frame (33) through a thread.

2. An easily replaceable impact-resistant wheel as claimed in claim 1, characterized in that: A rotating shaft sleeve (38) and a reinforcing member (37) are fixedly mounted on both left and right side walls of the third fixing frame (35), an end of the reinforcing member (37) being close to the front side of the third fixing frame (35), and an end of the rotating shaft sleeve (38) being close to the rear side of the third fixing frame (35).

3. An easily replaceable impact-resistant wheel as claimed in claim 2, characterized in that: The rotating shaft (39) is rotatably sleeved in the third fixing frame (35) and the two rotating shaft sleeves (38), and hexagonal nuts (46) are installed at both left and right ends of the rotating shaft (39), and the two wheels (47) are respectively installed between the two rotating shaft sleeves (38) and the hexagonal nuts (46).

4. An easily replaceable impact-resistant wheel as claimed in claim 3, characterized in that: Each of the reinforcing members (37) is V-shaped, and one end of each reinforcing member (37) is fixedly connected to the third fixing frame (35), and one end of each reinforcing member (37) not connected to the third fixing frame (35) is located on the rotating shaft sleeve (38), and the entire section is fixedly connected to the rotating shaft sleeve (38).

5. The easily replaceable impact-resistant wheel according to claim 1, characterized in that: The four side walls of the fourth fixing frame (4) are each provided with an inner slide groove (43), each of the sliding protrusions (44) is installed in the inner slide groove (43), and a second spring (45) is fixedly installed between the side wall of each sliding protrusion (44) and the side wall of the inner slide groove (43).

6. The easily replaceable impact-resistant wheel according to claim 1, characterized in that: A rectangular groove (41) is formed at the top of the fourth fixing frame (4), and a second thread groove (42) is formed through the upper and lower ends of the rectangular groove (41). A first thread groove (36) is formed through the upper and lower ends of the third fixing frame (35). When the fourth fixing frame (4) is located inside the second fixing frame (3), the bolt frame (33) is inserted into the rectangular groove (41), and the bolt (34) passes through the first thread groove (36), the second thread groove (42) and is connected to the bolt frame (33).

7. A scooter, comprising a scooter body (1), characterized in that: The front and rear sides of the skateboard body (1) are both installed with impact-resistant wheels according to any one of claims 1 to 6, and two thread grooves (12) are provided through the upper and lower ends of the skateboard body (1), and each thread groove (12) is provided with a U-shaped groove (13) on the left and right sides, and the two thread grooves (12) are respectively close to the front and rear sides of the skateboard body (1), and each bolt body (21) is installed in the thread groove (12) by means of threads.

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