Method for manufacturing a kettlebell

Abstract

The present invention discloses a method for manufacturing a kettlebell, comprising the following steps: S1, placing an injection molding material in an injection mold, which molds the injection molding material into a hard handle; S2, placing the handle in an upper mold of a rotational molding mold, such that the outer surface of the handle is in contact with the inner wall of the upper mold, and the outer periphery of the handle is lower than the inner wall of the upper mold; S3, placing the rotationally molded raw material in a lower mold, and connecting the lower mold to the upper mold; S4, rotating the upper mold and the lower mold along a base, heating the upper mold and the lower mold, melting the rotationally molded raw material and forming a kettle body; S5, separating the upper mold and the lower mold, and removing the formed kettlebell. The kettlebell manufactured by the present invention is strong, not easily damaged, and has a long service life.

Description

Technical Field

[0001] The present invention relates to the technical field of fitness equipment, and in particular to a method for manufacturing a kettlebell. Background Art

[0002] Kettlebells are a common piece of fitness equipment. Basic kettlebell exercises include kettlebell swings, two-arm kettlebell rows, kettlebell goblet squats, single-arm kettlebell floor presses, and kettlebell deadlifts. Kettlebell exercises can effectively strengthen upper limb, trunk, and lower limb muscles, as well as enhance endurance, balance, and flexibility. Kettlebells are suitable for both men and women.

[0003] Traditional kettlebells are made of cast iron and come in weights of 10 kg, 15 kg, 20 kg, 25 kg, 30 kg, and 50 kg. Kettlebells can be used for various exercises, including pushing, lifting, throwing, and squat jumps. Unlike dumbbells or barbells, kettlebell training is more effective at improving overall explosive power, making it a long-standing favorite among fighters and martial artists.

[0004] Common kettlebells have larger handles, making it easier for users to apply force during exercise. These can replace dumbbells. Newer kettlebells have larger bodies filled with water, allowing users to strike them with their hands or feet, effectively strengthening their upper and lower limbs. These new kettlebells can also replace sandbags.

[0005] The prior art discloses kettlebells made using molds. These molds typically consist of left and right molds. After demolding, a parting line remains along the axial direction of the kettlebell's body. During use, the kettlebells experience significant movement during exercise, and over time, the parting line can crack and become damaged. This can cause water within the kettlebell to leak out of the damaged parting line, rendering the entire kettlebell useless. Consequently, these conventional kettlebells lack strength and have a short service life. In light of this, the inventors conducted in-depth research addressing the aforementioned deficiencies in the prior art, leading to the present invention. Summary of the Invention

[0006] The present invention aims to solve at least one of the above-mentioned technical problems to a certain extent. To this end, the present invention is to provide a method for manufacturing a kettlebell, so that the kettlebell is strong, not easily damaged, and has a long service life.

[0007] To achieve the above objectives, an embodiment of the present invention provides a method for manufacturing a kettlebell, comprising the following steps:

[0008] S1, placing the injection molding material in the injection mold, and the injection mold injects the injection molding material into a hard handle;

[0009] S2, placing the handle in the upper mold of the rotational mold so that the outer skin of the handle fits against the inner wall of the upper mold and the outer periphery of the handle is lower than the inner wall of the upper mold;

[0010] S3, placing the rotationally molded material in the lower mold and connecting the lower mold with the upper mold;

[0011] S4, the upper mold and the lower mold rotate along the base, the upper mold and the lower mold are heated, the rotational molding material melts and forms the pot body;

[0012] S5, separate the upper mold and the lower mold, and take out the formed kettlebell.

[0013] Furthermore, in step S1, the injection mold injects the injection material into a handle having an inlet, and the inlet is blocked before the upper mold and the lower mold are closed.

[0014] Furthermore, before the upper mold and the lower mold are closed, a plug is inserted into the inlet of the handle to block it.

[0015] Furthermore, in step S1 , the manufactured handle has a handle portion and a connecting portion, and the handle portion has a through hole.

[0016] Furthermore, the rotational molding mold includes a lower mold, an upper mold and a base frame; a mold cavity for placing the rotational molding raw material is formed in the lower mold, the upper mold and the lower mold are detachable, a receiving groove is formed in the upper mold, the receiving groove includes an inner side wall, the inner side wall includes a fitting portion for fitting the outer skin of the handle and a non-contact portion that does not contact the handle, and the upper mold or the lower mold can be rotatably set on the base frame.

[0017] Furthermore, a first interface is provided at the end of the lower mold, and a second interface connected to the first interface is formed at the end of the upper mold.

[0018] Furthermore, the inner side wall includes a first inner side wall and a second inner side wall that are arranged opposite to each other. A first limiting protrusion for limiting one side of the handle is formed on the first inner side wall, and a second limiting protrusion for limiting the other side of the handle is formed on the second inner side wall.

[0019] Furthermore, a first through hole communicating with the outside is provided on the first limiting protrusion, and a second through hole communicating with the outside is provided on the second limiting protrusion, and the axial center line of the second through hole coincides with the axial center line of the first through hole.

[0020] Furthermore, a driving mechanism for driving the upper mold or the lower mold to rotate is provided on the base frame.

[0021] The present invention relates to a method for manufacturing a kettlebell, which has at least the following beneficial effects:

[0022] First, when making a kettlebell, the injection molding material is first placed in the injection mold. The mold then molds the injection molding material into a hard handle. The hard handle has great strength, making it less likely to deform when the kettlebell is lifted off the support surface. The handle is then placed in the upper mold of the rotational mold, so that the outer surface of the handle fits against the inner wall of the upper mold, and the outer edge of the handle is lower than the inner wall of the upper mold. This ensures that during rotational molding, the parting line is offset from the connection between the handle and the kettle body, and the parting line is circumferential. This ensures the overall strength of the kettlebell is high and its service life is long.

[0023] Second, the injection molding material is injected into a handle with an inlet through an injection mold, so that after the kettlebell is made, water can pass through the inlet into the kettle body for easy use.

[0024] Compared with the prior art, the present invention provides a handle and a kettle body, and the hard handle and the soft kettle body are manufactured separately. The soft kettle body is formed at the connection part of the hard handle during production, and the connection position between the kettle body and the handle is staggered at the closing position of the rotational molding mold. The kettlebell manufactured has high overall strength and a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of a kettlebell made by a kettlebell rotational molding mold according to an embodiment of the present invention;

[0026] Figure 2 Schematic diagram of the structure of the lower mold of the kettlebell rotational molding mold according to an embodiment of the present invention;

[0027] Figure 3 Schematic diagram of the structure of the upper mold of the kettlebell rotational molding mold according to an embodiment of the present invention;

[0028] Figure 4 Schematic diagram of the connection between the upper mold and the handle according to an embodiment of the present invention;

[0029] Figure 5 A schematic structural diagram of an upper mold according to an embodiment of the present invention;

[0030] Figure 6 is a schematic structural diagram of a kettlebell handle according to an embodiment of the present invention;

[0031] Figure 7 Schematic diagram of the connection between the upper mold, the handle and the lower mold according to an embodiment of the present invention;

[0032] Figure 8 Schematic diagram of the structure of the upper mold, handle and lower mold according to an embodiment of the present invention;

[0033] Figure 9 Schematic diagram of the structure of a kettlebell made by a kettlebell rotational molding mold according to an embodiment of the present invention;

[0034] Figure 10 2 is a schematic structural diagram of a kettlebell made from another kettlebell rotational molding mold according to an embodiment of the present invention;

[0035] Figure 11 is an exploded view of another kettlebell rotational molding mold according to an embodiment of the present invention;

[0036] Figure 12 Schematic diagram of the structure of a handle of another kettlebell rotational molding mold according to an embodiment of the present invention.

[0037] Label Description

[0038] Handle 1, inlet 11, plug 12, handle 13, connecting part 14, through hole 15, curved surface 16, pot body 2, rotational molding mold 3, lower mold 31, mold cavity 311, first interface 312, upper mold 32, accommodating groove 321, inner side wall 322, first inner side wall 3221, second inner side wall 3222, first limiting protrusion 3223, first limiting surface 32231, first abutting surface 32232, first arcuate transition surface 32233, second limiting protrusion 3224, second limiting surface 32241, second abutting surface 32242, second arcuate transition surface 32243, first through-hole 3225, second through-hole 3226, fitting part 323, non-contact part 324, second interface 325, base frame 33, parting line 4, connector 5, connecting groove 6. DETAILED DESCRIPTION

[0039] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0040] like Figures 1 to 12 As shown, a method for manufacturing a kettlebell according to an embodiment of the present invention includes the following steps:

[0041] S1, placing an injection molding material in an injection mold, and the injection mold injects the injection molding material into a hard handle 1. The handle 1 is a hard, solid handle 1. The hard handle 1 has great strength, so that the hard handle 1 is not easily deformed when the kettlebell is separated from the support surface.

[0042] S2: Place the handle 1 within the upper mold 32 of the rotational mold 3, ensuring that the outer surface of the handle 1 is in contact with the inner wall 322 of the upper mold 32, and that the outer periphery of the handle 1 is lower than the inner wall 322 of the upper mold 32. After the rotational mold 3 is completed and the kettle body 2 is removed from the mold, a parting line 4 remains. Because the outer periphery of the handle 1 is lower than the inner wall 322 of the upper mold 32, the parting line 4 is offset from the connection between the handle 1 and the kettle body 2. This parting line 4 is circumferential, enhancing the overall strength and longevity of the kettlebell.

[0043] S3, the rotationally molded raw material is placed in the lower mold 31, and the lower mold 31 is connected to the upper mold 32. Among them, the upper mold 32 can be provided with a connector 5, and the lower mold 31 can be provided with a connecting groove 6, and the connecting groove 6 is for the connector 5 to be inserted to connect the upper mold 32 and the lower mold 31. After connection, there is no gap after the inner side wall 3221 of the upper mold 32 is connected to the inner wall of the lower mold 31, so that the mold line 4 is difficult to be seen on the outer surface of the finished pot body 2, and the overall strength is high.

[0044] In step S4, the upper mold 32 and the lower mold 31 rotate along the base, heating the upper mold 32 and the lower mold 31, melting the rotationally molded material and forming the pot body 2. A common heating device can be used to heat the rotating upper mold 32 and the lower mold 31. A driving mechanism can be provided on the base frame 33 to drive the upper mold 32 and the lower mold 31 to rotate along the base. The driving mechanism can be a motor driving a gear, which in turn drives a rack. The driving mechanism is conventional technology and will not be described in detail here.

[0045] S5, the upper mold 32 is separated from the lower mold 31, and the formed kettlebell is taken out. It can be cooled first, and then the kettlebell body 2 is taken out. Since the kettlebell body 2 is a soft kettlebell body 2, the soft kettlebell body 2 is deformed during removal, making it easier to take out.

[0046] When making a kettlebell, the injection molding material is first placed in the injection mold, which then molds the injection molding material into a hard handle 1. The hard handle 1 has great strength, making it less likely to deform when the kettlebell is separated from the supporting surface. The handle 1 is then placed in the upper mold 32 of the rotational mold 3, so that the outer surface of the handle 1 is in contact with the inner wall 322 of the upper mold 32, and the outer periphery of the handle 1 is lower than the inner wall 322 of the upper mold 32. During rotational molding, the parting line 4 is offset from the connection between the handle 1 and the kettle body 2, and the parting line 4 is circumferential. This ensures that the kettlebell has high overall strength and a long service life.

[0047] When making kettlebells, Figure 8As shown, a hard handle 1 is placed in the receiving groove 321 so that the handle 1 is tightly attached to the inner wall 322 of the upper mold 32, wherein the depth of the inner wall 322 of the upper mold 32 is defined as L1, and the depth of the handle 1 is defined as L2. In this example, the depth L1 of the inner wall 322 of the upper mold 32 is greater than the depth L2 of the handle 1. Since the depth L1 of the inner wall 322 of the upper mold 32 is greater than the depth L2 of the handle 1, the connection position of the manufactured kettlebell handle 1 and the kettle body 2 is staggered at the clamping position of the upper mold 32 and the lower mold 31, making the overall strength of the kettlebell greater, less prone to damage, and having a long service life. After the clamping position of the upper mold 32 and the lower mold 31 is separated, a clamping line 4 is formed on the kettle body 2 corresponding to the clamping position.

[0048] Optionally, in step S1, the injection mold injects the injection molding material into the handle 1 having the inlet 11, and the inlet 11 is blocked before the upper mold 32 and the lower mold 31 are closed. The injection molding material is injected into the handle 1 having the inlet 11 by the injection mold, so that after the kettlebell is manufactured, water can enter the kettle body 2 through the inlet 11, making it easy to use.

[0049] Among them, before the upper mold 32 and the lower mold 31 are molded together, the plug 12 is inserted into the inlet 11 of the handle 1 to block it. By inserting the plug 12 into the inlet 11 of the handle 1, the plastic material can be effectively prevented from entering the inlet 11 during rotational molding, and the plastic material can be prevented from blocking the inlet 11. The end of the plug 12 protrudes from the arc surface 16 and protrudes from the kettle body 2 after being manufactured, so that an inlet connected to the inlet 11 is formed on the kettle body 2, so that after demoulding, the plug 12 can be squeezed out, and the kettlebell manufactured can allow water to enter the kettle body 2 through the inlet 11 and the inlet, which is convenient for use. When the end of the plug 12 is covered by the plastic material, a sharp object can be used to open it so that the plug 12 is squeezed into the kettle body 2 to facilitate water inlet.

[0050] In addition, a limit head can be directly formed on the upper mold 32 to replace the plug 12. When the handle 1 is placed in the upper mold 32, the inlet 11 on the handle 1 is just inserted by the limit head, so that when demolding, it can be directly demolded without squeezing out the plug 12.

[0051] In step S1, the manufactured handle 1 has a handle portion 13 and a connecting portion 14, and the handle portion 13 has a through hole 15. A limiting rod can be used to sequentially insert into the first through hole 3225, the through hole 15 of the handle 1, and the second through hole 3226, so that the handle 1 fits tightly against the first inner side wall 3221 and the second inner side wall 3222, preventing the handle 1 from separating from the upper mold 32 when the upper mold 32 rotates. At the same time, force can be applied to the through hole 15 to lift the kettlebell for exercise, and the kettlebell can also be hung through the through hole 15 to facilitate hitting the kettlebell body 2 to exercise limb strength. Because the outer periphery of the handle 1 is lower than the inner side wall 322 of the upper mold 32, the connection position of the kettlebell handle 1 and the kettlebell body 2 is staggered at the mold closing position of the upper mold 32 and the lower mold 31, and the overall strength of the kettlebell is high and the service life is long.

[0052] The connecting portion 14 is concave toward the handle 13 to form a curved surface 16. This curved surface 16 increases the contact area between the connecting portion 14 of the kettle body 2 and the handle 1, providing a more secure and strong connection and making the kettle body 2 and handle 1 difficult to separate. Furthermore, the curved surface 16 facilitates the flow of melted plastic into the groove formed by the curved surface 16, thus facilitating rapid molding of the kettle body 2.

[0053] The thickness of the connecting portion 14 gradually decreases from the direction closer to the handle 13 to the direction farther away from the handle 13. The arc surface 16 intersects with the outer surface of the handle 1, and the intersection line is located on the circumference of a circle. Therefore, during rotational molding, the melted rotational plastic can flow directly into the arc surface 16 along the intersection line, making the overall thickness of the formed pot body 2 more uniform and improving the overall strength of the pot body 2. If the arc surface 16 does not directly intersect with the outer surface of the handle 1, that is, the arc surface 16 is connected to the side end surface of the handle 1, during rotational molding, more material is formed at the connection between the arc surface 16 and the side end surface of the handle 1, resulting in an uneven thickness of the overall pot body 2 and insufficient overall strength of the pot body 2.

[0054] The kettlebell body 2, formed by the rotational molding mold 3, is a soft kettlebell body 2. After the kettlebell body 2 is filled with water, the hard curved surface 16 strengthens the connection between the handle 1 and the soft kettlebell body 2. Compared to a flat surface, the curved surface 16 of the handle 1 allows for a larger area of ​​connection with the kettlebell body 2, thereby increasing the overall strength of the kettlebell, making it less prone to cracking and extending its service life.

[0055] In this example, the rotational molding mold 3 includes a lower mold 31, an upper mold 32 and a base frame 33; a mold cavity 311 for placing the rotational molding raw material is formed in the lower mold 31, the upper mold 32 and the lower mold 31 are detachable, and a receiving groove 321 is formed in the upper mold 32, and the receiving groove 321 includes an inner wall 322, and the inner wall 322 includes a fitting portion 323 for fitting the outer skin of the handle 1 and a non-contact portion 324 that does not contact the handle 1, and the upper mold 32 or the lower mold 31 can be rotatably set on the base frame 33.

[0056] During use, the already injection-molded hard handle 1 can be placed in the upper mold 32 so that the hard handle 1 fits snugly against the fitting portion 323 of the inner side wall 322 of the upper mold 32. The rotationally molded raw material can then be placed in the mold cavity 311 of the lower mold 31 so that the upper mold 32 is connected to the lower mold 31. Finally, the upper mold 32 and the lower mold 31 are rotated along the base 33, and the upper mold 32 and the lower mold 31 can be heated so that the raw material in the mold cavity 311 melts and rotates to form the kettle body 2. Since the inner side wall 322 includes a fitting portion 323 for fitting against the outer skin of the handle 1 and a non-contact portion 324 that does not contact the handle 1, the connection position between the manufactured kettlebell handle 1 and the kettle body 2 is staggered from the closing position of the upper mold 32 and the lower mold 31, making the overall strength of the kettlebell greater, less prone to damage, and having a longer service life.

[0057] In some examples, a first interface 312 is provided at the end of the lower mold 31, and a second interface 325 is formed at the end of the upper mold 32 to connect to the first interface 312. The rotationally molded material is placed in the mold cavity 311 of the lower mold 31 through the first interface 312. The first interface 312 is connected to the second interface 325 to connect the upper mold 32 to the lower mold 31.

[0058] As an example, the inner sidewall 322 includes a first inner sidewall 3221 and a second inner sidewall 3222 disposed opposite each other. The first inner sidewall 3221 is formed with a first limiting protrusion 3223 for limiting one side of the handle 1, and the second inner sidewall 3222 is formed with a second limiting protrusion 3224 for limiting the other side of the handle 1. After the handle 1 is placed on the upper mold 32, during the rotation of the upper mold 32, the first limiting protrusion 3223 limits one side of the handle 1, while the second limiting protrusion 3224 limits the other side of the handle 1. This allows the upper mold 32 to rotate synchronously with the handle 1, effectively preventing the handle 1 from separating from the upper mold 32.

[0059] Furthermore, the first limiting protrusion 3223 is provided with a first through-hole 3225 communicating with the outside world, and the second limiting protrusion 3224 is provided with a second through-hole 3226 communicating with the outside world. The axial centerline of the second through-hole 3226 coincides with the axial centerline of the first through-hole 3225. After the handle 1 is placed in the upper mold 32, a limiting rod can be sequentially inserted through the first through-hole 3225, the through-hole 15 of the handle 1, and the second through-hole 3226 to ensure that the handle 1 is tightly attached to the first inner sidewall 3221 and the second inner sidewall 3222, preventing the handle 1 from separating from the upper mold 32 when the upper mold 32 is rotated.

[0060] The second limiting protrusion 3224 includes a second limiting surface 32241, a second abutting surface 32242 and a second arcuate transition surface 32243. The first limiting protrusion 3223 includes a first limiting surface 32231, a first abutting surface 32232 and a first arcuate transition surface 32233. The first limiting surface 32231 limits one side of the handle 13, and the second limiting surface 32241 limits the other side of the handle 13. One side of the connecting portion 14 partially abuts against the first abutting surface 32232. The other side of the connecting portion 14 rests on the second resting surface 32242, and the connecting position of the connecting portion 14 and the handle 13 rests on the first arc-shaped transition surface 32233 and the second arc-shaped transition surface 32243. The first limiting protrusion 3223 and the second limiting protrusion 3224 can effectively match the shape of the handle 1, so that the handle 1 fits tightly on the first inner side wall 3221 and the second inner side wall 3222, preventing the melted rolling plastic from entering the outer skin of the handle 1 during rotational molding.

[0061] Preferably, a driving mechanism is provided on the base frame 33 to drive the upper mold 32 or the lower mold 31 to rotate. This facilitates the rotation of the upper mold 32 or the lower mold 31 and facilitates heating of the upper mold 32 and the lower mold 31. The driving mechanism can be a conventional device, for example, a motor drives a gear to rotate to drive the upper mold 32 or the lower mold 31 to rotate.

[0062] When used, the kettlebell manufactured by this method can apply force to the through-hole 15 of the handle 1 to separate the kettlebell from the support surface. Since the handle 1 is a hard handle 1 made by an injection mold, it is strong and is less likely to deform during the process of the kettlebell being separated from the support surface. The kettlebell body 2 is a soft kettlebell body 2. When not in use, the soft kettlebell body 2 can be folded for easy carrying. The kettlebell is compact and lightweight. When in use, water can be poured into the kettlebell body 2 for ease of use. Since the kettlebell body 2 is formed at the connection portion 14 of the handle 1 by a rotational mold 3, i.e., the handle 1 and the kettlebell body 2 are manufactured separately, the handle 1 is relatively hard and the kettlebell body 2 is relatively soft. The connection between the kettlebell body 2 and the handle 1 is offset from the closing position of the rotational mold 3, i.e., the connection between the kettlebell body 2 and the handle 1 is different from the separation position between the upper mold 32 and the lower mold 31 of the rotational mold 3. This makes the kettlebell body 2 less likely to crack along the connection between the kettlebell body 2 and the handle 1, resulting in high overall strength and a long service life.

[0063] Compared with the prior art, the present invention provides a handle 1 and a kettle body 2, and the hard handle 1 and the soft kettle body 2 are manufactured separately. The soft kettle body 2 is formed at the connecting portion 14 of the hard handle 1 during manufacturing. The connection position between the kettle body 2 and the handle 1 is staggered at the closing position of the rotational molding mold 3. The manufactured kettlebell has high overall strength and a long service life.

[0064] As an example, Figures 1 to 9As shown, the kettlebell is a new kettlebell that can be hung through the through hole 15 for the user to hit, thereby exercising the user's limb strength. As another embodiment, Figures 10 to 12 As shown, the kettlebell produced is a traditional kettlebell. The user applies force to the through hole 15 to lift the traditional kettlebell and the user exercises. The handle 1 of the traditional kettlebell may include a first vertical rod, a horizontal rod and a second vertical rod. One end of the first vertical rod is connected to the connecting portion 14, the other end of the first vertical rod is connected to one end of the horizontal rod, the other end of the horizontal rod is connected to one end of the second vertical rod, and the other end of the second vertical rod is connected to the connecting portion 14. The first vertical rod is perpendicular to the horizontal rod, and the horizontal rod is perpendicular to the second vertical rod.

[0065] The above embodiments and drawings do not limit the product form and style of the present invention. Any appropriate changes or modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present invention.

Claims

1. A method for manufacturing a kettlebell, characterized by: The kettlebell comprises a handle and a kettlebell body; the handle comprises a handle portion and a connecting portion, the handle portion having a through hole, the connecting portion being concave inwardly toward the handle portion to form an arcuate surface, the thickness of the connecting portion gradually decreasing from close to the handle portion to away from the handle portion, the arcuate surface intersecting with the outer surface of the handle, the intersection line being located on the circumference of a circle; the kettlebell body is a soft kettlebell body, and the soft kettlebell body is formed at the connecting portion of the handle; The rotational molding mold includes a lower mold, an upper mold and a base frame. The upper mold and the lower mold are detachable, and the upper mold or the lower mold can be rotatably set on the base frame; a receiving groove is formed in the upper mold, and the receiving groove includes an inner side wall, the inner side wall includes a fitting portion for fitting the outer skin of the handle and a non-contact portion that does not contact the handle, and the inner side wall includes a first inner side wall and a second inner side wall arranged opposite to each other, a first limiting protrusion for limiting one side of the handle is formed on the first inner side wall, and a second limiting protrusion for limiting the other side of the handle is formed on the second inner side wall; a mold cavity for placing the rotational molding raw material is formed in the lower mold, a first interface is provided at the end of the lower mold, and a second interface connected to the first interface is formed at the end of the upper mold; The manufacturing method comprises the following steps: S1, placing the injection molding material in the injection mold, and the injection mold injects the injection molding material into a hard handle; S2, placing the handle in the upper mold of the rotational mold so that the outer skin of the handle is in contact with the inner wall of the upper mold and the outer periphery of the handle is lower than the inner wall of the upper mold, so that the connection position between the handle and the kettlebell body is staggered at the closing position of the upper and lower molds; S3, placing the rotationally molded material in the lower mold and connecting the lower mold with the upper mold; S4, the upper mold and the lower mold rotate along the base, the upper mold and the lower mold are heated, the rotational molding material melts and forms the pot body; S5, separate the upper mold and the lower mold, and take out the formed kettlebell.

2. The method for manufacturing a kettlebell according to claim 1, wherein: In step S1, the injection mold injects the injection material into a handle with an inlet, and the inlet is blocked before the upper mold and the lower mold are closed.

3. The method for manufacturing a kettlebell according to claim 2, wherein: Before closing the upper and lower molds, insert the plug into the inlet of the handle to block it.

4. The method for manufacturing a kettlebell according to claim 1, wherein: A first through hole communicating with the outside is provided on the first limiting protrusion, and a second through hole communicating with the outside is provided on the second limiting protrusion. The axial center line of the second through hole coincides with the axial center line of the first through hole.

5. The method for manufacturing a kettlebell according to claim 1, wherein: A driving mechanism for driving the upper die or the lower die to rotate is arranged on the base frame.

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