Method for manufacturing a silent ball and production device therefor

Abstract

The application discloses a manufacturing method of a mute ball, which comprises the following steps: first, polyether polyol, isocyanate and foaming agent are respectively mixed to prepare a first mixture and a second mixture, and the proportion of the foaming agent in the first mixture is smaller than that in the second mixture; second, the first mixture is injected into a mold, the mold is rotated at high speed, the first mixture is uniformly attached to the inner wall of the spherical cavity of the mold under the centrifugal force, and then the rotation is stopped; third, the mold is heated to make the first mixture foam to form a hollow spherical protective outer layer, and a filling port is formed in the protective outer layer; fourth, the second mixture is injected into the mold to enter the inside of the protective outer layer through the filling port, and the second mixture is heated to foam and extrude the protective outer layer, so that a spherical inner container which is adhered to the protective outer layer is formed; and fifth, the mold is demolded, and the formed mute ball is trimmed, wherein the mute ball is of an integrated structure, the inner and outer layers are synchronously deformed, and the mute ball is not separated when being hit.

Description

Technical Field

[0001] This invention relates to the field of ball manufacturing technology, specifically a method for manufacturing a silent ball and its production apparatus. Background Technology

[0002] Elastic balls are a common type of sports, entertainment, and training equipment. When hit, they produce a certain amount of noise. To reduce this noise, Chinese patent document CN222605354U discloses an elastic ball with an elastic cloth cover, which includes an elastic ball and an elastic cloth cover fitted on the outside of the elastic ball. The elastic cloth cover is elastic and can contract and compress the elastic ball, making it fit tightly against the outer surface of the elastic ball. The elastic cloth cover has an openable and closable inlet and outlet with a zipper for inserting or removing the elastic ball.

[0003] However, in the above solution, the elastic cloth cover and the elastic ball are separate structures, and the two are only fitted together by the elastic contraction of the cloth cover. When the elastic ball is hit and deforms, the elastic cloth cover and the elastic ball are prone to deformation out of sync, and cannot always maintain a tight fit. This affects the feel and the stability of the noise reduction effect. In addition, the separate cloth cover lacks sufficient structural rigidity and is prone to denting and deformation when held or lightly pressed, making it difficult to maintain a full spherical appearance and unable to simulate the feel of a basketball. Summary of the Invention

[0004] The purpose of this invention is to provide a method for manufacturing a silent ball and a production apparatus thereof, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for manufacturing a silent ball includes:

[0007] The first step involves mixing polyether polyol, isocyanate, and foaming agent in specific proportions to prepare a first mixture and a second mixture, wherein the proportion of foaming agent in the first mixture is less than that in the second mixture.

[0008] The second step is to inject the first mixture into the mold and then rotate the mold at high speed. Under the action of centrifugal force, the first mixture is evenly attached to the inner wall of the spherical cavity of the mold, and then the rotation is stopped.

[0009] The third step is to heat the mold to make the first mixture foam, forming a hollow spherical protective outer layer, and a filling port is formed in the protective outer layer;

[0010] The fourth step is to inject the second mixture into the mold, allowing it to enter the protective outer layer through the filling port. Heating causes the second mixture to foam and compress the protective outer layer, thereby forming a spherical inner liner that adheres to the protective outer layer.

[0011] The fifth step is to demold the spheres and trim the molded silent spheres.

[0012] A device for producing silent balls includes a mold with a spherical cavity inside. Electric slides are provided on both sides of the mold, and drive motors are installed on the moving ends of the two electric slides. A lifting device is provided below the two electric slides, and a push cylinder for pushing the mold onto the lifting device is provided behind the lifting device.

[0013] Furthermore, the mold includes a rotatable upper mold and a lower mold. The bottom of the upper mold and the top of the lower mold are respectively provided with cavities. A hemispherical cavity is fixedly installed in each of the two cavities. The two hemispherical cavities are joined together to form a complete spherical cavity. The upper mold and the hemispherical cavity inside it are provided with interconnected injection ports. A sealing plug that matches the injection port is provided on the injection port. The head of the sealing plug protrudes slightly from the inner wall surface of the hemispherical cavity.

[0014] Furthermore, the mold is provided with a heating component, which is connected to the spherical cavity.

[0015] Furthermore, multiple positioning pins are provided on both sides of the upper and lower molds, and a fixed platform is installed on the output shaft of each of the two drive motors. Multiple positioning slots are provided on the fixed platform, and the number and position of the positioning slots correspond to the positioning pins on one side of the mold.

[0016] Furthermore, both the upper and lower molds are made of high-temperature resistant plastic material, and the hemispherical cavity is made of thermally conductive metal material.

[0017] The beneficial effects of this invention are:

[0018] This invention involves directly foaming a spherical inner bladder inside the protective outer layer. During the foaming process, the second mixture is extruded outwards to the inner wall of the protective outer layer, forming a tightly bonded, integrated structure. This allows the inner and outer layers to deform and recover synchronously upon impact, maintaining a tight fit and ensuring noise reduction. Furthermore, because the proportion of foaming agent in the first mixture is lower than that in the second mixture, the density of the protective outer layer is greater than that of the spherical inner bladder. Consequently, its resistance to deformation is stronger than that of the inner bladder. This makes the protective outer layer less prone to denting or deformation under non-violent impact conditions such as gripping or light pressure, maintaining a full spherical shape and giving the silent ball a feel similar to an inflatable basketball.

[0019] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0020] Figure 1 : Structural diagram of the production apparatus of the present invention.

[0021] Figure 2 : Schematic diagram of the mold opening according to the present invention.

[0022] Figure 3 : Schematic diagram of mold locking according to the present invention.

[0023] Figure 4 : A structural diagram of the drive motor of the present invention.

[0024] Figure 5 : A structural diagram of the silent ball of the present invention.

[0025] Figure 6 : Cross-sectional view of the silent sphere of the present invention.

[0026] Figure 7 : A half-sectional schematic diagram of the protective jacket of the present invention.

[0027] Reference numerals: 1. Spherical inner liner; 2. Protective outer layer; 3. Mold; 4. Lifting device; 5. Pushing cylinder; 6. Electric slide table; 7. Drive motor; 23. Filling port; 31. Upper mold; 32. Lower mold; 33. Cavity; 34. Hemispherical cavity; 35. Spherical cavity; 36. Heating element; 37. Injection port; 38. Sealing plug; 39. Positioning pin; 71. Fixing platform; 72. Positioning slot. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0029] Please refer to Figure 1-7 ;

[0030] A device for producing silent balls includes a mold 3, which has a spherical cavity 35 inside. Electric slides 6 are provided on both sides of the mold 3. A drive motor 7 is installed on the moving end of each of the two electric slides 6. A lifting device 4 is provided below the two electric slides 6. A push cylinder 5 for pushing the mold 3 onto the lifting device 4 is provided behind the lifting device 4.

[0031] The mold 3 includes a rotatable upper mold 31 and a lower mold 32. A locking structure is provided between the upper mold 31 and the lower mold 32 to prevent them from loosening. The locking structure is described in reference to prior art document CN224406391U and will not be repeated here. The bottom of the upper mold 31 and the top of the lower mold 32 are respectively provided with cavities 33. A hemispherical cavity 34 is fixedly installed in each of the two cavities 33. The two hemispherical cavities 34 fit together to form a complete spherical cavity 35. In one embodiment, both the upper mold and the lower mold are supported by high-temperature resistant materials, and both hemispherical cavities 34 are made of thermally conductive metal materials.

[0032] The upper mold 31 and its internal hemispherical cavity 34 are provided with interconnected injection ports 37, which are used to inject the first mixture and the second mixture respectively. A sealing plug 38 is provided on the injection port 37, and after the sealing plug 38 is inserted into the injection port 37, its head slightly protrudes from the inner wall of the spherical cavity 35, thus utilizing physical positioning during centrifugal molding. A heating element 36 is provided on the mold 3, connected to the spherical cavity 35. The conductive end of the heating element 36 extends to the outside of the mold 3. During operation, an external power source can be connected to the conductive end to energize the heating element 36, thereby heating the spherical cavity 35. In one embodiment, the heating element 36 is a heating film, which is attached to the back of the hemispherical cavity constituting the spherical cavity; in another alternative embodiment, the heating element 36 is a heating wire, which is uniformly attached to the back of the hemispherical cavity to achieve uniform heating of the spherical cavity.

[0033] Multiple positioning pins 39 are provided on both sides of the upper mold 31 and the lower mold 32. Fixed platforms 71 are installed on the output shafts of the two drive motors 7. Multiple positioning slots 72 are provided on the fixed platforms 71. The number and position of the positioning slots 72 correspond to the positioning pins 39 on one side of the mold 3. After the mold 3 is closed, the two electric slides 6 drive their moving ends to move the two drive motors 7 towards each other. The positioning slots 72 on the fixed platforms 71 are engaged with the corresponding positioning pins 39 to lock and fix the mold 3, preventing it from opening when rotating at high speed.

[0034] A method for manufacturing a silent ball includes:

[0035] The first step involves mixing polyether polyol, isocyanate, and a blowing agent in specific proportions to prepare a first mixture and a second mixture. The proportion of the blowing agent in the first mixture is less than that in the second mixture, so that the density of the first mixture after foaming is greater than that of the second mixture after foaming. In one embodiment, the weight ratio of polyether polyol to isocyanate is 100:30-50. Based on 100 parts by weight of polyether polyol, the amount of blowing agent in the first mixture is 0.2-0.5 parts, and the amount of blowing agent in the second mixture is 2.0-3.0 parts. This is for reference only and not intended as a key protective element.

[0036] The second step is to close the empty mold 3 and push the mold 3 onto the lifting device 4 by the pushing cylinder 5. The lifting device 4 lifts the mold 3 to a preset height. Then, the two electric slides 6 drive the drive motors 7 to move towards each other, so that the positioning pins 39 on both sides of the mold 3 are inserted into the positioning slots 72 on the fixed table 71. The lifting device 4 is equipped with a positioning structure to ensure that several positioning slots 72 and positioning pins 39 are aligned and locked. After locking, the lifting device 4 immediately descends and resets, and the mold 3 is suspended and supported by the two drive motors 7.

[0037] Then, the pre-prepared first mixture is injected into the spherical cavity 35 of the mold 3 through the injection port 37. After injection, the sealing plug 38 is immediately inserted into the injection port 37 to seal it. At this time, the first mixture is in the flowable stage. Then, the two drive motors 7 are started to drive the mold 3 to rotate at high speed for 30 seconds, so that the first mixture is evenly attached to the inner wall of the spherical cavity 35 of the mold 3 under the action of centrifugal force. At this time, the first mixture gradually becomes viscous and forms a material layer of uniform thickness.

[0038] The third step involves energizing the heating element 36 by connecting an external power source, which heats the spherical cavity 35. The heat is conducted through the cavity wall of the spherical cavity 35 to the first mixture inside, causing it to foam and form a hollow spherical protective outer layer 2. Due to the occupancy of the sealing plug 38 head, a filling port 23 communicating with the injection port 37 is formed on the protective outer layer 2.

[0039] Fourth step, remove the sealing plug 38, and inject the second mixture into the protective outer layer 2 through the injection port 37 and the filling port 23. During injection, an exhaust gap is maintained between the injection tube and the inner wall of the injection port 37 so that the gas in the spherical cavity 35 can be discharged during the injection process. After the second mixture is injected, the sealing plug 38 is inserted again to seal it. Then, the heating element 36 is energized and heated to make the second mixture foam. Since the protective outer layer will be slightly deformed after the gas is discharged, the second mixture will squeeze the protective outer layer onto the inner wall of the spherical cavity 35 during the foaming process. Thus, the spherical cavity 35 is used to achieve bidirectional extrusion of the protective outer layer into a spherical shape, forming a spherical inner liner 1 that is tightly adhered to the protective outer layer 2.

[0040] The above heating process can be carried out in one of the following two ways:

[0041] In the first embodiment, after the first mixture is foamed, the internal temperature of the protective outer layer 2 can reach about 150°C. While the protective outer layer 2 is still in a high temperature state, the second mixture is injected into the interior of the protective outer layer 2 through the filling port 23 immediately after foaming. At the same time, the temperature of the mold 3 is heated by the heating component 36 and maintained at 50°C for heat preservation and replenishment. Under the combined action of the residual heat of the protective outer layer 2 and the heat replenishment of the mold 3, the second mixture initiates a foaming reaction and expands fully, squeezing outward the inner wall of the protective outer layer 2 to form a tightly adhered spherical inner liner 1.

[0042] In the second implementation method, after the first mixture has foamed and formed the protective outer layer 2, the mold 3 and the protective outer layer 2 are cooled to a preset temperature. Then, the second mixture is injected into the protective outer layer 2 through the filling port 23. Subsequently, the mold 3 is reheated by the heating component 36. The heat is transferred from the mold 3 to the protective outer layer 2 and then conducted inward to the second mixture, causing it to gradually heat up until a foaming reaction is initiated. After the foaming reaction is initiated, the exothermic reaction of the second mixture and the external heating work together to make it fully expand and squeeze the inner wall of the protective outer layer 2 to form a tightly adhered spherical inner liner 1.

[0043] Fifth step: After the spherical inner liner 1 is formed, the lifting device 4 rises again to support the mold 3, the electric slide 6 drives the drive motor 7 to move outward, so that the fixed platform 71 is separated from the mold 3, the lifting device 4 descends to reset, the mold 3 is opened, the formed silent ball is taken out, and finally it is manually trimmed to obtain the finished product.

[0044] By directly foaming the spherical inner bladder 1 inside the protective outer layer 2, the second mixture is squeezed outwards to the inner wall of the protective outer layer 2 during the foaming process, forming a tightly bonded integrated structure. Thus, when impacted, the inner and outer layers can deform and recover synchronously, always maintaining a tight fit, ensuring the noise reduction effect. At the same time, because the proportion of foaming agent in the first mixture is less than that in the second mixture, the density of the protective outer layer 2 is greater than that of the spherical inner bladder 1. Therefore, its resistance to deformation is stronger than that of the inner bladder. This makes the protective outer layer 2 less prone to denting and deformation under non-violent impact conditions such as holding and light pressure, maintaining a full spherical shape, and giving the silent ball a feel similar to an inflatable basketball. After the protective outer layer 2 and the spherical inner liner 1 are foamed, dense air-permeable pores are naturally formed inside the material. The spherical inner liner 1 has densely and interwoven air-permeable pores, forming a sponge-like porous structure. The protective outer layer 2 also has air-permeable pores. When the silent ball is hit, the spherical inner liner 1 is compressed and deformed. The air inside flows out through its own air-permeable pores and then is discharged through the air-permeable pores on the protective outer layer 2. When the air flows through the two layers of air-permeable pores, it is subject to throttling resistance and friction, and the impact kinetic energy is dissipated, thereby absorbing the impact energy and reducing the impact noise. After the external force is removed, the spherical inner liner returns to its original shape with its own rebound force, and drives the protective outer layer to recover synchronously. External air enters through the air-permeable pores on the protective outer layer and is then drawn into the spherical inner liner through the air-permeable pores, returning it to its original shape.

[0045] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

Claims

1. A method for manufacturing a silent ball, comprising: The first step involves mixing polyether polyol, isocyanate, and foaming agent in specific proportions to prepare a first mixture and a second mixture, wherein the proportion of foaming agent in the first mixture is less than that in the second mixture. The second step is to inject the first mixture into the mold (3), and then make the mold (3) rotate at high speed. Under the action of centrifugal force, the first mixture is evenly attached to the inner wall of the spherical cavity (35) of the mold (3), and then stop rotating. The third step is to heat the mold (3) to make the first mixture foam and form a hollow spherical protective outer layer (2), and a filling port (23) is formed in the protective outer layer (2); The fourth step is to inject the second mixture into the mold (3) so that it enters the protective outer layer (2) through the filling port (23), heat it to make the second mixture foam and squeeze the protective outer layer (2) to form a spherical inner liner (1) that adheres to the protective outer layer (2); The fifth step is to demold the spheres and trim the molded silent spheres.

2. The silent ball production device according to claim 1, characterized in that, The mold (3) includes a spherical cavity (35) inside the mold (3). Electric slides (6) are provided on both sides of the mold (3). A drive motor (7) is installed on the moving end of each of the two electric slides (6). A lifting device (4) is provided below the two electric slides (6). A push cylinder (5) for pushing the mold (3) onto the lifting device (4) is provided behind the lifting device (4).

3. The silent ball production device according to claim 2, characterized in that, The mold (3) includes a rotatable upper mold (31) and a lower mold (32). The bottom of the upper mold (31) and the top of the lower mold (32) are respectively provided with cavities (33). A hemispherical cavity (34) is fixedly installed in each of the two cavities (33). The two hemispherical cavities (34) are joined together to form a complete spherical cavity (35). The upper mold (31) and the hemispherical cavity (34) inside it are provided with a connected injection port (37). A sealing plug (38) is provided on the injection port (37) to cooperate with it. The head of the sealing plug (38) protrudes slightly from the inner wall surface of the hemispherical cavity (34).

4. The silent ball production device according to claim 2, characterized in that, The mold (3) is provided with a heating component (36), which is connected to the spherical cavity (35).

5. The device for producing silent balls according to claim 2, characterized in that, Multiple positioning pins (39) are provided on both sides of the upper mold (31) and the lower mold (32). A fixed platform (71) is installed on the output shaft of each of the two drive motors (7). Multiple positioning slots (72) are provided on the fixed platform (71). The number and position of the positioning slots (72) correspond to the positioning pins (39) on one side of the mold (3).

6. The device for producing silent balls according to claim 2, characterized in that, The upper mold (31) and lower mold (32) are both made of high-temperature resistant plastic material, and the hemispherical cavity (34) is made of thermally conductive metal material.

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