Multi-station linkage aluminum alloy precision forging forming automatic production line

Abstract

The invention relates to the field of intelligent casting, discloses a multi-station linkage aluminum alloy precision forging forming automatic production line, and relates to the field of metal forging machining. The production line comprises a hydraulic machine, a mold assembly, a material changing assembly and a conveying assembly. The hydraulic machine provides forging power; the conveying assembly is used for conveying the mold assemblies among the stations; the die assembly compresses internal air through forging downward pressure to store energy, and locking pressure maintaining is achieved through a mechanical buckle. And the reloading assembly positions the mold through a boss structure, mechanically triggers a buckle to unlock, releases stored air pressure to push the mold to automatically reset and eject out, and synchronously conducts an internal air path for cooling at the same time. By means of mechanical linkage, tight connection of pressure maintaining transportation, automatic demolding and cooling procedures of the mold is achieved, the equipment structure is simplified, and the forging efficiency and the forming quality are improved.

Description

Technical Field

[0001] This invention relates to the field of intelligent casting technology, specifically to an automated production line for precision forging of aluminum alloys with multiple workstations working together. Background Technology

[0002] Precision forging of aluminum alloys is a key process for manufacturing lightweight components and is widely used in the automotive, aerospace, and other fields. With increasing demands for efficiency and quality in industrial production, automated forging production lines have become a trend in the industry. However, existing automated aluminum alloy forging production processes still face some technical bottlenecks that restrict production efficiency and product quality.

[0003] In the demolding process, existing forging dies typically require an independent hydraulic cylinder, pneumatic cylinder, or electric push rod inside the die as a power source to achieve automated ejection, or they rely on external auxiliary equipment for forced demolding. This design not only complicates the internal structure of the die and increases the manufacturing and maintenance costs, but also consumes additional electrical or hydraulic power each time demolding is performed, resulting in high energy consumption during the production process.

[0004] In terms of mold transfer and workpiece quality control, aluminum alloy materials are heat-sensitive. If the forged workpiece loses pressure too quickly or experiences a drastic temperature drop at high temperatures, it is prone to stress deformation or even cracks. Existing automated production lines often lack effective locking and pressure-holding measures during the process of transporting the mold from the forging station to the subsequent processing station. This causes the workpiece to begin losing pressure during the transfer, and the lack of control over the internal airflow environment makes the workpiece prone to uncontrollable cooling and contraction due to environmental temperature differences during the transfer process, thereby reducing the yield of the final product.

[0005] Furthermore, in terms of production line control logic and process coordination, existing technologies largely rely on electronic components such as photoelectric sensors and limit switches to detect mold positions and execute positioning, unlocking, cooling, and demolding actions sequentially through complex electronic control systems. However, forging workshops typically experience harsh conditions such as high temperatures, vibrations, and oil evaporation, making electronic components highly susceptible to interference or even damage, leading to unstable production line operation. Simultaneously, this step-by-step control method lacks tight mechanical linkage, resulting in time gaps between processes and limiting further reductions in production cycle time and improvements in production efficiency. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an automated production line for precision forging of aluminum alloys with multiple workstations working together, which solves the problems of difficult demolding, low cooling efficiency, and complex process connections in existing forging production lines.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a multi-station automated production line for precision forging of aluminum alloys, comprising a hydraulic press, a mold assembly, a material changing assembly, and a conveying assembly. The hydraulic press provides a pressure source for workpiece processing; the mold assembly accommodates the workpiece and provides a shaping support cavity; the material changing assembly serves as a comprehensive processing station, used to adjust the state of multiple mold assemblies and perform secondary processing; the conveying assembly is located between the hydraulic press and the material changing assembly, used to clamp the mold assemblies and perform position switching and transport between the various stations.

[0008] Furthermore, in the above technical solution, the mold assembly adopts an inner and outer nested structure. Specifically, it includes an outer shell with an open top, a lower mold fixed to the inner wall of the outer shell, a lower forming mold slidably connected to the inner wall of the lower mold, an upper mold inserted into the top of the outer shell, and an upper forming mold connected to the bottom of the upper mold. The upper forming mold and the lower forming mold cooperate to form the forming space of the workpiece.

[0009] To achieve automatic demolding without an external power source, a pneumatically driven self-ejecting mechanism is installed on the inner wall of the outer casing. This mechanism includes a pneumatic sleeve fixed to the inner wall of the outer casing, and piston grooves and piston rods respectively positioned corresponding to the lower and upper molds. During forging under the pressure of the hydraulic press, the downward movement of the upper and lower molds compresses the piston rod, compressing the gas in the piston groove into the pneumatic sleeve for storage, thus completing the energy conversion and accumulation. When the mold assembly moves to the material changing station and the limit is released, the high-pressure gas in the pneumatic sleeve flows back to the piston groove, pushing the piston rod out, thereby lifting the upper and lower molds and achieving the initial separation of the workpiece from the mold.

[0010] To ensure the stability of the workpiece during transfer and the controllability of subsequent cooling, the mold assembly is equipped with a mechanical self-locking and air circuit on / off linkage mechanism. An upper latch is connected to the bottom of the lower mold, and a lower latch is rotatably connected to the bottom of the outer shell, along with an elastic element providing restoring force. At the end of the downward forging process, the upper latch compresses the lower latch, causing it to rotate and locking in place using the elastic element, limiting the lower mold's rebound and maintaining the mold in a closed, pressure-holding state. Simultaneously, the bottom of the outer shell is equipped with an air inlet pipe and a flow guide structure, and the bottom of the lower mold is connected to a vent pipe with an exhaust port. In the locked state, the vent pipe moves downward with the lower mold, misaligning the exhaust port with the flow guide channel of the outer shell, thus closing the air circuit. This closed space insulates the workpiece, preventing stress cracking caused by a sudden temperature drop after forging.

[0011] This invention achieves mechanical linkage between mold unlocking and cooling processes through a material changing assembly. The material changing assembly's support frame contains a boss structure and an air supply interface. When the mold assembly is conveyed from the conveyor assembly to the material changing assembly and passes over the boss, the boss inserts into a groove at the bottom of the outer shell for positioning and presses against the lower latch, causing it to rotate and releasing its engagement with the upper latch. The lower mold, now freed from constraint, moves upward under the aforementioned stored air pressure, aligning the exhaust port on the vent pipe with the flow channel of the outer shell. Simultaneously, the air supply interface on the boss connects to the air inlet pipe of the outer shell, injecting cooling medium or high-pressure air into the mold, directly acting on the workpiece surface for rapid cooling and secondary demolding.

[0012] The conveying assembly adopts a multi-degree-of-freedom adjustable structure. A rotary drive component rotates the rotating frame, and a hydraulically driven sliding sleeve and linkage mechanism control the opening and closing of the grippers, achieving stable gripping and stationary transfer of the mold assembly. The material changing assembly, through a lifting mechanism and transmission belt, enables vertical replacement and cyclic processing of the mold assembly.

[0013] This invention provides an automated production line for precision forging of aluminum alloys with multiple workstations operating in tandem. It offers the following advantages: 1. This invention utilizes the downward pressure during forging as a power source to achieve pneumatic energy storage and automatic ejection within the mold. During the downward pressing process of the hydraulic press, the piston rod is compressed into the pneumatic sleeve for storage; when the mold is released from its mechanical lock, the stored high-pressure gas is released and pushes the mold to reset, thus completing the initial demolding of the workpiece. This design avoids the need for a separate hydraulic or electric ejection device inside the mold, simplifies the internal structure of the mold, and reduces the energy consumption and maintenance costs of the equipment.

[0014] 2. This invention employs a structural design that links mechanical locking with air circuit on / off linkage, effectively ensuring the forming quality of the workpiece. During the transfer of the mold from the hydraulic press to the material changing assembly, the upper and lower latches remain locked, and the exhaust port of the vent pipe and the guide groove are in a staggered and closed state. This closed pressure-maintaining environment can insulate the aluminum alloy workpiece, preventing stress cracks or deformation caused by a sudden temperature drop after the workpiece is removed from the heat source, thereby improving the yield rate of precision forging.

[0015] 3. This invention achieves synchronized mechanical triggering of positioning, unlocking, and cooling processes through the boss structure of the material changing component. When the mold assembly moves above the boss, the boss positions the mold shell while mechanically pressing down on the latch to unlock it, causing the lower mold to float under air pressure and automatically opening the cooling air path. This purely mechanical triggering logic replaces complex sensor and electronic control detection systems, avoiding interference from high-temperature and oily environments on electronic components and improving the stability and reliability of the production line operation. Attached Figure Description

[0016] Figure 1 This is a perspective view of the present invention; Figure 2 This is a cross-sectional exploded view of the transmission component of the present invention; Figure 3 This is a cross-sectional schematic diagram of the mold of the present invention; Figure 4 This is a cross-sectional schematic diagram of the hydraulic sleeve of the present invention; Figure 5 This is a three-dimensional schematic diagram of the material changing component of the present invention; Figure 6 This is a schematic diagram showing the disassembled mold assembly of the present invention; Figure 7 This is a cross-sectional schematic diagram of the lower mold of the present invention; Figure 8 This is a cross-sectional schematic diagram of the support frame of the present invention.

[0017] The components include: 1. Hydraulic press; 2. Conveying assembly; 21. Base; 22. Rotating frame; 23. Clamping hydraulic rod; 24. Sliding sleeve; 25. Hinge rod; 26. Gripper; 3. Mold assembly; 31. Outer shell; 32. Lower mold; 33. Lower forming mold; 34. Upper mold; 35. Upper forming mold; 36. Upper buckle; 37. Lower buckle; 38. Spring; 39. Groove; 310. Guide plate; 311. Air inlet pipe; 312. Vent pipe; 313. Air pressure sleeve; 314. Piston groove; 315. Piston rod one; 316. Piston rod two; 317. Guide groove; 318. Exhaust hole; 4. Material changing assembly; 41. Support frame; 42. Material changing hydraulic rod; 43. Material changing plate; 44. Transmission belt; 45. Air inlet; 46. Boss; 47. Feed hopper. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example: Please see the appendix Figure 1 - Appendix Figure 8 This invention provides an automated production line for precision forging of aluminum alloys with multiple workstations working together, including... Hydraulic press 1 is used to process workpieces and provides power for the processing; Mold assembly 3 is used to accommodate the workpiece and provide support for shaping the workpiece; The material changing component 4, as a comprehensive processing center, is used to adjust multiple sets of mold components 3 and perform secondary processing on the mold components 3; The conveying component 2 is used to drive the mold component 3 to move between the material changing component 4 and the hydraulic press 1.

[0020] The mold assembly 3 includes an outer shell 31, which serves as the outer protective structure of the mold assembly 3 and supports the entire mold assembly 3. The outer shell 31 is a hollow shell with an open top. A lower mold 32 is fixedly connected to the inner wall of the outer shell 31, and a lower forming mold 33 is slidably connected to the inner wall of the lower mold 32. The lower forming mold 33 can slide up and down on the inner wall of the lower mold 32. The shape of the upper surface of the lower forming mold 33 is adapted to the lower surface of the workpiece. An upper mold 34 is inserted into the upper surface of the outer shell 31, and an upper forming mold 35 is fixedly connected to the lower surface of the upper mold 34. The shape of the upper forming mold 35 is adapted to the upper surface of the workpiece. The workpiece can be squeezed and shaped by the mutual approach of the upper forming mold 35 and the lower forming mold 33. When it is necessary to remove or install the workpiece, the upper mold 34 can be removed from bottom to top, and then the workpiece can be installed and removed.

[0021] The lower surface of the lower mold 33 is fixedly connected to an upper latch 36. The bottom end of the outer shell 31 is rotatably connected to a lower latch 37 that matches the upper latch 36. When the lower mold 33 moves downward, it will squeeze the lower latch 37 through the upper latch 36, forcing the lower latch 37 to rotate. The lower surface of the outer shell 31 is provided with a groove 39, and the inner wall of the groove 39 is provided with a spring piece 38. The spring piece 38 is made of elastic metal material and can undergo elastic deformation. When the upper latch 36 no longer squeezes the lower latch 37, the spring piece 38 can push the lower latch 37 to rotate and lock onto the outer wall of the upper latch 36. In this way, the lower mold 33 can be fixed and cannot move upward to reset. By using the upper mold 34 and the outer shell 31 to wrap the workpiece, a heat preservation effect can be achieved to prevent the workpiece from cooling down rapidly. The inner wall of the outer shell 31 is fixedly connected to a pneumatic sleeve 313. The pneumatic sleeve 313 is a hollow sleeve with an internal hollow core. Its upper surface is provided with a movable... There are two sets of piston grooves 314. One set of piston grooves 314 is located on the lower surface of the lower mold 33, and the other set of piston grooves 314 is located on the lower surface of the upper mold 34. The inner walls of the two sets of piston grooves 314 are respectively connected to piston rod 1 315 and piston rod 2 316. When the upper mold 34 moves downward, it will squeeze piston rod 2 316, forcing the high-pressure air inside the corresponding piston groove 314 to move into the pneumatic sleeve 313. When the lower mold 33 moves downward, it will squeeze piston rod 1 315, forcing the high-pressure air inside the corresponding piston groove 314 to move into the pneumatic sleeve 313. When the surface pressure of the upper mold 34 and the lower mold 33 disappears, the high-pressure gas inside the pneumatic sleeve 313 will return to the inside of the piston groove 314 and push piston rod 1 315 and piston rod 2 316 into the inside, thereby lifting the upper mold 34 and the lower mold 33, which makes it convenient for the operator to pick up the workpiece.

[0022] A guide plate 310 is fixedly connected to the inner wall of the outer shell 31 near the bottom. An air inlet pipe 311 is provided at the bottom of the guide plate 310, penetrating the lower surface of the outer shell 31. Gas can be introduced into the guide plate 310 through the air inlet pipe 311. A guide groove 317 is provided on the inner wall of the guide plate 310, and the gas entering the guide plate 310 can be discharged through the guide groove 317. A vent pipe 312 is fixedly connected to the lower end of the lower mold 33. The vent pipe 312 penetrates and is slidably connected to the upper surface of the guide plate 310. On the surface, the outer wall of the vent pipe 312 is provided with an exhaust hole 318. When the lower mold 33 is pressed and moves downward, the exhaust hole 318 will be misaligned with the guide groove 317. When the lower mold 33 moves upward and resets under the push of the mold assembly 3, the exhaust hole 318 will be aligned with the guide groove 317. At this time, high-pressure air or coolant can be injected into the interior of the lower mold 33 through the air inlet pipe 311. In this way, the workpiece can be cooled by high-pressure air and coolant, and the workpiece can be separated from the lower mold 33.

[0023] The conveying assembly 2 includes a base 21, which is directly installed in the processing workshop. A 27 is installed on the upper surface of the base 21. A rotating frame 22 is fixedly connected to the top of the output shaft of the 27. The rotating frame 22 can be rotated by adjusting the 27. A clamping hydraulic rod 23 is installed on the inner wall of the rotating frame 22. A sliding sleeve 24 is fixedly connected to the outer wall of the output shaft of the clamping hydraulic rod 23. A gripper 26 is hinged to the inner wall of the sliding sleeve 24 through a hinge rod 25. The gripper 26 slides on the inner wall of the rotating frame 22. The sliding sleeve 24 can be adjusted to move horizontally by clamping the hydraulic rod 23, which can drive the gripper 26 to move, thereby clamping the mold assembly 3. The position of the mold assembly 3 can be switched by rotating the rotating frame 22.

[0024] The material changing assembly 4 includes a support frame 41. Two sets of material changing hydraulic rods 42 are symmetrically installed at the upper and lower ends of the support frame 41. A material changing plate 43 is fixedly connected to one end of the material changing hydraulic rod 42 near the center line of the support frame 41. By adjusting the synchronous rise or fall of the two sets of material changing hydraulic rods 42, the two sets of material changing plates 43 can be moved synchronously, thus ejecting the mold assembly 3 held in the conveying assembly 2. Similarly, a new set of mold assemblies 3 can be brought into the conveying assembly 2, thereby realizing the replacement of the mold assembly 3. Four sets of transmission belts 44 are installed on the inner wall of the support frame 41. The four sets of transmission belts 44 are arranged symmetrically in pairs. By rotating the transmission belts 44, the mold assembly 3 can be moved back and forth. In this embodiment, a metal plate is installed on the outer wall of the transmission belt 44 to prevent the mold assembly 3 from directly contacting the belt body and to increase the friction on the mold assembly 3. The inner wall of the support frame 41 is close to the transmission belt. A hollow channel is provided below the moving belt 44, and a boss 46 is fixedly connected to the inner wall of the channel. When the mold assembly 3 passes through the channel, the boss 46 will insert into the inside of the groove 39 to achieve positioning of the outer shell 31. At the same time, the boss 46 will squeeze the lower buckle 37 to force it to rotate and separate from the upper buckle 36. In this way, the lower mold 33 will no longer be fixed and can move upward to drive the exhaust hole 318 to align with the guide groove 317. An air inlet 45 is installed on the inner wall of the support frame 41. The upper end of the air inlet 45 is set through the upper surface of the boss 46. When the mold assembly 3 moves above the boss 46, high-pressure air or coolant can be injected into the air inlet pipe 311 through the air inlet 45. This can cool the workpiece and drive the workpiece to separate from the lower mold 33. A feed hopper 47 is fixedly connected to the side of the support frame 41 away from the conveyor assembly 2, which can facilitate the operator to place or pick up the mold assembly 3.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-station automated production line for precision forging of aluminum alloys, characterized in that, include: A hydraulic press (1) is used to provide power for the processing of workpieces; Mold assembly (3) is used to accommodate the workpiece and provide support for shaping the workpiece; The material changing component (4) serves as a comprehensive processing center, used to adjust multiple sets of mold components (3) and perform secondary processing on the mold components (3); The conveying assembly (2) is used to drive the mold assembly (3) to move between the material changing assembly (4) and the hydraulic press (1); The conveying component (2) is located between the hydraulic press (1) and the material changing component (4), and the mold component (3) can be clamped by the conveying component (2) and its position can be switched.

2. The automated production line for precision forging of aluminum alloy with multi-station linkage according to claim 1, characterized in that, The mold assembly (3) includes an outer shell (31), which is a hollow shell with an opening at the top. The inner wall of the outer shell (31) is fixedly connected to a lower mold (32), and the inner wall of the lower mold (32) is slidably connected to a lower forming mold (33). The upper surface of the lower forming mold (33) is adapted to the lower surface of the workpiece. An upper mold (34) is inserted into the upper surface of the outer shell (31), and an upper forming mold (35) is fixedly connected to the lower surface of the upper mold (34). The shape of the upper forming mold (35) is adapted to the upper surface of the workpiece. The upper forming mold (35) and the lower forming mold (33) can approach each other to form the workpiece.

3. The automated production line for precision forging of aluminum alloys with multi-station linkage according to claim 2, characterized in that, The inner wall of the outer shell (31) is fixedly connected to a pneumatic sleeve (313), which is a hollow sleeve. The upper surface of the pneumatic sleeve (313) is provided with two sets of piston grooves (314), one set of piston grooves (314) is located on the lower surface of the lower mold (33), and the other set of piston grooves (314) is located on the lower surface of the upper mold (34). The inner walls of the two sets of piston grooves (314) are respectively connected to piston rod one (315) and piston rod two (316); the pneumatic sleeve (313) is configured such that when the upper mold (34) and the lower mold (33) are pressed and moved downward, piston rod two (316) and piston rod one (315) are squeezed respectively, forcing the high-pressure air in the piston groove (314) to enter the pneumatic sleeve (313) for storage; when the pressure disappears, the high-pressure gas in the pneumatic sleeve (313) flows back to the piston groove (314), pushing piston rod one (315) and piston rod two (316) to lift the lower mold (33) and the upper mold (34).

4. The automated production line for precision forging of aluminum alloy with multi-station linkage according to claim 2, characterized in that, The lower surface of the lower mold (33) is fixedly connected to an upper buckle (36), and the bottom end of the outer shell (31) is rotatably connected to a lower buckle (37) that is adapted to the upper buckle (36). The lower surface of the outer shell (31) is provided with a groove (39), and the inner wall of the groove (39) is provided with a spring sheet (38) capable of elastic deformation. The lower latch (37) is configured such that when the lower mold (33) is pressed and moves downward, the upper latch (36) squeezes the lower latch (37) to make it rotate; when the upper latch (36) no longer squeezes, the spring piece (38) pushes the lower latch (37) to rotate and engage with the outer wall of the upper latch (36) to restrict the lower mold (33) from resetting upward.

5. The automated production line for precision forging of aluminum alloys with multi-station linkage according to claim 4, characterized in that, A guide plate (310) is fixedly connected to the inner wall of the outer shell (31) near the bottom. An air inlet pipe (311) is provided at the bottom of the guide plate (310) through the lower surface of the outer shell (31). A guide groove (317) communicating with the air inlet pipe (311) is provided on the inner wall of the guide plate (310). The lower end of the lower mold (33) is fixedly connected to a vent pipe (312), which passes through and is slidably connected to the upper surface of the guide plate (310). The outer wall of the vent pipe (312) is provided with an exhaust hole (318). The position of the vent (318) is configured such that when the lower mold (33) is pressed and locked by the lower buckle (37), the vent (318) is misaligned with the guide groove (317); when the lower mold (33) moves upward and resets, the vent (318) is aligned and connected with the guide groove (317).

6. The automated production line for precision forging of aluminum alloy with multi-station linkage according to claim 1, characterized in that, The material changing assembly (4) includes a support frame (41), and four sets of transmission belts (44) are installed on the inner wall of the support frame (41) in pairs symmetrically arranged. The transmission belts (44) are used to drive the mold assembly (3) to move back and forth. A hollow channel is provided on the inner wall of the support frame (41) near the lower part of the transmission belt (44), and a boss (46) is fixedly connected to the inner wall of the hollow channel. The boss (46) is configured such that when the mold assembly (3) passes through the hollow channel, the boss (46) inserts into the groove (39) at the bottom of the mold assembly (3) to position the outer shell (31).

7. The automated production line for precision forging of aluminum alloy with multi-station linkage according to claim 6, characterized in that, Referring to the mold assembly (3) of claim 5, the upper surface of the boss (46) is provided with a through air inlet (45), and the inner wall of the support frame (41) is provided with an air supply pipe communicating with the air inlet (45). The boss (46) is also configured such that when inserted into the groove (39), the boss (46) presses the lower buckle (37) to force it to rotate and separate from the upper buckle (36), causing the lower mold (33) to move upward and drive the exhaust hole (318) to align with the guide groove (317); Meanwhile, the air inlet (45) is connected to the air inlet pipe (311) for injecting high-pressure air or coolant.

8. The automated production line for precision forging of aluminum alloy with multi-station linkage according to claim 6, characterized in that, Two sets of material changing hydraulic rods (42) are symmetrically installed at the upper and lower ends of the support frame (41), and a material changing plate (43) is fixedly connected to one end of the material changing hydraulic rod (42) near the center line of the support frame (41). The two sets of material changing hydraulic rods (42) can drive the two sets of material changing plates (43) to rise or fall synchronously, so as to push out the mold assembly (3) in the conveying assembly (2) or move the new mold assembly (3) into the conveying assembly (2); the support frame (41) is fixedly connected to the feed hopper (47) on the side away from the conveying assembly (2).

9. The automated production line for precision forging of aluminum alloy with multi-station linkage according to claim 1, characterized in that, The conveying assembly (2) includes a base (21) installed in the workshop, a rotary drive is installed on the upper surface of the base (21), and a rotating frame (22) is fixedly connected to the top of the output shaft of the rotary drive. The inner wall of the rotating frame (22) is equipped with a clamping hydraulic rod (23). The outer wall of the output shaft of the clamping hydraulic rod (23) is fixedly connected to a sliding sleeve (24). The inner wall of the sliding sleeve (24) is hinged to a jaw (26) via a hinge rod (25). The jaw (26) is slidably connected to the inner wall of the rotating frame (22). The clamping hydraulic rod (23) drives the sliding sleeve (24) to move so as to drive the jaw (26) to open and close to clamp the mold assembly (3).

10. The automated production line for precision forging of aluminum alloy with multi-station linkage according to claim 6, characterized in that, The outer wall of the transmission belt (44) is fitted with a metal plate, which is used to support the mold assembly (3) and increase friction.

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