External injection protection device, injection gun barrel of injection molding machine and control method of injection gun barrel

Abstract

The invention provides an external injection protection device, an injection gun barrel of an injection molding machine and a control method thereof.The external injection protection device comprises a movable baffle, a first fixing frame and a second fixing frame, the first fixing frame and the second fixing frame are rotationally connected to the two ends of the movable baffle respectively, the first fixing frame is provided with a first connecting part, and the second fixing frame is provided with a second connecting part; the injection gun barrel of the injection molding machine comprises a gun barrel body and a gun barrel head connected to the shaft end face of the gun barrel body through a plurality of first connecting bolts, a first connecting part and a second connecting part are fixed to the shaft end face of the gun barrel body through part of the first connecting bolts, and the injection gun barrel further comprises a driving component assembled on a first fixing frame. The driving part is used for driving the movable baffle to be switched between the protection state and the melt injection state. According to the assembly structure of the injection protection device and the injection gun barrel of the injection molding machine, the first connecting part and the second connecting part are utilized, the original connecting structure of the injection gun barrel is completely borrowed, the structure improvement cost is reduced, the use flexibility is improved, and the device is convenient to disassemble and assemble.

Description

Technical Field

[0001] This invention belongs to the field of injection molding machine design technology, specifically relating to an external injection protection device, an injection barrel for an injection molding machine, and a control method thereof. Background Technology

[0002] GB / T 22530 Safety Requirements for Rubber and Plastic Injection Molding Machines stipulates the following additional requirements for machines where the injection unit is directly facing the operating position: 1. Injection is not permitted when the interlocking protective device in the mold area is open (when the safety door on the operating side is open); Second, it must be equipped with a mechanical (such as spring) or power-operated baffle or closed nozzle, and it must meet the requirement that the baffle or self-locking nozzle automatically closes after the nozzle leaves the mold before the mold opens.

[0003] 3. Mechanical (such as spring) or power-operated baffles or closed nozzles and interlocking protective devices with locking mechanisms must meet the following requirements: 1. The protective device in the mold area can only be unlocked when the baffle or closed nozzle is closed; 2. The baffle or closed nozzle can only be opened when the protective device in the mold area is locked.

[0004] To meet the aforementioned national standards, existing technologies often employ injection barrels equipped with closed nozzles. However, injection barrels with closed nozzles are more expensive, thus increasing the overall cost of the injection molding machine. Furthermore, traditional closed nozzles pose a safety hazard: if the injection unit is accidentally activated due to uncontrollable factors, and the closed nozzle is in the closed state, a large injection pressure will build up in the barrel. If this pressure exceeds the system's maximum withstand capacity, it can damage the equipment and even cause personal injury. Based on cost and the aforementioned safety considerations, some customers require separate external protective devices when purchasing equipment to meet the aforementioned national standards' safety requirements while reducing equipment procurement costs, and therefore do not accept the closed nozzle approach. For example, utility model patent application number 2024210191451 discloses a novel nozzle anti-injection protective cover. This protective cover, placed outside the nozzle, ensures that the injection assembly meets GB / T standards. The 22530 safety requirements are met, but the assembly of the protective cover requires adaptive modifications to the structure of the injection barrel, which makes the adoption cost (modification cost) of the protective cover relatively high and the structure more complex, which is not conducive to the rapid assembly and disassembly of the device. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to provide an external injection protection device, an injection barrel for an injection molding machine and a control method thereof, which can overcome the technical problems of the existing external injection protection device requiring adaptation of the injection barrel structure for assembly, which increases the improvement cost, and the assembly structure is also more complicated, which is not conducive to the quick assembly and disassembly of the device.

[0006] To address the aforementioned problems, this invention provides an external injection protection device for use on the injection barrel of an injection molding machine. It includes a movable baffle and a first fixed frame and a second fixed frame rotatably connected to both ends of the movable baffle. The first fixed frame has a first connecting portion, and the second fixed frame has a second connecting portion. The injection barrel includes a barrel body and a barrel head connected to the axial end face of the barrel body via multiple first connecting bolts. The first connecting portion and the second connecting portion are fixed to the axial end face of the barrel body via a portion of the first connecting bolts. The device also includes a driving component assembled on the first fixed frame. The driving component drives the movable baffle to switch between a protection state and a melt injection state. When the movable baffle is in the protection state, it is positioned on the injection path of the barrel head to block the injection of melt into the barrel head. When the movable baffle is in the melt injection state, it is outside the injection path, allowing the barrel head to dock with the injection mold inlet.

[0007] In some embodiments, the first connecting portion is a connecting bent plate extending toward one side of the central axis of the gun barrel body, the second connecting portion is a connecting bent plate extending toward one side of the central axis of the gun barrel body, and each of the connecting bent plates is provided with two first through holes penetrating both sides of its plate body.

[0008] In some embodiments, the driving component is a stepper rotary motor, and the shaft of the stepper rotary motor is fixedly connected to the first end of the movable baffle so that the movable baffle can switch between the protective state and the melt injection state by rotation when the driving component is running.

[0009] In some embodiments, the first mounting bracket has an outer bending plate, and an assembly gap is formed between the outer bending plate and the side of the first mounting bracket away from the barrel body. The stepper rotary motor is located within the assembly gap and the housing of the stepper rotary motor is fixed to the outer bending plate; and / or, the stepper rotary motor is equipped with two second proximity switches capable of detecting the rotation angle of its shaft.

[0010] In some embodiments, an adjusting pad is sandwiched between the housing of the stepper rotary motor and the outer bending plate; and / or, the first end of the movable baffle is located within the assembly gap, and a first proximity switch is assembled on the outer bending plate, wherein the first proximity switch can detect the first end of the movable baffle when the movable baffle is in the protected state.

[0011] In some embodiments, the first end of the movable baffle has a first spacer sleeve on one side facing the barrel body, the first spacer sleeve has a threaded hole formed on one end face facing the first fixed frame, the first fixed frame has a second through hole coaxial with the threaded hole, and the second connecting bolt is threadedly connected to the threaded hole through the second through hole.

[0012] In some embodiments, the first end of the movable baffle also has a baffle flipping limiting structure. The baffle flipping limiting structure includes an inner bent plate extending toward the side close to the central axis of the barrel body and a third connecting bolt threadedly connected to the inner bent plate. When the movable baffle is in the protective state, the head of the third connecting bolt abuts against the axial outer end face of the first fixed frame. The central axis of the third connecting bolt has an offset distance from the threaded hole on the first spacer sleeve. Taking the rotation direction of the movable baffle from the protective state to the melt injection state as the first direction, the third connecting bolt is located on the upstream side of the first spacer sleeve in the first direction.

[0013] In some embodiments, the second end of the movable baffle is rotatably connected to the second fixed frame via a rotating shaft assembly. A third through hole is formed on the second end of the movable baffle, and a fourth through hole coaxial with the third through hole is formed on the second fixed frame. The rotating shaft assembly includes a second spacer sleeve, a fourth connecting bolt, and a connecting nut. The second spacer sleeve includes a sleeve inserted into the third through hole and a spacer ring located between the movable baffle and the second fixed frame. The fourth connecting bolt passes through the fourth through hole and is threadedly connected to the sleeve and the connecting nut.

[0014] The present invention also provides an injection barrel for an injection molding machine, including the aforementioned external injection protection device.

[0015] The present invention also provides a method for controlling the injection barrel of the above-mentioned injection molding machine, comprising the following steps: The direction of travel of the injection barrel and the distance between the injection port of the barrel head and the feed port of the injection mold are detected. When the direction of travel is close to the injection mold and the distance reaches the preset distance, the movable baffle is controlled to switch from the protection state to the melt injection state, and the injection barrel is controlled to continue to approach the injection mold inlet until the injection port is connected to the injection mold inlet. When the direction of travel is away from the injection mold and the distance reaches a preset distance, the movable baffle is controlled to switch from the melt injection state to the protection state.

[0016] This invention provides an external injection protection device, an injection barrel for an injection molding machine, and a control method thereof. On one hand, the injection protection device is externally mounted on the injection barrel of the injection molding machine and assembled independently. It meets user needs and national safety standards without the need for a closed nozzle, reducing equipment production and procurement costs and eliminating the risks of equipment damage and personal injury that can occur with uncontrolled closed nozzles. On the other hand, the assembly structure of the injection protection device and the injection barrel utilizes the first and second connecting parts and completely borrows the original connection structure of the injection barrel, greatly reducing the cost of structural modifications and improving the flexibility of the device. At the same time, the first fixing frame also serves as the mounting carrier for the drive component, resulting in a simple and compact structure and extremely convenient assembly and disassembly of the device. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of an external injection protection device in an embodiment of the present invention. The figure shows the injection barrel of an injection molding machine, and the movable baffle in the figure is in a protective state. Figure 2 yes Figure 1 Exploded view of the external injection protection device in the diagram; Figure 3 yes Figure 1 Top view; Figure 4 yes Figure 3 A magnified view of a section at point A in the middle; Figure 5 yes Figure 3 A magnified view of a section at point B in the middle; Figure 6 yes Figure 3 Side view.

[0018] The reference numerals in the attached figures are as follows: 1. Movable baffle; 11. First spacer sleeve; 12. Second connecting bolt; 13. Inner bending plate; 14. Third connecting bolt; 15. Anti-loosening nut; 2. First fixing frame; 21. First connecting part; 22. Outer bending plate; 3. Second fixing frame; 31. Second connecting part; 4. Drive component; 41. Adjusting pad; 42. Connecting screw; 5. First proximity switch; 6. Rotating shaft assembly; 61. Second spacer sleeve; 62. Fourth connecting bolt; 63. Connecting nut; 101. Cannon barrel body; 102. Cannon barrel head; 1021. Injection port; 103. First connecting bolt; 200. Assembly gap. Detailed Implementation

[0019] See also Figures 1 to 6 As shown, according to an embodiment of the present invention, an external injection protection device is provided for use on the injection barrel of an injection molding machine. It includes a movable baffle 1 and a first fixing frame 2 and a second fixing frame 3 respectively rotatably connected to both ends of the movable baffle 1. The first fixing frame 2 has a first connecting portion 21, and the second fixing frame 3 has a second connecting portion 31. The injection barrel of the injection molding machine includes a barrel body 101 and a barrel head 102 connected to the axial end face of the barrel body 101 by a plurality of first connecting bolts 103. The first connecting portion 21 and the second connecting portion 31 are fixed to the axial end face of the barrel body 101 via a portion of the first connecting bolts 103. That is, the first fixing frame 2 and the second fixing frame 3 are respectively fixedly connected to the barrel body 101 via the aforementioned first connecting portion 21 and second connecting portion 31. It is understood that the aforementioned first connecting bolts 103 are the original connecting structure of the injection barrel of the injection molding machine, used to detachably connect the barrel head 102 to the axial end face of the barrel body 101. See [reference needed]. Figure 1 As shown, each first connecting bolt 103 is bolted to each threaded hole (not marked in the figure) on the shaft end face of the barrel body 101 along the central axis of the barrel body 101. The aforementioned first fixing frame 2 and second fixing frame 3 in this application borrow some of the first connecting bolts 103 from the original connection structure of the injection barrel of the injection molding machine. They also include a driving component 4 assembled on the first fixing frame 2. The driving component 4 is used to drive the movable baffle 1 to switch between the protective state and the melt injection state. When the movable baffle 1 is in the protective state, the movable baffle 1 is in the injection path of the barrel head 102 to form a shield against the injection of melt by the barrel head 102. When the movable baffle 1 is in the melt injection state, the movable baffle 1 is outside the injection path so that the barrel head 102 can dock with the injection mold inlet.

[0020] In this technical solution, on the one hand, the injection protection device is externally mounted on the injection barrel of the injection molding machine and assembled independently. It meets user needs and national safety standards without the need for a closed nozzle, reduces equipment production and procurement costs, and eliminates the potential for equipment damage and personal injury caused by uncontrolled use of a closed nozzle. On the other hand, the assembly structure of the injection protection device and the injection barrel of the injection molding machine utilizes the first connecting part 21 and the second connecting part 22 and completely borrows the original connection structure of the injection barrel, which greatly reduces the cost of structural improvement and improves the flexibility of the device. At the same time, the first fixing frame 2 also serves as the mounting carrier for the drive component. The structure is simple and compact, and the device is extremely convenient to assemble and disassemble.

[0021] In some embodiments, the first connecting part 21 is a connecting bent plate extending toward the central axis of the barrel body 101, and the second connecting part 31 is a connecting bent plate extending toward the central axis of the barrel body 101. Each connecting bent plate is provided with two first through holes (not indicated in the figure) penetrating both sides of its plate body. It can be understood that each connecting bent plate is connected to the shaft end face of the barrel body 101 by two first connecting bolts 103. This can make the positions of the first fixing frame 2 and the second fixing frame 3 reliable and stable, thereby ensuring the position of the movable baffle 1 reliable and stable.

[0022] In some embodiments, the driving component 4 is a stepper rotary motor, and the rotating shaft of the stepper rotary motor is fixedly connected to the first end of the movable baffle 1 (for example, through multiple connecting screws 42) so that the movable baffle 1 can switch between the protective state and the melt injection state by rotation when the driving component 4 is running. That is, the first end of the movable baffle 1 is directly fixedly connected to the rotating shaft of the stepper rotary motor. When the motor is running, the movable baffle 1 will be driven to rotate synchronously with the rotating shaft, thereby realizing the rotational switching between the aforementioned protective state and the melt injection state. By using a stepper rotary motor to directly drive the rotation of the movable baffle 1, the structural compactness of the protective device is further improved.

[0023] In some embodiments, the first fixing frame 2 has an outer bending plate 22, and an assembly gap 200 is formed between the outer bending plate 22 and the side of the first fixing frame 2 away from the barrel body 101. The stepper rotary motor is located within the assembly gap 200 and the housing of the stepper rotary motor is fixed to the outer bending plate 22. Specifically, the outer bending plate 22 can be assembled or welded to the first fixing frame 2.

[0024] In this technical solution, the driving component 4 is assembled within the assembly gap 200 formed between the outer bending plate 22 and the first fixing frame 2, and the driving component 4 is fixed on the outer bending plate 22. The outer bending plate 22 and the first fixing frame 2 can limit the driving component 4 while also forming external protective isolation for the driving component 4.

[0025] In some embodiments, an adjusting shim 41 is sandwiched between the housing of the stepper rotary motor and the outer bending plate 22. The adjusting shim 41 enables the rotating shaft of the stepper rotary motor to maintain a suitable matching position with the first end of the movable baffle 1.

[0026] The first end of the movable baffle 1 is located within the assembly gap 200, and a first proximity switch 5 is assembled on the outer bending plate 22. When the movable baffle 1 is in the protective state, the first proximity switch 5 can detect the first end of the movable baffle 1.

[0027] In this technical solution, the first end of the movable baffle 1 is placed within the aforementioned assembly gap 200, and a first proximity switch 5 is assembled on the outer bending plate 22. The first end of the movable baffle 1 can be detected by the detection end of the first proximity switch 5, thereby enabling real-time detection of whether the movable baffle 1 is in a protective state and ensuring safe production.

[0028] In some embodiments, the stepper rotary motor is equipped with two second proximity switches (not shown or labeled in the figure) capable of detecting the rotation angle of its shaft to detect the real-time position of the stepper rotary motor shaft. This provides double protection with the detection result of the first proximity switch, ensuring the reliability of detection when the movable baffle 1 is in the protected state. Specifically, one of the two second proximity switches corresponds to the movable baffle 1 being in the protected state and is used to detect whether the movable baffle 1 is in the protected state. The other is used to detect whether the movable baffle 1 is in the melt injection state. When both the second proximity switch and the first proximity switch 5 detect the movable baffle 1, it indicates that the movable baffle 1 is indeed in the protected state, thereby effectively preventing adverse consequences caused by false detection by a single proximity switch.

[0029] In some embodiments, the first end of the movable baffle 1 has a first spacer sleeve 11 on the side facing the barrel body 101 (in a specific embodiment, the first spacer sleeve 11 is welded to the movable baffle 1), and a threaded hole (not shown in the figure, not marked) is formed on the end face of the first spacer sleeve 11 facing the first fixed frame 2. The first fixed frame 2 has a second through hole (not marked in the figure) coaxial with the threaded hole, and the second connecting bolt 12 is threadedly connected to the threaded hole through the second through hole.

[0030] In this technical solution, the first spacer sleeve 11 creates a certain gap between the movable baffle 1 and the first fixed frame 2, reducing the contact area between them, thereby making the rotation of the movable baffle 1 relative to the first fixed frame 2 smoother. It is understood that the aforementioned second connecting bolt 12 not only connects the movable baffle 1 to the first fixed frame 2, but also serves as the rotation axis of the movable baffle 1.

[0031] In some embodiments, the first end of the movable baffle 1 also has a baffle flipping limiting structure (not shown in the figure). The baffle flipping limiting structure includes an inner bent plate 13 extending toward the side near the central axis of the barrel body 101 and a third connecting bolt 14 (i.e., the inner bent plate 13 has a threaded hole) threadedly connected to the inner bent plate 13. When the movable baffle 1 is in the protective state, the head of the third connecting bolt 14 abuts against the axial outer end face of the first fixing frame 2. The central axis of the third connecting bolt 14 has an offset distance from the threaded hole on the first spacer sleeve 11. Taking the rotation direction of the movable baffle 1 from the protective state to the melt injection state as the first direction, the third connecting bolt 14 is located upstream of the first spacer sleeve 11 in the first direction. The aforementioned inner bent plate 13 is located below the movable baffle 1 (with the inner bent plate 13 having a threaded hole). Figure 1 (The orientation shown is for reference) It is formed by cutting and bending, that is, the inner bending plate 13 and the movable baffle 1 are an integrated structure.

[0032] In this technical solution, a third connecting bolt 14 is threaded onto the inner bending plate 13, and the head of the third connecting bolt 14 can abut against the axial outer end face of the first fixed frame 2 when the movable baffle 1 is in the protective state. Thus, the specific position of the movable baffle 1 can be adjusted by adjusting the length of the third connecting bolt 14 extending from the inner side of the inner bending plate 13 (the side closer to the first fixed frame 2). At the same time, since an offset gap is formed between the central axis of the third connecting bolt 14 and the threaded hole on the first spacer sleeve 11, which is also the rotation center point of the first end of the movable baffle 1, the head of the third connecting bolt 14 only abuts against the axial outer end face of the first fixed frame 2 when the movable baffle 1 is in the protective state. However, when the movable baffle 1 is not in the protective state, that is, when it is in the melt injection state or during the switching between the two states, there can be a gap between it and the axial outer end face of the first fixed frame 2, thereby ensuring the smooth switching of the movable baffle 1.

[0033] To prevent the third connecting bolt 14 from coming loose from the inner bending plate 13, a lock nut 15 is threaded onto the head of the third connecting bolt 14.

[0034] In some embodiments, the second end of the movable baffle 1 is rotatably connected to the second fixed frame 3 via a rotating shaft assembly 6. A third through hole (not indicated in the figure) is formed on the second end of the movable baffle 1, and a fourth through hole (not indicated in the figure) coaxial with the third through hole is formed on the second fixed frame 3. The rotating shaft assembly includes a second spacer sleeve 61, a fourth connecting bolt 62, and a connecting nut 63. The second spacer sleeve 61 includes a sleeve inserted into the third through hole and a spacer ring located between the movable baffle 1 and the second fixed frame 3. The fourth connecting bolt 62 passes through the fourth through hole in sequence, and the sleeve is threadedly connected to the connecting nut 63.

[0035] In this technical solution, a rotating shaft assembly with a second spacer sleeve 61 is used to realize the rotational connection between the second end of the movable baffle 1 and the second fixed frame 3. The structure is simple and the spacing effect of the second spacer sleeve 61 can be used to ensure the smooth rotation of the movable baffle 1 and the second fixed frame 3.

[0036] According to an embodiment of the present invention, an injection barrel for an injection molding machine is also provided, including the external injection protection device described above.

[0037] According to an embodiment of the present invention, a method for controlling the injection barrel of an injection molding machine as described above is also provided, comprising the following steps: The direction of travel of the injection barrel and the distance between the injection port 1021 of the barrel head 102 and the feed port of the injection mold are detected. When the direction of travel is close to the injection mold and the distance reaches the preset distance, the movable baffle 1 is controlled to switch from the protection state to the melt injection state, and the injection barrel is controlled to continue to approach the injection mold inlet until the injection port 1021 connects with the injection mold inlet. When the direction of travel is away from the injection mold and the distance reaches a preset distance, the movable baffle 1 is controlled to switch from the melt injection state to the protection state.

[0038] In a specific embodiment, the aforementioned preset distance is 50mm. At this time, when the movable baffle 1 is in the protective state, it can form a frontal block on the injection port 1021 of the barrel head 102, preventing the risk of injury caused by direct molten metal when the injection barrel is out of control. At the same time, a small gap is formed between the movable baffle 1 and the injection port 1021, which can also prevent the excessive pressure rise inside the barrel when the injection barrel is out of control, thus preventing damage to the equipment.

[0039] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0040] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. An external injection protection device for use on the injection barrel of an injection molding machine, characterized in that, The utility model provides an injection machine injection cannon barrel and the movable baffle (1) of movable baffle (1) and the first fixed frame (2) and second fixed frame (3) of rotating connection respectively in both ends of movable baffle (1), first fixed frame (2) has first connecting portion (21), second fixed frame (3) has second connecting portion (31), the injection machine injection cannon barrel includes cannon barrel body (101) and the cannon barrel head (102) of the shaft end surface of cannon barrel body (101) is connected through a plurality of first connecting bolt (103), first connecting portion (21) and second connecting portion (31) are fixed on the shaft end surface of cannon barrel body (101) via part first connecting bolt (103), still include the drive component (4) of assembling on first fixed frame (2), drive component (4) is used for driving movable baffle (1) switches between protection state and melt injection state, when movable baffle (1) is in protection state, movable baffle (1) is in the injection path of cannon barrel head (102) to form the shelter of cannon barrel head (102) injection melt, when movable baffle (1) is in melt injection state, movable baffle (1) is in the injection path to make cannon barrel head (102) can be docked with injection mold feed port.

2. An injection safety device according to claim 1, wherein, First connecting portion (21) is the connecting bent plate extending towards the center axis of cannon barrel body (101) one side, second connecting portion (31) is the connecting bent plate extending towards the center axis of cannon barrel body (101) one side, and each connecting bent plate is provided with two first through holes through the both sides of its plate body.

3. The external injection guard of claim 1, wherein, Drive component (4) is a stepping rotary motor, the rotating shaft of the stepping rotary motor is fixedly connected with the first end of movable baffle (1) to enable movable baffle (1) to switch between protection state and melt injection state in a rotating manner when drive component (4) operates.

4. An injection safety device according to claim 3, wherein, First fixed frame (2) has an outer bent plate (22), an assembly gap (200) is formed between the outer bent plate (22) and the side surface of the first fixed frame (2) away from the cannon barrel body (101), the stepping rotary motor is in the assembly gap (200), and the casing of the stepping rotary motor is fixed on the outer bent plate (22); and / or, the stepping rotary motor is provided with two second proximity switches capable of detecting the rotating angle of the rotating shaft.

5. An injection safety device according to claim 4, wherein the needle guard is biased towards the extended position by a spring. The casing of the stepping rotary motor and the outer bent plate (22) are clamped with an adjusting pad (41); and / or, the first end of the movable baffle (1) is in the assembly gap (200), and the first proximity switch (5) is assembled on the outer bent plate (22), when the movable baffle (1) is in the protection state, the first proximity switch (5) can detect the first end of the movable baffle (1).

6. An injection safety device according to claim 5, wherein, The first end of the movable baffle (1) has a first spacing sleeve (11) on one side surface of the barrel body (101), and a threaded hole is formed on one side end surface of the first spacing sleeve (11) towards the first fixed frame (2). The first fixed frame (2) has a second through hole coaxial with the threaded hole, and a second connecting bolt (12) is threadedly connected with the threaded hole through the second through hole.

7. An injection safety device according to claim 6, wherein, The first end of the movable baffle (1) also has a baffle overturning limiting structure, which includes an inner bending plate (13) extending towards one side close to the central axis of the barrel body (101) and a third connecting bolt (14) threadedly connected with the inner bending plate (13). When the movable baffle (1) is in the protection state, the head of the third connecting bolt (14) abuts against the axial outer end surface of the first fixed frame (2), and the central axis of the third connecting bolt (14) has a biasing distance from the threaded hole on the first spacing sleeve (11). The rotation direction of the movable baffle (1) from the protection state to the melt injection state is the first direction, and the third connecting bolt (14) is on the upstream side of the first spacing sleeve (11) in the first direction.

8. The injection safety device of claim 1, wherein, The second end of the movable baffle (1) is rotatably connected with the second fixed frame (3) through a rotating shaft assembly (6). The second end of the movable baffle (1) has a third through hole, and the second fixed frame (3) has a fourth through hole coaxial with the third through hole. The rotating shaft assembly includes a second spacing sleeve (61), a fourth connecting bolt (62), and a connecting nut (63). The second spacing sleeve (61) includes a sleeve inserted into the third through hole and a spacing ring between the movable baffle (1) and the second fixed frame (3). The fourth connecting bolt (62) passes through the fourth through hole, the sleeve, and is threadedly connected with the connecting nut (63) in sequence.

9. An injection molding machine injection barrel characterized by, The external injection protection device according to any one of claims 1 to 8.

10. A method of controlling the injection ram of an injection molding machine as defined in claim 9, wherein, The method comprises the following steps: detecting the moving direction of the injection barrel and the distance between the injection port (1021) of the barrel head (102) and the feed port of the injection mold; when the moving direction is towards the injection mold and the distance reaches a preset distance, controlling the movable baffle (1) to switch from the protection state to the melt injection state, and controlling the injection barrel to continue to approach the feed port of the injection mold until the injection port (1021) is connected with the feed port of the injection mold; when the moving direction is away from the injection mold and the distance reaches a preset distance, controlling the movable baffle (1) to switch from the melt injection state to the protection state.

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