A combined core-pulling mechanism for injection molds

Abstract

The application relates to a combined core-pulling mechanism of an injection mold, which comprises a seat block, a sliding block movably connected to the right side of the seat block to have left-right translation function, and two guide columns obliquely inserted in the sliding block and distributed in front and back and parallel to each other; a stroke extension mechanism is further arranged between the seat block and the sliding block, the stroke extension mechanism comprises an oil cylinder fixed to the right side of the seat block and located below the sliding block, and a driving block fixed to the telescopic end of the oil cylinder and connected with the sliding block; the combined core-pulling mechanism further comprises a stud forming assembly arranged on the sliding block, the stud forming assembly comprises two core blocks movably inserted in front and back of the sliding block respectively to have front-back translation function and be symmetrically arranged, and two guide blocks symmetrically arranged in front and back of the sliding block and matched with the two core blocks respectively; the application further eliminates the action contradiction between the sliding block and each ejector pin; the structure is simplified, the cost is reduced, and the installation difficulty is reduced.

Description

Technical Field

[0001] This invention relates to the field of injection mold technology, and in particular to a composite core-pulling mechanism for injection molds. Background Technology

[0002] Injection molds are industrial tools used for plastic injection molding. They produce plastic products with complex shapes and precise dimensions by injecting molten plastic into a closed cavity for cooling and shaping. Injection molds mainly consist of seven core components: moving mold, stationary mold, moving mold core, stationary mold core, gating system, core pulling mechanism, and cooling system.

[0003] The core-pulling mechanism is a key component in injection molds used to mold internal side holes or concave / convex features of products. Its core principle is to drive a slider (core-pulling block) laterally via a guide post, hydraulic cylinder, or motor to complete the lateral extraction action before or during mold opening, thereby avoiding interference between the product and the mold. Existing injection mold core-pulling mechanisms have short slider movement distances, and the movement is always a single step, unable to be segmented. In injection molds with ejector pins, the slider and ejector pins move separately. Furthermore, the slider requires a smaller stroke distance, while the ejector pin requires a larger stroke distance, creating a conflict between their actions. In addition, existing core-pulling mechanisms use a rotational ejection structure when disengaging from external threads, requiring a motor drive, resulting in a complex structure, high cost, and a high risk of interference with other components, making installation difficult and requiring urgent solutions. Summary of the Invention

[0004] In view of the current state of the prior art, the technical problem to be solved by the present invention is to provide a composite core-pulling mechanism for injection molds that extends the moving distance of the slider and divides the moving process into two stages, thereby eliminating the action contradiction between the slider and each ejector pin, and also realizes the rapid disengagement of the external threaded column to simplify the structure and reduce the cost, while reducing the installation difficulty.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problem is as follows: a composite core-pulling mechanism for injection molds, comprising a base block, a slider movably connected to the right side of the base block to have left and right translation function, and two guide pillars inclinedly interspersed in the slider and distributed front and back and parallel to each other, characterized in that:

[0006] A stroke extension mechanism is also provided between the seat block and the slider. The stroke extension mechanism includes a hydraulic cylinder fixed to the right side of the seat block and located below the slider, and a drive block fixed to the extension end of the hydraulic cylinder and connected to the slider. The extension end of the hydraulic cylinder is arranged laterally to the left.

[0007] A first T-shaped opening groove is provided between the top and bottom outer walls on the left side of the slider. Correspondingly, a T-shaped connector is formed on the right side of the drive block facing the slider. The T-shaped connector is movably embedded in the first T-shaped opening groove. The bottom front and rear inner walls of the first T-shaped opening groove slide against the front and rear outer walls of the head of the T-shaped connector, respectively.

[0008] It also includes a stud forming assembly on the slider. The stud forming assembly includes two core blocks that are symmetrically arranged and movably inserted into the front and rear sides of the slider, each having the function of forward and backward translation, and two guide blocks that are symmetrically arranged in front of and behind the slider and cooperate with the two core blocks respectively. The outer sides of the two core blocks are movably connected to the two guide blocks respectively, each having the function of left and right tilting and translation.

[0009] On the opposite side edges of the right outer wall of each of the two core blocks, a horizontally arranged semi-circular hoop is formed. The two semi-circular hoops are concentrically arranged and cooperate with each other. A mutually cooperating semi-circular threaded surface is formed on the inner wall of each of the two semi-circular hoops. The ends of the two semi-circular hoops extend movably to the front outside of the slider so that they can both have the function of forward and backward translation.

[0010] Preferably, the stud forming assembly further includes a feed cover located to the right of the slider. The opening of the feed cover faces left and is concentrically distributed with the two semi-circular hoops. The inner diameter of the feed cover is larger than the outer diameter of either semi-circular hoop.

[0011] Preferably, the feed cover has a feed hole at the center of its closed portion, and the inner diameter of the feed hole matches the inner diameter of the two semi-circular hoops.

[0012] Preferably, an annular conical positioning surface is formed at the edge of the inner opening of the feed hole, and correspondingly, a semi-circular conical positioning surface is formed at the outer edge of the ends of the two semi-circular hoops, and the two semi-circular conical positioning surfaces cooperate with the annular conical positioning surface.

[0013] Preferably, the distance between the inner walls of the left and right sides of the bottom of the first T-shaped opening groove is greater than the width of the head of the T-shaped connector in the left and right direction, and the width of the opening of the first T-shaped opening groove in the left and right direction is less than the length of the tail of the T-shaped connector in the left and right direction.

[0014] Preferably, the device further includes a lifting block located above the slider. The upper ends of the two guide posts are fixed to the bottom of the lifting block. A first back block and a second back block are formed on the upper right side of the slider, respectively arranged front and rear. A first positioning slope and a second positioning slope are formed on the left outer wall of the first back block and the second back block, respectively. Correspondingly, a third positioning slope and a fourth positioning slope are formed on the right outer wall of the lifting block, respectively cooperating with the first positioning slope and the second positioning slope.

[0015] Preferably, both the first back block and the second back block are provided with a plurality of ejector pin units distributed sequentially from top to bottom. Each ejector pin unit includes a plurality of ejector pins that are laterally and movably interwoven in the first back block or the second back block, each having an elastic tendency to return to the left and arranged sequentially from front to back.

[0016] Preferably, both the third and fourth positioning inclined surfaces are provided with a guide cavity. Each guide cavity has several stepped surfaces that are distributed sequentially from top to bottom and connected end to end on its bottom surface. The number of stepped surfaces is the same as the number of ejector pin units. The left end of each ejector pin in each ejector pin unit is engaged with a corresponding stepped surface. A transition inclined surface is also formed between any two adjacent stepped surfaces.

[0017] Preferably, a rectangular through hole is provided between the front and rear outer walls of the slider, and a waist-shaped through hole is provided between the right inner wall of the rectangular through hole and the right outer wall of the slider. The two core blocks in the stud forming assembly are respectively movably inserted into the openings at the front and rear ends of the rectangular through hole, and the semi-circular hoops on the two core blocks are movably disposed in the waist-shaped through hole.

[0018] Preferably, the top of the seat block is further fixed with a support plate horizontally disposed to the left of the guide notch, and the top of the support plate is also fixed with two micro switches respectively disposed to the left and right. The moving contacts of the two micro switches are disposed opposite to each other. The top of the drive block is also fixed with a limit rod, and the end of the limit rod is formed with a horizontally disposed bend. The end of the bend is disposed facing forward or backward and located between the moving contacts of the two micro switches.

[0019] Compared with the prior art, the advantages of the present invention are as follows:

[0020] This invention extends the sliding distance of the slider and divides the movement process into two stages. The slider moves using two guide posts, while each ejector pin moves using a stroke extension mechanism. This separates the actions of the slider and each ejector pin, eliminating any conflict between their actions. Furthermore, the invention utilizes a stud forming assembly to achieve rapid disengagement of the external threaded post, replacing the rotational disengagement structure. This eliminates the need for a motor drive and reduces interference with other components, thereby simplifying the structure, reducing costs, and simplifying installation. Attached Figure Description

[0021] Figure 1 This is an exploded top view of the left front side of the present invention;

[0022] Figure 2 This is an exploded view of the right front side of the present invention from below;

[0023] Figure 3 This is a top view of the right front side of the drive block of the present invention;

[0024] Figure 4 This is a front cross-sectional view of the first back block of the present invention during mold closing;

[0025] Figure 5 This is a front cross-sectional view of the first back block of the present invention during mold parting. Detailed Implementation

[0026] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly. The term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0027] To keep the following description of the embodiments of the present invention clear and concise, detailed descriptions of known functions and known components are omitted.

[0028] like Figures 1-5 As shown, a composite core-pulling mechanism for an injection mold includes a base block 1, a slider 2 movably connected to the right side of the base block 1 to have left and right translation function, and two guide pillars 3 inclinedly interspersed in the slider 2 and distributed front and back and parallel to each other.

[0029] A stroke extension mechanism is also provided between the seat block 1 and the slider 2. The stroke extension mechanism includes a hydraulic cylinder 4 fixed on the right side of the seat block 1 and located below the slider 2, and a drive block 5 fixed on the extension end of the hydraulic cylinder 4 and connected to the slider 2. The extension end of the hydraulic cylinder 4 is set horizontally to the left.

[0030] A first T-shaped opening groove 25 is provided between the top and bottom outer walls on the left side of the slider 2. Correspondingly, a T-shaped connector 51 is formed on the right side of the drive block 5 facing the slider 2. The T-shaped connector 51 is movably embedded in the first T-shaped opening groove 25. The bottom front and rear inner walls of the first T-shaped opening groove 25 slide against the front and rear outer walls of the head of the T-shaped connector 51, respectively.

[0031] It also includes a stud forming assembly 11 on the slider 2. The stud forming assembly 11 includes two core blocks 111 that are symmetrically arranged and movably inserted into the front and rear sides of the slider 2, each having the function of forward and backward translation, and two guide blocks 112 that are symmetrically arranged in front of and behind the slider 2 and cooperate with the two core blocks 111 respectively. The outer sides of the two core blocks 111 are movably connected to the two guide blocks 112 respectively, each having the function of left and right tilting and translation.

[0032] On the opposite side edges of the right outer wall of each of the two core blocks 111, a horizontally arranged semi-circular hoop 1111 is formed. The two semi-circular hoops 1111 are concentrically arranged and cooperate with each other. On the inner wall of each of the two semi-circular hoops 1111, a mutually cooperating semi-circular threaded surface 1112 is formed. The ends of the two semi-circular hoops 1111 extend movably to the front side of the slider 2 so that they can both have the function of forward and backward translation.

[0033] The stud forming assembly 11 also includes a feed cover 113 located to the right of the slider 2. The opening of the feed cover 113 faces left and is concentrically distributed with the two semi-circular clamps 1111. The inner diameter of the feed cover 113 is larger than the outer diameter of any one of the semi-circular clamps 1111.

[0034] The feed cover 113 has a feed hole 1131 at the center of its closed part. The inner diameter of the feed hole 1131 matches the inner diameter of the two semi-circular hoops 1111.

[0035] An annular conical positioning surface 1132 is formed at the inner opening edge of the feed hole 1131. Correspondingly, a semi-circular conical positioning surface 1113 is formed at the outer edge of the ends of the two semi-circular clamps 1111. The two semi-circular conical positioning surfaces 1113 cooperate with the annular conical positioning surface 1132.

[0036] The distance between the inner walls of the left and right sides of the bottom of the first T-shaped opening groove 25 is greater than the width of the head of the T-shaped connector 51 in the left and right direction, and the width of the opening of the first T-shaped opening groove 25 in the left and right direction is less than the length of the tail of the T-shaped connector 51 in the left and right direction.

[0037] A composite core-pulling mechanism for an injection mold further includes a lifting block 9 disposed above a slider 2. The upper ends of two guide pillars 3 are fixed to the bottom of the lifting block 9. A first back block 22 and a second back block 21 are formed on the upper right side of the top of the slider 2, respectively arranged front and rear. A first positioning inclined surface 26 and a second positioning inclined surface 27 are formed on the left outer wall of the first back block 22 and the second back block 21, respectively. Correspondingly, a third positioning inclined surface 91 and a fourth positioning inclined surface 92 are formed on the right outer wall of the lifting block 9, respectively cooperating with the first positioning inclined surface 26 and the second positioning inclined surface 27.

[0038] The first back block 22 and the second back block 21 are each provided with a number of ejector pin units distributed from top to bottom. Each ejector pin unit includes a number of ejector pins 10 that are horizontally and movably interwoven in the first back block 22 or the second back block 21, and are arranged from front to back, each having a tendency to elastically reset to the left.

[0039] Both the third positioning inclined surface 91 and the fourth positioning inclined surface 92 are provided with a guide cavity 93. On the bottom surface of each guide cavity 93, there are several stepped surfaces 94 that are distributed from top to bottom and connected end to end. The number of stepped surfaces 94 is the same as the number of ejector pin units. The left end of each ejector pin 10 in each ejector pin unit is engaged with a corresponding stepped surface 94.

[0040] A transition slope 95 is formed between any two adjacent step surfaces 94.

[0041] The first back block 22 and the second back block 21 have a first forming protrusion 24 and a second forming protrusion 23 formed to the right on their respective right outer walls.

[0042] A guide notch 101 is provided at the top right corner of the seat block 1. The slider 2 is movably connected in the guide notch 101. A second T-shaped opening groove 102 is provided between the bottom surface of the guide notch 101 and the bottom outer wall of the seat block 1. Correspondingly, a T-shaped connecting block 52 is formed at the bottom of the drive block 5. The T-shaped connecting block 52 is movably inserted into the second T-shaped opening groove 102. The telescopic end of the oil cylinder 4 is fixed on the T-shaped connecting block 52.

[0043] The distance between the inner walls of the left and right sides of the bottom of the second T-shaped opening groove 102 is greater than the width of the head of the T-shaped connecting block 52 in the left and right direction.

[0044] A rectangular through hole 29 is provided between the front and rear outer walls of the slider 2. A waist-shaped through hole 28 is provided between the right inner wall of the rectangular through hole 29 and the right outer wall of the slider 2. Two core blocks 111 in the stud forming assembly 11 are respectively movably inserted into the openings at the front and rear ends of the rectangular through hole 29. The semi-circular hoops 1111 on the two core blocks 111 are movably disposed in the waist-shaped through hole 28.

[0045] The top of the seat block 1 is also fixed with a support plate 7 horizontally positioned to the left of the guide notch 101. The top of the support plate 7 is also fixed with two micro switches 8 respectively positioned to the left and right. The moving contacts of the two micro switches 8 are positioned opposite each other. The top of the drive block 5 is also fixed with a limit rod 6. The end of the limit rod 6 forms a horizontally positioned bent portion 61. The end of the bent portion 61 is positioned facing forward or backward and located between the moving contacts of the two micro switches 8.

[0046] Working principle:

[0047] Fix the seat block 1 and the two guide blocks 112 in the stud forming assembly 11 to the fixed module of the injection mold and to one side of the fixed mold core; then fix the lifting block 9 to the moving module of the injection mold, and then fix the closed part of the feed cover 113 in the stud forming assembly 11 to the fixed mold core.

[0048] The extension end of the drive cylinder 4 retracts inward to drive the drive block 5 to move to the right, thereby driving the T-shaped connector 51 to move to the right within the first T-shaped opening groove 25 until the outer right side of the head of the T-shaped connector 51 is attached to the inner right side of the bottom of the first T-shaped opening groove 25, thereby separating the left side of the head of the T-shaped connector 51 from the left side of the bottom of the first T-shaped opening groove 25.

[0049] The drive module moves toward the fixed module to drive the two guide pillars 3 to move synchronously with the help of the lifting block 9, so that the ends of the two guide pillars 3 are gradually inserted into the slider 2, thereby forcing the slider 2 to move to the right, so that the first forming protrusion 24 and the second forming protrusion 23 are both embedded in the forming cavity located on the fixed mold core (existing technology); at this time, the semi-circular hoop 1111 on the two core blocks 111 in the stud forming assembly 11 will also move synchronously with the slider 2 and gradually approach the feed cover 113. The left outer wall of the head of the T-shaped connector 51 is attached to the bottom left inner wall of the first T-shaped opening groove 25, and the right side of the head of the T-shaped connector 51 is separated from the bottom right side of the first T-shaped opening groove 25.

[0050] Since the outer sides of the two core blocks 111 are movably connected to the two guide blocks 112 respectively, both of which have the function of tilting and translating left and right, the two core blocks 111 will also move closer to each other in the process of moving to the right, and slowly extend into the opening of the feed cover 113 until the semi-circular hoops 1111 on the two core blocks 111 are joined together to form a hollow cylinder, and the semi-circular threaded surfaces 1112 on the two semi-circular hoops 1111 will also be joined together to form a complete annular internal threaded surface. At this time, the semi-circular conical positioning surfaces 1113 on the two semi-circular hoops 1111 are all attached to the annular conical positioning surface 1132 on the feed hole 1131, thus playing a role in alignment to ensure coaxiality, and connecting the feed hole 1131 on the feed cover 113 with the interior of the hollow cylinder formed by the two semi-circular hoops 1111.

[0051] During the above process, the third positioning slope 91 and the fourth positioning slope 92 on the lifting block 9 will also move towards the first positioning slope 26 and the second positioning slope 27 respectively until they fit together. When the third positioning slope 91 and the fourth positioning slope 92 contact the left end of each ejector pin 10, they will force each ejector pin 10 to move to the right. Then, the left end of each ejector pin 10 will enter the corresponding guide cavity 93 in sequence, and then slide upward through each transition slope 95 and move further to the right until the left end of each ejector pin 10 is pressed against the corresponding step surface 94. In this way, each ejector pin 10 is pushed out to the right so that its right end is inserted into the fixed mold core.

[0052] Afterwards, the molten material enters the space between the moving mold core and the fixed mold core through the sprue in the moving module to complete the injection molding. After cooling, the injection molded part is formed (existing technology). A portion of the molten material enters the space between the two semi-circular clamps 1111 through the feed hole 1131, so the part located between the two semi-circular clamps 1111 forms an external threaded post; however, it does not enter the interior of the feed cover 113 and wrap around the exterior of the two semi-circular clamps 1111. In other words, the space between the two semi-circular clamps 1111 and the feed cover 113 is hollow, thus reserving space for the separation of the two semi-circular clamps 1111.

[0053] Next, the driving module is first driven to move in the opposite direction to gradually move away from the fixed module. Then, in the same way, the lifting block 9 and the two guide pillars 3 are driven to move synchronously, so that each ejector pin 10 moves to the left to reset so that its right end moves away from the fixed mold core. At the same time, the slider 2 is forced to move to the left to reset so that the first forming protrusion 24 and the second forming protrusion 23 move away from the fixed mold core. When the two guide pillars 3 move away from the slider 2, the outer right side of the head of the T-shaped connector 51 is attached to the inner right side of the bottom of the first T-shaped opening slot 25. The left side of the head of the T-shaped connector 51 is separated from the left side of the bottom of the first T-shaped opening slot 25. During this process, since the outer sides of the two core blocks 111 are movably connected to the two guide blocks 112 respectively, they have the function of tilting and translating left and right. Therefore, the two semi-circular hoops 1111 will gradually separate from each other while moving to the left, so that the semi-circular threaded surfaces 1112 on the two semi-circular hoops 1111 will move away from the formed external threaded column, thereby realizing the rapid demolding of the external threaded column.

[0054] Finally, the extension end of the drive cylinder 4 extends outward to drive the drive block 5 to continue moving to the left, thereby further increasing the distance between the slider 2 and the fixed mold core to facilitate demolding.

[0055] This invention extends the moving distance of the slider 2 and divides the moving process into two stages. The movement of the slider 2 is accomplished by means of two guide posts 3, and the movement of each ejector pin 10 is accomplished by means of a stroke extension mechanism. This separates the movements of the slider 2 and each ejector pin 10 to eliminate the contradiction between their movements. In addition, the stud forming assembly 11 is used to realize the rapid disengagement of the external threaded post, replacing the structure of rotational disengagement. This eliminates the need for motor drive and is less likely to interfere with other components, thereby simplifying the structure, reducing costs, and reducing installation difficulty.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite core-pulling mechanism for an injection mold, comprising a base block, a slider movably connected to the right side of the base block for left-right translation, and two guide pillars obliquely interspersed in the slider and distributed front-back and parallel to each other, characterized in that: A stroke extension mechanism is also provided between the seat block and the slider. The stroke extension mechanism includes a hydraulic cylinder fixed to the right side of the seat block and located below the slider, and a drive block fixed to the extension end of the hydraulic cylinder and connected to the slider. The extension end of the hydraulic cylinder is arranged laterally to the left. A first T-shaped opening groove is provided between the top and bottom outer walls on the left side of the slider. Correspondingly, a T-shaped connector is formed on the right side of the drive block facing the slider. The T-shaped connector is movably embedded in the first T-shaped opening groove. The bottom front and rear inner walls of the first T-shaped opening groove slide against the front and rear outer walls of the head of the T-shaped connector, respectively. It also includes a stud forming assembly on the slider. The stud forming assembly includes two core blocks that are symmetrically arranged and movably inserted into the front and rear sides of the slider, each having the function of forward and backward translation, and two guide blocks that are symmetrically arranged in front of and behind the slider and cooperate with the two core blocks respectively. The outer sides of the two core blocks are movably connected to the two guide blocks respectively, each having the function of left and right tilting and translation. The two core blocks each have a horizontally arranged semi-circular hoop formed on the opposite side edge of the right outer wall. The two semi-circular hoops are concentrically arranged and cooperate with each other. The inner walls of the two semi-circular hoops each have a mutually cooperating semi-circular threaded surface. The ends of the two semi-circular hoops extend movably to the front side of the slider so that they can both have the function of forward and backward translation. The distance between the inner walls of the left and right sides of the bottom of the first T-shaped opening groove is greater than the width of the head of the T-shaped connector in the left and right direction, and the width of the opening of the first T-shaped opening groove in the left and right direction is less than the length of the tail of the T-shaped connector in the left and right direction. It also includes a lifting block located above the slider. The upper ends of the two guide posts are fixed to the bottom of the lifting block. A first back block and a second back block are formed on the upper right side of the slider, respectively arranged front and back. A first positioning slope and a second positioning slope are formed on the left outer wall of the first back block and the second back block, respectively. Correspondingly, a third positioning slope and a fourth positioning slope are formed on the right outer wall of the lifting block, respectively cooperating with the first positioning slope and the second positioning slope.

2. The composite core-pulling mechanism for an injection mold according to claim 1, characterized in that, The stud forming assembly also includes a feed cover located to the right of the slider. The opening of the feed cover faces left and is concentrically distributed with the two semi-circular hoops. The inner diameter of the feed cover is larger than the outer diameter of either semi-circular hoop.

3. The composite core-pulling mechanism for an injection mold according to claim 2, characterized in that, The feed cover has a feed hole at the center of its closed portion, and the inner diameter of the feed hole matches the inner diameter of the two semi-circular hoops.

4. The composite core-pulling mechanism for an injection mold according to claim 3, characterized in that, The inner opening edge of the feed hole has an annular conical positioning surface. Correspondingly, the outer edges of the ends of the two semi-circular hoops each have a semi-circular conical positioning surface, and the two semi-circular conical positioning surfaces cooperate with the annular conical positioning surface.

5. The composite core-pulling mechanism for an injection mold according to claim 1, characterized in that, Both the first back block and the second back block are provided with a number of ejector pin units distributed from top to bottom. Each ejector pin unit includes a number of ejector pins that are horizontally and movably interwoven in the first back block or the second back block, all of which have a tendency to elastically reset to the left and are arranged from front to back.

6. The composite core-pulling mechanism for an injection mold according to claim 5, characterized in that, Both the third and fourth positioning inclined surfaces are provided with a guide cavity. On the bottom surface of each guide cavity, there are several stepped surfaces that are distributed from top to bottom and connected end to end. The number of stepped surfaces is the same as the number of ejector pin units. The left end of each ejector pin in each ejector pin unit is engaged with a corresponding stepped surface. A transition inclined surface is also formed between any two adjacent stepped surfaces.

7. The composite core-pulling mechanism for an injection mold according to claim 1, characterized in that, A rectangular through hole is provided between the front and rear outer walls of the slider, and a waist-shaped through hole is provided between the right inner wall of the rectangular through hole and the right outer wall of the slider. The two core blocks in the stud forming assembly are respectively movably inserted into the front and rear openings of the rectangular through hole, and the semi-circular hoops on the two core blocks are movably disposed in the waist-shaped through hole.

8. The composite core-pulling mechanism for an injection mold according to claim 7, characterized in that, The top of the seat block is also fixed with a support plate horizontally positioned to the left of the guide notch. The top of the support plate is also fixed with two microswitches respectively positioned to the left and right. The moving contacts of the two microswitches are positioned opposite each other. The top of the drive block is also fixed with a limit rod. The end of the limit rod forms a horizontally positioned bend. The end of the bend is positioned facing forward or backward and located between the moving contacts of the two microswitches.

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