Bag opening opening mechanism of packaging machine

Abstract

A bag opening opening mechanism of a packaging machine comprises a bag opening base, a first opening mechanism and a second opening mechanism. Each of the first opening mechanism and the second opening mechanism comprises an opening mechanism support, a swinging rotating shaft, a movable seat, an upper bag opening plate, a lower bag opening plate, an opening and closing rotating shaft, a first opening and closing connecting rod and a second opening and closing connecting rod, the swinging rotating shafts are rotatably mounted on the opening mechanism supports and move up and down, and the movable seats are mounted on the swinging rotating shafts; the opening and closing rotating shaft is rotatably installed on the movable seat and arranged in the horizontal direction, the rear end of the upper bag opening plate is connected with the opening and closing rotating shaft, the rear end of the lower bag opening plate is connected with the movable seat, the first end of the first opening and closing connecting rod is connected with the opening and closing rotating shaft, and the second end of the first opening and closing connecting rod is hinged to the first end of the second opening and closing connecting rod. The second end of the second opening and closing connecting rod is hinged to the opening mechanism support, and the opening mechanism support is provided with a swing mechanism capable of driving the swing rotating shaft to rotate. According to the utility model, pipeline arrangement and action process control can be simplified.

Description

Technical Field

[0001] This utility model relates to packaging machinery, specifically to a bag opening mechanism for a packaging machine. Background Technology

[0002] Chinese utility model patent specification CN204750687U discloses a bag-opening device for a fully automatic diaper packaging production line, including a bag-opening base, an adsorption device, a first opening mechanism, and a second opening mechanism. The first opening mechanism, the second opening mechanism, and the adsorption device are all mounted on the bag-opening base. The first opening mechanism and the second opening mechanism are located on the left and right sides of the bag-opening base, respectively, and the adsorption device is located in front of the first opening mechanism and the second opening mechanism. The first opening mechanism and the second opening mechanism each include a swing mechanism, a movable seat, an upper bag-opening plate, a lower bag-opening plate, and an opening and closing mechanism for driving the upper bag-opening plate and the lower bag-opening plate to open and close up and down. The swing mechanism is mounted on the bag-opening base. The movable seat is mounted on the power output end of the swing mechanism. The opening and closing mechanism is mounted on the movable seat. The rear ends of the upper bag-opening plate and the lower bag-opening plate are connected to the opening and closing mechanism. The swing mechanism includes a swing cylinder, a swing shaft, and a swing connecting rod. Both the swing shaft and the swing cylinder are mounted on the bag-opening base. One end of the swing connecting rod is connected to the swing shaft, and the piston rod of the swing cylinder is connected to the middle of the swing connecting rod. The movable seat is mounted on the second end of the swing connecting rod. The opening and closing mechanism includes a bracket, an opening and closing cylinder, an opening and closing shaft, and a connecting piece. The bracket is mounted on the movable seat. The opening and closing shaft is rotatably mounted on the upper end of the bracket. The connecting piece is fixedly mounted on the opening and closing shaft. The opening and closing cylinder is mounted on the bracket, and the piston rod of the opening and closing cylinder is hinged to the connecting piece. The rear end of the upper bag-opening plate is connected to the connecting piece. The rear end of the lower bag-opening plate is connected to the bracket. The opening height of the bag opening is determined by the opening amplitude of the upper and lower bag-opening plates.

[0003] In the aforementioned first and second opening mechanisms, a swing mechanism drives the upper and lower opening plates to open the bag openings outwards in a left-right direction. The extension and retraction of the piston rod of the swing cylinder pushes the swing connecting rod to rotate around the swing axis. The extension and retraction of the piston rod of the opening and closing cylinder causes the connecting piece to rotate with the opening and closing axis. The connecting piece causes the front part of the upper opening plate to swing up and down, opening or closing the front parts of the upper and lower opening plates. However, since each swing cylinder and opening and closing cylinder requires two inlet and outlet pipes, which are connected to a compressed air source via an electromagnetic reversing valve, the pipeline layout in the first and second opening mechanisms is complex and congested. Furthermore, the opening and closing cylinders require individual control, increasing the complexity of the operation process. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a bag opening mechanism for a packaging machine, which simplifies pipeline layout and operation process control. The technical solution adopted is as follows:

[0005] A bag opening mechanism for a packaging machine includes a bag opening base, a first opening mechanism, and a second opening mechanism. Both the first and second opening mechanisms are mounted on the bag opening base and are arranged side-by-side. The first and second opening mechanisms each include an opening mechanism bracket, a swing shaft, a movable seat, an upper bag opening plate, a lower bag opening plate, an opening and closing shaft, a first opening and closing connecting rod, and a second opening and closing connecting rod. The opening mechanism bracket is mounted on the bag opening base. The swing shaft is rotatably mounted on the opening mechanism bracket and runs vertically. The movable seat is mounted on the swing shaft. The opening and closing shaft is rotatably mounted on the movable seat and is arranged horizontally. The rear end of the upper bag opening plate is connected to the opening and closing shaft, and the rear end of the lower bag opening plate is connected to the movable seat. The first end of the first opening and closing connecting rod is connected to the opening and closing shaft, and the second end of the first opening and closing connecting rod is hinged to the first end of the second opening and closing connecting rod. The second end of the second opening and closing connecting rod is hinged to the opening mechanism bracket. The opening mechanism bracket is equipped with a swing mechanism capable of driving the swing shaft to rotate.

[0006] When the bag opening mechanism described above is working, in the initial state, the upper and lower opening plates of the first and second opening mechanisms are close to each other. After the bag feeding device delivers the packaging bag to the bottom of the adsorption device, and the adsorption device lifts the upper side of the packaging bag to open the bag opening, the upper and lower opening plates of the first and second opening mechanisms are inserted forward into the bag opening. Driven by the swing mechanism, they simultaneously swing outward around the swing axis, causing the bag opening to open to the left and right. At the same time, due to the outward swing of the movable seat around the swing axis, the position of the first end of the first opening and closing link changes (for example, it becomes closer to the second end of the second opening and closing link). Thus, under the pushing action of the second opening and closing link, the second end of the first opening and closing link swings around the opening and closing axis. The opening and closing axis rotates, thereby driving the front end of the upper opening plate to swing upward. The distance between the front end of the upper opening plate and the front end of the lower opening plate increases, causing the bag opening to open in the up and down direction, thereby opening the bag opening to a suitable width and height.

[0007] In the preferred embodiment, the second end of the first opening and closing link is hinged to the first end of the second opening and closing link via a first ball joint, and the second end of the second opening and closing link is hinged to the support of the opening mechanism via a second ball joint.

[0008] In the preferred embodiment, the second opening and closing link is an adjustable length member.

[0009] In a more preferred embodiment, the second opening / closing linkage includes a first connecting screw, a second connecting screw, and an internally threaded tube. The first and second connecting screws are respectively provided with external threads in opposite directions. The internally threaded tube has internal threads at both ends that match the first and second connecting screws. The end of the first connecting screw is hinged to the second end of the first opening / closing linkage, and the end of the second connecting screw is hinged to the support of the opening mechanism. More preferably, the internally threaded tube has two symmetrical notches in its middle section, which can be used with tools such as wrenches. When the length of the second opening / closing linkage needs to be adjusted, the two sides of the wrench opening are respectively inserted into these two notches, and then the internally threaded tube can be turned to adjust the length of the second opening / closing linkage.

[0010] As a first preferred embodiment of the swing mechanism, the aforementioned swing mechanism includes a swing cylinder and a first swing connecting rod. The cylinder body of the swing cylinder is hinged to the support of the opening mechanism. The first end of the first swing connecting rod is connected to the swing shaft or the movable seat, and the second end of the first swing connecting rod is hinged to the piston rod of the swing cylinder. When the piston rod of the swing cylinder extends or retracts, it drives the swing shaft to rotate through the first swing connecting rod, thereby realizing the swinging of the movable seat and the upper and lower opening bags.

[0011] As a second preferred embodiment of the swing mechanism, the aforementioned swing mechanism includes a swing cylinder, a first swing connecting rod, a second swing connecting rod, and a third swing connecting rod. The cylinder body of the swing cylinder is hinged to the support of the opening mechanism. The piston rod of the swing cylinder is provided with a hinge seat, and the hinge seat is provided with a pin. The first end of the first swing connecting rod is connected to the swing shaft or the movable seat, and the second end of the first swing connecting rod is hinged to the first end of the second swing connecting rod. The second end of the second swing connecting rod is provided with a circular pin hole that matches and fits with the pin. The first end of the third swing connecting rod is hinged to the support of the opening mechanism, and the second end of the third swing connecting rod is provided with a circular pin hole that matches and fits with the pin. When the piston rod of the swing cylinder extends or retracts, it drives the swing shaft to rotate through the second and first swing connecting rods, thereby realizing the swing of the movable seat and the upper and lower opening bag plates. The third swing connecting rod is used to move the hinge seat and the pin along a predetermined trajectory.

[0012] A more preferred embodiment of the second preferred embodiment of the swing mechanism is provided on the support of the aforementioned opening mechanism, with the limit block located directly in front of the hinge seat. When the piston rod of the swing cylinder extends, it reaches the predetermined stroke and stops moving forward when the hinge seat contacts the limit block. This allows for more precise control over the left and right swing angles of the upper and lower opening bags, as well as the upward swing angle of the upper opening bag. Preferably, the position of the limit block in the front-rear direction is adjustable.

[0013] In the preferred embodiment, the aforementioned opening mechanism support is equipped with a bag opening edge clamping plate, which is located outside the upper opening plate. A clamping gap exists between the front end of the bag opening edge clamping plate and the outer side of the upper opening plate. When the upper and lower opening plates of the first and second opening mechanisms are inserted forward into the bag opening of the packaging bag, the left and right sides of the bag opening edges enter the clamping gaps of the first and second opening mechanisms, respectively. Driven by the swing mechanism, the upper opening plate swings outward, opening the bag opening to the left and right. Simultaneously, the outer side of the upper opening plate and the front end of the bag opening edge clamping plate together clamp the bag opening edges in the clamping gaps, stabilizing the bag opening position. This facilitates the smooth pushing of sheet material into the innermost part of the packaging bag by the subsequent pusher mechanism, and also helps to make the sheet material in the packaging bag more compact.

[0014] In a more preferred embodiment, a rubber-coated screw is installed at the front end of the aforementioned bag opening edge clamping plate. The head of the rubber-coated screw is located on the side of the bag opening edge clamping plate facing the upper opening plate, and a clamping gap exists between the head of the rubber-coated screw and the outer surface of the upper opening plate. The head of the rubber-coated screw is covered with an elastic material (such as polyurethane), which serves to cushion and increase the coefficient of friction. When the upper opening plate swings outward under the drive of the swing mechanism, the outer surface of the upper opening plate and the head of the rubber-coated screw together clamp the bag opening edge.

[0015] In a further preferred embodiment, the front end of the bag opening edge clamping plate is provided with a strip-shaped limiting hole. The screw portion of the rubber-coated screw passes through the strip-shaped limiting hole, and a locking nut is installed on the screw portion. The locking nut and the head of the rubber-coated screw together clamp the front end of the bag opening edge clamping plate. By adjusting the position of the screw portion of the rubber-coated screw in the strip-shaped limiting hole, the position of the head of the rubber-coated screw can be adjusted, thereby adjusting the clamping position of the bag opening edge. The strip-shaped limiting hole can be vertically oriented, allowing the height of the head of the rubber-coated screw to be adjustable.

[0016] In another, more preferred embodiment, the front end of the bag opening edge clamping plate is provided with a screw hole, and the screw portion of the rubber-coated screw is screwed into the screw hole. By adjusting the screw depth of the screw portion, the initial gap between the head of the rubber-coated screw and the outer side of the upper opening plate can be adjusted, thereby adjusting the clamping force when the outer side of the upper opening plate and the head of the rubber-coated screw jointly clamp the bag opening edge.

[0017] Typically, the front end of the bag opening edge clamping plate is located behind the front end of the upper opening plate.

[0018] The distance between the first and second opening mechanisms can usually be adjusted according to the size of the bag opening. The specific adjustment mechanism can adopt existing technology, such as the first and second adjustment mechanisms in Chinese utility model patent publication number CN204750687U.

[0019] In operation, the upper and lower opening plates of the first and second opening mechanisms are inserted forward into the opening of the packaging bag. Driven by the swing mechanism, the upper and lower opening plates simultaneously swing outward around the swing axis, causing the bag opening to open to the left and right. Simultaneously, under the pushing action of the second opening and closing linkage, the second end of the first opening and closing linkage swings around the opening and closing axis, driving the front end of the upper opening plate to swing upward. This increases the distance between the front ends of the upper and lower opening plates, causing the bag opening to open vertically, thus opening the bag to a suitable width and height. Since the swing mechanism alone can achieve the left-right swinging and opening / closing control of the upper and lower opening plates, it simplifies pipeline layout and operational process control. Attached Figure Description

[0020] Figure 1 This is a schematic diagram (top view) of the preferred embodiment 1 of the present invention.

[0021] Figure 2 yes Figure 1 A schematic diagram of the first spreading mechanism (initial state);

[0022] Figure 3 yes Figure 1 A schematic diagram of the first opening mechanism (the state of the packaging bag opening);

[0023] Figure 4 This is a schematic diagram of the structure of the rubber-coated screw installed on the clamping plate at the edge of the bag opening in the preferred embodiment 1 of this utility model.

[0024] Figure 5 This is a schematic diagram of the structure of the rubber-coated screw installed on the clamping plate at the edge of the bag opening in the preferred embodiment 2 of this utility model. Detailed Implementation

[0025] Example 1, such as Figure 1 As shown, the bag opening mechanism of this packaging machine includes a bag opening base 2, a first opening mechanism 5, and a second opening mechanism 6. The first opening mechanism 5 and the second opening mechanism 6 are both installed on the bag opening base 2, and the first opening mechanism 5 and the second opening mechanism 6 are arranged side by side.

[0026] like Figure 2 and Figure 3 As shown ( Figure 2 and Figure 3The structure of the first opening mechanism 5 is shown. The structure of the second opening mechanism 6 is the same as that of the first opening mechanism 5 (the first opening mechanism 5 and the second opening mechanism 6 are symmetrical from left to right). Both the first opening mechanism 5 and the second opening mechanism 6 include an opening mechanism bracket 51, a swing shaft 52, a movable seat 53, an upper opening plate 54, a lower opening plate 55, an opening and closing shaft 56, a first opening and closing connecting rod 57, and a second opening and closing connecting rod 58. The opening mechanism bracket 51 is mounted on the opening base 2, and the swing shaft 52 is rotatably mounted on the opening mechanism bracket 51 and runs vertically. The movable seat 53 is mounted on the swing shaft 52. The opening and closing shaft 56 is rotatably mounted on the movable seat 53 and is arranged in the horizontal direction. The rear end of the upper opening plate 54 is connected to the opening and closing shaft 56, and the rear end of the lower opening plate 55 is connected to the movable seat 53. The first end of the first opening and closing link 57 is connected to the opening and closing shaft 56. The second end of the first opening and closing link 57 is hinged to the first end of the second opening and closing link 58. The second end of the second opening and closing link 58 is hinged to the support bracket 51 of the opening mechanism. The support bracket 51 of the opening mechanism is provided with a swing mechanism that can drive the swing shaft 52 to rotate.

[0027] In this embodiment, the second end of the first opening and closing link 57 is hinged to the first end of the second opening and closing link 58 via the first ball joint 59, and the second end of the second opening and closing link 58 is hinged to the support bracket 51 of the opening mechanism via the second ball joint 510.

[0028] In this embodiment, the second opening / closing link 58 is an adjustable length rod. The second opening / closing link 58 includes a first connecting screw 581, a second connecting screw 582, and an internally threaded tube 583. The first connecting screw 581 and the second connecting screw 582 are respectively provided with external threads in opposite directions. The two ends of the internally threaded tube 583 are respectively provided with internal threads that match those of the first connecting screw 581 and the second connecting screw 582. The end of the first connecting screw 581 is hinged to the second end of the first opening / closing link 57, and the end of the second connecting screw 582 is hinged to the support bracket 51 of the opening mechanism. The internally threaded tube 583 has two symmetrical notches 584 in its middle section, which can be used with tools such as wrenches. When the length of the second opening / closing link 58 needs to be adjusted, the two sides of the wrench opening are respectively inserted into the two notches 584, and then the internally threaded tube 583 can be turned to adjust the length of the second opening / closing link 58.

[0029] The aforementioned swing mechanism includes a swing cylinder 511, a first swing connecting rod 512, a second swing connecting rod 513, and a third swing connecting rod 514. The cylinder body of the swing cylinder 511 is hinged to the support bracket 51 of the spreading mechanism. A hinge seat 515 is provided on the piston rod of the swing cylinder 511, and a pin 516 is provided on the hinge seat 515. The first end of the first swing connecting rod 512 is connected to the swing rotating shaft 52 (or the movable seat 53), and the second end of the first swing connecting rod 512 is connected to the first end of the second swing connecting rod 513. The second swing link 513 has a circular pin hole at its second end that matches and engages with the pin 516 (this structure enables the second end of the second swing link 513 to be hinged to the hinge seat 515). The first end of the third swing link 514 is hinged to the support bracket 51 of the opening mechanism, and the second end of the third swing link 514 has a circular pin hole that matches and engages with the pin 516 (this structure enables the second end of the third swing link 514 to be hinged to the hinge seat 515). When the piston rod of the swing cylinder 511 extends or retracts, it drives the swing shaft 52 to rotate through the second swing link 513 and the first swing link 512, thereby realizing the swing of the movable seat 53, the upper opening bag plate 54, and the lower opening bag plate 55; the third swing link 514 is used to move the hinge seat 515 and the pin 516 along a predetermined trajectory.

[0030] A limiting block 517 is provided on the support bracket 51 of the opening mechanism, and the limiting block 517 is located directly in front of the hinge seat 515. When the piston rod of the swing cylinder 511 extends, the hinge seat 515 reaches the predetermined stroke and stops moving forward when it contacts the limiting block 517. This allows for more precise control of the left and right swing angles of the upper opening plate 54 and the lower opening plate 55, as well as the upward swing angle of the upper opening plate 54. Preferably, the position of the limiting block 517 in the front-back direction is adjustable.

[0031] In this embodiment, the support bracket 51 of the opening mechanism is provided with a bag opening edge clamping plate 518. The bag opening edge clamping plate 518 is located outside the upper opening plate 54, and there is a clamping gap 519 between the front end of the bag opening edge clamping plate 518 and the outer side surface 541 of the upper opening plate 54. Reference Figure 4A rubber-coated screw 520 is installed at the front end of the bag opening edge clamping plate 518. The head 521 of the rubber-coated screw 520 is located on the side of the bag opening edge clamping plate 518 facing the upper opening plate 54. A clamping gap 519 is formed between the head 521 of the rubber-coated screw 520 and the outer side 541 of the upper opening plate 54. The head of the rubber-coated screw 520 is covered with an elastic material 522 (such as polyurethane) to cushion the impact and increase the coefficient of friction. When the upper opening plate 54 and lower opening plate 55 of the first opening mechanism 5 and the second opening mechanism 6 are inserted forward into the bag opening of the packaging bag, the left and right sides of the bag opening edges enter the clamping gaps 519 on the first opening mechanism 5 and the second opening mechanism 6 respectively. After the upper opening plate 54 swings outward under the drive of the swing mechanism, while the bag opening opens to the left and right, the outer side 541 of the upper opening plate 54 and the head 521 of the rubber-coated screw 520 together clamp the bag opening edge 10 in the clamping gap 519, so that the bag opening position remains stable.

[0032] The front end of the bag opening edge clamping plate 518 is provided with a strip-shaped limiting hole 523. The screw portion 524 of the rubber-coated screw 520 passes through the strip-shaped limiting hole 523. A locking nut 525 is installed on the screw portion 524 of the rubber-coated screw 520. The locking nut 525 and the head 521 of the rubber-coated screw together clamp the front end of the bag opening edge clamping plate 518. By adjusting the position of the screw portion 524 of the rubber-coated screw in the strip-shaped limiting hole 523, the position of the head 521 of the rubber-coated screw can be adjusted, thereby adjusting the clamping position of the bag opening edge. In this embodiment, the strip-shaped limiting hole 523 is vertically oriented, making the height position of the head 521 of the rubber-coated screw adjustable.

[0033] The front end of the bag opening edge clamping plate 518 is located behind the front end of the upper bag opening plate 54.

[0034] The working principle of this bag opening mechanism is briefly described below:

[0035] When this bag opening mechanism is working, in the initial state, the front ends of the upper bag opening plate 54 and the lower bag opening plate 55 of the first opening mechanism 5 and the second opening mechanism 6 are close to each other. After the bag feeding device delivers the packaging bag to the bottom of the adsorption device, the adsorption device lifts the upper side of the packaging bag to open the bag opening. Then, the upper opening plate 54 and lower opening plate 55 of the first opening mechanism 5 and the second opening mechanism 6 are inserted forward into the bag opening. Driven by the swing mechanism, they swing outward around the swing axis 52, causing the bag opening to open to the left and right. At the same time, as the movable seat 53 swings outward around the swing axis 52, the position of the first end of the first opening and closing link 57 changes (for example, the first end of the first opening and closing link 57 is closer to the second end of the second opening and closing link 58). Thus, under the pushing action of the second opening and closing link 58, the second end of the first opening and closing link 57 swings around the opening and closing axis 56. The opening and closing axis 56 rotates, thereby driving the front end of the upper opening plate 54 to swing upward. The distance between the front end of the upper opening plate 54 and the front end of the lower opening plate 55 increases, causing the bag opening to open in the up and down direction, thereby opening the bag opening to a suitable width and height. When a reset is required, the first opening mechanism 5 and the second opening mechanism 6 retract. Driven by the swing mechanism, the upper opening plate 54 and the lower opening plate 55 swing inward around the swing axis 52. At the same time, as the movable seat 53 swings inward around the swing axis 52, the second end of the first opening link 57 swings in the opposite direction around the opening axis 56 under the action of the second opening link 58. The opening axis 56 rotates in the opposite direction, thereby driving the front end of the upper opening plate 54 to swing downward, and the front end of the upper opening plate 54 and the front end of the lower opening plate 55 move closer to each other.

[0036] Example 2, Reference Figure 5 In this embodiment, the rubber-coated screw 520 is installed on the bag opening edge clamping plate 518 as follows: the front end of the bag opening edge clamping plate 518 is provided with a screw hole 526, and the screw portion 524 of the rubber-coated screw 520 is screwed into the screw hole 526. By adjusting the screw depth of the screw portion 524, the initial gap between the head 521 of the rubber-coated screw and the outer side surface 541 of the upper opening plate 54 can be adjusted, thereby adjusting the clamping force when the outer side surface 541 of the upper opening plate 54 and the head 521 of the rubber-coated screw jointly clamp the bag opening edge. The rest of the structure in this embodiment is the same as in embodiment 1.

[0037] In another embodiment, as a different implementation of the swing mechanism, the swing mechanism includes a swing cylinder and a first swing connecting rod. The cylinder body of the swing cylinder is hinged to the support of the opening mechanism. The first end of the first swing connecting rod is connected to the swing shaft or the movable seat, and the second end of the first swing connecting rod is hinged to the piston rod of the swing cylinder. When the piston rod of the swing cylinder extends or retracts, it drives the swing shaft to rotate through the first swing connecting rod, thereby realizing the swing of the movable seat and the upper and lower opening bags.

Claims

1. A bag opening mechanism for a packaging machine, comprising a bag opening base, a first opening mechanism, and a second opening mechanism, wherein the first opening mechanism and the second opening mechanism are both mounted on the bag opening base and are arranged side by side, characterized in that: Both the first and second opening mechanisms include an opening mechanism bracket, a swing shaft, a movable seat, an upper opening plate, a lower opening plate, an opening and closing shaft, a first opening and closing connecting rod, and a second opening and closing connecting rod. The opening mechanism bracket is mounted on the opening base. The swing shaft is rotatably mounted on the opening mechanism bracket and runs vertically. The movable seat is mounted on the swing shaft. The opening and closing shaft is rotatably mounted on the movable seat and is arranged horizontally. The rear end of the upper opening plate is connected to the opening and closing shaft, and the rear end of the lower opening plate is connected to the movable seat. The first end of the first opening and closing connecting rod is connected to the opening and closing shaft, and the second end of the first opening and closing connecting rod is hinged to the first end of the second opening and closing connecting rod. The second end of the second opening and closing connecting rod is hinged to the opening mechanism bracket. The opening mechanism bracket is provided with a swing mechanism that can drive the swing shaft to rotate.

2. The bag opening mechanism of the packaging machine according to claim 1, characterized in that: The second end of the first opening and closing link is hinged to the first end of the second opening and closing link via a first ball joint, and the second end of the second opening and closing link is hinged to the support of the opening mechanism via a second ball joint.

3. The bag opening mechanism of the packaging machine according to claim 1 or 2, characterized in that: The second opening and closing linkage includes a first connecting screw, a second connecting screw, and an internally threaded tube. The first connecting screw and the second connecting screw are respectively provided with external threads with opposite directions of rotation. The two ends of the internally threaded tube are respectively provided with internal threads that match the first connecting screw and the second connecting screw. The end of the first connecting screw is hinged to the second end of the first opening and closing linkage, and the end of the second connecting screw is hinged to the support of the opening mechanism.

4. The bag opening mechanism of the packaging machine according to claim 1 or 2, characterized in that: The swing mechanism includes a swing cylinder, a first swing link, a second swing link, and a third swing link. The cylinder body of the swing cylinder is hinged to the support of the spreading mechanism. The piston rod of the swing cylinder is provided with a hinge seat, and the hinge seat is provided with a pin. The first end of the first swing link is connected to the swing shaft or the movable seat. The second end of the first swing link is hinged to the first end of the second swing link. The second end of the second swing link is provided with a circular pin hole that matches and fits with the pin. The first end of the third swing link is hinged to the support of the spreading mechanism. The second end of the third swing link is provided with a circular pin hole that matches and fits with the pin.

5. The bag opening mechanism of the packaging machine according to claim 4, characterized in that: The support frame of the spreading mechanism is equipped with a limiting block, which is located directly in front of the hinge seat.

6. The bag opening mechanism of the packaging machine according to claim 1 or 2, characterized in that: The swing mechanism includes a swing cylinder and a first swing link. The cylinder body of the swing cylinder is hinged to the support of the spreading mechanism. The first end of the first swing link is connected to the swing shaft or movable seat, and the second end of the first swing link is hinged to the piston rod of the swing cylinder.

7. The bag opening mechanism of the packaging machine according to claim 1 or 2, characterized in that: The support frame of the opening mechanism is provided with a bag opening edge clamping plate, which is located on the outside of the upper opening plate. There is a clamping gap between the front end of the bag opening edge clamping plate and the outer side of the upper opening plate.

8. The bag opening mechanism of the packaging machine according to claim 7, characterized in that: A rubber-coated screw is installed at the front end of the bag opening edge clamping plate. The head of the rubber-coated screw is located on the side of the bag opening edge clamping plate facing the upper opening plate, and there is a clamping gap between the head of the rubber-coated screw and the outer side of the upper opening plate.

9. The bag opening mechanism of the packaging machine according to claim 8, characterized in that: The front end of the bag opening edge clamping plate is provided with a strip-shaped limiting hole. The screw of the rubber-coated screw passes through the strip-shaped limiting hole, and a locking nut is installed on the screw of the rubber-coated screw. The locking nut and the head of the rubber-coated screw together clamp the front end of the bag opening edge clamping plate.

10. The bag opening mechanism of the packaging machine according to claim 8, characterized in that: The front end of the bag opening edge clamping plate is provided with a screw hole, and the screw part of the rubber-coated screw is screwed into the screw hole.

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