Automatic ultrasonic heat sealing device and packaging machine to prevent finger pinching

Abstract

The present invention relates to an automatic ultrasonic heat-sealing device that prevents finger pinching. The device comprises an ultrasonic generator, an upper heat-sealing die, a lower heat-sealing die, a drive mechanism, and an electrical control module. The ultrasonic generator is connected to the upper heat-sealing die, which is connected to the upper heat-sealing die via a rotating shaft. The drive mechanism is connected to the electrical control module and is also connected to the lower heat-sealing die to drive the lower heat-sealing die to rotate about the rotating shaft. The upper heat-sealing die is provided with a magnetic switch for detecting the gap between the upper heat-sealing die and the lower heat-sealing die. The electrical control module first controls the drive mechanism to drive the lower heat-sealing die toward the upper heat-sealing die with a small driving force; upon receiving a safety signal from the magnetic switch, the drive mechanism controls the drive mechanism to drive the lower heat-sealing die toward the upper heat-sealing die with a larger driving force. Compared with the prior art, the present invention detects the gap between the upper and lower dies using a magnetic switch. When the gap is greater than a safe distance, a smaller safety driving force is used to prevent hand pinching, thereby improving the safety of the ultrasonic heat-sealing device.

Description

Technical Field

[0001] The invention relates to the field of ultrasonic heat sealing, in particular to an automatic ultrasonic heat sealing device for preventing hand pinching. Background Art

[0002] Currently, a wide variety of packaging bags exist in the powder packaging industry, corresponding to a variety of bag-opening heat-sealing devices. For PE bags, existing bag-opening heat-sealing devices typically utilize electric heating strips, which are categorized as either instantaneous or constant-temperature heating. The instantaneous heating method applies a short, high current to the heating strip after the bag opening is clamped, instantly heating it to the PE melting point to achieve a heat seal. This method places stringent requirements on the size, mounting method, duration of power supply, and voltage of the heating strip, and is prone to temperature instability, resulting in either a weak seal or burns to the bag opening. Constant-temperature heating, on the other hand, applies a continuous, stable voltage to the heating strip, maintaining its temperature at a specific value near the PE melting point. This method poses risks such as burns to workers due to the constant high temperature of the heating element and consumes a lot of energy. Furthermore, regardless of the principle employed, conventional heat-sealing devices involve mechanical movement to close the bag opening. This action lacks comprehensive safety measures, and if a worker accidentally places their hand in the clamps to close the bag opening, serious consequences such as pinching can occur.

[0003] In order to solve the problem of burns, technicians in this field have developed an ultrasonic heat sealing device, which can drive the upper heat sealing mold to vibrate at high frequency, causing the PE layer material sandwiched between the upper and lower molds to generate heat and melt due to the high-frequency vibration, so no high temperature will remain. However, due to the lack of high temperature, when the hot air conduction warning is lost, and the lower mold generally adopts a semi-circular lower mold, it is easier to get your hands pinched due to carelessness. Summary of the Invention

[0004] The purpose of the present invention is to provide an automatic ultrasonic heat sealing device that can prevent fingers from being pinched. The gap distance between the upper and lower molds is detected by a magnetic switch. When the gap distance is greater than the safety distance, a smaller safety driving force is used to avoid pinching hands, thereby improving the safety of the ultrasonic heat sealing device.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] An automatic ultrasonic heat sealing device for preventing finger pinching includes an ultrasonic generator, an upper heat sealing die, a lower heat sealing die, a drive mechanism, and an electrical control module. The ultrasonic generator is connected to the upper heat sealing die, and the lower heat sealing die is connected to the upper heat sealing die via a rotating shaft. The drive mechanism is connected to the electrical control module and is connected to the lower heat sealing die to drive the lower heat sealing die to rotate around the rotating shaft. The device is characterized in that a magnetic switch for detecting the gap between the upper heat sealing die and the lower heat sealing die is provided on the upper heat sealing die, and the magnetic switch is connected to the electrical control module. The electrical control module is configured to perform the following steps:

[0007] When heat sealing operation is required, the driving mechanism is controlled to drive the heat sealing lower mold to close to the heat sealing upper mold with a first driving force;

[0008] When the safety signal of the magnetic switch is received, the driving mechanism is controlled to drive the heat-sealing lower mold to close to the heat-sealing upper mold with a second driving force, wherein the second driving force is greater than the first driving force, and the safety signal indicates that the gap distance between the heat-sealing upper mold and the heat-sealing lower mold is less than or equal to the set distance.

[0009] The driving mechanism includes two clamping cylinders.

[0010] The electrical control module includes a controller, an air source, a first controlled valve and a pressure reducing valve. The output end of the air source is connected to the two clamping cylinders through the first controlled valve, and is connected to the two clamping cylinders in turn through the first controlled valve and the pressure reducing valve. The first controlled valve is connected to the controller.

[0011] The first controlled valve is a solenoid valve.

[0012] The device also includes a lifting mechanism for adjusting the height of the heat-sealing upper mold and the heat-sealing lower mold, and the lifting mechanism is connected to the heat-sealing upper mold.

[0013] The lifting mechanism is a lifting cylinder.

[0014] The electrical control module includes a controller, an air source, and a second controlled valve. The output end of the air source is connected to the lifting cylinder through the second controlled valve, and the second controlled valve is connected to the controller.

[0015] The second controlled valve is a solenoid valve.

[0016] The set distance is 4 mm.

[0017] A packaging machine comprises the ultrasonic heat sealing device as described above.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1) The gap distance between the upper and lower molds is detected by a magnetic switch. When the gap distance is greater than the safety distance, a smaller safety driving force is used to avoid pinching hands and improve the safety of the ultrasonic heat sealing device.

[0020] 2) Two clamping cylinders are used to make the clamping opening and closing process more stable.

[0021] 3) Using 4 mm as the safety distance can improve efficiency while ensuring safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the magnetic switch arrangement according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the heat-sealed lower mold in an open state according to an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the downward movement of the heat sealing module according to an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the closed state of the heat-sealed lower mold according to an embodiment of the present invention;

[0027] Figure 6 is an electrical schematic diagram of an electrical control module in an embodiment of the present invention;

[0028] Among them: 1. Fixed frame, 2. Pressure reducing valve, 3. Third controlled valve, 4. Lifting cylinder, 5. Ultrasonic generator, 6. Clamping cylinder, 7. Bag opening pressure plate, 8. Valve bag, 9. Heat sealing lower mold, 10. Heat sealing upper mold, 11. Dust removal nozzle, 12. Magnetic switch, 13. Air source, 14. First controlled valve, 15. Two-valve plate, 16. Second controlled valve, 17. Muffler, 18. Throttle valve. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0030] An automatic ultrasonic heat sealing device for preventing finger pinching can be used in a fully automatic powder packaging machine with a valve bag, such as Figure 1As shown, it includes an ultrasonic generator 5, a heat-sealing upper mold 10, a heat-sealing lower mold 9, a driving mechanism, and an electrical control module. The heat-sealing lower mold 9 generally adopts a semicircular lower mold with high strength and high toughness. The ultrasonic generator 5 is connected to the heat-sealing upper mold 10, and the heat-sealing lower mold 9 is connected to the heat-sealing upper mold 10 through a rotating shaft. The driving mechanism is connected to the electrical control module and connected to the heat-sealing lower mold 9 to drive the heat-sealing lower mold 9 to rotate around the rotating shaft. It is characterized in that a magnetic switch 12 for detecting the gap distance between the heat-sealing upper mold 10 and the heat-sealing lower mold 9 is provided on the heat-sealing upper mold 10. Figure 2 As shown, the magnetic switch 12 is connected to the electrical control module, and the electrical control module is configured to perform the following steps:

[0031] When heat sealing operation is required, the driving mechanism is controlled to drive the heat sealing lower mold 9 to close to the heat sealing upper mold 10 with a first driving force;

[0032] After receiving the safety signal from the magnetic switch 12, the control driving mechanism drives the heat-sealing lower mold 9 to close to the heat-sealing upper mold 10 with a second driving force, wherein the second driving force is greater than the first driving force, and the safety signal indicates that the gap distance between the heat-sealing upper mold 10 and the heat-sealing lower mold 9 is less than or equal to the set distance.

[0033] The gap distance between the upper and lower molds is detected by a magnetic switch. When the gap distance is greater than the safety distance, a smaller safety driving force is used to avoid pinching hands, thereby improving the safety of the ultrasonic heat sealing device. When the gap distance between the heat sealing upper mold 10 and the heat sealing lower mold 9 is less than or equal to the set distance, it switches to a large driving force to ensure the clamping heat sealing effect.

[0034] In some embodiments, the semicircular lower mold with high strength and high toughness

[0035] In some embodiments, the relative position relationship between the heat-sealing upper mold 10 and the heat-sealing lower mold 9 can be that the heat-sealing lower mold 9 is on top. In other embodiments, the left and right settings can also be adopted, depending on actual needs. The heat-sealing upper mold 10 does not have to be in a vertically upper position.

[0036] In some embodiments, the driving mechanism includes two clamping cylinders 6, which are driven by cylinders to facilitate integrated control. Correspondingly, the electrical control module includes a controller, an air source 13, a first controlled valve 14 and a pressure reducing valve 2. The output end of the air source 13 is connected to the two clamping cylinders 6 through the first controlled valve 14, and is connected to the two clamping cylinders 6 through the first controlled valve 14 and the pressure reducing valve 2 in turn. The first controlled valve 14 is connected to the controller. In some embodiments, the first controlled valve 14 is a two-position five-way solenoid valve. When the output of the magnetic switch 12 is a low level, the output end of the first controlled valve connected to the clamping cylinder 6 is closed, and the output end connected to the pressure reducing valve 2 is turned on, thereby achieving a small driving force. Conversely, when the output of the magnetic switch 12 is a high level, the output end of the first controlled valve connected to the clamping cylinder 6 is turned on, and the output end connected to the pressure reducing valve 2 is disconnected, thereby achieving a large driving force.

[0037] In some embodiments, the device also includes a lifting mechanism for adjusting the height of the heat-sealing upper mold 10 and the heat-sealing lower mold 9. The lifting mechanism is connected to the heat-sealing upper mold 10, so that the heat-sealing component can descend to the valve port of the valve bag when working, and can rise and retract to a safe position after the heat sealing is completed to avoid the bag clamping gripper. In some embodiments, the lifting mechanism is a lifting cylinder, and correspondingly, the electrical control module includes a controller, an air source 13, and a second controlled valve 16. The output end of the air source 13 is connected to the lifting cylinder through the second controlled valve 16, and the second controlled valve 16 is connected to the controller. In one embodiment, the second controlled valve 16 is a two-position five-way solenoid valve.

[0038] In some embodiments, setting the distance to 4 mm can improve efficiency while ensuring safety.

[0039] In some embodiments, the entire device is mounted on a packaging machine or other equipment by a fixing frame 1 , and the fixing frame 1 adopts a beam mode as shown in the figure. Of course, in other embodiments, other forms can also be adopted.

[0040] In some embodiments, the device also includes a lifting mechanism for adjusting the height of the heat-sealing upper mold 10 and the heat-sealing lower mold 9, but the lifting mechanism is realized by a motor-driven rack and pinion mechanism or a ball screw mechanism. Similarly, the drive can also be realized by a motor-driven rack and pinion mechanism or a ball screw mechanism.

[0041] In one embodiment, a lifting mechanism is included and driven by a cylinder. The electrical schematic diagram is as follows: Figure 6 As shown in the figure, when the powder filling is completed, Figure 3 As shown, the valve bag 8 moves to the heat-sealing position, at which time the clamping mechanism consisting of the heat-sealing upper mold 10 and the heat-sealing lower mold 9 is opened, and then Figure 4 As shown, the lifting mechanism works to move the heat seal to the bag opening. Figure 5As shown, the clamping mechanism is closed. During this process, the air pressure in the clamping cylinder 6 is approximately 0.05 MPa, regulated by the pressure reducing valve 2. The cylinder driving force is approximately 50 N. Even if a finger is pinched, it will not cause harm. If a foreign object is trapped between the upper and lower molds, the cylinder will not retract to the safe position, the magnetic switch 10 will not respond, and the clamping and heat-sealing operations will cease. When the distance between the upper heat-sealing mold 10 and the lower heat-sealing mold 9 is less than or equal to 4 mm, the system determines that the safe position has been reached and the air pressure driving the cylinder is switched to a high pressure of approximately 0.6 MPa. Once the upper and lower molds are in place, the ultrasonic generator 5 is activated, causing the PE layer sandwiched between the upper and lower molds to generate heat and melt due to the high-frequency vibration, thereby firmly bonding them together. A dust removal nozzle 11 is provided at the front end of the heat-sealing clamp, facing the bag opening. This dust removal nozzle 11 is connected to the vacuum cleaner pipeline to effectively remove fine powder that flies out of the bag opening during clamping.

Claims

1. An automatic ultrasonic heat-sealing device for preventing finger pinching, comprising an ultrasonic generator (5), a heat-sealing upper die (10), a heat-sealing lower die (9), a driving mechanism, and an electrical control module, wherein the ultrasonic generator (5) is connected to the heat-sealing upper die (10), the heat-sealing lower die (9) is connected to the heat-sealing upper die (10) via a rotating shaft, the driving mechanism is connected to the electrical control module, and is connected to the heat-sealing lower die (9) to drive the heat-sealing lower die (9) to rotate around the rotating shaft, and is characterized in that: The heat-sealing upper mold (10) is provided with a magnetic switch (12) for detecting the gap distance between the heat-sealing upper mold (10) and the heat-sealing lower mold (9). The magnetic switch (12) is connected to an electrical control module, and the electrical control module is configured to perform the following steps: When a heat sealing operation is required, the driving mechanism is controlled to drive the heat sealing lower mold (9) to close toward the heat sealing upper mold (10) with a first driving force; When receiving a safety signal from the magnetic switch (12), the control driving mechanism drives the heat-sealing lower mold (9) to close toward the heat-sealing upper mold (10) with a second driving force, wherein the second driving force is greater than the first driving force, and the safety signal indicates that the gap distance between the heat-sealing upper mold (10) and the heat-sealing lower mold (9) is less than or equal to a set distance; The driving mechanism includes two clamping cylinders (6), and the electrical control module includes a controller, an air source (13), a first controlled valve (14) and a pressure reducing valve (2). The output end of the air source (13) is connected to the two clamping cylinders (6) through the first controlled valve (14), and is connected to the two clamping cylinders (6) in turn through the first controlled valve (14) and the pressure reducing valve (2). The first controlled valve (14) is connected to the controller. When the output of the magnetic switch (12) is a low level, the output end of the first controlled valve connected to the clamping cylinder (6) is closed, while the output end connected to the pressure reducing valve (2) is turned on, thereby achieving a small driving force. Conversely, when the output of the magnetic switch (12) is a high level, the output end of the first controlled valve connected to the clamping cylinder (6) is turned on, while the output end connected to the pressure reducing valve (2) is turned off, thereby achieving a large driving force.

2. The automatic ultrasonic heat sealing device for preventing finger pinching according to claim 1, characterized in that: The first controlled valve (14) is a solenoid valve.

3. The automatic ultrasonic heat sealing device for preventing finger pinching according to claim 1, characterized in that: The device further comprises a lifting mechanism for adjusting the height of the heat-sealing upper die (10) and the heat-sealing lower die (9), and the lifting mechanism is connected to the heat-sealing upper die (10).

4. The automatic ultrasonic heat sealing device for preventing finger pinching according to claim 3, characterized in that: The lifting mechanism is a lifting cylinder.

5. The automatic ultrasonic heat sealing device for preventing finger pinching according to claim 4, characterized in that: The electrical control module comprises a controller, an air source (13), and a second controlled valve (16); the output end of the air source (13) is connected to the lifting cylinder via the second controlled valve (16); and the second controlled valve (16) is connected to the controller.

6. The automatic ultrasonic heat sealing device for preventing finger pinching according to claim 5, characterized in that: The second controlled valve (16) is a solenoid valve.

7. The automatic ultrasonic heat sealing device for preventing finger pinching according to claim 1, characterized in that: The set distance is 4 mm.

8. A packaging machine, characterized in that: The ultrasonic heat sealing device comprises the ultrasonic heat sealing device as claimed in any one of claims 1 to 7.

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