Automatic sealing device for food packaging bags

Abstract

The present invention belongs to the technical field of packaging bag sealing, and specifically provides an automatic sealing device for food packaging bags, including a sealing box and a constant linear speed rotating heat sealing mechanism that is mirror-symmetrically distributed on the inner wall of the sealing box, the two constant linear speed rotating heat sealing mechanisms are respectively arranged on the bottom wall and the top wall inside the sealing box, and the constant linear speed rotating heat sealing mechanism includes a base frame, a slide frame, a rotating heat sealing component, a variable speed drive component and a hydraulic diameter adjustment component. The present invention utilizes the transfer of hydraulic oil to adjust the position of the rotating shaft and the rotation radius, and the moving distance of the rotating shaft is the same as the change value of the rotation radius, so that the rotation areas of the telescopic heat pressing arms on the upper and lower sides of the long cylindrical packaging bag are tangent, and the linear speed of the outer edge of the heat pressing head is consistent with the conveying speed of the food packaging bag by changing the rotation speed, so that the equipment can seal food packaging bags of different lengths, effectively solving the technical problem that the automatic sealing equipment in the prior art can only be applied to food packaging bags of a single length.

Description

Technical Field

[0001] The invention belongs to the technical field of packaging bag sealing, and in particular relates to an automatic sealing device for food packaging bags. Background Art

[0002] During the operation of the food packaging production line, the food needs to be placed at intervals on the strip-shaped plastic packaging paper conveyed at a uniform speed, and then the two sides of the strip-shaped plastic packaging paper need to be turned up and connected to form a long cylindrical packaging bag using a guide device, and then the long cylindrical packaging bag conveyed at a uniform speed needs to be sealed at intervals using an automatic sealing device, and finally each sealing point is cut one by one to realize automatic food packaging. In the prior art, the sealing process has many defects:

[0003] In the prior art, a hot-pressing sealer with a fixed rotation radius is often used to perform interval sealing on long cylindrical packaging bags. The rotational linear speed of the outer edge of the hot-pressing sealer is consistent with the conveying speed of the long cylindrical packaging bags. However, this structural design is only applicable to the sealing of food packaging bags of a single length, and it is necessary to ensure that the length of the food packaging bag is consistent with the rotational circumference of the hot-pressing sealer. If the length of the food packaging bag is changed, the rotational circumference of the hot-pressing sealer will no longer match the length of the food packaging bag. Whether the conveying speed or the rotational speed of the hot-pressing sealer is adjusted, the food packaging bag cannot be accurately sealed.

[0004] The above structural design requires disassembling the equipment and adjusting the rotating shaft position and rotation radius of the hot-pressing sealing component and the conveying speed of the long cylindrical packaging bag to achieve interval sealing of different food packaging bags. Once the conveying speed of the long cylindrical packaging bag is changed, the entire production line will need to be adjusted, and the operation is very cumbersome. This reduces the applicability of the existing automatic sealing equipment and makes it only applicable to food packaging bags of a single length.

[0005] The prior art lacks a device that can automatically adjust the structural dimensions according to the length of the food packaging bag to be sealed so as to ensure that the rotation line speed at the hot pressure sealing point remains unchanged and can automatically perform interval sealing on food packaging bags of different sizes without changing the conveying speed of the food packaging bags. Summary of the invention

[0006] The present invention overcomes the shortcomings of the prior art and provides an automatic sealing device for food packaging bags. The device uses a constant linear speed rotating heat sealing mechanism to synchronously rotate, extrude and heat seal the upper and lower sides of a long cylindrical packaging bag that is conveyed at a uniform speed. The position of the rotating shaft and the rotation radius are adjusted by the transfer of hydraulic oil. The moving distance of the rotating shaft is the same as the change value of the rotation radius, thereby ensuring that after the adjustment, the rotating areas of the telescopic heat pressing arms on the upper and lower sides of the long cylindrical packaging bag can still be tangent. At the same time, by changing the rotation speed, the rotation linear speed of the outer edge of the heat pressing head is kept consistent with the conveying speed of the food packaging bag, effectively solving the technical problems of the automatic sealing equipment in the prior art that has low applicability and can only be applied to food packaging bags of a single length.

[0007] The technical scheme adopted by the present invention is as follows: This scheme provides an automatic sealing device for food packaging bags, including a sealing box and a constant linear speed rotary heat sealing mechanism which is mirror-symmetrically distributed on the inner wall of the sealing box, the two constant linear speed rotary heat sealing mechanisms are respectively arranged on the bottom wall and the top wall inside the sealing box, the constant linear speed rotary heat sealing mechanism on the inner bottom wall of the sealing box includes a base frame, a slide, a rotary heat sealing component, a variable speed drive component and a hydraulic diameter adjustment component, the base frame is fixedly arranged on the inner bottom wall of the sealing box, the slide is vertically slidably arranged on the inner side wall of the base frame, the rotary heat sealing component is rotatably arranged on the inner side wall of the slide, the variable speed drive component is arranged on the side wall of the slide, the variable speed drive component and the rotary heat sealing component are driven, the hydraulic diameter adjustment component is arranged on the outer side wall of the slide, the inner bottom wall of the base frame is provided with a telescopic support, the upper end of the hydraulic diameter adjustment component is through-connected with the rotary heat sealing component, and the hydraulic diameter adjustment component The lower end of the component is connected with the telescopic support component, the rotary heat sealing assembly includes a hollow rotating shaft and a telescopic hot pressing arm, the telescopic hot pressing arm is provided with one or two, the hollow rotating shaft is rotatably arranged on the inner side wall of the slide, the telescopic hot pressing arm is fixedly arranged on the outer wall of the hollow rotating shaft, the telescopic hot pressing arm includes a diameter-adjusting hollow sleeve, a diameter-adjusting slide and a hot pressing head, the diameter-adjusting hollow sleeve is fixedly arranged on the circumferential outer wall of the hollow rotating shaft, the diameter-adjusting slide is slidably and closely arranged on the inner wall of the diameter-adjusting hollow sleeve, the hot pressing head is fixedly arranged at the end of the diameter-adjusting slide away from the hollow rotating shaft, the telescopic support component includes a supporting sleeve and a supporting slide, the supporting sleeve is fixedly arranged on the inner bottom wall of the bottom frame, the supporting slide is vertically slidably and closely arranged on the inner wall of the supporting sleeve, the sum of the internal clearance cross-sectional areas of all the supporting sleeves is equal to the sum of the internal clearance cross-sectional areas of the diameter-adjusting hollow sleeves in all the telescopic hot pressing arms, that is:

[0008] A = x·A1;

[0009] Wherein, A represents the sum of the internal clearance cross-sectional areas of all supporting sleeves, A1 represents the internal clearance cross-sectional area of ​​the diameter-adjusting hollow sleeve plate in a single telescopic hot-pressing arm, and x represents the number of telescopic hot-pressing arms;

[0010] The hydraulic diameter adjustment component includes a fixed pipe, a hydraulic pump and a pressure hose. The fixed pipe and the hydraulic pump are respectively fixed on the outer side wall of the slide. The upper end of the fixed pipe passes through the side wall of the slide and is connected with one end of the hollow rotating shaft. The hydraulic pump is set in the middle of the fixed pipe. The upper end of the pressure hose is connected with the lower end of the fixed pipe. The lower end of the pressure hose passes through the lower edge of the side walls of all the supporting sleeves. All the supporting sleeves are connected to each other through the pressure hose. The space connected inside the diameter adjustment hollow sleeve, the hollow rotating shaft, the fixed pipe, the pressure hose and the supporting sleeve is filled with hydraulic oil.

[0011] Furthermore, the variable speed drive assembly includes a power base, a drive motor and a reducer. The power base is fixed to the outer wall of the slide, the drive motor and the reducer are respectively fixed on the power base, the output shaft of the drive motor and the input end of the reducer are coaxially fixedly connected, and the output end of the reducer and the hollow rotating shaft are coaxially fixedly connected.

[0012] Preferably, a frequency converter and a control box are fixedly provided on the inner wall of the sealing box, the control box and the frequency converter are electrically connected, the frequency converter and the drive motor are electrically connected, an operation screen is fixedly provided on the outer wall of the sealing box, a single-chip microcomputer is installed inside the control box, the operation screen and the single-chip microcomputer are electrically connected, the frequency converter and the single-chip microcomputer are electrically connected, the hydraulic pump and the single-chip microcomputer are electrically connected, and the single-chip microcomputer adjusts the constant linear speed rotation heat sealing mechanism according to the length of the food packaging bag to be sealed.

[0013] Taking the constant linear speed rotary heat sealing mechanism at the bottom as an example, the process of adjusting the constant linear speed rotary heat sealing mechanism according to the length of the food packaging bag to be sealed by the single chip microcomputer includes the following steps:

[0014] S1: The microcontroller automatically sets the reference length;

[0015] S2: The operator inputs the length of the food packaging bag to be sealed through the operation screen;

[0016] S3: The single chip microcomputer obtains the length data of the food packaging bag to be sealed, calculates the ratio and difference between the length of the food packaging bag to be sealed and the reference length, controls the operation of the hydraulic pump according to the difference, controls the frequency converter to adjust the frequency according to the ratio, and controls the drive motor to adjust the speed.

[0017] The formula for calculating the ratio and difference of the microcontroller is as follows:

[0018] y=L1 / L0;

[0019] L = L1 - L0;

[0020] Wherein, y represents the ratio, L represents the difference, L1 represents the length of the food packaging bag to be sealed, and L0 represents the reference length. Since the food packaging bag is continuously conveyed in a straight line and the hot pressing head is in a rotating motion, the length of the food packaging bag is the length of the arc swept by the outer edge of the hot pressing head when it passes through the same point twice, that is, L0 is the length of the arc swept by the outer edge of the hot pressing head when the telescopic hot pressing arm is in a contracted state and appears at the same point twice in a row, and L1 is the length of the arc swept by the outer edge of the hot pressing head when the telescopic hot pressing arm is extended and appears at the same point twice in a row;

[0021] The microcontroller controls the operation of the hydraulic pump. The calculation formula for the operating time of the hydraulic pump is as follows:

[0022] t=V / v;

[0023] V = A·d;

[0024] Wherein, t represents the operating time of the hydraulic pump, V represents the volume of hydraulic oil that the hydraulic pump needs to pump, v represents the volume of hydraulic oil pumped by the hydraulic pump per unit time, and d represents the distance the support slide moves;

[0025] The hydraulic pump runs, pumping the hydraulic oil in the support sleeve into the hollow shaft, causing the support slide to move downward, and the diameter adjustment slide moves to the outside of the diameter adjustment hollow sleeve due to the pressure injection of the hydraulic oil, that is, the telescopic support shrinks, and all the telescopic hot pressing arms extend synchronously. Through the above calculation process, it can be seen that the distance the support slide moves into the support sleeve is d, and the height of the slide drop is d. Since the volume of the hydraulic oil remains unchanged, the hydraulic oil reduced in the support sleeve is consistent with the hydraulic oil volume increased in the diameter adjustment hollow sleeve, that is:

[0026] V = A·d =x·A1·d1;

[0027] The extension distance of the telescopic hot pressing arm is:

[0028] d1=[x·(L1-L0)] / (2π);

[0029] Among them, d1 represents the extension distance of a single telescopic hot press arm, that is, the increase in the rotation radius of the outer edge of the hot press head. Since A=x·A1, d=d1. The increase in the rotation radius of the outer edge of the hot press head and the height of the slide falling are both d. It can be seen that before and after the hydraulic pump is running, the contraction distance of the support slide pipe is the same as the extension distance of the diameter adjustment slide. When the hot press head rotates, the height of the top of its outer edge does not change.

[0030] This setting method enables the heat pressure heads on the two constant linear speed rotating heat sealing mechanisms to remain in close contact with each other after the equipment is adjusted according to the length of the food packaging bag to be sealed, and will not move too far away or squeeze too much when approaching each other.

[0031] As the rotation radius of the thermal head increases, in order to ensure that the outer edge of the thermal head still maintains a constant linear speed, the single chip microcomputer controls the inverter to adjust the frequency according to the ratio, thereby adjusting the speed of the drive motor. The calculation formula is as follows:

[0032] n0=60·f0 / p;

[0033] n = n0 / y;

[0034] Then f=n·p / 60= n0·p / (60·y)= f0 / y;

[0035] Among them, n0 represents the initial speed of the drive motor, f0 represents the initial frequency of the inverter, p represents the number of magnetic pole pairs of the drive motor, n represents the adjusted speed of the drive motor, and f represents the adjusted frequency of the inverter.

[0036] Furthermore, a vibrating pressing block is slidingly provided on the outer wall of the hot pressing head, and the sliding direction of the vibrating pressing block is parallel to the movement direction of the diameter adjusting slide relative to the diameter adjusting hollow sleeve plate. The vibrating pressing block has a built-in electric heating wire for hot-melting the packaging bag. A magnet plate is fixedly provided on the outer wall of the vibrating pressing block. When the hot pressing heads on the upper and lower constant linear speed rotating heat sealing mechanisms approach and contact, the magnetic poles of the magnet plates of the two hot pressing heads on the sides approaching each other are opposite, and the two magnet plates attract each other to squeeze the packaging bag. The vibrating pressing block has a built-in vibrating plate, which causes the vibrating pressing block to vibrate, thereby improving the extrusion sealing quality.

[0037] Preferably, the model of the single chip microcomputer is STM32F030C8T6.

[0038] The beneficial effects achieved by the present invention are as follows:

[0039] (1) The automatic sealing device for food packaging bags provided by the present invention uses a constant linear speed rotating heat sealing mechanism to synchronously rotate, extrude and heat seal the upper and lower sides of a long cylindrical packaging bag conveyed at a uniform speed, and uses the transfer of hydraulic oil to adjust the position of the hollow rotating shaft and the rotation radius of the telescopic heat pressing arm, and the moving distance of the hollow rotating shaft is the same as the change value of the rotation radius of the telescopic heat pressing arm, thereby ensuring that after the adjustment, the equipment can still make the rotation areas of the telescopic heat pressing arms on the upper and lower sides of the long cylindrical packaging bag tangent to each other, and the heat pressing heads can still be closely attached when approaching each other without being too far away or over-extended, and at the same time, by changing the rotation speed, the rotation linear speed of the outer edge of the heat pressing head is kept consistent with the conveying speed of the food packaging bag, so that the equipment can effectively extrude and heat seal food packaging bags of different lengths without changing the conveying speed of the food packaging production line, and the control method of the above adjustment process is very simple, and can be achieved only by simple geometric relationship calculation, which effectively solves the technical problem that the automatic sealing equipment in the prior art has low applicability and can only be applied to food packaging bags of a single length;

[0040] (2) The sum of the internal clearance cross-sectional areas of all the supporting sleeves is equal to the sum of the internal clearance cross-sectional areas of the diameter-adjusting hollow sleeves in all the telescopic hot pressing arms. This arrangement ensures that the increase in the rotation radius of the outer edge of the hot pressing head during the transfer of the hydraulic oil is equal to the moving distance of the hollow rotating shaft, thereby ensuring that the outer edge rotation areas of the hot pressing heads on the two constant linear speed rotating heat sealing mechanisms are always tangent;

[0041] (3) A magnet plate is fixed on the outer wall of the vibration pressing block. When the heat pressing heads on the upper and lower constant linear speed rotating heat sealing mechanisms approach and touch each other, the magnetic poles of the magnet plates of the two heat pressing heads on the sides approaching each other are opposite, and the two magnet plates attract each other to squeeze the packaging bag. The vibration pressing block has a built-in vibration plate, which causes the vibration pressing block to vibrate, thereby improving the quality of extrusion sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The structure of an automatic sealing device for food packaging bags in Example 1 is shown in FIG. Figure 1 ;

[0043] Figure 2 The structure of an automatic sealing device for food packaging bags in Example 1 is shown in FIG. Figure 2 ;

[0044] Figure 3 The structure of the constant linear speed rotating heat sealing mechanism in the first embodiment is shown in FIG. Figure 1 ;

[0045] Figure 4 The structure of the constant linear speed rotating heat sealing mechanism in the first embodiment is shown in FIG. Figure 2 ;

[0046] Figure 5 is a side cross-sectional view of the rotary heat sealing assembly in Example 1;

[0047] Figure 6 A schematic diagram of the control principle among the frequency converter, single chip microcomputer, operation screen and constant linear speed rotation heat-sealing mechanism proposed in the present invention;

[0048] Figure 7 It is a side cross-sectional view of the constant linear speed rotary heat sealing mechanism in the first embodiment before and after adjustment;

[0049] Figure 8 A side cross-sectional view of an automatic sealing device for a food packaging bag in the first embodiment performing a sealing operation on a food packaging bag;

[0050] Fig. 9 This is a schematic structural diagram of an automatic sealing device for food packaging bags in Example 2;

[0051] Fig.10It is a structural schematic diagram of the constant linear speed rotation heat sealing mechanism in the second embodiment;

[0052] Fig.11 is a front cross-sectional view of the rotary heat sealing assembly in Example 2;

[0053] Fig.12 It is a side cross-sectional view of an automatic sealing device for a food packaging bag in the second embodiment performing a sealing operation on a food packaging bag.

[0054] Among them, 1. Sealing box, 11. Frequency converter, 12. Control box, 121. Single chip microcomputer, 13. Operation screen, 2. Constant linear speed rotating heat sealing mechanism, 21. Base frame, 211. Telescopic support, 2111. Support sleeve, 2112. Support slide, 22. Slide, 23. Rotary heat sealing assembly, 231. Hollow shaft, 2311. Connecting gear, 232. Telescopic heat pressing arm, 2321. Diameter adjustment center Empty sleeve plate, 2322, diameter adjustment slide plate, 2323, hot pressing head, 2324, synchronous rack, 2325, vibration block, 2326, heating wire, 2327, magnet plate, 2328, vibration plate, 24, variable speed drive assembly, 241, power base, 242, drive motor, 243, reducer, 25, hydraulic diameter adjustment assembly, 251, fixed pipe, 252, hydraulic pump, 253, pressure hose.

[0055] Figure 7 In the figure, (i) shows a side cross-sectional view of the constant linear speed rotary heat sealing mechanism before adjustment, and (ii) shows a side cross-sectional view of the constant linear speed rotary heat sealing mechanism after adjustment.

[0056] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0057] Example 1: Please refer to Figure 1-Figure 5The present embodiment provides an automatic sealing device for food packaging bags, comprising a sealing box 1 and a constant linear speed rotary heat sealing mechanism 2 which is arranged on the inner wall of the sealing box 1 in a mirror-symmetrical manner. The two constant linear speed rotary heat sealing mechanisms 2 are respectively arranged on the bottom wall and the top wall inside the sealing box 1. The constant linear speed rotary heat sealing mechanism 2 on the bottom wall inside the sealing box 1 comprises a bottom frame 21, a slide 22, a rotary heat sealing assembly 23, a variable speed drive assembly 24 and a hydraulic diameter adjustment assembly 25. The bottom frame 21 is fixedly arranged on the bottom wall inside the sealing box 1, and the slide 22 is vertically arranged on the bottom wall inside the sealing box 1. The rotary heat sealing assembly 23 is rotatably arranged on the inner wall of the carriage 22, the speed change drive assembly 24 is arranged on the side wall of the carriage 22, the speed change drive assembly 24 and the rotary heat sealing assembly 23 are arranged for transmission, the hydraulic diameter adjustment assembly 25 is arranged on the outer wall of the carriage 22, and the inner bottom wall of the carriage 21 is provided with a telescopic support 211, the upper end of the hydraulic diameter adjustment assembly 25 is connected with the rotary heat sealing assembly 23, and the lower end of the hydraulic diameter adjustment assembly 25 is connected with the telescopic support 211, and the rotary heat sealing assembly 23 is provided with a telescopic support 211. The hollow rotating shaft 231 and the telescopic hot pressing arm 232 are rotatably arranged on the inner wall of the slide 22, and the telescopic hot pressing arm 232 is fixedly arranged on the outer wall of the hollow rotating shaft 231. In this embodiment, the telescopic hot pressing arm 232 is provided with a telescopic hot pressing arm 232, which includes a diameter-adjusting hollow sleeve plate 2321, a diameter-adjusting slide plate 2322 and a hot pressing head 2323. The diameter-adjusting hollow sleeve plate 2321 is fixedly arranged on the outer wall of the circumference of the hollow rotating shaft 231, and the diameter-adjusting slide plate 2322 is slidably and closely arranged on the diameter-adjusting hollow sleeve plate 2321. The hot pressing head 2323 is fixedly arranged on the end of the diameter adjusting slide plate 2322 away from the hollow rotating shaft 231, and the telescopic support member 211 includes a support sleeve 2111 and a support slide tube 2112. The support sleeve 2111 is fixedly arranged on the inner bottom wall of the bottom frame 21, and the support slide tube 2112 is vertically slidably and closely arranged on the inner wall of the support sleeve 2111. The sum of the internal clearance cross-sectional areas of all the support sleeves 2111 is equal to the sum of the internal clearance cross-sectional areas of the diameter adjusting hollow sleeve plate 2321, that is:

[0058] A = x·A1;

[0059] Wherein, A represents the sum of the internal clearance cross-sectional areas of all the support sleeves 2111, A1 represents the internal clearance cross-sectional area of ​​the diameter-adjusting hollow sleeve plate 2321 in the telescopic hot-pressing arm 232, and x represents the number of the telescopic hot-pressing arm 232. In this embodiment, x=1;

[0060] The hydraulic diameter adjustment component 25 includes a fixed pipe 251, a hydraulic pump 252 and a pressure hose 253. The fixed pipe 251 and the hydraulic pump 252 are respectively fixed on the outer side wall of the slide 22. The upper end of the fixed pipe 251 passes through the side wall of the slide 22 and is connected with one end of the hollow rotating shaft 231. The hydraulic pump 252 is connected in the middle of the fixed pipe 251. The upper end of the pressure hose 253 is connected with the lower end of the fixed pipe 251. The lower end of the pressure hose 253 passes through the lower edge of the side wall of all the supporting sleeves 2111. All the supporting sleeves 2111 are connected to each other through the pressure hose 253. The space connected inside the diameter adjustment hollow sleeve 2321, the hollow rotating shaft 231, the fixed pipe 251, the pressure hose 253 and the supporting sleeve 2111 is filled with hydraulic oil.

[0061] See also Figure 2 and Figure 3 The variable speed drive assembly 24 includes a power base 241, a drive motor 242 and a reducer 243. The power base 241 is fixedly arranged on the outer wall of the slide 22. The drive motor 242 and the reducer 243 are respectively fixedly arranged on the power base 241. The output shaft of the drive motor 242 and the input end of the reducer 243 are coaxially fixedly connected. The output end of the reducer 243 and the hollow rotating shaft 231 are coaxially fixedly connected.

[0062] See also Figure 1-Figure 6 A frequency converter 11 and a control box 12 are fixedly provided on the inner wall of the sealing box 1, the control box 12 and the frequency converter 11 are electrically connected, the frequency converter 11 and the drive motor 242 are electrically connected, an operation screen 13 is fixedly provided on the outer wall of the sealing box 1, a single-chip microcomputer 121 is installed inside the control box 12, the operation screen 13 and the single-chip microcomputer 121 are electrically connected, the frequency converter 11 and the single-chip microcomputer 121 are electrically connected, the hydraulic pump 252 and the single-chip microcomputer 121 are electrically connected, and the single-chip microcomputer 121 adjusts the constant linear speed rotation heat sealing mechanism 2 according to the length of the food packaging bag to be sealed.

[0063] Taking the constant linear speed rotating heat sealing mechanism 2 at the lower part as an example, the process of adjusting the constant linear speed rotating heat sealing mechanism 2 according to the length of the food packaging bag to be sealed by the single chip microcomputer 121 includes the following steps:

[0064] S1: The single chip microcomputer 121 automatically sets the reference length;

[0065] S2: The operator inputs the length of the food packaging bag to be sealed through the operation screen 13;

[0066] S3: The single chip microcomputer 121 obtains the length data of the food packaging bag to be sealed, calculates the ratio and difference between the length of the food packaging bag to be sealed and the reference length, and the single chip microcomputer 121 controls the operation of the hydraulic pump 252 according to the difference, and the single chip microcomputer 121 controls the frequency converter 11 to adjust the frequency according to the ratio, and the frequency converter 11 controls the drive motor 242 to adjust the speed.

[0067] The formula for calculating ratio and difference by single chip microcomputer 121 is as follows:

[0068] y=L1 / L0;

[0069] L = L1 - L0;

[0070] Wherein, y represents the ratio, L represents the difference, L1 represents the length of the food packaging bag to be sealed, and L0 represents the reference length;

[0071] Since x=1, L0 is equal to the rotation circumference of the outer edge of the heat pressing head 2323 when the telescopic heat pressing arm 232 is in the contracted state, and L1 is equal to the rotation circumference of the outer edge of the heat pressing head 2323 after the telescopic heat pressing arm 232 is extended;

[0072] The single chip computer 121 controls the operation of the hydraulic pump 252. The operation time of the hydraulic pump 252 is calculated as follows:

[0073] t=V / v;

[0074] V = A·d;

[0075] Wherein, t represents the operation time of the hydraulic pump 252, V represents the volume of hydraulic oil that the hydraulic pump 252 needs to pump, v represents the volume of hydraulic oil pumped by the hydraulic pump 252 per unit time, and d represents the distance that the support slide pipe 2112 moves;

[0076] The hydraulic pump 252 is running to pump the hydraulic oil in the support sleeve 2111 into the hollow rotating shaft 231, so that the support slide 2112 moves downward, and the diameter adjustment slide plate 2322 moves toward the outside of the diameter adjustment hollow sleeve plate 2321 due to the pressure injection of the hydraulic oil, that is, the telescopic support member 211 contracts, and the telescopic hot pressing arm 232 extends. It can be seen from the above calculation process that the distance that the support slide 2112 moves into the support sleeve 2111 is d, and the height of the slide 22 is d. Since the volume of the hydraulic oil remains unchanged, the hydraulic oil reduced in the support sleeve 2111 is consistent with the hydraulic oil volume increased in the diameter adjustment hollow sleeve plate 2321, that is:

[0077] V = A·d =x·A1·d1;

[0078] The extension distance of the telescopic hot pressing arm 232 is:

[0079] d1=[x·(L1-L0)] / (2π);

[0080] Wherein, d1 represents the extension distance of the telescopic hot pressing arm 232, that is, the increase in the rotation radius of the outer edge of the hot pressing head 2323;

[0081] Since A=x·A1, then d=d1, and the increase in the rotation radius of the outer edge of the hot pressing head 2323 and the descending height of the slide 22 are both d. It can be seen that before and after the operation of the hydraulic pump 252, the contraction distance of the support slide 2112 and the extension distance of the diameter adjustment slide 2322 are the same, and when the hot pressing head 2323 rotates, the height of the uppermost part of its outer edge does not change;

[0082] This arrangement enables the heat pressing heads 2323 on the two constant linear speed rotating heat sealing mechanisms 2 to still be in close contact with each other without being too far away or overly squeezed after the equipment is adjusted according to the length of the food packaging bag.

[0083] Since the rotation radius of the thermal pressing head 2323 becomes larger, in order to ensure that the outer edge of the thermal pressing head 2323 still maintains a constant linear speed, the single chip microcomputer 121 controls the frequency of the inverter 11 according to the ratio, thereby adjusting the speed of the driving motor 242. The calculation formula is as follows:

[0084] n0=60·f0 / p;

[0085] n = n0 / y;

[0086] Then f=n·p / 60= n0·p / (60·y)= f0 / y;

[0087] Among them, n0 represents the initial rotation speed of the drive motor 242, f0 represents the initial frequency of the inverter 11, p represents the number of magnetic pole pairs of the drive motor 242, n represents the adjusted rotation speed of the drive motor 242, and f represents the adjusted frequency of the inverter 11.

[0088] like Figure 1-Figure 8 As shown, a vibrating pressing block 2325 is slidingly provided on the outer wall of the hot pressing head 2323, and the sliding direction of the vibrating pressing block 2325 is parallel to the movement direction of the diameter adjusting slide plate 2322 relative to the diameter adjusting hollow sleeve plate 2321. The vibrating pressing block 2325 has a built-in electric heating wire 2326 for hot-melting the food packaging bag. A magnet plate 2327 is fixedly provided on the outer wall of the vibrating pressing block 2325. When the hot pressing heads 2323 on the upper and lower constant linear speed rotating heat sealing mechanisms 2 approach and contact, the magnetic poles of the magnet plates 2327 of the two hot pressing heads 2323 approaching each other are opposite, and the two magnet plates 2327 attract each other to squeeze the food packaging bag. The vibrating pressing block 2325 has a built-in vibrating plate 2328, and the vibrating plate 2328 causes the vibrating pressing block 2325 to vibrate, thereby improving the extrusion sealing quality.

[0089] The model of single chip microcomputer 121 is STM32F030C8T6.

[0090] The constant linear speed rotating heat sealing mechanism 2 on the top wall inside the sealing box 1 has the same structure as the constant linear speed rotating heat sealing mechanism 2 on the bottom wall inside the sealing box 1, and the only difference is that they are arranged in a mirror-symmetrical manner, which will not be repeated.

[0091] During specific use, an automatic sealing device for food packaging bags provided by the present invention is installed in a continuous food packaging production line, so that the food packaging bags pass between two constant linear speed rotating heat sealing mechanisms 2. The food packaging bags that have not reached between the constant linear speed rotating heat sealing mechanisms 2 are long cylindrical packaging bags, and the food has been placed at a certain distance. After the constant linear speed rotating heat sealing mechanisms 2 are extruded and heat-sealed at intervals, the food packaging bags are sealed one by one, and then automatic cutting equipment is used to cut at each sealing position, thereby completing the entire food packaging process.

[0092] L0 is equal to the rotation circumference of the outer edge of the heat pressing head 2323 when the telescopic heat pressing arm 232 is in the contracted state. This parameter is automatically calculated according to the length of the telescopic heat pressing arm 232. Then, by executing steps S1-S3, the hydraulic pump 252 is controlled to run for a time t, and the speed of the driving motor 242 is adjusted to n, thereby realizing the adjustment of the constant linear speed rotation heat sealing mechanism 2, as shown in FIG. Figure 7 As shown, Figure 7 In the figure, (i) shows a side cross-sectional view of the constant linear speed rotary heat sealing mechanism 2 before adjustment, and (ii) shows a side cross-sectional view of the constant linear speed rotary heat sealing mechanism 2 after adjustment. After the constant linear speed rotary heat sealing mechanism 2 is adjusted, the constant linear speed rotary heat sealing mechanism 2 performs interval heat sealing on the whole strip-shaped food packaging bag on the production line, such as Figure 8 As shown, when the heat pressing heads 2323 on the upper and lower constant linear speed rotating heat sealing mechanisms 2 approach and touch each other, the magnetic poles of the magnet plates 2327 of the two heat pressing heads 2323 that are close to each other are opposite, and the two magnet plates 2327 attract each other to squeeze the food packaging bag, and the vibration sheet 2328 causes the vibration pressing block 2325 to vibrate, thereby improving the extrusion sealing quality.

[0093] Example 2: Please refer to Figure 9-12 , the difference between this embodiment and the first embodiment is that, in this embodiment, two telescopic heat pressing arms 232 are provided in the single constant linear speed rotating heat sealing mechanism 2, x=2;

[0094] The telescopic hot pressing arm 232 is symmetrically distributed with the hollow rotating shaft 231 as the axis, and two groups of hot pressing heads 2323 are provided. The two hot pressing heads 2323 are respectively fixed on the ends of the diameter adjusting slide plate 2322 away from the hollow rotating shaft 231. The angle between the center of the two hot pressing heads 2323 and the axis of the hollow rotating shaft 231 is 180°. Since there are two hot pressing heads 2323, the sum of the internal clearance cross-sectional areas of all the supporting sleeves 2111 is equal to twice the sum of the internal clearance cross-sectional areas of the diameter adjusting hollow sleeve plates 2321 corresponding to the single hot pressing heads 2323. To ensure that the diameter adjusting slide 2322 can be evenly extended and retracted so that the outer edges of the two hot pressing heads 2323 and the axial center distance of the hollow rotating shaft 231 remain equal, a connecting gear 2311 is provided inside the hollow rotating shaft 231 for rotation, the diameter adjusting slide 2322 is hollow, and a synchronous rack 2324 is fixedly provided on the inner wall of the diameter adjusting slide 2322. The synchronous racks 2324 in the two diameter adjusting slides 2322 are respectively meshed with the connecting gear 2311. The setting of the connecting gear 2311 and the synchronous rack 2324 makes the two synchronous racks 2324 connected to each other, so that the two diameter adjusting slides 2322 can be extended and retracted synchronously.

[0095] Then L0 in this embodiment is equal to half of the rotation circumference of the outer edge of the heat pressing head 2323 when the telescopic heat pressing arm 232 is in the contracted state, and L1 is equal to half of the rotation circumference of the outer edge of the heat pressing head 2323 after the telescopic heat pressing arm 232 is extended.

[0096] The rest of the structural design, working process and calculation method are the same as those in the first embodiment and will not be described in detail.

[0097] The present invention and its implementation modes are described above. Such description is not restrictive. What is shown in the drawings is only one of the implementation modes of the present invention. The actual structure is not limited thereto.

Claims

1. An automatic sealing device for food packaging bags, comprising a sealing box (1), characterized in that: The inner wall of the sealing box (1) is provided with constant linear speed rotary heat sealing mechanisms (2) in a mirror-symmetrical manner. The two constant linear speed rotary heat sealing mechanisms (2) are respectively arranged on the bottom wall and the top wall of the inner wall of the sealing box (1). The constant linear speed rotary heat sealing mechanism (2) on the inner bottom wall of the sealing box (1) comprises a base frame (21), a slide (22), a rotary heat sealing component (23), a variable speed drive component (24) and a hydraulic diameter adjustment component (25). The base frame (21) is fixedly arranged on the inner bottom wall of the sealing box (1). The slide (22) is vertically slidably arranged on the inner side wall of the base frame (21). The rotary heat sealing component (23) is rotatably arranged on the inner side wall of the slide (22). The variable speed drive component (24) and the rotary heat sealing component (23) are arranged in a transmission manner. The hydraulic diameter adjustment component (25) is arranged on the outer side wall of the slide (22). The inner bottom wall of the bottom frame (21) is provided with a telescopic support member (211), and the rotary heat sealing assembly (23) comprises a hollow rotating shaft (231) and a telescopic heat pressing arm (232), wherein the hollow rotating shaft (231) is rotatably arranged on the inner side wall of the sliding frame (22), and the telescopic heat pressing arm (232) is fixedly arranged on the outer wall of the hollow rotating shaft (231), and the telescopic heat pressing arm (232) is provided with one or two telescopic heat pressing arms (232). ) comprises a diameter-adjusting hollow sleeve plate (2321), a diameter-adjusting slide plate (2322) and a hot pressing head (2323), wherein the diameter-adjusting hollow sleeve plate (2321) is fixedly arranged on the circumferential outer wall of the hollow rotating shaft (231), the diameter-adjusting slide plate (2322) is slidably and closely arranged on the inner wall of the diameter-adjusting hollow sleeve plate (2321), and the hot pressing head (2323) is fixedly arranged on the end of the diameter-adjusting slide plate (2322) away from the hollow rotating shaft (231); The telescopic support member (211) comprises a support sleeve (2111) and a support slide tube (2112); the support sleeve (2111) is fixedly arranged on the inner bottom wall of the base frame (21); the support slide tube (2112) is vertically slidably and closely arranged on the inner wall of the support sleeve (2111); the sum of the internal clearance cross-sectional areas of all the support sleeves (2111) is equal to the sum of the internal clearance cross-sectional areas of the diameter-adjusting hollow sleeve plates (2321) in all the telescopic hot-pressing arms (232); the upper end of the hydraulic diameter-adjusting component (25) passes through the side wall of the slide frame (22) and is arranged to be connected with one end of the hollow rotating shaft (231); the lower end of the hydraulic diameter-adjusting component (25) passes through the lower edges of the side walls of all the support sleeves (2111); and the space connected to the diameter-adjusting hollow sleeve plates (2321), the hollow rotating shaft (231), the hydraulic diameter-adjusting component (25) and the support sleeve (2111) is filled with hydraulic oil.

2. The automatic sealing device for food packaging bags according to claim 1, characterized in that: The hydraulic diameter adjustment assembly (25) comprises a fixed pipe (251), a hydraulic pump (252) and a pressure hose (253). The fixed pipe (251) and the hydraulic pump (252) are respectively fixedly arranged on the outer side wall of the slide (22). The upper end of the fixed pipe (251) penetrates the side wall of the slide (22) and is arranged in communication with one end of the hollow rotating shaft (231). The hydraulic pump (252) is arranged in communication with the middle of the fixed pipe (251). The upper end of the pressure hose (253) is connected to the lower end of the fixed pipe (251). The lower end of the pressure hose (253) penetrates the lower edge of the side wall of all the supporting sleeves (2111). All the supporting sleeves (2111) are arranged in communication with each other through the pressure hose (253).

3. The automatic sealing device for food packaging bags according to claim 2, characterized in that: The variable speed drive assembly (24) comprises a power base (241), a drive motor (242) and a reducer (243); the power base (241) is fixedly arranged on the outer side wall of the slide (22); the drive motor (242) and the reducer (243) are respectively fixedly arranged on the power base (241); the output shaft of the drive motor (242) and the input end of the reducer (243) are coaxially fixedly connected; and the output end of the reducer (243) and the hollow rotating shaft (231) are coaxially fixedly connected.

4. The automatic sealing device for food packaging bags according to claim 3, characterized in that: A frequency converter (11) and a control box (12) are fixedly provided on the inner wall of the sealing box (1), the control box (12) and the frequency converter (11) are electrically connected, the frequency converter (11) and the drive motor (242) are electrically connected, an operation screen (13) is fixedly provided on the outer wall of the sealing box (1), a single-chip microcomputer (121) is installed inside the control box (12), the operation screen (13) and the single-chip microcomputer (121) are electrically connected, the frequency converter (11) and the single-chip microcomputer (121) are electrically connected, the hydraulic pump (252) and the single-chip microcomputer (121) are electrically connected, and the single-chip microcomputer (121) adjusts the constant linear speed rotation heat sealing mechanism (2) according to the length of the food packaging bag to be sealed.

5. The automatic sealing device for food packaging bags according to claim 4, characterized in that: The process of the single chip computer (121) adjusting the constant linear speed rotating heat sealing mechanism (2) according to the length of the food packaging bag to be sealed comprises the following steps: S1: The single chip microcomputer (121) automatically sets the reference length; S2: The operator inputs the length of the food packaging bag to be sealed through the operation screen (13); S3: the single chip computer (121) obtains the length data of the food packaging bag to be sealed, the single chip computer (121) controls the hydraulic pump (252) to operate, the single chip computer (121) controls the frequency converter (11) to adjust the frequency, and the frequency converter (11) controls the drive motor (242) to adjust the rotation speed; In step S3, the single chip computer (121) controls the hydraulic pump (252) to operate. The operating time of the hydraulic pump (252) is calculated using the following formula: t=V / v; V = A·d =x·A1·d1; d1=[x·(L1-L0)] / (2π); Wherein, t represents the operating time of the hydraulic pump (252), V represents the volume of hydraulic oil that the hydraulic pump (252) needs to pump, v represents the volume of hydraulic oil pumped by the hydraulic pump (252) per unit time, d represents the distance moved by the support slide tube (2112), A represents the sum of the internal clearance cross-sectional areas of all support sleeves (2111), A1 represents the internal clearance cross-sectional area of ​​the diameter-adjusting hollow sleeve plate (2321) in a single telescopic heat-pressing arm (232), d1 represents the extension distance of the telescopic heat-pressing arm (232), x represents the number of telescopic heat-pressing arms (232) in a single constant linear speed rotating heat-sealing mechanism (2), L1 represents the length of the food packaging bag to be sealed, and L0 represents the reference length.

6. The automatic sealing device for food packaging bags according to claim 1, characterized in that: The outer wall of the heat pressing head (2323) is slidably provided with a vibration pressing block (2325), and the outer wall of the vibration pressing block (2325) is fixedly provided with a magnet plate (2327). When the heat pressing heads (2323) on the upper and lower constant linear speed rotating heat sealing mechanisms (2) approach and contact each other, the magnetic poles of the magnet plates (2327) of the two heat pressing heads (2323) on the sides approaching each other are opposite.

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