JP7598428B2 - Sealing device for bag making and filling machines - Google Patents

Description

The present invention relates to a sealing device, such as a horizontal sealing device installed in a bag making and filling machine.

2. Description of the Related Art Conventionally, a vertical form-fill-seal machine has been proposed as a form-fill-seal machine that continuously forms bags filled with contents, for example, as described in Patent Document 1.
The vertical bag filling and filling machine described in Patent Document 1 fills a cylindrical packaging material with a horizontally sealed bottom and a vertically sealed vertical part with a powder or other contents, and then heats and seals the top opening of the packaging material. Two motors, consisting of a master motor and a slave motor, which are small and consume little power, are provided as a drive source for opening and closing a pair of heater blocks that heat and seal the packaging material. The produced bag is formed by heat-sealing the horizontal seals at the top and bottom of the film and the vertical seal (back lining) connecting both ends of the film with the heater blocks.

JP 2008-230693 A

However, in the bag making and filling machine described in the above-mentioned Patent Document 1, since the two motors perform the same operation, when contents such as powder become caught in the lateral seal of the packaging material, the accuracy of detecting the catch is sometimes insufficient.
In addition, because the two motors operate in the same way, there is a problem that leakage is likely to occur due to differences in thickness at the boundary between the vertical seal and the horizontal seal. Also, there is a limit to the accuracy of detecting whether or not something is caught due to differences in thickness caused by the vertical seal.

The present invention was made in consideration of these circumstances, and aims to provide a sealing device for a bag making and filling machine that has high sealing performance and can detect with high accuracy whether or not a foreign object is caught in the bag.

The sealing device of the bag making and filling machine according to the present invention is characterized in that it comprises a pair of sealing blocks which can be opened and closed to sandwich and seal the packaging material, two drive sources which open and close the sealing blocks, a pair of linking members which open and close the pair of sealing blocks in conjunction with the drive of the drive sources, and a torque value command means which changes the magnitude of the torque of the drive sources to be different from each other when the pair of sealing blocks are closed to seal the packaging material.
According to the present invention, when the sealing blocks are opened and closed via a pair of linking members by driving the driving source using a torque value command means and the pair of sealing blocks are closed to seal the packaging material, the magnitude of the torque of each driving source transmitted to the sealing blocks via a pair of linking members is changed to be different, so that the strong sealing point of the pair of sealing blocks that sandwich the packaging material moves from one end to the other end, thereby enabling high-precision sealing to be performed, including the boundary with other sealing portions such as the vertical seal portion.

The sealing device of the bag making and filling machine according to the present invention is characterized in that it comprises a pair of sealing blocks which can be opened and closed to sandwich and seal packaging material, a drive source which opens and closes the sealing blocks, a pair of linking members which open and close the pair of sealing blocks in conjunction with the drive of the drive source, a position detection means which detects two gaps spaced apart in the longitudinal direction of the sealing blocks at the sealing timing, and an entrapment judgment means which detects the presence of a foreign object when the gap exceeds a preset threshold range.
According to the present invention, when the sealing blocks are closed by clamping the packaging material by driving the drive source, the size of the gap between the sealing blocks in the closed position is detected by the position detection means based on fluctuations in the torque pressing against the sealing blocks, and if the size of the gap exceeds a predetermined threshold range, the jamming judgment means detects the jamming of a foreign object.

In addition, the jamming judgment means may select at least one of the size of the gap between the seal blocks in the closed position detected by the two position detection means, the sum of the gaps, or the difference in the gaps, and detect the jamming of a foreign object if any of them exceeds a threshold range.
At least one of the size of the gap in the closed position, the sum of the gaps, and the difference in the gaps corresponding to the two driving sources in a pair of seal blocks in the closed position can be selected, and if any of the selected values exceeds a threshold range, it is possible to detect the presence of a foreign object.

Furthermore, the upper and lower limits of the threshold value can be made variable depending on the closing timing for sealing the packaging material from one end side to the other end side of the seal block.
When detecting the size of the gap between the seal blocks in the closed position and comparing it with a threshold value, the threshold value can be varied depending on the timing of closing of the pair of seal blocks, thereby making it possible to accurately determine whether or not a foreign object is caught.

The sealing device may further comprise a torque value command means for changing the magnitude of the torque of the drive source so as to be different from each other when the pair of sealing blocks are closed to seal the packaging material.
When the sealing blocks are opened and closed via a pair of linking members by driving the driving sources using a torque value command means to seal the packaging material, the magnitude of the torque of each driving source transmitted to the sealing blocks via a pair of linking members is changed differently, so that the strong sealing point of the pair of sealing blocks that sandwich the packaging material moves from one end to the other end, thereby enabling high-precision sealing to be performed, including at the boundary with other sealing sections such as the vertical seal section.

The sealing device of the present invention provides high sealing performance because the point at which the pair of sealing blocks that sandwich the packaging material seal with maximum torque moves from one end to the other when the packaging material is sealed by the pair of sealing blocks.

In addition, with the sealing device according to the present invention, when a pair of sealing blocks are closed by being driven by a drive source to sandwich the packaging material, the size of the gap between the sealing blocks at two positions spaced apart in the longitudinal direction of the sealing blocks at the sealing timing can be detected by two detectors, and the jamming determination means determines whether the size of each of the gaps detected by the two detectors, the sum of the gaps, or the difference between the gaps exceeds a preset threshold range, making it possible to detect with high accuracy whether a foreign object is jammed.

1 is a main part explanatory diagram showing a schematic configuration of a vertical bag making and filling machine according to an embodiment of the present invention. FIG. 2 is a front view of the manufactured bag. 2 is an explanatory view of a main part of a horizontal sealing device of the vertical bag making and filling machine shown in FIG. FIG. 13 is a diagram showing changes in torque of two motors in a jamming determination section. 1A and 1B are explanatory diagrams showing the state in which a bag is heat-sealed by a heater block, in which FIG. 1A shows the start point of heat sealing, and FIG. 6A and 6B are graphs for determining whether or not the heater block is caught, in which FIG. 6A shows the gap at the closed position on the first motor side, and FIG. 6B shows the gap at the closed position on the second motor side. FIG. 13 is a diagram showing the relationship between the sum of the gaps on the first motor side and the second motor side and a threshold value. 13 is a diagram showing the relationship between the difference in the gap between the first motor side and the second motor side and a threshold value. FIG. 4A to 4D are diagrams showing the gaps between heater blocks in a closed state.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A horizontal sealing device for a bag making and filling machine according to an embodiment of the present invention will now be described with reference to the accompanying drawings.
1 includes a film supplying device 2 that pays out film f as a packaging material, and a vertical form-fill-seal machine 3 that manufactures bags F from the paid-out film f. The film supplying device 2 includes a film roll 4 that pays out sheet-like film f, and a roller mechanism 5 having a plurality of rollers arranged therein that transports the paid-out film f to the vertical form-fill-seal machine 3.

In the vertical bag making and filling machine 3, a bag making tube 8 is installed vertically below a hopper 7 into which the contents are fed. The film f conveyed from the roller mechanism 5 of the film roll 4 is guided by a former 9 and fed to the bag making tube 8, where it is formed into a cylindrical shape. The lower end of the bag making tube 8 is formed into a cylindrical shape according to the horizontal cross-sectional shape of the bag F. The film f formed into a cylindrical shape by the bag making tube 8 has both folded circumferential ends sealed vertically by a vertical sealer 10 to form a vertical seal section S3 (see Figure 2).

The cylindrical film f is intermittently conveyed downward along the bag-making tube 8 by the payout belt 12. The roughly cylindrical film f conveyed downward along the bag-making tube 8 seals the top opening of the preceding bag F by the horizontal sealing device 15 and also seals the bottom of the next bag F. The bag F with the sealed bottom is filled with the contents dropping from the hopper 7, and the top opening and the bottom of the next bag F are simultaneously sealed by the horizontal sealing device 15 and cut by a cutter (not shown). In this way, the square cylindrical bags F shown in FIG. 2 are produced one after another.

In the bag F shown in FIG. 2, the bottom and top horizontal seals are sealed as a top horizontal seal S1 and a bottom horizontal seal S2, respectively, and the vertical seal S3 is sealed perpendicular to the top horizontal seal S1 and the bottom horizontal seal S2.

Next, the horizontal sealing device 15 of the vertical bag making and filling machine 3 will be described with reference to FIG.
In Fig. 3, the horizontal sealing device 15 is disposed below the bag-making tube 8 in a horizontal plane perpendicular to the cylindrical film f unwound from the bag-making tube 8. A pair of heater blocks 16a, 16b are disposed in the horizontal sealing device 15 so as to be openable and closable on both sides of the cylindrical film f. The heater blocks 16a, 16b have an upper portion that seals the bottom of the bag F and a lower portion that seals the top of the bag F, sandwiching a cutter (not shown). A pair of shafts 17, 17 are disposed on both sides of each heater block 16a, 16b in a direction perpendicular to the heater blocks 16a, 16b. A horizontal sealer bracket 18 and a connecting bracket 19 are connected to both ends of the shafts 17, 17. A horizontal sealer bracket 20 is supported on the shafts 17 so as to be slidable. The shaft portions 17, 17, the horizontal seal bracket 18 and the connecting bracket 19 are formed into an approximately rectangular frame shape, sandwiching the heater blocks 16a, 16b and the horizontal seal bracket 20, and are supported by joints not shown in the figure so as to be able to move back and forth in the longitudinal direction of the shaft portion 17.

The horizontal sealer bracket 18 is connected to one heater block 16a via support portions 18a and 18b. The pair of support portions 18a and 18b are connected to both ends of the heater block 16a in the longitudinal direction at positions spaced apart from each other. The horizontal sealer bracket 20 is connected to the other heater block 16b via support portions 20a and 20b. The pair of support portions 20a and 20b are connected to both ends of the heater block 16b in the longitudinal direction at positions spaced apart from each other.
Between the horizontal seal bracket 20 and the connecting bracket 19, a first linking member 22 and a second linking member 23 in the shape of a crankshaft are disposed at a distance from each other. The first linking member 22 has a first motor M1, a crank lever 24a connected to the output shaft of the first motor M1 at the center in the longitudinal direction, and crank arms 25a rotatably supported at both ends of the crank lever 24a. One end of the crank arm 25a is supported by a joint 26a fixed to the horizontal seal bracket 20, and the other end of the crank arm 25a is supported by a joint 27a fixed to the connecting bracket 19. The second linking member 23 has a similar configuration to the first linking member 22, and has a second motor M2, a crank lever 24b, crank arms 25b on both sides of the crank lever 24b, and joints 26b and 27b. The pair of joints 26a and 26b are connected to both ends of the horizontal seal bracket 20 in the longitudinal direction at positions spaced apart from each other.

In FIG. 3, when the first motor M1 rotates clockwise and the second motor M2 rotates counterclockwise, the first linking member 22 and the second linking member 23 contract, and the horizontal sealer bracket 20 and heater block 16b move in a direction away from the other heater block 16a. In conjunction with this, the connecting bracket 19 moves closer to the heater block 16b, so the shaft 17, the horizontal sealer bracket 18, and the heater block 16a also move in a direction away from the heater block 16b.

Conversely, when the first motor M1 is rotated counterclockwise and the second motor M2 is rotated clockwise, the first linking member 22 and the second linking member 23 expand, and the horizontal sealer bracket 20 and heater block 16b move in a direction approaching the other heater block 16a. In conjunction with this, the connecting bracket 19 moves in a direction away from the heater block 16b, so the shaft 17, the horizontal sealer bracket 18, and the heater block 16a also move in a direction approaching the heater block 16b. The heater blocks 16a and 16b then sandwich and press the cylindrical film f to heat seal it.

The first motor M1 is provided with, for example, an encoder 28a as a position detection means for the first motor M1, which detects the rotation angle (amount of rotation) of the first motor M1. The rotation angle of the first motor M1 detected by the encoder 28a is output to the first motor drive control means 30. Similarly, the second motor M2 is provided with an encoder 28b as a position detection means for the second motor M2, which outputs the rotation angle (amount of rotation) of the second motor M2 detected by the encoder 28b to the second motor drive control means 31.
The first motor drive control means 30 and the second motor drive control means 31 are included in the control unit 32. The first motor drive control means 30 and the second motor drive control means 31 control the outputs of the first motor M1 and the second motor M2 based on command torque values outputted from a first torque command means 35a and a second torque command means 35b, respectively, of a torque value command means 35, which will be described later.

However, when the heater blocks 16a and 16b are closed, the contents that fall from the hopper 7 through the bag-making tube 8 into the bag F (cylindrical film f) do not all fall at the same time, and there is variation in the timing of the falling. If the range of variation exceeds an expected range, the contents may become caught in the top transverse seal portion S1 or bottom transverse seal portion S2 of the bag F between the heater blocks 16a and 16b that perform heat sealing. The control unit 32 can determine whether the contents have become caught between the heater blocks 16a and 16b when the heater blocks 16a and 16b heat-seal the cylindrical film f.
The control unit 32 has a timing command means 34 for operating the heater blocks 16a, 16b to heat-seal the film f when making the bag F, and a torque value command means 35 having a first torque command means 35a for outputting a torque value of the first motor M1 and a second torque command means 35b for outputting a torque value of the second motor M2 in response to a command from the timing command means 34. Command signals output from the first torque command means 35a and the second torque command means 35b are output to the first motor drive control means 30 and the second motor drive control means 31, which drive and control the first motor M1 and the second motor M2, respectively.

Figure 4 is a diagram showing the change in the ratio of generated torque (load torque) as a torque monitor, with the rated torque of the first motor M1 and the second motor M2 set to 100%. In Figure 4, the total sealing time of the bag F by the heater blocks 16a and 16b is T, the first half of the sealing time is the jamming judgment section t1, which judges whether the contents are jammed or not, and the second half of the sealing time is the sealing completion section t2, which completes the sealing of the bag F.

In the jamming determination section t1, the torque of the first motor M1 is gradually increased from the start, and the torque of the second motor M2 is greater than the torque of the first motor M1 at the start and gradually decreases, forming a descending slope. Moreover, the torque changes of the first motor M1 and the second motor M2 are formed into a substantially X-shaped crossover midway.
5(a) and (b), heater blocks 16a, 16b heat and seal one end of bag F with the strongest torque at strong sealing point p where the second motor M2 side is pressed more strongly than the first motor M1 side at the beginning of jamming judgment section t1. Note that Fig. 5 is a diagram that shows the magnitude of the torque acting on heater blocks 16a, 16b by first motor M1 and second motor M2, and does not show the size of the gap between heater blocks 16a, 16b.

Then, as the torque of the second motor M2 gradually decreases and the torque of the first motor M1 gradually increases, the strong sealing point p of the heater blocks 16a, 16b is heated and sealed so as to move from one end to the other end in the longitudinal direction. In the sealing completion section t2, the bag F is stably heated and sealed over the entire surface of the heater blocks 16a, 16b with the same torque.
The control unit 32 judges whether or not the contents filled in the bag F are caught when the top opening and the bottom of the bag F are heat-sealed by the heater blocks 16a, 16b in the jamming judgment section t1. The jamming judgment can be made by selecting one of the first to third judgment means.

The first determination means outputs the rotation amounts measured by the encoders 28a, 28b when the heater blocks 16a, 16b are heat-sealed to the first motor drive control means 30 and the second motor drive control means 31, respectively. The measured values of the encoders 28a, 28b output from the first motor drive control means 30 and the second motor drive control means 31 are converted by conversion means 39a, 39b into the size of the gap between the heater blocks 16a, 16b in the closed position, and input to the jamming determination means 37. The size of the gap between the heater blocks 16a, 16b in the closed position is detected on the first motor M1 side and the second motor M2 side, i.e., at both longitudinal ends between the heater blocks 16a, 16b.
The jamming determination means 37 determines whether or not a foreign object such as a content is jammed depending on whether or not the gap at the closed position is outside of preset upper and lower thresholds. The upper and lower thresholds are stored in advance in the memory 36, and each threshold is variable according to the passage of sealing time.

In the second judgment means, the outputs of the conversion means 39a, 39b are added by the closed position sum calculation means 40, and the result is input to the jamming judgment means 37, which judges whether the contents are jammed or not based on whether the gap in the closed position falls outside the upper and lower threshold values.
In the third judgment means, the outputs of the conversion means 39a, 39b are subtracted by the closed position difference calculation means 41, and the result is input to the jamming judgment means 37 to judge whether the contents are jammed or not based on whether the gap in the closed position falls outside the upper and lower threshold values.
In the first to third judgment means, the upper and lower thresholds are determined in advance by collecting test data in accordance with the progress of the closing operation of the heater blocks 16a and 16b of the horizontal sealing device 15. The upper and lower thresholds fluctuate in accordance with the closing timing (progress of the closing operation) of the heater blocks 16a and 16b. Therefore, the presence or absence of jamming can be detected with high accuracy in accordance with the actual situation.

Figures 6 to 8 show the change in the gap at the closed position of heater blocks 16a, 16b in jamming judgment section t1 in the first to third judgment means. The position where heater blocks 16a, 16b abut against each other is set as the closed position of 0 μm, and this position is used as the reference. Then, when the film f of the bag F is sandwiched between heater blocks 16a, 16b, and when a foreign object such as contents is jammed, the rotation angles of first motor M1 and second motor M2 are measured by encoders 28a, 28b, and the measured value of the gap between heater blocks 16a, 16b is calculated as the "gap at closed position" (μm) by conversion means 39a, 39b.

In the first determination means, the rotation angles of the first motor M1 and the second motor M2 during heat sealing are measured by the encoders 28a, 28b, and the gap at the closed position of the film f is calculated. The memory 36 provided in the control unit 32 stores in advance an upper threshold value and a lower threshold value that are set based on data on the "gap at the closed position" between the heater blocks 16a, 16b when the film f is heat sealed without jamming.
Fig. 6(a) shows the relationship between the upper and lower threshold values and the actual measured value of the gap between the heater blocks 16a, 16b on the first motor M1 side during heat sealing, and Fig. 6(b) shows the relationship between the upper and lower threshold values and the actual measured value of the gap between the heater blocks 16a, 16b on the second motor M2 side.

In Fig. 3, the actual rotation amounts of the first motor M1 and the second motor M2 measured by the encoders 28a and 28b are input to the first motor drive control means 30 and the second motor drive control means 31 of the control unit 32, respectively. When the jamming determination means 37 of the control unit 32 determines that the gap between the heater blocks 16a and 16b at the closed position on the first motor M1 side input from the first motor drive control means 30 is within the range of upper and lower threshold values, it determines that jamming will not occur (see Fig. 6(a)). Similarly, when the gap dimension between the heater blocks 16a and 16b at the closed position on the second motor M2 side is determined to be within the range of upper and lower threshold values, it determines that jamming will not occur (see Fig. 6(b)).
In addition, if the gap at each closed position on the first motor M1 side or the second motor M2 side falls outside the upper or lower threshold, the jamming judgment means 37 judges that jamming has occurred and issues a stop command to the torque value command means 35.

The second determination means determines whether or not there is jamming based on whether the sum of the gaps at the closed positions on the first motor M1 side and the second motor M2 side between the heater blocks 16a and 16b is within the range of upper and lower threshold values. The threshold value is also calculated by calculating the sum of the gaps at the closed positions from the rotation amounts of the first motor M1 and the second motor M2 measured by the encoders 28a and 28b when no contents are jammed in the bag F.

As shown in FIG. 7, the closed position difference calculation means 41 calculates the closed positions (gap) from the measured values of the rotation angles of the first motor M1 and the second motor M2 between the heater blocks 16a and 16b measured by the encoders 28a and 28b, and calculates the sum of these. If the jamming determination means 37 determines that the sum of the closed positions is within the range of the upper and lower threshold values, it determines that jamming has not occurred. On the other hand, if it determines that the sum of the closed positions is outside the range of the upper and lower threshold values, it determines that jamming has occurred. The second determination means can indicate the overall size of the gap (center of gravity) between the heater blocks 16a and 16b.

The third determination means determines whether or not there is jamming based on whether the difference in the gap between the heater blocks 16a, 16b at the closed positions on the first motor M1 side and the second motor M2 side is within the range of upper and lower threshold values. Note that the third determination means also calculates the difference in the gap at the closed positions as a threshold value from the rotation angles of the first motor M1 and the second motor M2 measured by the encoders 28a, 28b when no contents are jammed into the film f. Then, the upper and lower threshold values are stored based on this data.

As shown in FIG. 8, the closed position difference calculation means 41 calculates the gaps at the respective closed positions from the measured values of the rotation angles of the first motor M1 and the second motor M2 between the heater blocks 16a and 16b measured by the encoders 28a and 28b, and calculates the difference. If the jamming determination means 37 determines that the difference in the closed positions is within the range of the upper and lower threshold values, it determines that jamming has not occurred. On the other hand, if it determines that the difference in the closed positions is outside the range of the upper and lower threshold values, it determines that jamming has occurred. The third determination means can indicate the overall degree of twisting of the gap between the heater blocks 16a and 16b.

The transverse sealing device 15 of the bag making and filling machine 1 according to this embodiment has the above-mentioned configuration. Next, the transverse sealing method thereof will be described.
When filling the bag F with contents and sealing it, the bag F is judged for the presence or absence of the contents being caught when the top seal portion S1 or the bottom seal portion S2 of the horizontal seal portion is heat-sealed by selecting any one of the first to third judgment means or a combination thereof. First, the case where the first judgment means is selected will be described.
In the vertical bag making and filling machine 3, the vertical seal portion S3 of the tubular film f descending the bag making tube 8 is vertically sealed, and then horizontal sealing is performed by the horizontal sealing device 15. For example, when the top opening of a bag F and the bottom of the next bag F are heat sealed, a specified torque is output from the torque value command means 35 to the first motor drive control means 30 and the second motor drive control means 31 in response to an instruction from the timing command means 34 of the control unit 32. Then, the first motor M1 and the second motor M2 are rotated.

By driving the first motor M1 and the second motor M2, the heater blocks 16a and 16b are operated via the first linkage member 22 and the second linkage member 23 to sandwich the bag F. At this time, as shown in FIG. 4, in the bite judgment section t1 of the sealing time, the torque of the first motor M1 gradually rises from a position close to 100% of the torque monitor, and the torque of the second motor M2 gradually falls from a position exceeding approximately 100%, and they cross each other in the middle. As a result, as shown in FIG. 5, the heater blocks 16a and 16b are initially pressed most strongly at the strong sealing point p on the second motor M2 side while sandwiching the bag F, and the strong sealing point p shifts to the first motor M1 side, allowing the bag F to be horizontally sealed all over with high precision.

The rotation angle (amount of rotation) of each of the motors M1 and M2 is measured by the encoders 28a and 28b attached to the first motor M1 and the second motor M2. The measured values of each rotation angle are converted into the dimensions of the gaps in the closed positions of the heater blocks 16a and 16b by the conversion means 39a and 39b via the first motor drive control means 30 and the second motor drive control means 31 of the control unit 32. These gaps in the closed positions are input to the jamming determination means 37.

The jamming determination means 37 determines that there is no jamming between the heater blocks 16a and 16b when the size of the gap at the closed position based on the encoder 28a on the first motor M1 side is within upper and lower threshold values as shown in Fig. 6(a).Similarly, it determines that there is no jamming when the size of the gap at the closed position based on the encoder 28b on the second motor M2 side is within upper and lower threshold values as shown in Fig. 6(b).
In addition, when the size of the gap between the heater blocks 16a, 16b at the closed position on either the first motor M1 side or the second motor M2 side falls outside the upper and lower thresholds, it is determined that jamming has occurred. In this case, a stop command is output from the jamming determination means 37 to the torque value command means 35 to stop driving the first motor M1 and the second motor M2.

Next, the case where the second determination means is selected will be described with reference to FIG.
In this case, the first and second motors M1, M2 are driven to clamp the bag F with the open top opening and close the heater blocks 16a, 16b of the horizontal sealing device 15. The rotation angles of the first and second motors M1, M2 measured by the encoders 28a, 28b are then converted into the dimensions of the gap at the closed position by conversion means 39a, 39b via the first motor drive control means 30 and the second motor drive control means 31 of the control unit 32. This data on the gap at the closed position is input to the closed position sum calculation means 40.

The closed position sum calculation means 40 calculates the sum of the gaps at the closed position on the first and second motors M1 and M2 sides and inputs it to the jamming determination means 37. As shown in FIG. 7, the jamming determination means 37 determines that there is no jamming if the sum of the gaps at the closed position is within the upper and lower thresholds, and determines that there is jamming if the sum of the gaps at the closed position is outside the upper and lower thresholds. If the sum of the gaps at the closed position is outside the thresholds, the jamming determination means 37 outputs a stop command to the torque value command means 35 to stop driving the first motor M1 and the second motor M2.

Next, the case where the third determination means is selected will be described with reference to FIG.
In this case as well, the first and second motors M1, M2 are driven to clamp the bag F with the open top opening and close the heater blocks 16a, 16b of the horizontal sealing device 15. Then, the rotation angles of the first and second motors M1, M2 measured by the encoders 28a, 28b are converted into the size of the gap at the closed position by the conversion means 39a, 39b via the first motor drive control means 30 and the second motor drive control means 31 of the control unit 32. This gap at the closed position is input to the closed position difference calculation means 41.
The closed position difference calculation means 41 calculates the difference in the closed position gap between the first and second motors M1, M2 and inputs it to the jamming determination means 37. As shown in Fig. 8, the jamming determination means 37 compares the difference in the closed position gap between the first and second motors M1, M2 with a threshold value. If the difference in the closed position gap is within the upper and lower threshold values, it is determined that there is no jamming, and if the difference in the closed position gap is outside the upper and lower threshold values, it is determined that there is jamming. If the difference in the closed position gap is outside the threshold value, the jamming determination means 37 outputs a stop command to the torque value command means 35 to stop driving the first motor M1 and the second motor M2.

Next, Figures 9(a) to (d) show the gap between heater blocks 16a and 16b in the closed operation. In Figure 9(a), the gap on the first motor M1 side is a1, and the gap on the second motor M2 side is b2. The sum of the gaps between closed heater blocks 16a and 16b is (a1 + b2), and the difference is (a1 - b2). The same is true for the other examples in Figures 9(b) to (d).
9(a) to 9(d), the film f on the front and back sides of the bag F is sandwiched in the gap between the heater blocks 16a and 16b, and if a foreign object such as contents is sandwiched, the foreign object is also included. In each gap shown in Fig. 9(a) to 9(d), the sum of the gaps on both sides between the heater blocks 16a and 16b represents the overall size of the closed position, and the difference represents the degree of twist between the heater blocks 16a and 16b.

As described above, according to the horizontal sealing device 15 of the bag making and filling machine 1 of this embodiment, in the jamming judgment section t1 of the bottom horizontal seal section S1 and the top horizontal seal section S2, the strong seal point p of the maximum torque value output from the first torque command means 35a and the second torque command means 35b of the torque value command means 35 moves from one of the heater blocks 16a, 16b to the other. Therefore, the boundary portion with the vertical seal section S3, which has a different thickness from the other portions, can be reliably sealed, achieving a highly reliable seal.

In addition, the lateral sealing device 15 has a jamming judgment section t1 set at the timing when the torque magnitude during lateral sealing by the heater blocks 16a, 16b is changed so that they are different from each other, so that the presence or absence of jamming at the bottom lateral seal section S1 and the top lateral seal section S2 can be detected with high accuracy.
In the control unit 32, when the size of the gap in the closed position between the heater blocks 16a, 16b based on the measurements of the encoders 28a, 28b of the first motor M1 and the second motor M2, or the sum or difference thereof, exceeds the upper or lower threshold value, the jamming determination means 37 determines that jamming has occurred in the bottom horizontal seal portion S1 or the top horizontal seal portion S2, so that the presence or absence of jamming can be detected with high accuracy. Moreover, because the threshold value is variable, the presence or absence of jamming can be detected with even higher accuracy.

The horizontal sealing device 15 according to an embodiment of the present invention has been described in detail above, but the present invention is not limited to the above-mentioned embodiment, and appropriate modifications and substitutions are possible without departing from the gist of the present invention, and all of these are included in the present invention. Below, we will explain modified examples of the present invention, but the same reference numerals will be used for parts and members that are the same or similar to those in the above-mentioned embodiment, and explanations will be omitted.

In the horizontal sealing device 15 according to the embodiment described above, two motors, a first motor M1 and a second motor M2, are provided, and the torque value pressing both longitudinal ends of the heater blocks 16a, 16b of the horizontal sealing device 15 is detected as a rotation angle by encoders 28a, 28b and converted into the size of the gap in the closed position.
However, the number of motors as the drive source for opening and closing the heater blocks 16a, 16b may be one. In this case, output shafts may be provided on both sides of the motor and connected to both longitudinal ends of the heater blocks 16a, 16b via the first linking member 22 and the second linking member 23. Even in this case, the measured values of the encoders 28a, 28b can be received by the first motor drive control means 30 and the second motor drive control means 31 using the control unit 32 shown in FIG. 3, and control can be performed in the same manner as in the first embodiment.

In the horizontal sealing device 15 according to the embodiment described above, the rotation angles of the first motor M1 and the second motor M2 measured by the encoders 28a, 28b are converted by the conversion means 39a, 39b into the size of the gap between the heater blocks 16a, 16b, and either the sum of the values calculated by the closed position sum calculation means 40 or the difference of the values calculated by the closed position difference calculation means 41 is selected and the presence or absence of jamming is judged by the jamming judgment means 37.
However, instead of this configuration, any two or three of the values converted by the conversion means 39a and 39b, the sum of the values calculated by the closed position sum calculation means 40, and the difference of the values calculated by the closed position difference calculation means 41 may be combined. In this case, it may be determined that a foreign object has been caught when any of the values exceeds a threshold value.

Furthermore, in the above embodiment, when the jamming determination means 37 in the control unit 32 determines that the size of the gap at the closed position exceeds a threshold value, the jamming determination means 37 outputs a stop command to the torque value command means 35 to stop the driving of the first motor M1 and the second motor M2. However, it is also possible to continue making bags F without stopping the bag making and filling machine 1, and to select as defective bags F those that exceed the threshold value during lateral sealing out of the large number of bags F that have been manufactured.
In the present invention, the heater blocks 16a and 16b are included in the seal block, and the encoders 28a and 28b and the conversion means 39a and 39b are included in the position detection means.
In addition, in the above-mentioned embodiments and variant examples, the horizontal sealing device 15 of the vertical bag making and filling machine 3 has been described, but the present invention can also be applied to a case where the horizontal sealing device 15 is installed on a horizontal bag making and filling machine as the bag making and filling machine 1.

REFERENCE SIGNS LIST 1 Bag making and filling machine 3 Vertical bag making and filling machine 15 Horizontal sealing device 16a, 16b Heater blocks 28a, 28b Encoder 30 First motor drive control means 31 Second motor drive control means 32 Control unit 34 Timing command means 35 Torque value command means 37 Jamming determination means 39a, 39b Conversion means 40 Closed position sum calculation means 41 Closed position difference calculation means M1 First motor M2 Second motor f Film F Bag

Claims (2)

A pair of seal blocks capable of sandwiching and sealing a packaging material by opening and closing the seal blocks;
a drive source for opening and closing the seal block;
a pair of linking members that open and close the pair of seal blocks in cooperation with the driving of the driving source;
a position detection means for detecting two gaps spaced apart in a longitudinal direction of the seal block when the seal block is in a closed position;
a jamming determination means for detecting jamming of a foreign object when the gap exceeds a threshold range at a preset timing within a jamming determination period;
Equipped with
a torque value command means for changing the magnitude of the torque of the drive source so as to be different from each other when the pair of seal blocks are closed to seal the packaging material,
The drive sources are provided in pairs corresponding to the pair of linking members,
When the torque change is plotted as a percentage change in generated torque when the rated torque of the drive source is 100% on the vertical axis and time on the horizontal axis, the torque change of a first drive source and the torque change of a second drive source of the pair of drive sources form a substantially X-shape that intersects in the jamming determination section.
A sealing device for a bag making and filling machine. 2. The sealing device for a bag making and filling machine according to claim 1 , wherein the upper and lower limits of the threshold value are variable depending on timing within the jamming determination period.

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