JP7777334B2 - Bag thickness measuring device - Google Patents

Description

The present invention relates to a device for measuring the thickness of chain bags.

A chain bag is made up of a plurality of pouches containing products connected together via seals.
After chain bags are manufactured by a form-fill-seal packaging machine, in which products are placed in bags, they are transported from the machine to a discharge conveyor via a discharge chute, and then to a first transport conveyor, where their weight is measured by a weight checker while they are being transported on the first transport conveyor.They are then transported from the first transport conveyor to a second transport conveyor on which a thickness measuring device is installed, where the thickness of each bag is measured.
In this case, on each conveyor, the chain bag is transported in the length direction in which a plurality of bags are connected.
Patent document 1 proposes a technology that detects the leading edge of a chain of packets in the conveying direction on a second conveyor, and determines the timing for measuring the thickness of the bag body based on the conveying speed and the length of each bag body.

Japanese Patent Application Laid-Open No. 2021-123398

However, since the chain of packets are discharged by their own weight from a discharge chute that extends almost vertically toward a discharge conveyor that extends almost horizontally, a phenomenon known as jamming can easily occur, in which the discharged chain of packets bends at the sealed portion on the discharge conveyor.
Furthermore, in order to ensure accurate weight checker measurements, the transport speed of the first transport conveyor is often set slower than that of the discharge conveyor, and as a result, the transport speed suddenly drops when the chain of packets moves from the discharge conveyor to the first transport conveyor, which can easily cause the chain of packets to bend at the seal, as described above.
When such bending occurs, the positional relationship of each bag body relative to the leading end of the chain of packets in the conveying direction becomes inconsistent and varies compared to when no bending occurs.
Therefore, if the leading edge of the chain of packets in the conveying direction is detected and the timing for measuring the thickness of each bag is determined based on the conveying speed and the length of each bag, as in the above-mentioned conventional technology, the measurement timing for each bag may not be optimal, and the thickness may be measured at a point away from the center of the bag, which may reduce the accuracy of the thickness measurement.
The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a thickness measuring device for chain bags that is advantageous in measuring the thickness of the bag body of a chain bag with high accuracy.

In order to achieve the above-mentioned object, one embodiment of the present invention is a thickness measuring device for chain bags constructed by connecting a plurality of bags containing products via a seal portion having a perforation, and is characterized by comprising: a conveying section that conveys the chain bag in the direction in which the plurality of bags are connected at a preset conveying speed; a thickness detecting section that detects the thickness of each of the plurality of bags in the chain bag conveyed along the conveying section; a light detecting section that is provided upstream of the thickness detecting section in the conveying direction of the chain bag, and that irradiates detection light onto the chain bag and detects the intensity of the detection light that is transmitted through or reflected by the chain bag; and a control section that detects the leading end of the chain bag in the conveying direction and the perforation based on the intensity of the detection light, and that determines the timing of the detection operation for each of the bags by the thickness detecting section based on the detection result, the length of the bag along the conveying direction, and the conveying speed.
In addition, one embodiment of the present invention is characterized in that the thickness detection unit includes a moving body that is formed to be able to rise and fall in the thickness direction of the bag body and press against the upper surface of the bag body, an electric motor that raises and lowers the moving body, a motor control unit that controls the electric motor based on the timing determined by the control unit and controls the pressing force of the moving body on the bag body based on the torque load of the electric motor when the moving body is pressed against the upper surface of the bag body, and a thickness calculation unit that calculates the thickness of the bag body based on the amount of rotation of the electric motor.
In addition, one embodiment of the present invention is characterized in that the light detection unit is composed of a transmission type photoelectric sensor having a light emitting unit that irradiates the detection light and a light receiving unit that detects the detection light that has passed through the chain bag.
In one embodiment of the present invention, the chain bag is formed from an opaque packaging film.
In one embodiment of the present invention, the product is a snack food.

According to one embodiment of the present invention, the optical detection unit detects the leading edge of the chain bag in the conveying direction and the perforations, and the timing of the detection operation for each bag body by the thickness detection unit is determined based on this detection result, the length of the bag body along the conveying direction, and the conveying speed.
Therefore, even if the chain bag bends at the seal, the thickness detection unit can detect the thickness at the center of the length of each bag, which is advantageous for accurately measuring the thickness of the bag in the chain bag.
Furthermore, by controlling the pressing force applied to the bag body by the moving body based on the torque load of the electric motor when the moving body is pressed against the upper surface of the bag body, and calculating the thickness of the bag body based on the amount of rotation of the electric motor, the conditions for measuring the thickness of the bag body can be maintained constant by appropriately setting the pressing force applied to the bag body by the moving body, which is advantageous for accurately measuring the thickness of the bag body of a chain bag.
Furthermore, if the light detection unit is configured as a transmission type photoelectric sensor having a light emitting unit that irradiates detection light and a light receiving unit that detects the detection light that has passed through the continuous packet, this is advantageous in simplifying the configuration of the thickness detection device.
Furthermore, if the chain link bag is made of an opaque packaging film, this is advantageous in that the light detection unit can more reliably detect the leading edge of the chain link bag in the conveying direction and the perforations.
Furthermore, if the product is a snack, detecting the thickness of the bag containing the snack can determine whether the amount of air contained in the bag is appropriate, which is advantageous in preventing damage to the snack during transport while ensuring that the chain of packets is securely placed in the cardboard box.

1 is an explanatory diagram showing the process of transporting a chain of bags discharged from a bag making, filling and packaging machine to a thickness measuring device according to an embodiment of the present invention. FIG. 1A is a side view showing the configuration of a packet thickness measuring device according to an embodiment, and FIG. 1B is a plan view of FIG. 1A. FIG. 2 is a block diagram showing the configuration of a thickness detection unit.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, the chain packet 10 will be described with reference to FIGS.
The chain bag 10 is constructed by connecting a plurality of pouches 12 containing products via seals 14 .
In this embodiment, the chain bag 10 is formed from an opaque packaging film, and as such a packaging film, an aluminum vapor deposition film with light-blocking properties is used to prevent oxidation of products such as snack foods.
The chain bag 10 has a length in the direction in which the plurality of bag bodies 12 are connected, the bag bodies 12 and the seal portion 14 have a length along the length direction of the chain bag 10, and the seal portion 14 is located at both ends of the bag body 12 in the length direction.
A perforation 16 is provided in the middle of the seal portion 14 in the longitudinal direction to allow the bag body 12 to be torn.
The dimensions of adjacent perforations 16 in the longitudinal direction of the chain bag 10, in other words, the lengths of the individual bags 12, are the same.
In this embodiment, the chain bag 10 is constructed by connecting four bag bodies 12 via three seal portions 14, and the seal portions 14 are located at both ends of the chain bag 10 in the longitudinal direction.
A header part 18 having a hole 18A for hanging the chain bag 10 at a store or the like is provided at a seal part 14 at one end in the longitudinal direction of the chain bag 10, and such a chain bag 10 is called a chain bag with a header.
Therefore, the header portion 18 is located at one end in the length direction of the chain bag 10, and the seal portion 14 is located at the other end in the length direction.
It should be noted that the present invention is of course applicable to chain packets that do not have a header portion 18.
The product contained in the bag 12 is, for example, a snack food such as potato chips, but the type of product is not limited thereto. In addition, the bag 12 is inflated to a certain extent by filling the bag 12 with air together with the product by the form-fill-seal machine 20 described below. This is to ensure the thickness of the bag 12 with air, thereby absorbing shocks during transportation and protecting the product.

As shown in Figure 1, the chain bag 10 is manufactured by a form-fill-seal packaging machine 20 in which the product is placed in each bag 12 together with air, and then the chain bag 10 is discharged by its own weight from a discharge chute 22 that extends almost vertically onto a discharge conveyor 24 that extends at a gentle slope and becomes higher the further downstream in the conveying direction it is transported.
In the drawing, reference numeral 20A denotes a horizontal sealing section of the bag making, filling and packaging machine 20, and the seal section 14 of the chain bag 10 is formed by the horizontal sealing section 20A.
In addition, the chain bag 10 is discharged onto the discharge conveyor 24 so that the header portion 18 at one end of the length of the chain bag 10 is located at the upstream end in the conveying direction, and the seal portion 14 at the other end of the length of the chain bag 10 is located at the downstream end in the conveying direction.
A first conveying conveyor 26A constituting the weight checker 26 is arranged downstream of the discharge conveyor 24 in the conveying direction, and the weight of one chain bag 10 is measured while it is being conveyed on the first conveying conveyor 26A.
The weight of the chain bag 10 measured by the weight checker 26 is determined to be within a predetermined acceptable range, and if the weight of the chain bag 10 is not within the acceptable range, it is deemed a defective product and is rejected by the defective rejection section 50 described below.

As shown in Figure 1, when the chain of chain bags 10 is discharged downward from the discharge chute 22, which extends almost vertically, due to its own weight, it is prone to a phenomenon known as jamming, in which the chain of chain bags 10 bends at the seal portion 14 on the discharge conveyor 24.
Furthermore, in order to ensure the accuracy of weight measurement by the weight checker 26, the conveying speed of the first conveying conveyor 26A is set to be slower than the conveying speed of the discharge conveyor 24. Therefore, when the chain of chains 10 moves from the discharge conveyor 24 to the first conveying conveyor 26A, the conveying speed suddenly drops, which can easily cause the chain of chains 10 to bend at the seal portion 14, as described above.
In the drawing, the straight line α indicates the position of the seal portion 14 in the thickness direction when the chain packet 10 is not bent.

As shown in Figures 2(A) and (B), the chain bag thickness measuring device 28 of this embodiment is configured to include a second transport conveyor 30 (transport section), a thickness detection section 32, a light detection section 34, and a control section 36.
The second transfer conveyor 30 transfers the chain bag 10 transferred from the first transfer conveyor 26A at a preset transfer speed in the direction in which the plurality of bag bodies 12 are connected.
In this embodiment, a gap S is formed between the downstream end of the first transfer conveyor 26A and the upstream end of the second transfer conveyor 30.
In the drawing, reference numeral 52 denotes a third transfer conveyor of the defective removal section 50 connected downstream of the second transfer conveyor 30 in the transfer direction.

The thickness detection unit 32 detects the thickness of each of the plurality of bag bodies 12 of the chain bag 10 being transported on the second transport conveyor 30 .
As shown in FIG. 3, the thickness detection unit 32 includes a moving body 38, an electric motor 40, a motor control unit 42, and a thickness calculation unit 44.
As shown in FIG. 2A, the moving body 38 has a pressing surface 3802 having a length along the conveying direction of the second conveyor 30 and a width in a direction perpendicular to the length.
The moving body 38 is configured to be able to move up and down in the thickness direction of the bag body 12 and press the upper surface of the bag body 12 with the pressing surface 3802 .
The moving body 38 has, for example, a number of free rollers (not shown) on the pressing surface 3802 that are rotatable along the conveying direction of the chain bag 10, and even if the pressing surface 3802 presses the upper surface of the bag body 12 of the chain bag 10 during conveyance, the free rollers rotate following the chain bag 10, so as not to interfere with the conveyance of the chain bag 10.
Furthermore, as will be described later, the thickness of the bag body 12 is designed to be measured most accurately when the center of the length of the upper surface of the bag body 12 in the conveying direction is pressed at the center of the length of the pressing surface 3802 of the moving body 38.

The electric motor 40 moves the moving body 38 up and down via a power transmission mechanism (not shown), and is configured, for example, as a servo motor capable of servo control.
The motor control unit 42 controls the rotation of the electric motor 40 based on the timing determined by the control unit 36, which will be described later.
The motor control unit 42 also controls the pressing force of the moving body 38 against the bag body 12 based on the torque load of the electric motor 40 when the moving body 38 is pressed against the upper surface of the bag body 12 .
The pressing force is controlled to a predetermined constant value, thereby maintaining the measurement conditions for the thickness of the bag body 12 constant.

The thickness calculation unit 44 calculates the thickness of the bag body 12 based on the rotation amount of the electric motor 40 .
For example, the thickness calculation unit 44 counts the drive pulses corresponding to the amount of rotation of the electric motor 40 supplied from the motor control unit 42, and calculates the height position of the moving body 38 from the top surface of the second conveying conveyor 30, i.e., the thickness of the bag body 12, based on the counting result of the drive pulses.
It is then determined whether the calculated thickness of the bag body 12 is within a predetermined acceptable range, and if the thickness of the bag body 12 is not within the acceptable range, the chain bag 10 is deemed to be a defective product and is rejected by the defective rejection section 50.

As shown in Figure 2 (A), the light detection unit 34 is located upstream of the thickness detection unit 32 in the conveying direction of the chain bag 10, and irradiates detection light L onto the chain bag 10 and detects the intensity of the detection light L that passes through or is reflected by the chain bag 10.
In this embodiment, the light detection unit 34 is composed of a transmission type photoelectric sensor including a light emitting unit 46 and a light receiving unit 48 arranged to sandwich the gap S between the first transport conveyor 26A and the second transport conveyor 30 from above and below.
The light emitting section 46 emits detection light L toward the chain bag 10 , and the light receiving section 48 detects the detection light L that has passed through the chain bag 10 .
Although the shape and number of the detection light L emitted from the light-emitting unit 46 are not limited, it is preferable that, for example, multiple detection lights (light beams) L are emitted along the length of the perforation 16 so that the perforation 16 can be detected reliably.
Therefore, various conventionally known transmission type photoelectric sensors such as an area sensor having a plurality of optical axes can be used as the light detection unit 34 .
The detection light L passes through the perforations 16 of the chain bag 10, but the detection light L does not pass through the portions of the chain bag 10 other than the perforations 16 because they are made of opaque packaging film.
Therefore, the intensity of the detection light L detected by the light detection unit 34 is at its maximum when the chain bag 10 is not present, at its minimum in the part of the chain bag 10 other than the perforation 16, and at its intermediate value in the part of the perforation 16.
Therefore, the intensity of the detection light L changes from a maximum value to a minimum value at the tip of the chain bag 10 in the conveying direction, and also changes from a minimum value to an intermediate value before and after the perforation 16, and from the intermediate value to a minimum value.Therefore, it is possible to detect the tip of the chain bag 10 in the conveying direction and the perforation 16 based on the intensity of the detection light L.
Furthermore, even if the packet bag 10 is formed from a transparent packaging film, the amount of transmission of the detection light L is reduced in the packaging film area compared to when no packaging film is present, so the perforation 16 can be detected using the same principle as above.

The control unit 36 detects the tip of the chain bag 10 in the conveying direction and the perforation 16 based on the intensity of the detection light L, and determines the timing of the detection operation of each bag body 12 by the thickness detection unit 32 based on this detection result, the length A of the bag body 12, and the conveying speed V of the second conveyor 30.
More specifically, the timing of the detection operation for each bag body 12 by the thickness detection unit 32 is determined based on the detection result, the length A (cm) of the bag body 12, the conveying speed V (cm/sec) of the second conveying conveyor 30, and the distance B (cm) between the detection light L along the conveying direction of the second conveying conveyor 30 and the center of the length direction of the pressing surface 3802 of the moving body 38.
That is, if the timing for executing the detection operation is T seconds based on the time when the tip of the chain bag 10 or the perforation 16 is detected, the timing T is calculated by the following equation (1).
T=((A/2)+B)/V (seconds)...(1)
That is, the control unit 36 instructs the motor control unit 42 of the thickness detection unit 32 on the timing of the detection operation for the bag body 12 .
As a result, the motor control unit 42 raises and lowers the moving body 38 between an upper waiting position where the pressing surface 3802 of the moving body 38 is spaced upward from the continuous packet bag 10 and a lower pressing position where the pressing surface 3802 of the moving body 38 presses the bag body 12 with a predetermined pressing force, and the thickness calculation unit 44 calculates the thickness of the bag body 12 for each bag body 12.
The timing of the detection operation for each bag body 12 is set to the timing when the center of the length of each bag body 12 in the conveying direction by the second conveying conveyor 30 is pressed by the center of the pressing surface 3802 of the moving body 38, so that the thickness of the bag body 12 can be measured with the highest accuracy.

Next, the effects of this embodiment will be described.
According to this embodiment, the light detection unit 34 detects the tip of the chain bag 10 in the conveying direction and the perforation 16, and the timing of the detection operation for each bag body 12 by the thickness detection unit 32 is determined based on this detection result, the length of the bag body 12 along the conveying direction, and the conveying speed.
Therefore, even if the chain bag 10 is bent at the seal portion 14, the thickness detection unit 32 can detect the thickness at the center of the length of each bag body 12, which is advantageous in accurately measuring the thickness of the bag body 12 of the chain bag 10.

In addition, in this embodiment, the thickness detection unit 32 controls the pressing force of the moving body 38 on the bag body 12 based on the torque load of the electric motor 40 when the moving body 38 is pressed against the upper surface of the bag body 12, and calculates the thickness of the bag body 12 based on the amount of rotation of the electric motor 40.
Therefore, by appropriately setting the pressing force applied to the bag body 12 from the moving body 38, the measurement conditions for the thickness of the bag body 12 can be maintained constant, which is advantageous in accurately measuring the thickness of the bag body 12 of the chain bag 10.

In addition, in this embodiment, the light detection unit 34 is composed of a transmission type photoelectric sensor having a light emitting unit 46 that irradiates detection light L and a light receiving unit 48 that detects the detection light L that has passed through the chain bag 10, which is advantageous in simplifying the configuration of the thickness detection device.
The light detection unit 34 may be configured as a reflective photoelectric sensor having a light emitting unit 46 that emits detection light L and a light receiving unit 48 that detects the detection light L reflected by the chain packet 10.
In this case, the detection light L is reflected at a certain rate from the parts of the packet 10 other than the perforation 16, while at the location of the perforation 16, part of the detection light L passes through the perforation 16, reducing the intensity of the reflected detection light L.
Therefore, the intensity of the detection light L detected by the light detection unit 34 is at its minimum when the chain bag 10 is not present, at its maximum in the part of the chain bag 10 other than the perforation 16, and at its intermediate value in the part of the perforation 16.
Therefore, the intensity of the detection light L changes from a minimum value to a maximum value at the tip of the chain bag 10 in the conveying direction, and also changes from a maximum value to an intermediate value and from an intermediate value to a maximum value before and after the perforation 16, so it is possible to detect the tip of the chain bag 10 in the conveying direction and the perforation 16 based on the intensity of the detection light L.
However, when a reflective photoelectric sensor is used as the light detection unit 34, the intensity of the detection light L reflected by the chain bag 10 is easily affected by the surface condition of the chain bag 10, and therefore the process of distinguishing between the intensity of the detection light L reflected by the chain bag 10 and the intensity of the detection light L reflected by the perforation 16 is considered to be somewhat complicated.
Therefore, using a transmission type photoelectric sensor as the light detection unit 34 as in this embodiment is more advantageous in that it allows the light detection unit 34 to detect the tip of the chain bag 10 in the conveying direction and the perforation 16 with a simple configuration.

In addition, in this embodiment, the chain bag 10 is formed from opaque packaging film. Therefore, when a light transmission sensor is used as the light detection unit 34, the detection light L passes through the perforations 16, but is not transmitted by parts of the chain bag 10 other than the perforations 16. This is advantageous in that the light detection unit 34 can more reliably detect the leading edge of the chain bag 10 in the conveying direction and the perforations 16, compared to when the chain bag 10 is formed from transparent packaging film.

In addition, in this embodiment, since the product is a snack food, each bag 12 contains the snack food together with an appropriate amount of air.
This is because if the amount of air contained in the bag body 12 is too small, the snack food will be easily broken due to vibrations and shocks during transportation, and if the amount of air contained in the bag body 12 is too large, the chain bag 10 will not fit into the cardboard box when it is stored in the cardboard box, so it is necessary to contain an appropriate amount of air in the bag body 12.
In this embodiment, by detecting the thickness of the bag 12 containing such snacks, it is possible to determine whether the amount of air contained in the bag 12 is appropriate, which is advantageous in preventing damage to the snacks during transportation while ensuring that the chain of packets 10 are securely contained in the cardboard box.

In this embodiment, the case where the thickness detection unit 32 measures the thickness of the bag body 12 based on the amount of movement of the movable body 38 has been described, but a non-contact (photoelectric) thickness sensor that measures the thickness of the bag body 12 may be used separately from the movable body 38 that presses the bag body 12. In that case, the function of calculating the thickness of the bag body 12 based on the amount of rotation of the electric motor 40 is not necessary.
This configuration is also advantageous in measuring the thickness of the bag body 12 of the continuous packet 10 with high accuracy, as in this embodiment.

10: Chain of pouches 12: Bag body 14: Sealed section 16: Perforation 18: Header section 18A: Hole 20: Bag making, filling and packaging machine 20A: Horizontal sealing section 22: Discharge chute 24: Discharge conveyor 26: Weight checker 26A: First conveyor 28: Chain of pouch thickness measuring device 30: Second conveyor (conveyor section)
32 Thickness detection unit 34 Light detection unit 36 Control unit 38 Moving body 3802 Pressing surface 40 Electric motor 42 Motor control unit 44 Thickness calculation unit 46 Light emitting unit 48 Light receiving unit 50 Third transport conveyor L Detection light S Gap

Claims (5)

1. A device for measuring the thickness of each bag body of a chain bag formed by connecting a plurality of bags containing products via a seal portion having a perforation,
a conveying section that conveys the chain bag at a preset conveying speed in a direction in which the plurality of bags are connected;
a thickness detection unit that detects the thickness of each of the plurality of bags in the chain bag conveyed through the conveying unit;
a light detection unit that is provided upstream of the thickness detection unit in the transport direction of the chain of chains, and that irradiates the chain of chains with detection light and detects the intensity of the detection light that is transmitted through or reflected by the chain of chains;
a control unit that detects the leading end of the chain bag in the conveying direction and the perforations based on the intensity of the detection light, and determines the timing of the detection operation of the thickness detection unit for each of the bags based on the detection result, the length of the bag along the conveying direction, and the conveying speed ,
The length of the bag body is A (cm),
The conveying speed is V (cm/sec),
The distance between the detection light and the thickness detection unit along the transport direction of the chain bag is defined as B (cm),
When the timing of the detection operation of each bag body by the thickness detection unit based on the time when the tip of the chain bag or the perforation is detected by the control unit is T seconds, the control unit calculates the timing T using the following formula (1):
T=((A/2)+B)/V (seconds)...(1)
1. A device for measuring the thickness of each bag body of a chain bag. The thickness detection unit
a moving body configured to move up and down in a thickness direction of the bag body and to press the upper surface of the bag body;
an electric motor for raising and lowering the moving body;
a motor control unit that controls the electric motor based on the timing determined by the control unit and controls the pressing force of the moving body against the bag body based on a torque load of the electric motor when the moving body is pressed against the upper surface of the bag body;
a thickness calculation unit that calculates the thickness of the bag body based on the rotation amount of the electric motor;
2. The device for measuring the thickness of each bag body of a chain bag according to claim 1, further comprising: The light detection unit is composed of a transmission type photoelectric sensor including a light emitting unit that irradiates the detection light and a light receiving unit that detects the detection light that has passed through the chain bag.
3. The device for measuring the thickness of each bag body of a chain bag according to claim 1 or 2. The continuous bag is formed from an opaque packaging film.
4. The device for measuring the thickness of each bag body of a chain of bags according to claim 3. The product is a snack food.
5. The device for measuring the thickness of each bag body of a chain bag according to claim 1.