JPS63272610A - Packing apparatus - Google Patents

Abstract

PURPOSE:To surely close a seal part by keeping the optimum seal pressure, by applying feedback control to the seal pressure of a seal apparatus brought into contact with the predetermined part of a sheet under pressure while moving in synchronous relation to the feed speed of the sheet to seal said part. CONSTITUTION:In a packing apparatus constituted so that the film like sheet drawn out from a sheet roll 6 is formed into a cylindrical form and the article thrown in the cylindrical sheet is hermetically sealed to be packed by said sheet, longitudinal and lateral seal apparatuses 12, 14 are brought into contact with the predetermined part of the sheet 7 under pressure to seal the same. The third and second servo-motors 15, 16 are driven in synchronous relation to the feed speed of the sheet 7 supplied to the seal apparatus 14 and an operation apparatus 53 operates the torque value determining the seal pressure necessary for the sheet from the material quality and thickness of the sheet, a bag dimension and the feed speed of the sheet to output the same. A pressure transducer 52 detects the torque value actually applied to the seal apparatuses, and a counter 54 and a servo-valve 52 control seal pressure from the detected torque value and the set torque value.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to packaging in which various block-shaped frozen foods and snack foods are sealed and packaged in flexible bags formed from film-like sheets such as polyethylene. Regarding equipment.

(Prior Art) Today, a transaction format in which products are weighed by a set weight, packaged using continuous packaging means, and distributed is becoming popular. A variety of packaging devices have been developed for this purpose, but one consists of a combination of a cylinder that supplies the packaged items and a former that forms the packaging material into a cylindrical shape. Vertical pillow packaging machines are efficiently preferred for continuously packaging weighed products, and are widely used.

In this vertical pillow packaging machine, a film-like sheet is continuously fed from a sheet roll, and the contents are filled during or immediately after forming a cylindrical sheet into a bag.
Since the bags are sealed using thermocompression bonding or other methods and separated into individual bags, it is possible to automate the bagging process for a wide range of products such as solid bulk items, powders, granules, liquids, and sticky items. can. The performance of this type of packaging machine is determined by the accuracy with which the timing can be adjusted when various mechanisms such as the feeding mechanism for packaging material from sheet rolls, the sealing mechanism, and the cutting mechanism are continuously driven. It depends on whether you do it well or not.

(Problems to be Solved by the Invention) When attempting to accurately adjust the timing in such a packaging device, various sealing conditions must be considered in order to reliably close the sealed portion. Moreover, sealing devices that seal predetermined parts of continuously supplied sheets by pressure welding are usually equipped with two sealing or welding tools that can press against each other, and follow the sheets for the time required for sealing. It is necessary to move 8 times.

Conventionally, improvements to the sealing device of such a packaging device have been made, such as the idea disclosed in Japanese Patent Application Laid-open No. 190422/1983, which attempts to accurately match the sealing pressure during the sealing operation to a target value. However, if the sealing device does not move 8 times according to the sheet speed and the sealing pressure is set high, the sealing time per seal will be longer, and the sheet will have to be stopped or fed at a low speed, making it difficult to reach the specified speed. It becomes impossible to feed the sheet at that speed. In particular, if the packaging equipment is a general-purpose type that can be used to package a variety of products, the material of the sheet changes depending on the product, and the sealing equipment differs depending on the shape of the bag, such as the length and width of the bag. The position of the seal to be applied also changes, so not only the sealing time for sealing but also the sealing conditions such as the pressure in the sealing device and the heat (temperature) required for welding must be adjusted widely depending on the sealing time. It takes.

The present invention has been made in view of the above points, and it is possible to set the optimum sealing conditions according to the type of sheet, and to set the optimum sealing pressure for each different shape and shape from continuously fed sheets. It is an object of the present invention to provide a packaging device that can manufacture bags whose sealed portions are reliably closed while maintaining the following.

(Means for Solving the Problems) According to the present invention, in a packaging device that forms a sheet pulled out from a film-like sheet roll into a cylindrical shape, and seals and packages an article introduced into the cylindrical shape, the above-mentioned A sealing device that presses and seals a predetermined portion of a sheet, a servo motor that drives this sealing device in synchronization with the feeding speed of the supplied sheet, and a system that calculates the necessary sealing pressure for the sheet from the feeding speed of the sheet. The sealing apparatus includes a calculation means for calculating a torque value to be determined, a detection means for detecting a torque value actually applied by the sealing device, and a pressure control means for controlling a sealing pressure from the detected torque value and the set torque value. It is possible to provide a packaging device characterized by the following features.

(Function) In the packaging device of the present invention, the sealing pressure is feedback-controlled for the sealing device that presses and seals a predetermined portion of the sheet while moving 8 times in synchronization with the feeding speed of the supplied sheet. The sealing portion can be reliably closed by maintaining the optimum sealing pressure.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a perspective view schematically showing an example of a packaging device that continuously processes products weighed by set weight in flexible polyethylene bags, and Fig. FIG. 3 is a diagram for further schematically explaining the sheet processing process.

The packaging device 1 is connected to a polymerization hopper of a combination weighing device (not shown) via a cone-shaped chute 3 provided at the top of a frame 2, and includes a power source, a control device 4, and a computer 5. At the rear, a polyethylene film-like sheet roll 6 of a predetermined size is provided in a replaceable manner, and the sheet 7 pulled out from the roll is a predetermined combination and weighed sheet that is discharged from above via a chute 3 in a preset cycle. In order to accommodate a heavy article 8, it is formed into a cylindrical sheet 10 by a former 9.

A feeding device 11 for the cylindrical sheet 10 is arranged a predetermined distance below the vertical sealing device 12, and is connected to the cylindrical sheet 10 at a predetermined pressure from a first servo motor 13 via a shaft, a transmission belt, a link mechanism, etc. The vertical sealing device 12 is moved 9 times at a speed synchronized with the contact and sent downward at a predetermined speed, and the vertical joint portion of the cylindrical sheet 10 is sealed by the sealing mechanism having a thermal welding action. are doing. This vertical sealing operation is repeated by the box motion of the vertical sealing device 12 corresponding to the sealable length of the sealing mechanism, thereby continuously forming bags in which the longitudinal direction of the cylindrical sheet 10 is sealed. be done.

The horizontal sealing device 14 includes a sealing mechanism that sandwiches the vertically sealed cylindrical sheet 10 from the front and back and thermally welds it by a predetermined length in the width direction using heat from a heater inserted therein, and a central portion in the width direction. It has a cutter for cutting the cylindrical sheet 10 from the sheet. Further, this horizontal sealing device 14 is driven by a third servo motor 1 that drives the sealing mechanism and cutter.
5, which together form a second servo motor 16.
The cylindrical sheet 10 is moved at a constant speed in the vertical direction, that is, in the feeding direction of the cylindrical sheet 10, by an elevator bar 17 that converts the rotational force of the cylindrical sheet 10 and moves up and down.

As will be described in detail later, the horizontal sealing mechanism 14 is returned at a predetermined timing to a position corresponding to the vertical width of a bag 18 of a predetermined size in which the article 8 is sealed. This movement is a so-called box motion.

Based on FIG. 2, the three servo motors 13,
The process control from the sheet roll 6 to the packaging of the article according to 15.16 will be explained.

The first servo motor 13 is an AC servo motor that feeds the sheet 7 from the sheet roll 6 at a constant speed.

The sheet 7 is accurately positioned and supplied from the pinch roller 19 to the former 9 by a sheet tracking motor 20 that controls and tracks the sheet roll 6 in the axial direction. And the cylindrical sheet 10
A vertical sealing device 12 equipped with a heater for vertical sealing seals the sheet formed into a cylinder at the joints on both sides, and lowers the sheet at a speed synchronized with the servo motor 13 to form a cylinder in a predetermined cycle. It is being processed.

Further, the second servo motor 16 is an AC servo motor for lowering the horizontal sealing device 14 in synchronization with the sheet feeding speed, and the horizontal sealing device 14 seals and cuts the cylindrical sheet 10 in the horizontal direction. It is lowered at the same speed as the sheet feeding speed for a period of time, and raised along the rack 17 for lifting/lowering control with a predetermined lifting stroke, and returned to a position corresponding to the upper end of the bag 18 in the next cycle. There is. The horizontal sealing heater and knife unit provided in the horizontal sealing device 14 are operated by the third servo motor 15.
Articles inputted from the weighing device 21 and bags 1 to be described in detail later
It is driven to open and close at a predetermined timing with an opening and closing stroke according to the set width of No. 8. Note that the rising speed v1 of the horizontal sealing device 14 is greater than the descending speed v2, which will be detailed later (
Vl>V2), forming a quick return cycle.

22 is a dancer bar, which adjusts the tension of the sheet 7. Further, a sensor 23 for detecting an eye mark and a printer 24 are arranged close to the sheet 7. The eye mark is
It forms a reference signal for the position at which the bag 18 is closed and cut by the horizontal sealing device 14, and also by the printer 2.
4, the manufacturing date and the like are imprinted at a predetermined position on the sheet 7. Furthermore, a vibrator is required when the article 8 that is inserted while sealing the joint in the longitudinal direction by the vertical sealing device 12 has viscosity, for example.
Also provided are an accelerator 25 for accelerating the falling speed of the article 8 from the weighing device 21, an air pressure generator 26 connected to the vertical and horizontal sealing devices 12, 14, and the like.

FIG. 3 is a block diagram showing an example of a controller that controls the packaging device 1 including the packaging process configured as described above.
A controller unit 30 that controls sheet feeding timing including three servo motors 13 and 15° 16, and a bag 18
It is comprised of a sequencer section 31 that performs sequence control of heaters that perform vertical and horizontal sealing.

The controller unit 30 has a control panel 34, and is configured to be connectable to a program loader 32, a teaching pendant 33, etc. via the control panel 34. In other words, setting data is input to the controller 35 composed of a CPU board, and while controlling the weighing operation in the weighing device 21, the position and speed of the servo motors 13, 15, and 16 are transmitted via AC servo drivers 361, 362, and 363, respectively. It also receives and receives information 37 from limit switches such as the horizontal seal device 14 and the dancer bar 22.
Accelerator 25, printer 24, and horizontal sealing device 1
It is connected to the knife drive unit 141 of No. 4 and controls their drive timing.

The sequencer section 31 controls heater H1 for the vertical seal, heater H2 for the horizontal seal, tK K control of i3, on/off control of the motor 20 for sheet tracking, and pressure control for pressing from the air pressure generator 26. , performs on/off control of the accelerator 25, etc. As a man-machine interface for this purpose, heaters H1 and H
2.) A graphic programmer 4 that changes the temperature setting of 13 and displays and changes the control sequence of the operation switch 38 and sequencer 39, which mainly performs manual operation of the tracking motor 20, and monitors its operating state.
0, a mini programmer 41, etc. are configured to be connectable to the sequencer section 31.

In the packaging device of the present invention, three servo motors Ml
. The operation of the sealing mechanism is controlled according to the precisely set bag size without interrupting the packaging process. In addition, bag size setting,
The sealing time can be determined independently of the type of article to be packaged, and by setting the timing appropriately depending on the material of the sheet, reliable packaging becomes possible.

As mentioned above, in the sequencer section 31, the heaters H1 and H
2. Setting and changing the temperature of H3 and the air pressure for pressing the sealing device are performed.

FIG. 4 shows a block diagram of the air pressure generator 26,
Control of the sealing pressure of the sealing device according to the present invention will be explained below based on FIG. 4.

The sealing pressure of the sealing device is controlled by a servo valve 51, a pressure transducer 52, an arithmetic circuit 53, and a counter 5.
This is done by feedback control of a closed servo loop including 4. The set pressure is output to the servo valve 51, and feedback control is performed by the pressure quadrature transducer 52.

Since the sealing pressure is set based on the bag width of 200 mm, a pressure value converted to a value multiplied by bag width/200 is given to the counter 54 according to the bag width, and the counter 54 outputs a frequency of 691 kHz. Divide the clock signal of F/
A voltage signal is outputted to the servo valve 51 as a pressure control means by V-transforming. The pressure transducer 52 as a detection means in the feedback loop detects the pressure value, converts it to voltage and performs negative feedback control, and the pressure is corrected to the set sealing pressure and applied to each sealing device 1.
Provided on 2.14.

Therefore, according to the present invention, it is possible to set and change the sealing pressure and temperature, and it is also possible to always perform sealing at an appropriate sealing pressure.

Although this invention has been described in some detail with respect to its most preferred embodiment, the description of the preferred embodiment does not include modifications in the detailed parts of the structure unless they are contrary to the spirit of the invention as described in the claims. It is clear that various modifications or combinations of these can be made.

(Effects of the Invention) As explained above, according to the present invention, by feedback-controlling the sealing pressure, automatic operation is always possible with the optimal sealing pressure depending on the material and dimensions of the seat. To provide a packaging device with good packaging efficiency, and also to provide a versatile packaging device without damaging bags or their contents during continuous refining.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing a packaging device according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing an outline of the sheet processing process controlled by a servo motor, and FIG. 3 is a diagram showing each part of the packaging device. FIG. 4 is a block diagram showing a controller that controls the mechanical section. FIG. 4 is a block diagram of a seal pressure control system. 1... Packaging device, 7... Sheet, 8... Article, 1
1... Feeding device, 12... Vertical sealing device, 13...
・First servo motor, 14... Lateral seal device, 15
...Third servo motor, 16...Second servo motor, 26...Air pressure generator, 51...Servo pulp, 52...Transducer, 53...Arithmetic circuit, 54...Counter.

Claims (4)

[Claims] (1) In a packaging device that forms a sheet pulled out from a film-like sheet roll into a cylindrical shape and seals and packages an article placed therein, a sealing device that presses and seals a predetermined portion of the sheet. a servo motor that drives the sealing device in synchronization with the feeding speed of the sheet being supplied; a calculation means that calculates a torque value that determines the sealing pressure necessary for the sheet from the feeding speed of the sheet; and the sealing device. detection means for detecting the torque value actually applied at the
A packaging apparatus characterized by comprising: a pressure control means for controlling a sealing pressure from a detected torque value and the set torque value. (2) The sealing device has a sealing condition setting means for setting a sealing pressure and a sealing temperature in accordance with the sealing time in which the sealing device is in pressure contact with the sheet. packaging equipment. (3) It has a storage means for storing a plurality of sealing conditions for each material of the sheet, and a means for specifying the material of the sheet to be supplied, and the sealing condition corresponding to the specified sheet is adjusted to the moving speed of the sheet. The packaging device according to claim 1 or 2, wherein the sealing device is selectively driven according to the timing. (4) The device according to claim 2 or 3, comprising an operation panel for setting sealing conditions and a monitor means for monitoring sealing conditions and issuing a warning. packaging equipment.