CN113165758A

CN113165758A - Packaging machine and product packaging method

Info

Publication number: CN113165758A
Application number: CN201980070636.4A
Authority: CN
Inventors: C·A·阿尔基利
Original assignee: Delta Park Ltd
Current assignee: Delta Park Ltd
Priority date: 2018-09-04
Filing date: 2019-09-04
Publication date: 2021-07-23
Also published as: WO2020049476A1; KR20210053298A; US20210253283A1; EP3847101A1

Abstract

Product packaging machine (1) using stretchable film, comprising: a dispensing unit (9) for dispensing a portion of the continuous stretchable film; and a rear gripping unit (8) for unwinding said portion of said stretchable film in an operating direction (B) inside a packaging area (3) inside a packaging machine (1), in cooperation with said dispensing unit (9); further comprising two side gripping units (11, 12) movable towards and away from each other in a direction (F1) transversal to the operating direction (B), laterally gripping the stretchable film and placing it under the product (10) to be packaged; each of the side gripping units (11, 12) comprises a plurality of grippers, each gripper (13) having an upper jaw and a lower jaw, wherein at least one of the upper jaw or the lower jaw comprises a contact surface (14A, 15A) for interacting with the stretchable film, the width (D) of the contact surface in the operating direction (B) being larger than 50 mm.

Description

Packaging machine and product packaging method

The present invention relates to a packaging machine for packaging products using a stretchable film, which is equipped with a side clamping unit that laterally clamps the stretchable film.

For example, in supermarkets, automatic packaging machines are known for packaging food products, in particular fresh food such as meat, fish, fruits and vegetables or gourmets. Such packaging machines receive a feed product prepared in advance by an operator and placed on a tray made of cardboard, expanded polystyrene or other similar material, and wrap the product with a stretchable transparent film so that the product can be displayed on a shelf or in a refrigerator display window.

Document EP0619227a1 discloses a packaging machine in which a stretchable film fed from a reel is held in four directions while packaging products placed on a tray. The front dispenser and the rear gripper hold the film and act in two opposite directions with respect to the direction in which the film unwinds from the reel and the two units on which the side grippers are arranged, transversely, to grip the film in a direction transverse to the direction in which the film unwinds. The tray with the product is placed on an elevator, lifted to a preset height so that the product contacts the film under tension, and then two side holding units place the drooping portion of the film under the product. The rear flap of the film is folded by the rear gripper under the tray, while the front flap is folded by a front folder arranged above the front dispenser during the subsequent movement of the tray to the outlet area of the packaging machine.

The cycle start position of the rear gripper relative to the front dispenser determines the tray size that the machine can pack. To pack a tray of a smaller length than the tray packed in the previous cycle, the rear gripper approaches the front dispenser at a preset length at the start of a new packing cycle, under the command of the control unit. The latter receives information on the dimensions of the new product to be packaged from a sensor placed at the inlet area of the packaging machine, which detects the presence and the dimensions of the product at the beginning of the packaging cycle.

Today, supermarkets need to meet the consumer demand of packaging small quantities of fresh food in small portions, so that each portion of the package, once opened, can be consumed by just two or one person.

The packaging machine disclosed in EP0619227a1 has a geometrical limit to the cycle start position of the rear gripper relative to the front dispenser, on the basis of which the machine of EP0619227a1 can package products on trays whose side edges have a minimum length of 130 mm.

In the known machines, after the side grippers have folded the film under the product, the side grippers are opened in order to release the film and allow the post-folder to perform the subsequent folding step. It is not uncommon for the stretchable film to fail to separate properly from the side gripper, meaning that the package deforms due to unintended pulling of the stretchable film; either because the stretchable film is torn or because the film is wrapped around the internal parts of the machine, forcing the machine to stop releasing the jammed film.

It is an object of the present invention to provide structural improvements to the side gripping units of packaging machines which use stretchable films for packaging products, of the type known per se, for example, from EP0619227a 1.

It is a further object of the present invention to provide a side gripper unit shaped to enable a packaging machine using stretchable film to package trays having side lengths of less than 130mm, for example, to provide single serving or double serving trays.

Another object is to provide a gripping unit for packaging machines using stretchable films, which has a relatively simple structure compared to known mechanisms and is easy to maintain.

Another object is to provide a packaging machine using stretchable film which enables trays carrying products to be packaged automatically and relatively large and wide range of trays to be packaged, in particular trays for single or double serving.

A further object is to provide a side gripping unit that allows the stretchable film to be safely released after being folded under the product and that suppresses or even eliminates the risk that the film will still adhere to the side gripping unit.

These and other objects are achieved by the packaging machine of the present invention, which is equipped with a side gripping unit as defined in the claims.

The invention may be better understood and put into practice with reference to the accompanying drawings, which illustrate, by way of non-limiting example, embodiments of the invention and in which:

FIG. 1 is a perspective view of a packaging machine without a guard;

fig. 2 is a partial top view of the packaging machine of fig. 1, showing a rear clamping unit, a dispensing unit and two side clamping units;

FIG. 3 is a partial perspective view of the dispensing unit and two side clamping units;

fig. 4 is a perspective view of a labelling device with which the packaging machine of fig. 1 is equipped.

In fig. 1 a packaging machine 1 is shown for packaging products, for example food products, in particular fresh food products such as meat, fish, fruits and vegetables or gourmets, using a stretchable film. The packaging machine 1 shown here is of the automatic type, without guarding, i.e. receives the feed product to be packaged, for example fresh food prepared by an operator and placed on a tray made of cardboard, expanded polystyrene or other similar material, and supplies the outfeed product, fresh food and the accompanying tray, wrapped in a transparent stretchable film, on which a label is applied. Thus, in a grocery store or supermarket, by using the packaging machine 1, the operator can take the packaged and labeled product out of the packaging machine 1 and put the packaged and labeled product on a shelf or in a display window of a refrigerator for display to the customer, saving a lot of time.

The packaging machine 1 includes: an inlet area 2, where the operator places the product 10 to be packaged, for example a fresh food product placed on a tray; an interior or package region 3 in which the product is wrapped in stretchable film; a label area 4; and an outlet area 5 which receives the packaged and labelled product 10, awaiting removal by an operator.

The exit area 5 and the entrance area 2 are located on the same side of the packaging machine 1, for example on the front side of the packaging machine, which will enable an operator both to supply the packaging machine 1 with products to be packaged and to access the packaged products, for example to load the packaged products onto pallets and then to deliver the packaged products to the corresponding display areas in the store.

The packaging machine 1 comprises different units or groups which perform different tasks but interact with each other, for example the units or groups disclosed in EP0619227a 1.

At the inlet of the packaging machine 1 there is a supply unit 20, the supply unit 29 comprising: a weighing unit 21 for weighing the product 10; and a conveyor belt conveyor 22 for conveying the products 10 in the supply direction a. A rest element 23 is inserted between the conveyor belts of the conveyor 22, defining a support surface for the products 10 in the inlet area 2 of the machine 1. The resting element 23 is directly connected to the scale 24 of the weighing device 21, located below the conveyor belt of the conveyor 22, to detect the weight of the products 10. The conveyor is provided with carriages 25, these carriages 25 being aligned with each other to push the products 10 slidingly placed on the resting elements 23, moving from the inlet area 2 to the central area 3, i.e. the centre of the packaging machine 1, during the advancement of the upper branch of the conveyor. Furthermore, during the advancement of the products 10 in the supply direction a, the carriages 25 induce the products 10 to align parallel to the carriages, with one side of the products 10 parallel to the thrust surface defined by the carriages 25. In other words, the tray 25 enables the trays of products 10 to be set up for packaging. This is very convenient for the operator, who does not have to be particularly concerned with how the products 10 are placed on the conveyor 22, since the products can be placed in the inlet area 2 in any direction.

The inlet area 2 further comprises laser sensors, not shown in the figures, for detecting the length, width and height of the products 10 and transmitting these data to the computer of the packaging machine 1, which adjusts the relative units according to the detected dimensions.

The conveyor belt of the conveying device 22 conveys the products 10 (weighed by the weighing device 21 and measured by the sensors) to a lift provided inside the packaging machine 1, of a type well known and therefore not shown in the figures and not disclosed in detail. The elevator performs the function of lifting the products 10 from the level of the conveyor to the level of the package. The elevator comprises a plurality of supports which are partially inserted between one conveyor belt and the other in the end region of the conveyor 22. For example, the elevator may include four legs. When the length of the trays to be packaged is less than the maximum length that can be packaged by the machine 1, one or both of the supports, which are distant from the outlet area 5, are adjusted according to the size of the trays to be packaged, to prevent them from interfering with the other components of the machine 1 to be packaged.

A plurality of lowerable support members are mounted on each of the brackets; these supports are generally vertical and arranged in a row, with a convex upper surface for supporting the products 10; and these are initially arranged below the ideal plane comprising the upper branch of the conveyor belt in the conveying device 22, so as to avoid interference with the arriving products 10. The bracket can also be provided with a plurality of rows of support members capable of being lowered.

The elevator is vertically driven by a motor through a conveyor belt and a pulley transmission, and a slider fixed on a linear guide rail is connected to the conveyor belt. Unlike the motor-driven screw and nut drives typically used on elevators on known types of packaging machines, such as those known from EP0619227a1, the drive of the present type is able to achieve the required lifting speed at a lower installation power and reduce the noise of the elevator.

The stretchable film extends in the interior region 3 between the dispensing unit 9 and the rear clamping unit 8 while the elevator lifts the tray to package height. Thus, when the tray reaches the raised position, the upper surface of the product 10 meets the stretchable film, which is ready for packaging.

The dispensing unit 9 is intended to dispense a portion of the continuous stretchable film and the rear gripping unit 8 is intended to cooperate with the dispensing unit 9 to unwind the portion of stretchable film in the operating direction B in the packaging zone 3 inside the packaging machine 1.

In this region, in addition to the rear gripper unit 8 and the dispensing unit 9, there are two

side gripper units

11 and 12. The

side gripping units

11 and 12 each include therein a plurality of grippers 13, the grippers 13 being identical to each other and placed side by side; specifically, six grippers are included in each of the

side gripper units

11 and 12. Each gripper 13 comprises an upper jaw 14 and a lower jaw 15. When the dispensing unit 9 is stretching the film in the inner region 3, the flanks of the film are inserted between the lower jaw 15 and the upper jaw 14, the side gripper 13 being in a position of the open state, which is not indicated in the figures. The

side gripper units

11 and 12 grip the film laterally by means of the gripper 13, wherein the gripper 13 is in a closed state as shown in fig. 3 and places the respective side wings of the film gripped by the gripper 13 below the product 10 to be packaged, the product 10 being lifted to the highest packaging level of the upper surface of the side gripper.

For this purpose, the

side clamping units

11 and 12 are movable relative to each other and away from each other in a direction Fl transverse to the operating direction B. The

gripping units

11 and 12 are each equipped with a

respective carriage

71, 72, the

carriages

71, 72 being movable along the same guide 77 and fixed to branches of the same conveyor belt 73; and a transmission system 70, controlled by the computer of the packaging machine 1, in which a conveyor belt 73 is wound around two transmission wheels 74 and 75, the drive motor 74 being driven by a motor 76 equipped with an inverter. In particular, as shown on the right side of fig. 3, the gripping unit 11 is mounted to the upper branch of the conveyor belt 73, and, with reference to the left side of fig. 3, the gripping unit 12 is mounted to the lower branch of the same conveyor belt 73, at a distance from the gripping unit 11 equal to half of the reverse advance or retreat stroke. Therefore, the synchronous movement of the two

gripper units

11 and 12 can be achieved only by the movement of the conveyor belt 73 in one of the two directions along F1.

The drive system of the

side clamping units

11 and 12 is equally effective, but simpler and less costly, compared to the drive system of the side clamping units realized by two movable mechanisms in a single guide guided by respective ring screws guided by respective motors provided in EP0619227a1, and therefore the packaging machine 1 also becomes relatively easy to manufacture and maintain.

Each of the upper jaw (upper jaw)14 and the lower jaw (lower jaw)15 has a

respective contact surface

14A and 15A for interacting with the stretchable film held by the gripper 13. At least one of the

contact surfaces

14A and 15A has a width D in the operating direction B greater than 50 mm.

Adjusting the width D of the upper contact surface to 50mm can ensure a sufficiently wide contact area, so that the load of the lateral pulling force on the stretchable film is well distributed, and stress concentration is suppressed, thereby preventing the stretchable film from being locally deformed unexpectedly, and preventing wrinkles from being generated on the package or tear points from being generated on the stretchable film.

In particular, at least one of the two

contact surfaces

14A and 15A has a width comprised between 51mm and 60mm, and more particularly it takes 57 mm. With this width of the side grippers, it is possible to provide less than 7 (i.e. 6) side grippers with the same maximum size of the packageable tray, which reduces the number of parts of the machine 1 with respect to known machines, thus significantly reducing the production time and the machine costs.

For example, a contact surface having such a width is provided in the lower jaw 15. In this manner, an upper jaw of smaller width than the lower jaw can be used, the stretchable film being more easily detached from the side gripper after the film has been folded under the product, while still maintaining sufficient contact surface between the gripper and the stretchable film to facilitate lateral stretching and proper folding. In this way, the risk of the stretchable film remaining stuck on the side gripper can be reduced when the rear gripper unit advances to the rear wing of the folded film of the dispensing unit and pushes the product to the outlet area 3. For example, in one embodiment, if the contact surface of the lower jaw is 57mm wide, the contact surface on the upper jaw may be 45mm wide.

The size of the side grippers 13 is greater than 50mm, which enlarges the range of sizes of the packageable trays compared with the known types of packaging machines (as disclosed in EP0619227a 1) and enables the control of the transverse tension of the stretchable film to be maintained, preventing undesired local overstretching stresses.

In fact, due to the size of the contact surface, the stretchable film can be wrapped around a tray having the size-length x width x height-100 mm x 100mm x10mm or 80mm x 80mm x10mm even if only two adjacent side grippers 13 are driven to grip the film laterally. This significantly increases the range of sizes of products that can be packaged by the packaging machine 1, thereby meeting the demand for small portions of product that can be packaged.

A packaging method executable by a packaging machine 1, comprising the steps of: dispensing a portion of the continuous stretchable film and unwinding the portion of stretchable film in an operating direction B in a wrapping region 3 inside the wrapping machine 1; further comprising the steps of: laterally clamping the stretchable film, placing the film under the product to be packaged 10, wherein laterally clamping the stretchable film comprises clamping the film only between two adjacent side clamps on each side.

In this way, the range of sizes of trays that can be packed is expanded, with the direction of expansion being more biased towards smaller sizes.

The gripper unit 8 comprises a rear gripper (not visible in fig. 3) which is arranged below the plane defined by the rear folder 81. The rear gripping unit 8 is movable along an operating direction B transverse to the feeding direction a of the packaging machine 1. When the movable rear gripper is in the advanced position, it grips the head end of the stretchable film leaving the dispensing unit 9 and retracts, extending the stretchable film in the inner zone 3 by means of the side grippers 13 in the open condition; the stretchable film is unwound from a reel 6 (fig. 1) mounted to the packaging machine 1. During its advance to the dispensing unit 9, the rear gripper 81 folds the film under the product 10, and the pusher 82 pushes the product 10 to the labelling area 4.

The rear clamping unit 8 comprises a carriage 83, which carriage 83 is driven by a motor and controlled by the computer of the machine via a system with belts and drive wheels (not shown). This way of driving also makes the machine simpler in structure and easier to maintain.

When the products 10 are close to the dispensing unit 9, the film is cut by cutting means of known type, the front flaps of which are folded under the products 10 by a front folder, also of known type, during the advancement of the products 10.

The product 10 then reaches a heated surface 7 which holds the flaps folded underneath together. There is a label unit 40, the label unit 40 applying a label 60 (e.g., an adhesive label) to the product 10, the label 60 having predefined information thereon and/or information selected by an operator via a screen 30 connected to a computer.

If the presence sensor detects the presence of a packaged product 10 at a predetermined location, the label 60 will be automatically posted.

The labeling unit 40 includes: a labelling machine 41, known devices; and an applicator 42, the applicator 42 removing the label 60 from the applicator 41 and applying the label 60 to the underlying product 10.

The applicator 42 comprises a first arm 44, which first arm 44 is substantially horizontal and parallel to the side of the labelling machine 41 having the outlet 53 from which outlet 53 the labels 60 printed by the labelling machine 41 exit.

The first arm 44 is equipped with a head plate 54, which head plate 54 supports the application pad 52, for example, the application pad 52 is of a deformable type to adapt to the conformation of the product surface when it is pressed; the mat 52 is located above the outlet 53.

The deformable pad 52 may be provided with a suction element that fits over the head plate 54, capturing the label by a suction action.

The first arm 44 is supported by the second arm 43, the second arm 43 also being substantially horizontal and parallel to a second lateral surface of the labelling machine 41, which is substantially orthogonal to the first lateral surface.

The applicator 42 further comprises a substantially vertical third arm 48, the third arm 48 supporting the second arm 43 and connecting the second arm 43 to the frame of the packaging machine 1. A support plate 55 for supporting the labelling machine 41 is further fixed to the third arm 48. The third arm 48 also supports the moving means; the moving means are intended to move the applicator 42, moving the second arm 43 and the first arm 44 upwards and/or downwards, according to the application direction V, between a top rest position and an application position in contact with the product 10. The moving means comprises a pair of drive wheels 47, on which drive wheels 47 a conveyor belt 45 driven by a motor 46 is wound. The second arm 43 is connected to the conveyor belt 45 and moves along a guide orthogonal to the conveyor belt 45, and a guide 56 is mounted in parallel on the third arm 48.

The support plate 55 further supports a fan 49, the outlet end of which fan 49 is connected to the tapered outlet duct 50, so that the fan circuit thus formed can form a wind knife below the outlet end 53 of the labelling machine 41. The air knife is able to support the label 60 for the time required before the deformable pad 52 reaches the label 60.

When packaged product 10 is positioned below outlet 53, deformable pad 52 captures label 60 and presses label 60 against the surface of product 10. The second arm 43 and the first arm 44 are driven downwards by a height calculated on the basis of the height of the product detected in the inlet zone 2.

Thanks to the labelling unit 40, the product 10 leaves the packaging machine 1 with a label having packaging information and other information selectable by the operator. Upon reaching the exit area, the product 10 waits to be placed on the store shelf.

The applicator 42 may be applied to any type of labelling machine having a substantially horizontal outlet. In an embodiment not shown, the length of the first arm 44 and the second arm 43 is adjustable so as to be able to adapt to different types of labelling machines with different lateral edge sizes.

Claims

1. Packaging machine (1) of products for packaging the products with stretchable film, comprising: a dispensing unit (9) arranged for dispensing a portion of the continuous stretchable film; and a rear gripping unit (8) arranged for cooperating with said dispensing unit (9) to unwind said portion of stretchable film in an operating direction (B) within a wrapping area (3) inside said wrapping machine (1); further comprising two side gripping units (11, 12) movable with respect to and away from each other in a direction (F1) transversal to said operating direction (B), laterally gripping a stretchable film and placing it under a product (10) to be packaged, each of said side gripping units (11, 12) comprising a plurality of grippers, each gripper (13) having an upper jaw and a lower jaw, characterized in that at least one of said upper or lower jaws comprises a contact surface (14A, 15A) for interacting with said stretchable film, said contact surface having a width (D) in said operating direction (B) greater than 50 mm.

2. Packaging machine (1) according to claim 1, wherein said width (D) is between 51mm and 60mm, in particular equal to 57 mm.

3. Packaging machine (1) according to claim 1 or 2, wherein said contact surfaces (14A, 15A) are provided at said lower jaw portion.

4. A packaging machine (1) according to any one of claims 1 to 3, wherein said plurality of grippers consists of only 6 grippers.

5. Method for packaging products with stretchable film, wherein a portion of said continuous stretchable film is dispensed and said portion of said stretchable film is unwound in an operating direction (B) within a packaging area (3) inside a packaging machine (1), further comprising: laterally clamping a stretchable film and placing the stretchable film under a product (10) to be packaged, characterized in that said lateral clamping comprises: on each side of the film, the film is clamped only between two side clamps (13).

6. Packaging method according to claim 5, wherein each of said side grippers (13) comprises at least one contact surface (14A, 15A) arranged for interacting with said stretchable film and having a width along said operating direction (B) greater than 50 mm.