JPH07291210A - Stretch film welding apparatus in automatic packaging line - Google Patents

Abstract

PURPOSE:To execute efficient heat sealing in an automatic packaging line with steadiness in sealability ensured for welding overlapped ends of a stretch film wrapping a container on the under bed of the container. CONSTITUTION:A heater 1, with its upper bed formed of a plurality of projecting faces, is provided to a position between the tail end of a stage in which containers 2 transferred by a conveyer are wrapped with stretch film and the starting point of the conveyer for the next stage in an automatic packaging line, and to a position where the heater contacts with overlapped parts 7a and 7b of the stretch film on the front and the rear parts on the under bed of the container 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretch film welding apparatus in an automatic packaging line in which a container containing an article to be packaged such as food is wrapped with a stretch film and the overlapping portion of the bottom film is welded.

[0002]

BACKGROUND OF THE INVENTION An example of a conventional automatic packaging line is shown in FIG. 5 (showing the plane of the line) and FIG. 6 (showing the side of the line). This packaging line is belt line A, B, C
The belt conveyor 30 conveys the container 31 in each line. The direction of the arrow in the figure is the transfer direction for advancing the container.

In the belt line A, the container 31 containing the articles to be packaged is transported in the forward direction indicated by the arrow, and at the end thereof, the roll of the stretch film 32 wound with the roll 32a is parallel to the upper side of the belt surface. The film 32 is installed by the forward transfer of the container 31.
Surrounds the container 31 in the vertical direction from the front, and also surrounds the rear end of the film 32 cut by the cutting means so as to be wound around the bottom surface of the container 31.

In the belt line B, a stretch film 33 wound around a roll 32b is erected at the lateral position of the belt in the middle of this line, and the container 31 from the previous step is transferred in the forward direction, thereby stretching. The film 32 is wound in the lateral direction from the front of the container 31 to be surrounded. At this time, the film 32 surrounded laterally from the front
As a result, both ends of the film are wound around the bottom surface of the container 31 after cutting, and at the stage where the packaging of the film 32 in the vertical direction and the horizontal direction described above is completed, the end portions of the film 32 are multilayered at the front and rear positions of the bottom surface of the container 31. Film overlapping part 32
a and 32b (see FIG. 7) are formed.

A heater 34 is installed at the end of the belt line B. The heater 34 comprises a filament 35 provided on the lower surface of a flat heater plate 36.
Pass while contacting the upper surface of the heater plate 36. As a result, the film overlapping portions 32a and 32b on the bottom surface of the container 31 come into contact with the heater plate 36, and the heater plate 36 is heated and welded.

Next, in the belt line C, the containers 31 which have been film-wrapped and welded are transferred and taken out, and then the boxes are stacked.

[0007]

By the way, when a vinyl chloride film is used as the above-mentioned packaging film 32, the film 32 is self-adhesive, so that the film 32 is mutually overlapped at the film overlapping portions 32a and 32b on the bottom surface of the container 31. It adheres, but when using a polyolefin film, it is impossible to stack and adhere to each other because it does not have self-adhesiveness, and the cellophane tape is difficult to adhere, especially when it contains water . Therefore, the film 32 is heat-welded by the heater 34 as described above.
It is necessary to weld the overlapping portions 32a and 32b of each other.

FIG. 7 shows a side surface state of the container 31 reaching the heater plate 36 via the belt lines A and B described above. In FIG. 7, the direction of the arrow is the forward direction of transfer.

As described above, on the bottom surface of the container 31, the end portions of the film 32, which is surrounded in the vertical and horizontal directions, are overlapped in multiple layers before and after the bottom surface of the container 31 along the forward direction. , 32b are formed, the film 32 is rarely overlapped at the central portion of the bottom surface, and the void 37 is formed at this portion.

The film 32 on the bottom of such a container 31
When the upper surface of the above-mentioned conventional heater plate 36 is brought into contact and heat-welded with respect to the overlapping state of the film overlapping portion 32,
Since a and 32b contact the heater plate 36, the central void 37 of the bottom face cannot contact the heater plate 36, and welding at this location is impossible, resulting in waste of the thermal efficiency of the heater 34.

In addition, since the heater plate 36 has a flat surface and the heating of the heater plate 36 causes uniform thermal welding on the plate surface, the film overlapping portions 32a and 32b before and after contact with the heater plate 36 are formed. Even if welding is performed evenly, as a result, only the surface layers of the film overlapping portions 32a and 32b are heat-welded, and the sealing performance thereof is very weak, and the film easily peels off after heat-welding. It had a drawback.

The present invention has been made in order to solve such a drawback, and in an automatic packaging line, a container is wrapped with a stretch film and an effective heat is applied to weld the overlapping portion of the bottom film. An object of the present invention is to provide a stretch film welding device in an automatic packaging line which is welded to achieve a firm sealing property.

[0013]

In order to achieve the above object, a stretch film packaging apparatus in an automatic packaging line according to the present invention is provided with an end of a conveyor for carrying out stretch film packaging of containers transferred in the automatic packaging line and the next step. A heater having an upper surface having a plurality of projecting surfaces is provided at a position between the starting end of the conveyor and the film overlapping portion formed before and after the bottom surface of the container.

The plurality of projecting surfaces of the heater may be arranged in parallel to form linear projecting surfaces.

[0015]

In the stretch film wrapping apparatus for the automatic wrapping line constructed as described above, the heater has a plurality of projecting surfaces formed on the upper surface thereof, and the heaters are spaced apart in the front-rear direction along the advancing direction of the line. The container transferred to this heater is subjected to partial concentrated heating by the protrusion of the heater on the film overlapping part on the bottom surface, and at the point where this heating is applied, compared to conventional full surface welding. Can make a much tighter seal.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view of a stretch film welding apparatus according to the present invention. FIG. 2 is a top view of FIG. FIG. 3 is a side view showing a contact state between the heater surface and the film overlapping portion of the container in the present invention. FIG. 4 is a bottom view showing the positional relationship between the film overlapping portion of the container and the heater.

The heater 1 shown in FIG. 1 is installed between the belt lines B and C shown in FIGS. 5 and 6, and the structure of the belt lines A, B and C is as shown in FIGS. A rubber belt 11 may be used between the driving wheels 10 that are rotationally driven.
Is provided, and the container 2 is placed on this and transferred in the direction of the arrow.

The above-mentioned heater 1 is provided with two holding cases 4, 4 on the upper surface of the heater case 3 at front and rear positions along the transfer direction of the belt 11, and the recess formed in the holding case 4. Two cylindrical radiators 5 containing nichrome wires inside are accommodated in parallel inside the station, as shown in FIG. 2, and with such a structure, the upper surfaces form linear protrusion surfaces in parallel. The front and rear heaters 1a and 1b are configured.

In order to make the upper surfaces of the front and rear heaters 1a and 1b parallel to each other and project in a linear shape, the cylindrical radiators as described above are provided in parallel, and the upper surfaces of the front and rear heaters 1a and 1b are corrugated plates. It may be integrally formed by heating with a nichrome wire provided on the lower surface of the corrugated plate.

In addition, the upper surfaces of the front and rear heaters 1a and 1b are arranged in parallel to form a linear projecting surface.
The upper surface of 1b may have a shape protruding in a plurality of peaks.

Such front and rear heaters 1a and 1b are installed at the front and rear heaters 1a and 1b in the front and rear of the bottom surface of the container 2 when the container 2 is placed vertically on the upper surface along the forward direction of the line. Should be placed on the upper surface of each.

Further, connecting plates 6, 6 are provided extending along the upper surfaces of the front and rear heaters 1a, 1b on the terminal end of the belt line B and the starting end of the belt line C, and the front and rear heaters 1a, 1b are connected from the belt line B. The container 2 passing through and reaching the belt line C is smoothly transferred.

The nichrome wire (not shown) housed inside each radiator 5 is connected to a controller 8 installed at the bottom of the heater case 3, and the controller 8 controls the temperature of the front and rear heaters 1a and 1b. I am trying to do.

If a means for pressing the container 2 passing therethrough from above is provided above the heater 1, the stretch films 7 can be reliably attached to each other at the bottom of the container 2.

In the stretch film wrapping apparatus in the automatic wrapping line configured as described above, the container 2 transferred to the end of the belt line B has already been subjected to the film wrapping process of the previous process from the longitudinal direction and the lateral direction. The stretch film 7 is transported in an enclosed state, and at this time, as shown in FIGS. 3 and 4, the bottom surface of the container 2 has multi-layered overlapping portions 7a and 7b of the stretch film 7 along the forward and backward directions. The situation has been formed.

When the container 2 is placed on the heater 1 by the transfer of the belt line B, the front and rear heaters 1a, 1a
b are film overlapping portions 7a and 7b on the bottom surface of the container 2, respectively.
On the other hand, intensive partial heating can be performed, and a firm seal can be performed.

Then, in FIG. 1, the container 2a following the transfer of the belt line B pushes the container 2 whose heating is finished to the front belt line C, and then the following container 2a is placed on the heater 1. The film welding of the container 2a is performed in the same manner as described above.

[0029]

As described above, according to the stretch film welding apparatus in the automatic packaging line of the present invention,
The heater is able to be used efficiently because the partial heating is performed only on the front and rear film overlapping parts that are generated at the bottom of the container by the film packaging process. It is possible to weld all the layers of the overlapping portion to each other, and it is possible to form a much firmer seal as compared with the conventional welding of only the surface layer by the whole surface heater.

[Brief description of drawings]

FIG. 1 is a side sectional view of a stretch film welding device according to the present invention.

FIG. 2 is a top view of FIG.

FIG. 3 is a side view showing a contact state between a heater surface and a film overlapping portion of a container according to the present invention.

FIG. 4 is a bottom view showing a positional relationship between a film overlapping portion of a container and a heater.

FIG. 5 is a top view of a conventional film packaging line.

FIG. 6 is a side view of FIG.

FIG. 7 is a side view showing a contact state of a film overlapping portion with a heater in a conventional film packaging line.

[Description of References] 1 ... Heater, 1a, 1b ... Front / rear heater, 2 ... Container, 3 ...
Heater case, 4 ... Holding case, 5 ... Heat radiator, 6 ... Communication plate, 7 ... Stretch film, 7a, 7b ... Front and rear film overlapping portions, 10 ... Drive wheel, 11 ... Rubber belt, A,
B, C ... Belt line.

Claims (2)

[Claims] 1. A contact between a film overlapping portion formed before and after a bottom surface of the container between the end of a conveyor for packaging stretch films of a container transferred in an automatic packaging line and the start of a conveyor in the next step. A stretch film wrapping device in an automatic wrapping line, characterized in that a heater having an upper surface having a plurality of protruding surfaces is installed at a position to be set. 2. A stretch film wrapping apparatus in an automatic wrapping line, wherein a plurality of projecting surfaces of the heater form parallel linear projecting surfaces.