GB2118133A

GB2118133A - A form-fill-seal packaging machine

Info

Publication number: GB2118133A
Application number: GB8305986A
Authority: GB
Inventors: Roger S Levy
Original assignee: EUROBREVA ENG TRUST
Current assignee: EUROBREVA ENG TRUST
Priority date: 1982-04-06
Filing date: 1983-03-04
Publication date: 1983-10-26
Also published as: GB8305986D0; FR2524421A1; SE8301437D0; JPS5916737A; SE8301437L; DK115083A; DE3307320A1; NO831200L; DK115083D0

Abstract

A form-fill-seal machine for packaging lettuces or the like in film bags, comprises conveyor belts 12 in the interior of a loading pipe 3. These endless conveyor belts 12 are supported by supporting rails 19, 20 so as to prevent them from sagging to a considerable extent. The lettuces or the like introduced in the direction of the arrow A are moved downwardly in timed sequence by the conveyor belts 12 which are provided on opposite sides, the drive being effected by a crank drive 44 and a rack 34 via intermittently driven sprocket wheels 28. There is formed around the loading pipe 3, on the outside thereof, a tube from a plastics-material film with a longitudinal welded seam. When the lettuce or the like has been introduced, the bag is shut at the bottom by a transverse welded seam. In this way, it is possible to package lettuces or the like in thin plastics- material bags in a simple manner without any manual work. <IMAGE>

Description

SPECIFICATION A machine forming tubular bags The invention relates to a tubular-bag forming machine which is provided with a film die, a vertical loading pipe, over which the film is pulled, and with longitudinal welding elements, with the aid of which the film can be formed into a tube, and with transverse welding elements for the bag formation and with a film take-off device.

During the packaging of vegetables, more especially lettuces, there arises the problem that such relatively bulky yet compressible goods get stuck in the vertical loading pipe. On the other hand, it is impossible to provide the loading pipe with a cross-section of any desired size since the packaged goods should be made available in as compact a shape as possible and, in addition, the film consumption would rise considerably because the film, from which the bags are made, is located around the outside of the loading pipe and determines the diameter thereof.

The problem to be solved by the invention consists in designing a tubular-bag forming machine in such a way that it is also suitable for the automatic packaging of compressible goods, more especially lettuces.

According to the invention there is provided a tubular-bag forming machine which is provided with a film die, a loading pipe, over which the film is pulled, and with longitudinal welding elements, with the aid of which the film can be formed into a tube, and with transverse welding elements for the bag formation and with a film take-off device, characterised in that there are provided in the interior of the loading pipe at least two endless conveyor belts, which are opposite to each other and can be driven in timed sequence, for the transportation of the goods to be packed, there being associated with each side of the conveyor belts that is directed towards the goods to be packed supporting elements which are provided in the interior of the loading pipe or loading funnel.

A tubular-bag forming machine designed in such a way allows compressible foods, more especially lettuces, to be packaged in bags in a space-saving manner and without any manual work, which has hitherto been impossible with conventional packaging machines.

An exemplified embodiment of the subject matter of the invention is shown in the drawings, in which: Figure 1 shows a diagrammatical view of the lower part of a tubular-bag forming machine, Figure 2 shows a vertical section through the upper loading zone of the tubular-bag forming machine, Figure 3 shows a horizontal section through the loading zone of the tubular-bag forming machine shown in Fig. 2, and Figure 4 shows a section through the rack bearing.

A flat thin plastics-material film is fed to the tubular-bag forming machine shown in Fig. 1.

This film is withdrawn from a roll and is formed by a film die into a tube which, to begin with, is still open at the periphery. This tube surrounds a vertical loading pipe 3. Such film moulds are known 'per se', for example from CH PS 627 413, for which reason the design thereof will not be described in greater detail herein. The overlapping vertical film edges are then welded together by heat action by means of a vertical longitudinal welding die 4.

After the introduction of the goods to be packaged, the tube thus formed is subdivided into individual bags by the formation of a transverse seam by means of a transverse welding die 8. The downward movement of the tube placed around the outside of the loading pipe 3 is effected by a film take-off device 7 by means of belts 11 which are driven in timed sequence. As emerges from Fig. 2, there is provided above the loading pipe 3 a loading funnel, into which the goods to be packaged are fed in the direction of the arrow A, for example by a conveyor belt.

In the interior of the loading pipe 3 surrounded by the tube there are two opposite endless conveyor belts 12 which are flat and are passed around deflection pulleys 1 5 at the top of the loading funnel. Beneath these deflection pulleys 15, there are provided smaller supporting pulleys 16, with which the belts 14 are in abutting contact. Adjustable belt tensioning pulleys 1 7 are provided for tensioning the conveyor belts 12.

The horizontal shafts 22 of the deflection pulleys are supported at their two ends by angular supports 1 8. The distance between the conveyor belts 12 is wider at the top than in the central and bottom zones. At the lower end of the preferably oval loading pipe 3 there are provided relatively small return pulleys (not shown in the drawings) for the belts 14. Inclined flat supporting rails 19 are provided for supporting the belts 14 in the loading zone. These supporting rails 19 as well as the belts 14 extending parallel thereto from an angle of 22--350, preferably of approximately 280.In the zone beneath the supporting pulleys 1 6 and in the inlet zone to the loading pipe 3, the supporting rails 20 and consequently also the belts 14 extend vertically and parallel to one another, the distance between the belts 14 and the supporting rails 20 being short. When goods to be packaged are loaded in the direction of the arrow A, the opposite parts of the belts 14 are supported by the supporting rails 19, 20, any further sagging of the belts 14 thus being prevented. The returning belt side 14 of each of the two conveyor belts 12 is located in the interior of the loading pipe 3 between the inside wall thereof and the supporting rails 20.

The drive of the conveyor belts 12 is effected in that the sense of rotation of the two deflection pulleys 1 5 is opposed, as indicated by the arrows B, C. For this purpose, the shafts 22 are non rotatably connected to sprocket wheels 24 and are in contact with driving sprocket wheels 28 via chains 26. As emerges from Fig. 3, there are fastened on the shafts 30 of the driving sprocket wheels 28 spur gears 27 which mesh. The two deflection pulleys 1 5 and the belts 14 driven by these are thus driven jointly and at the same speed. On the one shaft 30 there sits, nonrotatably connected to the driving sprocket wheel 28, a pinion 32 which is in engagement with a rack 34. This rack 34 is kept in mesh with the pinion 32 by two rollers 36.The two rollers 36 sit on a rocker 38 which is mounted so as to be pivotable around the shaft 30 (Fig. 4). In the bore of the pinion 32 there is provided a single-way clutch 40 which takes, for example, the form of a free-wheeling clutch that is effective in one direction of rotation and is provided with grip rollers. This clutch 40 causes a rotational movement of the driven pinion 32 to be transmitted in only one direction of rotation to the shaft 30 and thus to the sprocket wheels 28 and finally to the conveyor belts 12, so that the senses of rotation B, C are maintained. The rack 34 is connected via a joint 46 to a crank arm 44 which is rotatable around a pivot 42. By displacing the joint 46 in the slot 48 one can vary the stroke of the rack 34 and consequently the advance of the belts 14 brought about with a rotation of the crank arm 44.The drive of the crank arm 44 and the movement of the film take-off device 7 are preferably interdependent. The timed feed motion is chosen to be such that a portion of the material to be packed is respectively advanced by one bag length.

The mode of operation of this tubular-bag forming machine is as follows:- The goods to be packed, for example lettuces, are individually introduced into the loading zone in the direction of the arrow A. They are seized by the opposite two belts 14 and taken along by friction. The rotation of the crank arm 44, and consequently the movement of the rack 34, causes the deflection pulleys 1 5 to be driven in the direction of the arrows B, C so that the belts 14 intermittently transport the goods downwardly and, in doing so, compress them to some extent in the interior of the loading pipe 3.At the same time, there is formed from the film which is withdrawn from a roll and which may be, in particular, a transparent thin plastics-material film, around the exterior of the loading pipe 3 a tube with a vertical longitudinal welded seam, in that the take-off devices 7 are driven. The transverse welding die 8 produces a horizontal double seam, in that the lower bag filled with the goods to be packed is shut and the bottom seam for the subsequent bag is simultaneously formed.

Thereafter, the material to be packed is moved on into the interior of the thus formed bag which is open at the top and is placed around the loading pipe 3. The described process is then repeated in timed sequence.

Instead of two conveyor belts 12, it would be possible to provide in the interior of the loading pipe 3 three or four of such conveyor belts 12 which are jointly driven. Furthermore, the conveyor belts 12 and the supporting rails 20 could slightly converge downwardly in the interior of the loading pipe 3 so as to continuously compress the goods to be packed to a greater extent.

Claims

1. A tubular-bag forming machine which is provided with a film die (2), a loading pipe, over which the film is pulled, and with longitudinal welding elements (4), with the aid of which the film can be formed into a tube, and with transverse welding elements (8) for the bag formation and with a film take-off device (7, 11), characterised in that there are provided in the interior of the loading pipe (3) at least two endless conveyor belts (12), which are opposite to each other and can be driven in timed sequence, for the transportation of the goods to be packed, there being associated with each side of the conveyor belts (12) that is directed towards the goods to be packed supporting elements (19, 20) which are provided in the interior of the loading pipe (3) or loading funnel.

2. A tubular-bag forming machine as claimed in Claim 1, characterised in that the supporting elements are designed as elongate supporting rails (19,20).

3. A tubular-bag forming machine as claimed in Claim 1 or 2, characterised in that the loading pipe (3) is arranged so as to be vertical and in that the distance between the conveyor belts (12) is wider at the top than at the bottom.

4. A tubular-bag forming machine as claimed in one of Claims 1 to 3, characterised in that the drive in timed sequence of the conveyor belts (12) is effected jointly by a crank drive (44) with a rack (34) and a single-way clutch (40) via driving pulleys (15).

5. A tubular-bag forming machine as claimed in one of Claims 1 to 3, characterised in that the cross-section of the loading pipe (3) is oval.

6. A tubular-bag forming machine substantially as herein described with reference to the accompanying drawings.