Device for packaging continuous webs of materials such as selvedges generated on thermoforming units

The present invention has for object a device for packaging continuous webs of material such as selvedges generated on thermoforming units during container production methods for the food packaging.

These units use thermoforming films of plastic materials that scroll continuously and they transform heat to create containers. Once filled and sealed, the containers obtained were cut from these films, in order to identify the packaged products, this results in drops that are in the form of strips must be phased out to release the machine and allow the further manufacture.

Already known several methods for continuously removing and conditioning of those bands, including that described in the document <patcit id="pcit0001" dnum="US2251312A"><text>US 2251312</text></patcit>Which is to cut the strips into calibrated pieces that can be recovered in containers.

Also known by the document <patcit id="pcit0002" dnum="EP0624440A"><text>EP 0624440</text></patcit> the name of the Applicant, a machine operating according to a similar method, and preferably includes feed means adapted to advance the bands step ahead of the thermoforming units so as to obtain pieces of short length, and comprising input control means of the strips. The band feeding means bringing in a jerky motion, said belt to a type of cutting means guillotine, said advancing means and the cutting means being moved by a single cylinder.

If this machine allows to obtain pieces of smaller bands, so as to reduce the volume they occupy in the container, it has disadvantages particularly in that it is intended to be fixed to a thermoforming machine that which, because of its relative size, can sometimes prove impossible.

This machine also has the drawback of sometimes prone to jamming phenomena during the strips cutting operation, which requires repeated interventions of the operators. These phenomena are more common when the film material used consists of flexible plastic, which is bound to advance and cutting modes used.

The present invention aims to provide a device for packaging continuous webs adaptable to any thermoforming unit allowing to overcome the various aforesaid drawbacks by being able to effectively perform pieces of bands occupying a small volume and may be packed optimally .

The device for packaging continuous webs of material such as selvedges generated on thermoforming units according to the invention is of the type having input control means of webs, means for guiding and driving said webs, and a cutting means and, downstream thereof, means for collecting pieces of tapes, and it is essentially characterized in that said cutting means consist of at least one knife animated by a movement back and forth against cooperating with a blade, and in that said guide and drive means are associated with means of feeding air stream of said strips, arranged immediately before said blade and said blade against.

According to an additional characteristic of the device according to the invention, the guiding and driving means include two rollers which roll against each other in counter-rotation, driven step by step, so as to be capable of gripping the band and exercise at a pace determined to means for feeding.

According to another additional characteristic of the device according to the invention, the rollers are driven by a pneumatic jack in association with a freewheel and a gear train.

According to another additional characteristic of the device according to the invention, the means for feeding a flow of air consist of a generally tubular workpiece comprising an inlet end through which the band is introduced from the guide means and drive, and an outlet end through which said strip exits and at least part of the edge is against the blade, while inner means are capable of allowing, in association with a source of pressurized air, to create an air flow in the direction input / output.

Advantageously, the generally tubular member is conical and tapers from the inlet to the outlet.

According to another additional characteristic of the device according to the invention, the knife is driven through a pneumatic jack which also constitutes the pressurized-air source which generates the air flow.

Preferably, the device of the invention comprises a controller adapted to synchronize the action of the drive cylinder to that of cutting jack.

The design point of view, the knife moves in a horizontal plane while the feeding of the strip is vertically directed. In addition, a device according to the invention preferably comprises two parallel feeder means, one for each of two edges, one associated cutting means.

Advantageously, the device according to the invention is associated with return means comprising a set of pulleys for conveying the strip from the thermoforming unit regardless of the location of said device with respect to the latter.

According to a preferred embodiment of the device according to the invention; the strip pieces of the collection means comprise a bag removably mounted on a drawer, which is associated with a mechanism capable of causing, when opening said drawer, the deployment of a flap under the cutting means for said pieces to collect the time of replacement of said bag.

Advantageously the security point of view, the flap also prevents access to the blade.

The advantages and features of the device according to the invention will become clear from the following description which refers to the attached drawing, which represents a non-limiting embodiment.

In the accompanying drawing:<ul><li>1 shows a schematic perspective view of the device according to the invention,</li><li>2 shows a schematic perspective view of a part of the same device.</li><li>3 shows a schematic perspective view of another part of the same device.</li><li>4 shows a schematic perspective view from below of the same part.</li><li>5 shows a schematic view in exploded perspective of another portion of the same device</li></ul>

Referring to Figure 1, one can see that the device according to the invention is in the form of a machine to be positioned near a thermoforming unit, not shown.

This device comprises means 1, partially shown, for guiding and driving for each of the strips B coming from the thermoforming unit, of cutting means 2, not visible, and means 3 for collecting pieces of bands.

Strips B are delivered from the thermoforming unit via transmission means 4 comprising a ramp 40 provided with pulleys 41. The ramp 40 is carried by a structure 42 which is secured to reversibly device so that the ramp 40 can extend in different directions, while the pulleys 41 are movable on the ramp 40, thus allowing an adaptation to installations having different configurations, and independently of the thermoforming unit.

The means 1 for guiding and driving each associated with a control means, not shown, of known type, such as for example that disclosed in <patcit id="pcit0003" dnum="EP0624440A"><text>EP 0624440</text></patcit>, For controlling the supply of a pair 10 of rollers 11 also visible in Figure 2, which represents the means 1 for guidance and driving.

Note that the means 1 for guidance and driving comprise two pairs 10 of rollers 11, one for each band B, but only one is visible in the figures.

The rollers 10 are driven step by step against rotation and so as to pinch a band B by means of a pneumatic cylinder 12 driving a system 13 which comprises a free wheel 14 and a gear train 15.

Strips B are thus taken from the top downwards to open at the cutting means 2 shown in Figures 3 and 4.

Referring to these figures, it can be seen that the cutting means 2 comprise a plate 20 traversed by two pieces 21 of conical tubular shape, whose upper opening 22 is tapered while the lower opening 23 is narrow. The lower opening 23 of each of the tubular parts is bordered by a cons-blade 24 intended to cooperate with a knife 25 comprising four cutting edges 26 and 27 mounted on a driven pivoting shaft via a pneumatic cylinder 28 attached to the top of the plate 20. the reciprocating stroke of the pneumatic cylinder 28 generates a reciprocating movement of the knife 25 which scans the two lower openings 23.

Moreover, the two tubular parts 21 internally includes means, not shown, capable of generating an air flow from top to bottom, in association with a pressurized air source, for example after the pneumatic cylinder 28.

The two tubular parts 21 are each arranged in line with a pair of rollers 11 10 so that they cause the end of the strip B they entail, in the tubular part 21.

It will be understood that the end of the band B is, after passing between the rollers 11, guided by the air flow to the lower end 23 of the piece 21 where it is cut between the blade 25 and the blade against 24, either in one direction or another of the pivot due to the presence of the four cutting edges 26.

Particularly advantageously, the air cylinder 12 is controlled by a controller, not shown, and synchronized to the cutting cylinder 28 which controls the knife 25.

The frequency of the cylinder 27 is preferably constant, the length of strip pieces B depends on the speed of the pneumatic cylinder 12 which is adjustable.

The feeding of the end of the band B by the air flow, that is to say without contact, and its guide, because of the conicity of the part 21, advantageously make it possible to avoid jamming phenomena especially when the bands B are made of a flexible material.

Referring now to Figure 5, one can see that the collection means 3, intended to be arranged immediately below the cutting means 2 comprises a box 30 provided with a slide 31 carrying a removable bag 32.

The box 30 is fitted internally with a flap 33 pivotally movable to assume two positions in horizontal and vertical know to respectively open or close access to the bag 32. In this case the flap 33 is made in two parts 34 hinged to the side walls 35 of the box 30.

The passage from one position to the other is controlled in the maneuverability of the drawer 31, as the extraction thereof causes the closure of flap 33 and vice versa.

The closing of the shutter 33 will retrieve the pieces from cutting the strips during the replacement of the bag 32, without having to stop the cutting process, nor the thermoforming and prevent access to the blade 25.

The flap 33 is disposed in the box 30 at a certain height so as to delimit a volume V which satisfies the time of extraction of the drawer 31 and the replacement of the bag 32. Advantageously, it is provided means for determine that the volume V is filled, so as to warn and optionally the process, in the case of prolongation of the opening period of the drawer 31. These means may consist of sensors, but also means that, depending the known flow rate to determine the duration of filling volume V which is also known.