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DESCRIPTION

The present invention refers to a sealing and transversal cutting device for packaging machines of loose elongated material in motion along a horizontal plane.

The operations of filling and closing plastic bags containing loose elongated material, in particular pasta such as spaghetti or similar, are extremely critical.

In the conventional machines the sealing and cutting of the plastic film come about by means of a pair of pincers rotating in reverse directions that support sealing means and a blade. When said pincers meet during the rotation, they tighten the film between them, sealing it and cut it.

A common drawback with these machines is that it is necessary to prevent the filling material from remaining caught between the pincers.

Object of the present invention is to produce a film sealing and cutting device for elongated filling material that flows along a horizontal plane, which comprises a flexible mechanism, that occupies little space and is easy to use, and which is capable of preventing said elongated filling material from being blocked between the sealing and cutting pincers compromising the very sealing and cutting operations.

In accordance with the invention this object is achieved with a device for sealing and cutting film in packaging machines for loose elongated material which is mobile along a horizontal plane, comprising transversal rotating shafts synchronised with each other, to which a pair of pincers is secured comprising sealing and cutting means, characterised in that said pincers are connected to mechanisms comprising front preflattening plates and rear preflattening plates moved in predefined positions by springs that react to an almost circular preset path that brings the two pincers into contact

one above the other, so that said plates separate the loose elongated material which is upstream of from that downstream of the device and carry out a preflattening of the film, so as to prepare the film itself for sealing and cutting without any interposition of loose elongated material.

The presence of the springs gives flexibility to the mechanism guaranteeing the opening of the plates and thus the preflattening of the film in function of the position of the mechanisms themselves. The preflattening plates are thus mobile in relation to the pincers. In addition when they are not in a working position, the above-mentioned plates tend to "wind" the pincers, so that the rotating mechanism occupies an extremely reduced space.

The characteristics of the present invention will be made more evident from the following detailed description of an embodiment thereof illustrated as non-limiting example in the enclosing drawings, in which:

Figure 1 shows a partially sectioned side view of a device according to the invention;

Figure 2 shows a section view according to the line II-II of Figure 1;

Figure 3 shows a section view according to the line III-III of Figure 1;

Figure 4 shows a section view according to the line VI-VI of Figure 1;

Figure 5 shows a schematic view similar to that of Figure 2 with the pincers in a position prior to the opening of the plates;

Figure 6 shows a schematic view similar to that of Figure 2 with the pincers in a position successive to that of Figure 5;

Figure 7 shows a schematic view similar to that of Figure 2 with the pincers in a position successive to that of Figure 6;

Figure 8 shows a schematic view similar to that of Figure 2 with the pincers in a position successive to that of Figure 7;

Figure 9 shows a schematic view similar to that of Figure 2 with the pincers in a position successive to that of Figure 8;

Figure 10 shows a schematic view similar to that of Figure 2 with the

pincers in a position successive to that of Figure 9;

Figure 11 shows a schematic view similar to that of Figure 2 with the pincers in a position successive to that of Figure 10;

Figure 12 shows a side view of a mechanism of the device of Figure 1 separated from the device itself;

Figure 13 shows a front view of the mechanism of Figure 12;

Figure 14 shows a section view according to the line XIV-XIV of Figure 12;

Figure 15 shows a plan view from above of Figure 12;

Figure 16 shows a section view according to the line XVI-XVI of Figure 15.

A first rotating transversal shaft 1 and a second rotating transversal shaft 2 synchronised with each other are shown in Figure 1, controlled by a motor 120 by means of a transmission 24 (Figure 4) comprising a sprocket motor 25 and a first gear wheel 26 connected by a belt 40. A second gear wheel 121 is splined to the same shaft 2 of the first gear wheel 26, engaging said second gear wheel 121 with a third gear wheel 27 splined to the shaft 1.

A frame 22 supports said shafts 1-2 by means of bearings 23 suitable for ensuring the rotation in relation to the same frame 22.

Rigid forks 5 connect the shafts 1-2, to which they are splined, to revolving support bodies 3-4 respectively.

Bodies 150 (Figure 3) are splined to said shafts 1-2 fitted with side arms 151 to which the first ends of springs 152 are connected, the second ends of said springs 152 being connected to the above-mentioned revolving support bodies 3-4.

Rotating mechanisms 6-7, which are supported by said support bodies 3-4 respectively, comprise each one a parallelogram 133 (Figure 13) which supports a front wheel 130 and a back wheel 51 and to which a front articulated mobile body 8 and a rear articulated mobile body 9 are hinged.

The front body 8 comprises front mobile arms 160 connected to arms

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162 of the parallelogram 133 by means of springs 10.

In the same way the rear body 9 comprises rear mobile arms 161 connected to arms 163 of the parallelogram 133 by means of springs 11.

The springs 10-11 have a first end fixed to the arms 160-161 of the mobile bodies 8-9 by means of pins 45-46, and a second end connected to arms 162-163 of the parallelogram 133 by means of pins 70-71.

The support bodies 3-4 support pincers 32 and 34 which in the working position (Figures 5-11) tighten and then release a plastic film 100 suitable for collecting elongated filling material 101.

The wheel 130 engages with the front cam 131, while the wheel 51 engages with the rear cam 132 (Figure 2).

In addition the support body 3 supports a mobile blade 15 (Figures 1, 15-16) between a working and a resting position by means of a pneumatically activated mechanism 16.

Said mechanism 16 comprises a horizontal pneumatic piston 136 connected to a driving rotating arm 137 which together with a driven rotating arm 138 moves the blade 15 vertically by means of a spacer 139 to which said arms 137-138 (Figure 16) are connected.

The blade 15 moves through a slit 31 made in the pincers 32, and when it is in the working position (Figure 7) the end of the blade 15 partially occupies a slit 33 made in the pincers 34.

In addition the mobile bodies 8-9 respectively support front preflattening plates 28 and rear preflattening plates 29.

Wheels 20 (Figures 1 and 15), associated to the support bodies 3-4, engage in recesses 21 (Figure 3) enabling the mechanisms 6-7 to carry out an almost circular path.

Further wheels 140, connected to the same support bodies 3-4 by means of arms 141, engage on cams 142 (Figures 3 and 15).

In regard to the operation, the motor 120 moves the shaft 2 (Figure 4), by means of the transmission 24. The engagement between the toothed

wheels 121 and 27 also enables the second shaft 1 to rotate.

Considering as a starting position of the device that of Figure 5, the two shafts 1-2 rotate in an opposite direction thus permitting the two mechanisms 6-7 to meet where the plastic film 100 runs horizontally (line L Figures 2-11) in the straight line of the path defined by the cam 142. The entrance direction of the elongated filling material 101 is indicted with a large arrow F (Figures 2-4).

The preflattening plates 28, 29 in the Figures 5-11 are drawn with a thicker line than the other details drawn so as to highlight the relative motion.

In Figure 6 the front plates 28 that meet can be seen, as well as the rear plates 29 preflattening the film 100.

Observing the Figures 5-7 in sequence it is possible to see the variation of the orientation of pincers 32 and 34 due to the profile of the cams 142 with which the wheels 140 engage connected to the support bodies 3-4 by means of the arms 141.

The rear plates 29 open because the rear wheels 51 engage with the rear cam 132 thus generating the movement of the arms 161 of the mobile body 9.

Similarly the front plates 28 open because the front wheels 131 engage with the front cam 131 thus generating the movement of the arms 160 of the mobile body 8.

Until the detachment between the mechanisms 6-7 comes about the filling material 101 is upstream or downstream of the sealing and cutting zone.

When the pincers 32 and 34 have the slits 31 and 33 perfectly vertical, thanks to the orientation set by the cam 142 to the support bodies 3-4, and the same pincers 32 and 34 meeting tightening the film 100 (Figure 8), the device is ready for the sealing and cutting operations.

In the position of Figure 8, in fact, sealing means 102, 104 associated

to the front of the pincers 32, 34 tighten the film 100 together, sealing the opposite flaps of the same. In addition an external command moves the pneumatic piston 136, which, by means of the arms 137-138 and the spacer 139, moves downwards the blade 15, which cuts the film 100.

With the cut having been made the mechanisms (6-7) move away from each other (Figure 11) to complete the disengagement of the wheels 130 and 51 from the cams 131 and 132 respectively. Consequently the plates 28-29 close.

From Figure 2 it can be seen that the pincers 32 and 34 are double at 180° between each other. This permits the productivity to be increased.