DESCRIPTION

This invention regards an automatic packaging machine.

As is known, packaging machines can be horizontal or vertical, manual or automatic, and are used to obtain finished packs of loose products. In automatic packaging machines, a certain quantity of loose product is put into a hollow tubular element which provides the form of the desired pack. A film made of plastic material is wrapped around this tubular element and is drawn downwards and subjected to longitudinal sealing by means of sealers. When this longitudinal sealing is complete, the film that will form the pack of product must be sealed transversally in such a way as to close the top and bottom of the packs.

One of the main problems of known machines is that it is only possible to make packs in a single format, given that there is only one tubular forming element of given dimensions. In order to make packs of different formats on the same machine it is necessary at the very least to change the tubular forming element and associated reel or, alternatively, use a different machine. In both cases, as can be intuited, the packaging process for obtaining packs of a different format presents considerable problems from an economic standpoint and from the point of view of the complexity and slowness of the operations.

The aim of this invention is therefore the creation of an automatic packaging machine by means of which it is possible to obtain a plurality of packs of different formats in a fast, simple and economical manner, without in any way influencing the packaging speed in accordance with a determined format while always guaranteeing optimum efficiency of the entire packaging process.

This aim is achieved by this invention by means of an automatic packaging machine in accordance with claim 1.

Further characteristics and advantages of this invention will be better understood in the course of the following description, considered for exemplificative and not limiting purposes and with reference to the attached drawings, in which:

fig. 1 illustrates a frontal view of a fast packaging machine in accordance with this invention and comprising a plurality of forming groups for making packs with different formats, one of which is positioned in correspondence with a fixed filling station;

fig. 2 illustrates a partial frontal view of this machine in which a forming unit that differs from the one illustrated in fig. 1 is used in correspondence with the fixed filling station;

fig. 3 illustrates a partial frontal view of one of the forming units of this machine provided with associated means for changing the reel of film of plastic material for making the packs; and

fig.4 illustrates a side elevation view partly in section of this machine.

With reference to these attached drawings and with particular reference to fig. 1 of the same, 1 indicates the frame of a fast multi-format packaging machine in accordance with this invention. This frame 1 comprises a base platform 101, columns 201 and a head mount 301. Positioned at the centre of this frame 1, which has a substantially rectangular form frontally, is a fixed station 2 for filling the packs comprising two fixed sides 102, fixed above the head mount 301 and below the base platform 101. Partially shown in a central position with regard to said sides 102 and above the frame 1 is a hopper 3 from which the loose product to pack is fed into the machine. Positioned inside this frame 1 are three mobile forming units 4a, 4b and 4c one of which, forming unit 4c in this case, is positioned in the centre of the fixed filling station 2. Each of these units, 4a, 4b and 4c, is capable of making a pack of product with a given format and comprises: a tubular forming element 5a, 5b and 5c; a first active reel 6a, 6b and 6c for feeding one or more layers of film of plastic material for making the packs; and a second reserve reel 7a, 7b and 7c for fast changing of the first active reel when the latter runs out of film of plastic material. Each of the tubular forming elements 5a, 5b and 5c is provided at the top with an inlet and is hollow internally, and the film of plastic material drawn from the associated active reel 6a, 6b and 6c is wound around it. Furthermore, each of these tubular forming elements 5a, 5b and 5c can have any form, depending on the form of the pack or packet of product to be obtained and therefore can have a circular, square, rectangular or polygonal section or the like. As has been said, each of these three forming units 4a, 4b and 4c makes a pack with a given format: the tubular element 5c of the forming unit 4c has a greater width than that of tubular element 5b of unit 4b which, in turn, has a greater width than the tubular element 5a of unit 4a. The first and second reels associated with each unit also have a different width depending on the size of the tubular forming element and therefore the width of reels 6c and 7c is greater than that of reels 6b and 7b which, in turn, have a greater width than reels 6a and 7a. To exemplify what has been described so far, it is possible to imagine that this machine can make packs of 1 kg of product with forming unit 4c, for example, provided with the largest tubular forming element 5c, it can make packs of 1/2 kg of product with tubular element 5b of the intermediate forming unit 4b, and with forming unit 4a fitted with the smallest tubular forming element 5a it can make packs of 250 g of product. It goes without saying that the number of forming units could be different from the three illustrated and in general this multi-format machine can envisage two or more forming units of different formats on the frame. The three forming units 4a, 4b and 4c are connected to a single mobile bottom frame 10, provided with a plurality of blocks 8 moving along a guide 9 located on the base platform 101 of the frame 1. Preferably there is at least one associated block for each of the forming units 4a, 4b and 4c. Fixed at the end of this mobile frame 10 is the end of a flexible motion transmission means, a belt or a chain 12 for example, which is passed around a pair of rollers 13 located on the columns of the frame 1. At least one of these rollers 13 is connected to driving means, not illustrated, for moving the chain 12 and therefore translating the mobile frame 10 and blocks 8 in one direction or the other. At the top, the forming units 4a, 4b and 4c comprise a single mobile frame 14 connected to which are all the tubular forming elements 5a, 5b and 5c of the three units. A block 15 moving on a guide 16 placed on the top of the head mount 301 of the frame 1 is envisaged in this mobile frame 14 for each of these tubular forming elements 5a, 5b and 5c. In this case too, the ends of a chain 17, or other flexible means of transmission of movement for translating the top mobile frame 14 in one direction or the other, are fixed to the ends of the frame 14 itself. This chain 17 is passed round two rollers 18 located on the side columns 201 of the frame 1. In this case too, at least one of these rollers 18 is connected to driving means, not illustrated, for moving the chain 17 and therefore translating the mobile frame 14 and blocks 15 in one direction or the other.

Each of the active reels of film of plastic material 6a, 6b and 6c or the reserve ones 7a, 7b and 7c of each of the forming units 4a, 4b and 4c comprises a free central pin 19 and rests on a pair of idle rollers 20; also see fig.4 in which the active reel 6c is illustrated. Each of these idle rollers 20 is capable of rotating around an associated central pin fixed at the ends of a pair of sides 21. These sides 21 are supported by the bottom mobile frame 10 provided with the blocks 8 sliding on the double guide 9. Downstream from the reel 6c in fig. 4 this machine comprises two pairs of rollers 22 that draw the film 23 of plastic material towards the fixed pack filling station 2. This film 23 of plastic material passes across a series of transmission rollers 24 and junction means

25 are envisaged between two pairs of traction rollers 22 capable of making it possible to effect the changeover between the film of the active reel and the reserve reel in such a way as not to interrupt the pack filling process. The film 23 of plastic material is wound around a forming collar

26 of a type known per se and appropriately shaped. The purpose of this forming collar 26 is to wrap the film 23 of plastic material correctly around the tubular forming element 5c and therefore give it a tubular form. This film 23 is drawn along the tubular forming element 4c by means of the traction rollers 27 connected to an arm 28 pivoted at one end on a fixed pin 29 and capable of oscillating compared with said pin 29. This arm 28 is driven to make the rollers 27 adhere to the film 23 in tubular form, or to retract the rollers from the film by means of an actuator 30. On the opposite side of these traction rollers 22, this machine comprises a device 31 for sealing the superimposed longitudinal and vertical edges of the film 23 of plastic material. This device 31 is made to approach or withdraw from the tubular forming element 5c by means of an actuator 32 provided with an associated support 33. Positioned downstream from the tubular forming element 5c in said fixed station 2 is a unit 34, known per se, for the transversal sealing of the top of a given pack and the bottom of a pack following this given pack. This unit 34 will also effect the separation of two successive packs in the packaging process of this machine. Also envisaged on the base platform 101 of the machine frame is a conveyor belt 35 for collecting the finished packs.

As seen above, the forming units 4a, 4b and 4c all move together and translate in one direction or the other compared with the frame 1, and therefore it is possible on this machine to position one of them in correspondence with the fixed central pack filling station 2. Fig. 1 shows the situation in which the unit 4c provided with the largest tubular element 5c is positioned in this filling station 2 in order, therefore, to make the packs with the largest size or format. Fig. 2 shows another exemplificative situation of the operation of this machine positioned in which is the forming unit 4a comprising the smallest tubular forming element 5a, in correspondence with the fixed central station 2, thanks to the translation o f all the units 4a, 4b and 4c by means o f the movement o f the mobile top frame 14. With the succession o f the operations for making and filling the packs by means o f this tubular forming element 5 a, the film o f p lastic material o f the active reel 6a will therefore run out and this active reel will be replaced by reserve reel 7 a lo cated beside this active reel. This situation is illustrated in fig . 3 in which it is possible to see that the reserve reel 7a has been brought into correspondence with the tubular forming element 5 a by means o f the translation o f the bottom mobile frame in the direction o f arrow A, thereby becoming the new active reel in the packaging process effected by this machine .

In the op eration o f this machine , the mo st suitable forming unit for the desired pack format will therefore be selected automatically and therefore , in this case, the unit 4 c for the largest size o f packs, the unit 4b for packs with the intermediate format or the unit 4a for packs with the smallest format. This unit will be positioned in correspondence with the central fixed filling station 2 bearing the hopper 3 for transferring the product to pack to the tubular forming element of the selected unit at the top . It goes without saying that the means 3 1 for longitudinally sealing the plastic film 23 wrapped around the tubular forming element and the means for transversal sealing and cutting 34 will always be the same whichever forming unit is selected. It is therefore possible with this machine to pass quickly and automatically from one format to another for every p ack or series o f packs . As mentioned above, there can be any number o f forming units on the frame, depending on the number of formats to be obtained on this packaging machine .