The state of the art comprises thermoforming machines in which opposite edges of sheet material are made to travel forwards through a plurality of operating stations comprising at least one welding station, in which pockets are formed from the edges, and at least one forming station in which the pockets are inflated until containers are obtained therefrom having the desired dimension and shapes.

The containers are subsequently filled at a filling station and sealed at a sealing station downstream of the filling station whilst they are united by non-deformed parts of the edges of sheet material so as to form a continuous strip of filled and sealed shaped containers that may be sent to a cooling station and be separated from the strip, singularly or in groups of containers, at a trimming station situated downstream of the sealing station.

Between the sealing station, or cooling station, and the trimming station guide means is arranged by which the strip of containers is accompanied from a substantially vertical plane in which the containers of the strip are at the outlet of the cooling station, or of the sealing station-as the case may be-to a substantially horizontal plane in which the containers of the strip are at the trimming station.

A machine of the type disclosed above has been known to the art since 1973 by the code SG12, and is manufactured by the applicant.

However, the prior-art guide means has a defect consisting of that when the transversal dimensions. of the sheet material are changed to enable other containers to be formed having dimensions and/or shapes and/or capacity other than those of a

previously shaped batch of containers, the guide means must be adjusted or replaced to be adapted to the size of these other containers.

Furthermore, the prior-art guide means has a preset geometrical shape and therefore ensures strip contact only if the latter is arranged on a plane that corresponds to that specific geometrical shape.

Furthermore, the prior-art guide means cooperates with a moving plane of the machine, which means that the design and construction of the machine are subject to undesirable constraints.

One object of the invention is to improve the guide means of strips of prior-art containers.

Another object is to obtain guide means of strips of containers that does not need to be adjusted or replaced when it is desirable to change the size of the containers, or of the sheet material from which the latter are shaped.

A further object is to find guide means that enables a more uniform contact of the strip.

A yet further object is to provide guide means for strips of containers that constitute independent units.

According to the invention, an apparatus is provided comprising a plurality of operating units arranged to interact with sheet material to form containers therefrom, and guide means of said sheet material along an advancing path of said sheet material placed between one of said operating units and an operating unit immediately downstream along said path, characterised in that said guide means has a tubular body such as to receive said sheet material within its interior.

In this way, the sheet material can be brought into contact with a pair of contact lines arranged on opposite sides of the tubular body that defines the guide means in a manner that is substantially independent of the containers at least for a rather varied range of sizes.

Furthermore, the strip may rest by gravity, depending on the shapes of the containers and of the stiffness of the material that makes up the strip, on the tubular guide-means walls, finding there suitable support.

In order that the invention may be clearly and completely disclosed, reference will now be made, by way of examples that do not limit the scope of the invention, to the accompanying drawings, in which: Figure 1 is a transparent schematic perspective view of guide means of a strip of containers according to the invention; Figure 2 is a transversal cross-section of tubular guide means showing a plurality of positions taken up by the strip of containers; Figure 3 is a cross-section like the one in Figure 2, showing all the possible positions adopted by strips of containers having transversal dimensions differing from one another; Figure 4 is a longitudinal view of the guide means in Figure 1; Figure 5 is a transparent schematic perspective view of guide means of a strip of containers in a different implementation.

As Figures 1, 2 and 4 show, the apparatus comprises guide means 1 having a body 2 with a tubular shape, for example having a circular transversal cross-section that extends between a first operating unit A of a forming machine of a strip 3 of containers 4 and a second operating unit B arranged downstream of the first operating unit A along a rectilinear forward-travel path P of the strip 3.

In one embodiment, the operating unit A is a sealing station of the containers 4 that have already been shaped and filled at stations of a form-fill-and-seal machine arranged upstream of the operating unit A.

In another embodiment, unit A is a cooling unit 4 of containers formed, filled and sealed at stations of a form-

fill-and-seal machine arranged upstream of the operating unit A.

In a further embodiment, the operating unit A is a forming station of tray containers and unit B is a filling station of said containers.

The guide means 1 has an inlet port 5 arranged near the first operating unit A in such a way as to affect an end of a guide means 1 and an outlet port 6 that affects the end opposite the guide means 1.

If necessary, the inlet port 5 and/or the outlet port 6 may be equipped with closing walls that are not shown, each one of which is equipped with a fissure to enable the passage therethrough of the strip 3. In this way the path P defined by the guide means 2 is insulated from the external environment and enables contamination of the exposed parts of the containers 4 to be avoided whilst the containers 4 traverse the guide means 1.

The strip 3 enters through the inlet port 5 in a vertical configuration V and rests with its own initially bottom first rim 7 on a bottom zone of the tubular body 2 facing it, whilst between a second rim 8, initially top, of the strip 3 and the zone of the tubular body facing it a gap G is defined that is sufficient to prevent excessive rubbing between the strip 3 and the tubular body 2 that could cause the strip 3 to jam.

The strip 3 emerges from the outlet port 6 in a horizontal configuration 0 in which both the first rim 7 and the second rim 8 rub against substantially diametrically opposite portions of the internal surface of the tubular body 2.

The strip 3 performs a rotation R of approximately 90° to go from the vertical configuration V to the horizontal configuration 0, and progressively assumes a plurality of intermediate configurations I, corresponding to different slants that are progressively nearer a horizontal plane ; in each of said intermediate configurations I the first rim 7 and

the second rim 8 always rest on corresponding internal surface sections of the body 2.

As Figure 4 shows, if the position of the inlet port 5, or of the outlet port 6 needs to be adjusted, it is sufficient to use adjusting means 9,10 respectively.

As Figure 3 shows, if a strip 3 has a dimension that substantially corresponds to the diameter of the body 2, the contact zones between the strip 3 and the body 2 are substantially diametric.

Nevertheless, if the strip 3'has a transversal dimension that is even noticeably less than the diameter of the body 2 the guide means 1 can perform its task equally well but in such a case the contact zones between the first rim 7'and the internal surface of the body 2 and the second rim 8'and the internal surface of the body 2 are arranged along the chords of the transversal cross-section of the body 2. During the rotation R'that takes the strip 3'from a vertical configuration V'to a horizontal configuration O', the strip 3'takes on intermediate slanted positions I'.

As Figure 5 shows, the body 2 may also extend for a non- rectilinear section, in particular it may form a route P1 that has two consecutive rectilinear sections that substantially form a right angle.