GB2067153A - A machine for packaging parcels in heat-shrinkable plastics film - Google Patents

Abstract

A machine for packaging parcels (4) in heat-shrinkable thermoplastic film, wherein said film is applied to and shrunk on parcels at a single operating station, comprises a horizontal frame (2) provided, at the centre thereof, with an opening so sized as to encompass the parcel (4) and vertically movable along four uprights (1), two bobbins (7) of heat-shrinkable plastics film rotatably fixed on respective ones of two adjoining sides of said frame (2), two grippers (8) associated with respective ones of the bobbins (7) and slidable along the sides of said frame (2) to deliver the free ends of film unwound from the bobbins to respective ones of two further grippers (9) which are rotatable about their longitudinal axes to wind film thereon and are located the sides of the frame (2) opposite to those provided with the bobbins (7), at least two heaters (5) fixed on each side of said frame (2), and cutters for cutting the films (7') and (7'') at the bottom end of the stroke off said frame (2). <IMAGE>

Description

SPECIFICATION A machine for packaging parcels by a thermoshrinkable plastics material film The present invention relates to a machine effective to automatically carry out, by a single sequential operation, the packaging of parcels by using a thermoshrinkable plastics material film.

As it is known some types of parcels are coated, for protection, impermeabilization purposes and the like, by a thermoshrinkable plastics material film e.g. polyethylene.

The thus coated parcel is then subjected to a thermal processing step for shrinking and laterally seal the thermoplastics film.

These coating and thermoshrinking operations are usually carried out in suitable packaging lines, formed by a plurality of operating stations. Accordingly the thermoshrinkable plastics film packaging of parcels carried out by using the conventional procedures is of high cost since it requires a great amount of labout and a comparitively long time.

The object of the present invention is to provide a machine for packaging parcels in thermoshrinkable plastics films which allows for the complete working cycle to be carried out in a single operating station, thereby remarkably reducing the required size: time and labour.

According to the present invention, this object is achieved by a packaging machine comprising four uprights located at the corners of a parallelogram, therealong is effective to vertically slide a horizontal frame which, at the centre thereof, is provided with an opening so sized as to encompass the parcel to be packaged.

On each adjacent side of the horizontal frame a thermoshrinkable plastics material film bobbin is fixed the width thereof being greater than the side of the parcel to be packaged.

Along the sides of said horizontal frame two suitably shaped pliers slide. at different heights, which pliers, by gripping the ends of the films of the bobbins stretch said films perpendicularly to one another on the parcel to be packaged.

At the end of their strokes, said pliers release the films to corresponding pliers, having a shape which is complementary to that of the first pliers, which, by rotating about themselves, storage a suitable linear film amount being sufficient to cover the sides of the parcel to be packaged.

On each side of the horizontal frame, at least two convectors are fixed, each provided with a hot fluid horizontally extending delivery mouth, and effective to thermoseal the overlapping edges of the thermoshrinkable films and to cause said films to thermally shrink in such a way as to envelope the parcel.

More specifically, said horizontal frame, by downwardly sliding, covers or coats the parcel to be packaged by the two plastics films, owing to the film stock present on the aforesaid rotating pliers pairs.

At the end of the downwardly directed stroke of the frame, the pliers release the films, these latter being cut by suitable cutters at the bobbins.

Upon the starting of the raising movement of the horizontal frame, the convectors are caused to operate which, by blowing hot air, laterally seal the films and cause said films to shrink.

As the horizontal frame reaches the upper end of its stroke, the convectors operate for a further predetermined period of time, in such a way as to cause the film portions located on the top plane of the parcel to be packaged to shrink.

The functional and constructional characteristics of the machine effective to package parcels by a thermoshrinkable plastics material film according to the invention will become more apparent from the following description with reference to the figures of the accompanying drawings illustrating an exemplary and not limitative preferred embodiment of the instant machine and where:: Figure 1 illustrates a front schematic view of the instant packaging machine, the frame being located at the top end of stroke position; Figure 2 schematically illustrates how the two thermoshrinkable films supplied by the bobbins and stretched by the movable pliers are arranged above the parcel to be packaged; Figure 3 illustrates a front schematic view of the machine illustrated in Fig. 1. the frame being located at the bottom end of stroke position; Figure 4 illustrates a top schematic view of the machine illustrated in Figs. 1 and 3; Figure 5 illustrates a perspective view of one of the pliers pulling the thermoshrinkable film; Figure 6 illustrates a partial schematic top view of a cooperating pliers pair, one whereof is effective to form a film reserve sufficient to cover one of the side walls of the parcel to be packaged;; Figure 7 is a detail schematic view illustrating the film cutting blade, located downstream of the supplying bobbins; and Figure 2 illustrates a schematic perspec-tive view representing a parcel as packaged by a thermoshrinkable plastics material film by using the packaging machine of the preceding figures.

Referring to the figures. the packaging machine according to the present invention comprises four uprights (1) located at the corners of a parallelogram, therealong is able of verti cally sliding a horizontal frame (2), this latter being preferably formed by four horizontal rods connected to one another.

At the base of the uprights (1) a conveyor (3) is located effective to transfer the parcel (4) to be packaged to the center of the frame (2) and effective to remove said parcel.

To each side of the frame (2), at least two convectors (5) are fixed.

Each convector (5) comprises, substantially, an electrofan, a plurality of electric resistances, a mixing chamber and a hot air delivery mouth (6), horizontally extending and having one end facing towards the parcel (4) to be packaged.

Said frame (2) is furthermore provided, at two adjacent sides, of two thermoshrinkable plastics material film bobbins (7).

Two pliers (8) located at each bobbin (7) and effective to slide along suitable guides (not shown in the figure), as formed at suitable heights, along the sides of the frame (2), spread out the film of each bobbin (7) above the parcel (4) to be packaged, in such a way as to locate the film bands (7') and (7") at mutually perpendicular positions.

Other two pliers (9) effective to rotate about their longitudinal axis due to the action of independent motors or known types of gearings (not shown in the figure) are fixed to the frame (2) at the sides opposite to those provided with the pliers (8).

Each pliers (8) and (9) is formed by two toothed adjoining rods.

More specifically, each rotating pliers (9) is provided with projecting portions (10), and each pliers (8) is provided with recessed portions (11) as formed at opposing positions with respect to the coresponding projecting portions (10).

Owing to this approach, the portions (10) of the pliers (9), by engaging the recessed portions (11) of the pliers (8), grip the bands (7') and (7") as conveyed by the pliers (8).

Said pliers (9), by successively rotating about themselves, wind up a film band (7') and (7") which is sufficient to cover at least a side wall of the parcel (4) to be packaged.

Then, the frame (2) moves downwardly, thereby covering the four walls of the pc rcel (4).

As the frame (2) reaches the bottom stroke end, the film (7') and (7") is cut downwardly from the bobbins (7) by means of suitable cutters (1 2).

The pliers (9), by rotating in an opposing direction with respect to the first direction, release the opposing edges of the film bands (7') and (7").

Then said convector (5) are operated which, starting from the bottom, seal said thermoplastics material film and cause said film to withdraw, said convectors continuing to operate as the frame (2) moves upwardly.

The convectors (5) continue to supply hot air for a predetermined period of time even as the frame (2) reaches the top end of stroke, thereby providing a full shrinking of the film spread out on the top of the parcel (4) to be packaged.

From the above description and the observation of the figures of the accompanying drawings, the functionality and use facility characterizing the machine for packaging parcels by shrinkable thermoplastic material film according to the invention are self evident.

Modifications, variations and changes can be brought about in the packaging machine of the invention which has been thereinabove described by way of an exemplary, illustrative but not limitative example, within the spirit and the scope of the invention.

Claims (10)

1. A machine for packaging parcels by a shrinkable thermoplastic material film, wherein said film is spread out, withdrawn and sealed by means of a single sequential operation, characterized in that it comprises: a) a frame formed by four uprights located at the corners of a parallelogram; b) a horizontal frame provided, at the centre thereof, with an opening so sized as to encompass the parcel to be packaged and vertically movable along said four uprights; c) two thermoshrinkable plastics material film bobbins, each thereof being rotatably fixed on each side of two adjoining sides of said frame; d) two pliers, located at each bobbin and effective to slide along guides as formed, at different heights, along the sides of said frames;; e) two pliers rotating about the longitudinal axis thereof, and fixed to the sides of the frame opposite with respect to the sides provided with the said pliers; f) at least two convectors fixed on each side of the frame, and; g) cutters for cutting the films at the bottom end of stroke of said frame.

2. A machine according to Claim 1.

wherein said horizontal frame is formed by four horizontal rods connected to one another.

3. A machine according to Claims 1 or wherein said thermoshrinkable plastics material films has a width greater that the side of the parcel to be packaged.

4. A machine according to any preceding Claims, wherein, each pliers is formed by two adjoining toothed rods.

5. A machine according to Claim 4, wherein said pliers is provided with recessed portions and said pliers with projecting portions said recessed portion being opposite to said projecting portions.

6. A machine according to any preceding Claims, wherein each convector comprises an electrofan, a plurality of electrical resista.1-?s, a mixing chamber and a hot air delivery mouth, this latter extending horizontally and having its end facing towards the parcel to be packaged.

7. A machine according to any preceding Claims, wherein said rotating pliers are effective to wind upon themselves a thermoshrinkable plastics material film amount sufficient to cover at least one of the sides of the parcel to be packaged.

8. A machine, according to any preceding Claims, wherein the convectors operate as the frame moves from the bottom end of the stroke position thereof to its top end of stroke position and for a precetermined subsequent period of time thereby causing the top portion of the parcel to thermoshrink.

9. A machine according to any preceding Claims, wherein at the base of the four uprights a conveyor belt is located.

10. A machine for packaging by a single sequential operation parcels in a thermoshrinkable plastics material film as described in the specification and illustrated in the figures of the accompanying drawings.