Compact and reduceable combined apparatus for packaging by means of a plastic sleeve

Abstract: The present invention relates to a combined hooding apparatus for packaging by means of a plastic sleeve of the type comprising a support frame on which there is provided: a system for forming a hood of heat-shrinkable plastic material obtainable from a tubular material folded in pleated fashion; a system for supplying said hood to a delivery point arranged at the top of said support frame; a device for fitting said hood, apt to pick up the hood from said system for supplying and fit it onto a load to be wrapped; and an annular structure which is movable vertically on said frame and on which there is fixed a circle group of burners inside which heating of said heat-shrinkable hood is performed, wherein said annular structure is suspended from a top section of said support frame by means of first raising means and is pivotably mounted on a support bracket displaceable vertically on a column of said support frame by means of second raising means, said annular structure being able to be stowed down by pivoting about an axis of rotation of said support bracket.

Description: Field of the invention The present invention relates to a wrapping hooding machine for packaging by means of a plastic sleeve. In particular, it relates to a combined hooding apparatus. As is known, a hooding apparatus is an apparatus which is widely used in specific fields of the wrapping sector in order to arrange bags or hoods of heat-shrinkable plastic material around loads which are supported on platforms or pallets. In the case of a standard hooding machine, after the hood has been fitted, the load is introduced into an oven where heat-shrinking of the said hood is performed so as to obtain a solid and stable wrapping. In combined hooding machines, on the other hand, these two operations are performed in the same apparatus. For this purpose, a combined hooding machine is normally composed of a support bridge on which various movable devices are mounted, said devices being intended to pick up, open and fit onto the load a hood of heat-shrinkable plastic material; on the same support bridge there is also mounted an annular structure on which a circle group of burners is arranged, said burners being displaced, at a suitable time, around the load to be wrapped so as to apply uniformly the heat for heating the hood. Usually, once the hood has been fitted, the circle group of burners lowers to the base of the load, where the open mouth of the hood is arranged, and starts to exert its heating action (expulsion of hot air up to 300°C) as it gradually rises up to the top of the hood. However, owing to the constructional design and the specific operating process, the combined hooding machines at the art have a few problems. First of all, it must be pointed out that, in order to be able to process standard-size goods (namely cross-section dimensions of 1,200 x 1,000 mm for standard euro-pallets), the annular structure for heating the hood must have minimum dimensions such that, when added to the typical dimensions of the bridge-type support structure, they result in the overall dimensions of the apparatus being greater than the maximum volume which can be transported on standard vehicles or in standard containers. In fact, normally, the annular structure is guided during its vertical translatory movement at the four corners of a quadrilateral by means of suitable guiding and raising systems which are housed in four vertical columns of the bridge frame which thus inevitably has considerable dimensions. Therefore, in most cases, once constructed, the hooding apparatus must be completely assembled in the production workshop and then for the most part disassembled so as to be able to load it onto a transportation vehicle and then reassemble it at the purchaser's premises. This gives rise, as can be appreciated, to two series of problems: on the one hand, the inevitable costs of disassembly and reassembly and transfer of the specialised personnel to the purchaser's premises and, on the other hand, the loss of time arising from the attempt to obtain again the correct calibration and play which, having already been set by the manufacturer, cannot be exactly repeated after disassembly and reassembly. From this point of view, therefore, there exists the need to provide a combined hooding machine structured in such a way that it may be disassembled as little as possible for transportation. Moreover, it must be noted that the application of heat in all of the combined hooding apparatuses results in intrinsic disadvantages which are all related; in particular a problem for persons skilled in the art consists in disposal of the heat which is necessarily produced for heat-shrinking of the whole hood. In fact, the considerable amount of heat supplied to the system naturally tends, as a result of convection, to be dispersed upwards, interacting with the structure of the support bridge and with the other movement mechanisms as well as with the said plastic film of the hoods which, according to the known art, is located ready for use in the top part of the support bridge. In fact, the hood of heat-shrinkable plastic material is formed (from a tubular material folded in pleated fashion and unwound from commercially available reels) and delivered at the top of the hooding machine. The mechanisms for opening the tubular material and for performing welding and cutting and fitting of the hood are therefore all located in the top part of the apparatus, where the heat produced during heat-shrinking has a significant effect. Even if a protective screen is arranged in the top part of the support structure, as has already been proposed, these drawbacks are not entirely overcome; moreover, in this way, the heat is unable to be dispersed naturally upwards and therefore tends to remain and accumulate in the wrapping zone, thereby modifying the working conditions in an undesirable manner. Furthermore, the market has not still provided hitherto efficient systems for forming and moving the hood which do not necessarily have to be located at the top of the machine frame, except bearing enormous constructional complications which adversely affect the reliability and the manufacturing costs. The object of the present invention is to solve the abovementioned problems associated with the dimensions and the presence of high temperatures in combined hooding machines. Brief description of the invention In particular, the aim is to provide a combined hooding machine which is both compact and has a volume which can be further reduced easily, quickly and without the need for major disassembly of vital components of the apparatus, so as to allow transportation and assembly thereof also by personnel who are not highly specialised. According to another aspect, the aim is to provide a combined hooding machine in which the drawbacks arising from the supply of considerable quantities of heat to the main movement mechanisms and to the plastic material of the hoods being formed are overcome. These objects are achieved by a hooding apparatus according to claim 1, i.e. an apparatus in which the annular structure, on which the circle group of burners is arranged, is pivotably mounted on a support frame with reduced dimensions. At the same time, the device for conveying and supplying the hood, which is separate from the fitting mechanism, is located on the side of the frame, in a position protected from the heat generated during the heating process, and supplies the hood to the delivery point only at the appropriate moment. Brief description of the drawings Further characteristic features and advantages of the device according to the invention will appear more evident from the following detailed description of some preferred embodiments thereof, provided by way of example and illustrated in the accompanying drawings, in which: Fig. 1 is a partially transparent, side elevation view of a preferred embodiment of the invention showing (in solid lines and dot-dash lines) the two positions which the annular heating structure is able to assume; Fig. 2 is an enlarged side elevation view of the gripping, cutting and welding device provided on the hooding machine according to the invention; Fig. 3A is a partial cross-sectional view, along the line III-III of Fig. 2, of the gripping device in a rest condition; Fig. 3B is a view, similar to that of Fig. 3A, of the gripping device in the working position; Fig. 4 is a partial side-elevation view corresponding to Fig. 3A; Fig. 5 is a side elevation view (showing half of the annular structure and the load) of another embodiment of the invention during cutting and welding of the hood; Fig. 6 is a view, similar to that of Fig. 2, showing the step of cutting and welding of the hood; Fig. 7 is a view, similar to that of Fig. 5, during conveying of the hood towards the delivery point; Fig. 8 is a view, similar to that of Fig. 5, during delivery and opening of the hood; and Fig. 9 is a top plan view, with parts removed, of the embodiment according to Fig. 1. Detailed description of some preferred embodiments The combined hooding machine according to the invention will now be described in detail, illustrating also operation thereof, in chronological order of the hood processing steps. As can be seen in Fig. 1, according to the invention, a combined hooding machine is composed of a support structure 1, which is substantially in the form of an overturned L and which supports reels B of heat-shrinkable tubular material T, a line 2 for supplying and delivering a hood, a vertically displaceable annular structure 3 on which a series of burners 4 and a device for opening and fitting the hood are mounted. The support frame 1 is arranged in the vicinity of a distribution line 5 - or a simple support base - on which a load 100 of varying nature, positioned on a pallet and intended to be wrapped, is transported. The hood C is formed from the tubular material T wound on a reel B. The tubular material is folded in pleated fashion so that unfolding and opening thereof may be easily achieved using automatic systems. The tubular material therefore has at least two pleated lips which extend along each of the two side edges. According to the invention, both a guiding and gripping system and a hood cutting and welding device are provided at the bottom of the frame 1. The guiding and gripping system comprises (Figs. 2-4) a guiding assembly, consisting of a pair of rails 10a and 10b with a U-shaped cross-section and a pair of strip-like guides 11, and a gripping assembly comprising a gripping fork 12. This system is dual so as to be able to act on both edges of the pleated tubular material T (only one of which, for the sake of simplicity, is shown in Figs. 3A and 4). Preferably, the U-shaped rails 10a and 10b are mounted parallel to each other, in a floating manner, so as to be able to move towards and away from each other as required. The two pleated lateral lips T1 and T2 of the tubular material T are inserted inside the U-shaped rails, for example manually. The rails 10a and 10b therefore have the function of vertically guiding the pleated tubular material, keeping the two lips T1 and T2 separate and at a distance. In order to force the tubular material to run along a substantially vertical plane, preventing it from collapsing onto itself, the strip-like guides 11 are arranged in pairs on either side of the tubular material (Figs. 2, 3A and 3B) so as to support it upstanding and guide it at least along a certain initial path. The strip-like guides 11 are also preferably mounted on a floating system 11a able to absorb the inevitable irregularities in the travel movement of the tubular material T, without snatching or jamming occurring. The gripping fork 12 has three prongs 12a, 12b and 12c. The central prong 12b is apt to be inserted between the two U-shaped rails 10a and 10b, if necessary displacing them and moving them away during insertion. The two external prongs 12a and 12c are intended to be arranged adjacent to the external surfaces of the two rails 10a and 10b, respectively. Facing pistons 13a and 13b are also provided between the prongs 12a-12c and are able, by means of a suitable pneumatic or hydraulic circuit (not shown), to protrude towards each other from their seats and grip the lip of tubular material T which is arranged between them. Therefore, in the rest condition, the fork 12 is displaced laterally, as shown in Figs. 3A and 4, in a position which does not interfere either with the rails 10a, 10b or with the pleated tubular material T. During a gripping operation, the fork 12 is inserted (arrow A1) between the rails 10a and 10b so as to be inserted correctly also between the two folds T1 and T2 of the tubular material T kept separate. In view of the intrinsic rigidity of the rails 10a and 10b, the lips of the folds T1 and T2, which by nature are somewhat flimsy, are prevented from being folded incorrectly, hindering correct gripping by the fork 12. Then the fork is raised (arrow A2) by a sufficient amount to come into direct contact with the lips of the folds T1 and T2 above the rails (position referenced by 12' in Fig. 4). At this point, the pressure circuit is able to activate the pistons 13a and 13b so as to grip, respectively, the lips T1 and T2 (Fig. 3B). Once the pleated tubular material T is firmly gripped along both its edges, the two gripping forks 12 (one of which is not shown) are drawn upwards in parallel fashion by means of a movement system which is schematically illustrated in the form of a chain 14 endlessly mounted around pulleys 15. During this movement, the gripping forks 12 unwind a section of tubular material T having a predefined length equal to the travel movement performed by the said forks. Once the gripping forks 12 have reached the desired height on the frame 1 (Fig. 5), the tubular material is cut and welded at the bottom so as to form a hood C. For this purpose a cutting and welding device 16 is provided, said device consisting of two oscillating facing blocks 16a and 16b on which mutually interacting cutting blades 17a and 17b and welding bars 18a and 18b are mounted. By performing rotation about respective axes of oscillation from the rest position (Fig. 2), in which there is no interference with the tubular material T, into the working position (Fig. 6), in which the blades 17a and 17b and the welding bars 18a and 18b interact with each other and with the tubular material T, the blocks 16a and 16b cut and weld the tubular material T so as to produce a separate hood C. According to a preferred embodiment of the invention, more than one guiding assembly for the tubular material is provided, so as to be able to handle simultaneously two or more reels of pleated tubular material which are different, for example, in terms of the material or transverse dimensions. As can be seen in Fig. 2, a further assembly of strip-like guides 111, mounted on a floating system 111a, and associated U-shaped rails (not shown) are mounted on the same drawer-type support S, in common with the guiding assembly previously described. A second pleated tubular material T' supplied from a second reel B' leads to the strips 111 and to the associated rails. The drawer-type support S is displaceable horizontally on suitable guides S1. In this way it is possible to position a given guiding assembly, carrying the corresponding tubular material which is intended to be used at that time for the specific wrapping required, along the working plane of the gripping fork 12 and the cutting and welding device. The reels may be mounted at a certain distance from the support frame of the hooding machine (Fig. 5), so as to define a sufficient space where the operator may work to insert manually the pleated tubular material into the corresponding guiding assemblies. Alternatively, the reels are preferably mounted on suitable supports arranged directly next to the frame of the hooding machine (Fig. 1), but the drawer-type support S may be displaced (in the direction of the arrow F) by an amount sufficient to extract it from the zone obstructed by the reels so that there may be easy access thereto. For example, a handle S 2 is provided, by means of which locking members of the drawer (not shown in detail) may be released and at the same time a pulling force applied so as to pull out the drawer towards oneself. The parts described above together form a system for forming and supplying the hood C. All of this first stage of extension of the tubular material and formation of the hood C, since it takes place along the vertical section of the frame 1 which is located laterally with respect to the heat-shrinking zone and is suitably screened without any difficulty, is not affected by the heat generated around the load to be wrapped. One of the objects of the invention has therefore been achieved, namely that of providing a hooding machine in which the hood, during the process for formation thereof, is not exposed to the heat and is therefore not modified before the due time. At the same time, since the whole system is housed along the main vertical section of the support structure, it does not need to be disassembled in order to reduce the dimensions of the apparatus, thus helping to achieve also the other object of the invention. As soon as the stage involving heating of a previous package has been completed and most of the heat has now been freely dissipated, the hood C is further conveyed by the gripping forks 12 along the horizontal top section of the frame 1 (Fig. 7) and then transferred vertically downwards so as to be brought to a delivery member with the lips of the folds T1 and T2 fully open and extended, ready to be gripped by the hood opening and fitting device. If this latter device is of the oscillating-arm type (Figs. 5, 7 and 8), the delivery point is situated just underneath the horizontal top section of the frame 1; if, on the other hand, the hood opening and fitting device is of the pin-type (Fig. 1), which is located in the bottom part of the annular structure 3, the delivery point is located slightly further down, namely by an amount sufficient for transferring the lips of the hood underneath the annular structure when it is located in its raised position (solid lines in Fig. 1). Here we shall not describe further the hood opening and fitting device since it does not form part of the present invention. However, it should be remembered that the most advantageous results, for the purposes of the teachings offered here, are obtained if this device is mounted integrally with the annular structure and therefore physically separate (except for the electrical, pneumatic and other connections) from the remaining mechanisms housed on the support frame. The annular structure 3, to which the burners 4 for the production of hot air are fixed, is mounted on a movement system which guides and controls displacement thereof in a vertical direction over the height of the load to be wrapped. Once the hood C has been opened, the annular structure 3 is displaced downwards, so that the hood itself may be fitted onto the load. At this point, the fitting devices, for example the gripping arms 21-24, release the lips of the hood and the operation of heating the heat-shrinkable hood may begin, starting up the burners 4 and gradually displacing the annular structure upwards at a speed which depends on the characteristics of the hooding machine and the hood. Meanwhile, the gripping fork 12 is brought back by the chain 14 into its base position, where it is ready to perform subsequent gripping and drawing of another section of tubular material T. According to the invention, the annular structure 3 is hung in a barycentric position from a first raising chain 31 and is pivotably mounted, by means of a pivot pin 34, on a guide bracket 32 which is vertically displaceable. The guide bracket 32 is slidable along a vertical column of the support frame 1 by means of suitable sliding guides and a second raising system. Preferably this second raising system also consists of a chain 33 which is attached to the bracket 32 and endlessly mounted around a driving pulley and a driven pulley. The chains 31 and 33 are driven, preferably by means of the same motor, in a synchronised manner, so as to lower and raise at the same time the two points of attachment of the annular structure 3 which is thus able to be displaced vertically so as to perform its function. When the hooding machine according to the invention must be reduced in size for transportation, it is sufficient to slacken the barycentric fastening chain 31, while keeping the pivoting pin 34 at a standstill, so as to allow vertical "stowing down" of the annular structure (indicated by 3' in the stowed down position). The bracket 32 is positioned at a height sufficient to allow the annular structure 3 to be tilted down entirely without this interfering with the ground. In this way, without having to perform major disassembly of any vital component of the apparatus, it is possible to obtain a significant reduction in the dimensions which allows easy transportation thereof. Reassembly also does not require particular technical skills and may be performed by non-specialised operators present at the purchaser's premises. Obviously a person skilled in the art will be able to devise other raising systems which are equivalent to those illustrated above, whereby it is important to point out that the support frame does not necessarily need four bulky guide pedestals and that the annular structure may be provisionally stowed down vertically by means of pivoting about the lateral pivot pin 34. The apparatus according to the invention, therefore, overcomes in a brilliant manner the drawbacks of the known art. Owing to the fact that all the delicate components of the hood forming system are housed in the bottom and lateral portion of the support frame and the fact that the annular structure, on which the circle group of burners and the hood opening and fitting system is carried, can be pivoted and stowed down, the apparatus may be provisionally reduced in size, without having to disassemble complex and vital parts which are difficult to adjust, resulting in considerable simplification and savings in terms of transportation and installation. The apparatus is overall more streamlined and less bulky also in the operating condition, which represents an advantage for the user. Finally, the specific structure and arrangement of the working parts, which are arranged so that they may be easily screened, minimises the problems arising from the generation of the heat used for heat-shrinking. In this sense, the objects expressed in the introduction are fully achieved. It is understood, however, that the invention is not limited to the particular configurations illustrated above, which constitute only non-limiting examples of the scope of the invention, but that numerous variations are possible, all within the reach of a person skilled in the art, without departing from the scope of the same invention. For example, if particular requirements dictate that the support frame must be constructed in a traditional manner, with a "bridge" design in the form of an inverted U, it would be possible to arrange, next to the structure illustrated in Fig. 1, a corresponding complementary part of the frame, for example only with structural functions and devoid of any functional device illustrated in the description above: this complementary part could, however, be easily disassembled and separated from the functional main part without particular difficulty. The dimensions could also be reduced without problems for transportation proposes.

Claims: Combined hooding apparatus, of the type comprising a support frame (1) on which there is arranged: a system for forming a hood (C) of heat-shrinkable plastic material obtainable from a tubular material (T) folded in pleated fashion; a system for supplying said hood (C) to a delivery point arranged at the top of said support frame (1); a device (21, 21a) for fitting said hood, able to pick up the hood (C) from said system for supplying and fit it onto a load (100) to be wrapped; and an annular structure (3) which is movable vertically on said frame and on which there is fixed a circle group of burners (4) inside which heating of said heat-shrinkable hood is performed; characterized in that said annular structure is suspended from a top section of said support frame by means of first raising means (31) and is pivotably mounted on a support bracket (32) displaceable vertically on a column of said support frame by means of second raising means (32, 33), said annular structure being able to be stowed down by means of pivoting about an axis of rotation (34) of said support bracket. Hooding apparatus according to Claim 1, in which said systems for forming and supplying the hood and said device for fitting are completely separate and are apt to cooperate at a delivery point located at an end of the top section of the support frame. Combined hooding apparatus according to claim 1, in which said fitting device is completely arranged integrally on said annular structure, cooperating with said supply system only at said delivery point. Combined hooding apparatus according to any one of the preceding claims, in which said second raising means are in the form a chain mounted endlessly around at least one toothed driving wheel. Combined hooding apparatus according to any one of the preceding claims, in which said first raising means are in the form of a chain attached to said annular structure and movable by motor means. Combined hooding apparatus according to any one of the preceding claims, in which said annular structure is hung barycentrically from said first raising means. Combined hooding apparatus according to any one of the preceding claims, in which the system for forming the hood is housed entirely inside a vertical lateral section of the support frame. Combined hooding apparatus according to Claim 7, in which the systems for forming and supplying are integrated and comprise: at least one short U-shaped rail for each fold of said tubular material folded in pleated fashion, inside which the fold is able to be guided substantially vertically along one side of said support frame, said rails forming a pair of. guiding assemblies arranged along two edges of the tubular material; a gripping fork for each guiding assembly, having prongs which are provided with gripping elements and which can be inserted horizontally between said rails and outside thereof and movable vertically so as to be positioned at the end of the rails and grip lips of said folds of the tubular material; said gripping fork being able to be drawn, by means of a movement system, into proximity of said delivery point. Combined hooding apparatus according to Claim 8, in which the rails in each assembly of rails are movable away and towards each other in a mutually floating manner. Combined hooding apparatus according to Claim 8 or 9, in which said movement system comprises a chain drive which follows an endless path, said gripping fork being joined to a cross-member fixed to said chain drive. Combined hooding apparatus according to any one of Claims 8 to 10, in which said guiding assembly also comprises guiding strips arranged, in pairs, on either side of the pleated tubular material so as to guide the movement thereof. Combined hooding apparatus according to Claim 11, in which said strips are mounted in a floating manner. Combined hooding apparatus according to any one of Claims 8 to 12, in which a cutting and welding device is also present above said guiding assemblies and is apt to close and separate from the tubular material the bottom side of a hood being formed. Combined hooding apparatus according to any one of Claims 8 to 13, in which said pair of guiding assemblies is mounted on a displaceable drawer, at least one other pair of guiding assemblies being arranged on the same drawer in order to guide another portion of tubular material folded in pleated fashion, said drawer arranging the desired pair of guiding assemblies along the working plane of said gripping fork. Combined hooding apparatus according to Claim 14, in which said displaceable drawer is extractable by an amount sufficient to expose it to an operator who may have easy access in order to insert the initial lips of the tubular material into the respective guiding assemblies.

Inventors: TACCHINI FRANCO, TACCHINI, FRANCO
Applicants: SESTESE OFF MEC, OFFICINA MECCANICA SESTESE S.P.A.
Application year: 2000
Main classification: B65B9
IPC codes: B65B53, B65B9