FR2777258A1 - Packaging machine using heat sealed plastic pockets - Google Patents

Abstract

The machine has a sealing table and a heat sealing head, which has heat sealing profiles formed in it, arranged to heat seal the film behind (or upstream of) the current product in the direction of product flow, and in front of (or downstream of) the next product. A removal system removes the piece of material that is left between the two heat seals, using a gripper to tear it from the heat seals.

Description

Improved packaging machine and method "under

pocket "by film or film.

  The present invention relates to the technical sector of so-called "film-forming" machines, the function of which is to package, under a film or film of the heat-sealable and / or heat-shrinkable plastic type,

  manufactured objects of various shapes.

  The general aim is to protect the objects in question, and / or their

  give an attractive appearance to the offer for sale.

  Many machines of this type are known, which can be characterized by the following common characteristics, which have

  shown in Figure 1 attached.

  The machines 1 of the prior art are fed by a plastic film 2 wound in double thickness, this film being "open" on one side, ie that the two surfaces 3, 4 forming the double thickness do not

  are neither welded nor joined in any other way, on this side 5.

  These machines also include a thermo-welding frame 6 of generally rectangular or square shape, and of the same longitudinal axis as the direction of travel of the film, which is materialized.

by the arrow f ..

  The film is unwound from a storage reel 7, and passes

  on a plate or horizontal table 8.

  The objects 9 to be packaged are presented laterally, i.e.

  perpendicularly to the running of the film, a known and therefore not shown device separating or now separating the two surfaces 3, 4 of the film to allow a lateral pusher 10 to insert the object into the "pocket" 11 thus opened. The operator then folds the heat-sealing frame over the object placed in the pocket. Known frames have two adjacent heating sides, one 12 in the direction of travel and above the open side of the film, and the other 13

  upstream from the direction of travel.

  The contact of the arm with the double thickness film therefore produces a lateral weld 14 where the pocket was open and a transverse weld 15 "behind" the object. It will be understood that the packaging of the previous object, by the same manipulation, had already made a transverse weld 16 "in front" of the object. The object is thus wrapped

  in a square or rectangular pocket.

  Downstream, the assembly is directed or not towards a thermal retraction tunnel 17, which comprises an oven adapted to operate in a manner

  known shrinkage or shrinkage of the plastic film around the object.

  We can see that if the objects to be packaged are of general shape

  substantially rectangular or square, the result is correct.

  It is understood in the same way that if the object has rounded shapes or forming an angle with the direction of travel, these machines can only lead to very approximate packaging. Thus, on a round shape, the central part of the object can be properly wrapped, but an excess of film inevitably remains around the lateral parts of the object. This surplus will form upon removal of completely unsightly clumps or beads, and naturally the film corresponding to these areas is lost. It is possible to cut out the surplus parts, but

  this is done at the cost of an additional handling step.

  The problem is further aggravated if the object to be packaged has protuberances, such as handles, a handle, etc. In fact, it is understood that the more the object is, either in form deviating from the rectangle or the square , either irregular or asymmetrical, the more problems

  appearance and excessive film consumption will arise.

  For example, it will be extremely difficult for the weld to follow

  the form, which is however much sought after for the visual aspect.

  An example of such objects is represented by pans and utensils of this type. Such objects combine a round or oval or rounded square shape and the like, a large "tail", and most often a lateral surface established according to a truncated cone or a

  rounded shape in pan or the like.

  These objects are currently, and for more than ten or fifteen years,

  processed by machines of the type shown in Figure 1.

  This results in the aforementioned drawbacks, which are particularly damaging in the case of consumer products, offered on the shelves, and where the visual appearance strongly influences, so

  conscious or not, the purchase decision.

  No significant improvement has been proposed to date,

  l0 despite the obvious need and the size of the market concerned.

  An object of the invention is to provide a machine and a method which solve all of the stated problems in a simple manner. Other characteristics and advantages of the invention will appear

  better by reading the description which follows, and by referring to the

  attached drawing, in which: - Figure 1 shows a machine of the prior art, as indicated above; - Figure 2 shows the result which the invention achieves, on a

skillet.

  - Figure 3 shows a top view schematizing the principle

  of the invention, in the same nonlimiting example of a pan.

  - Figure 4 shows a schematic side sectional view of the essential functional elements of the machine according to the invention; - Figure 5 shows an entirely preferred embodiment of the invention. Figure 1 has already been described in detail in the foregoing. We can refer to it but only for the understanding of

  generalities such as direction of scrolling, etc ...

  FIG. 2 represents the result obtained according to the invention, on an object which is particularly difficult to treat. As can be seen, and as will be explained in detail below, the pan 20 is wrapped very narrowly and very aesthetically by a film 23 which includes a

  part of the tail 25 without causing significant clumps or bulges.

  Note that the weld 27 is in the median plane of the lateral surface of the object, which gives a particularly visually attractive appearance. As we will see below, machine settings or the fact of using interchangeable parts make it possible to modify the result, for example to completely wrap the tail if it is

  desired, place the weld higher or lower if required, etc.

  FIG. 3 very schematically represents the principle of the invention, according to which the welding head (not shown for simplicity and clarity, since it is above the plane) comprises welding profiles suitable for welding the film behind (or upstream) de) lI'objet of rank (n) in the direction of travel, welding 30, and in front (or

  downstream of) the object of rank (n + 1), welding 38.

  According to the invention, a means 32 is provided for detaching the drop 34 which remains between the two welds 30 and 38. Advantageously, this means will be pliers capable of pinching the drop and tearing it from its points of adhesion with welds 30 and 38 or the welding table. Preferably, the clamp will be driven by an alternating movement in the plane of the welding table, as represented by the

double arrows.

  The invention therefore makes it possible, for the first time and in a simple manner, to recover the scraps of film occurring around objects of non-rectangular shape, in the form of fragments of the original film, and therefore to recycle these scraps, which represents an economic effect

  important when operating on a large number of objects.

  The two welding operations are preferably simultaneous,

  but can possibly be slightly shifted in time.

  The welding profiles are adapted to the general shape of the object

seen from above.

  The welding profiles are integrated into a welding head

  interchangeable according to the shapes of the objects.

  Figure 4 shows a schematic side view of a mode

  for producing a machine according to the invention.

  The machine according to the invention essentially consists of a frame 40, a welding head 42, which is mounted on vertical guides 43 and can thus be lowered or raised by means of a hydraulic cylinder 44, a welding table 45, a lateral pusher system 46 capable of passing each object to be packaged successively from an introductory mat 47 to the upper surface of the welding table, and a means of supply and presentation of the film,

preferably a pin 48.

  The welding head 42 comprises two welding profiles 50 (downstream) and 51 (upstream), preferably mounted on a removable welding form, easily interchangeable according to the shape of the objects, this

  form being for example mounted on a sliding fastening system.

  According to a variant which will be preferred for many forms of objects, the welding table has a drop 52 whose value is chosen to be substantially equal to half the height of the lateral surface of the object in question. The elevation is used to operate the welding in the median or substantially median plane of the object, with a result

incomparably more aesthetic.

  To illustrate the operation of the machine according to Figure 4, we

  represented two objects of rank (n) and (n + 1).

  The object (n) was the subject, when it was in the place (n + 1l) of a welding operation which carried out its downstream welding 80 by the upstream welding profile 51. The two objects being in the position shown, the lowering of the head 42 will cause, between the objects (n) and (n + 1), the formation of two welds. These will be the upstream weld 81 of the object (n), which will then be completely packaged, and the downstream weld 82 of the object (n + 1). We

  note that the weld 81 is produced in the median plane of the object.

  The following operation will consist of removing the drop formed between the welds 81 and 82, and advancing the objects one row with the

  push device and an ejection mat.

  The object (n) is thus driven towards the retraction tunnel disposed at the outlet of the machine, the object (n + 1) replaces the object (n) and, in doing so, causes a corresponding length of film, thanks to its downstream or "head" weld 82, while the object (n + 2) enters the welding zone. FIG. 5 shows in more detail the device 70 for feeding the film, which preferably consists of a "pin" 71 bordered by

  a round rod 72 with an edge. The film is delivered by the reel 73.

  In known manner, the pin is a "U" shape, the two branches of which are horizontal, and which has been cut at 45 o as shown, with an edge round 72. The unwinding of the film with two thicknesses on such a form, the film being brought to the cylindrical side of the horizontal "U" shape, reverses the film 90 ° as

shown schematically by the arrow r90.

  FIG. 5 also represents the detail of the profiles 50 and 51, as well as the movement P of the pusher device, the objects being brought laterally onto the presentation tray from a

  conveyor C or other device not shown.

  As can be seen in FIG. 5, the welding profiles 50 and 51 preferably have an edge 60 which gives them a triangular section. This gives better precision in the

  welding, and it also facilitates the detachment of the scrap.

  The invention also relates to a method for packaging objects in film by a plastic bag welding technique, of the type comprising the application of a welding head to a film, characterized in that one applies to the film a welding head which has welding profiles suitable for welding the film behind (or upstream of) the object of rank (n) in the direction of travel, welding 30, and in front (or

  downstream of) the object of rank (n + 1), welding 38.

  The invention also relates to a method as described above and characterized in that it comprises a step in which a means 32 is provided for detaching the scrap 34 which remains between the two

welds 30 and 38.

  The invention also relates to a method as described above and characterized in that the two welding operations are preferably simultaneous, but may possibly be slightly

shifted in time.

  The invention also relates to a method as described above and characterized in that the welding profiles are adapted to the general shape of the object seen from above. The invention finally relates to objects of all types, characterized in that they have been placed in a pocket film by a machine or by a process according to the invention, as described above, in particular pans

and the like.

  Those skilled in the art will be able to adapt the above operating modes and mechanical elements to many other configurations.

  objects, more complex or different in shape.

Claims (14)

  1.- Machine for packaging in film by a plastic bag welding technique, of the type comprising a welding table and a welding head, characterized in that the welding head comprises welding profiles suitable for welding the film behind (or upstream of) the object of rank (n) in the direction of scrolling,   welding 30, and in front of (or downstream of) the object of rank (n + 1), welding 38.   2. - Machine according to claim 1, characterized in that there is provided a means 32 for detaching the drop 34 which remains between the two welds 30 and 38.   3. - Machine according to claim 2, characterized in that said means 32 consists of a device capable of grasping the fall and tearing it from its points of adhesion with the welds 30 and 38 or the welding table, like pliers.   4. - Machine according to any one of claims 1 to 3,   characterized in that the two welding operations are preferably simultaneous, but may possibly be slightly shifted in time.   5. - Machine according to any one of claims 1 to 4,   characterized in that the welding profiles are adapted to the shape general view of the object seen from above.   6. - Machine according to any one of claims 1 to 5,   characterized in that the welding profiles are integrated into a welding head   interchangeable welding according to the shapes of the objects.   7. - Machine according to any one of claims 1 to 6,   characterized in that it essentially consists of a frame 40, a welding head 42, which is mounted on vertical guides 43 and can thus be lowered or lifted by means of a jack 44, _d'une table 45, a lateral pusher system 46 capable of successively passing each object to be packaged from a presentation tray 47 to the upper surface of the welding table, and a means for supplying and presenting the film, preferably one pin 48.   8. - Machine according to any one of claims 1 to 7,   characterized in that the welding head 42 has two profiles welding 50 (downstream) and 51 (upstream).   9. - Machine according to any one of claims 1 to 8,   characterized in that the welding profiles 50 (downstream) and 51 (upstream) are mounted on a removable, interchangeable form of welding, this   form being for example mounted on a sliding fastening system.   10. - Machine according to any one of claims 1 to 9,   characterized in that the welding table has a drop 52 whose value is chosen to be substantially equal to half the height   of the lateral surface of the object under consideration. -   11. - Method for packaging objects under film by a plastic bag welding technique, of the type comprising the application of a welding head on a film, characterized in that a head is applied to the film welding which includes welding profiles suitable for welding the film behind (or upstream of) the object of rank (n) in the direction of travel, welding 30, and in front (or downstream   de) the object of rank (n + l), welding 38.   12. - Method according to claim 11, characterized in that it comprises a step in which a means 32 is provided for detaching   the fall 34 which remains between the two welds 30 and 38.   13. - Method according to claim 11 or 12, characterized in that the two welding operations are preferably simultaneous,   but can possibly be slightly shifted in time.   14. - Method according to any one of claims 11 to 13,   characterized in that the welding profiles are adapted to the general shape of the object seen from above 15. - Objects characterized in that they have been placed in a pocket film   by a machine according to any one of claims 1 to 10 or   by a method according to any one of claims 11 to 14, including pans and the like.