Machine and method for wrapping products

Abstract

 A machine for wrapping with a film (50) a group of products (100) arranged inside a containing casing (200) open above and below, comprises carriage means (3) slidably supported by frame means (2) along a movement direction (A) and rotatably supporting ring means (4) rotating around a wrapping axis (Z), in particular parallel to the movement direction (A), and supporting a reel of film (50) and an unwinding unit (5) of the film (50); the machine (1) further comprises a movement unit (10) slidably connected to the carriage means (3) and movable along the movement direction (A) at least for hooking, lifting and progressively disengaging the containing casing (200) from the group of products (100), in a wrapping step, such as to enable the film (50) unwound from the unwinding unit (5) to wrap portions of the group of products (100) left uncovered by the containing casing (200).

Description

[0001] The invention relates to machines and methods for wrapping products with a stretch film of plastic material. In particular, the invention relates to a machine and a method for wrapping a film around a group of products with an irregular shape and/or which is unstable and/or which is difficult to stack, which products being grouped on flatbeds or pallets.

[0002] Wrapping machines are known comprising a frame provided with two or more vertical columns suitable for slidably supporting a load-bearing structure, or carriage, that in turn rotatably supports a horizontal rotating ring. This horizontal rotating ring supports a reel of stretch plastic film and a corresponding unwinding unit arranged for unwinding and stretching, or elongating, the aforesaid plastic film. The unwinding unit is generally provided with a pair of prestretching rollers comprising a slow roller and a fast roller, respectively upstream and downstream of the film motion, to stretch and unwind the stretch film and one or more deviating rollers for deviating the film during unwinding.

[0003] The load-bearing structure, which is movable along a vertical axis, supports the ring, which is rotated around said vertical axis. In this manner, in use, the reel of film and the unwinding unit are rotated around the group of products arranged on pallets and moved in a vertical direction, optionally with reciprocating movement, such as to wrap said group of products with a series of plaited bands or strips of film over the entire height thereof.

[0004] Some machines are further set up to lay onto the group of products a covering sheet onto which the stretch plastic film is subsequently wrapped. The covering sheet, which is also made of a plastic material, separates and insulates more effectively the group of products from the external environment.

[0005] These machines include a horizontal conveying plane that extends through the frame and enables the group of products to be positioned at the horizontal ring.

[0006] In such wrapping machines, the prestretching rollers enable the plastic film to be stretched and elongated by a set percentage before the latter is wound on the products, both to use the available film as well as possible and to change the mechanical features of the film material according to the products to be wrapped. The suitably stretched plastic material can in fact pass from an elastic behaviour, in which the film tends to recover the original dimension when the stress stops, to a plastic behaviour in which the film undergoes a permanent deformation and does not recover the initial dimensions when the stress stops. In this latter case, the film of plastic material behaves as a flexible and inextensible element, the same as a rope or a belt.

[0007] The aforesaid wrapping machines can wrap groups of products that assume a stable composition or arrangement on the pallet, i.e. products that are stackable and superimposable.

[0008] On the other hand, in the case of products having irregular or variable shapes and/or dimensions and/or having little consistency or compactness, i.e. products that cannot be stacked or superimposed stably on pallets, such machines cannot be used automatically. It is in fact necessary to use one or more operators who proceed in several successive steps to stack partially the products and to wrap the products gradually with film. It is clear that this procedure, in addition to requiring the manual intervention of operators, requires a great deal of time and is thus particularly burdensome.

[0009] An object of the present invention is to improve the machines and the known methods for wrapping groups of products with a stretch plastic film.

[0010] Another object is to devise a machine and a method that enable groups of products to be wrapped with a stretch plastic film and possibly with a covering sheet, automatically without manual intervention of operators, the groups of products having shapes, dimensions and consistency that are such that they are difficult to stack and/or group securely and stably on flatbeds or pallets.

[0011] A further object is to devise a machine and a method that enable adhering and stable wrappings to be achieved on said groups of instable products, operating at high speeds, such as to increase productivity compared with known machines and methods.

[0012] In a first aspect of the invention a machine is provided for wrapping a plurality of products with a stretch plastic film according to claim 1.

[0013] In a second aspect of the invention, a method is provided for wrapping a plurality of products with a stretch plastic film with the wrapping machine of the first aspect according to claim 13.

[0014] In a third aspect of the invention a method is provided for wrapping a plurality of products with a stretch plastic film according to claim 18.

[0015] Owing to these aspects of the invention it is possible to wrap and bind with a stretch plastic film, and possibly with an upper covering sheet, groups of products having a shape, dimensions and consistency such as to be difficult to stack and/or group securely and stably on flatbeds or pallets. A group of products, housed inside a respective containing casing, can in fact be wrapped with the film without compromising the stability and the conformation thereof, raising gradually, at suitably calculated speed, the containing casing and at the same time wrapping with the film the external portions, or surfaces, of the group of products left uncovered by the aforesaid outer casing, in this manner binding and stabilising the corresponding products. The products are thus maintained stable, correctly stacked, or superimposed, and correctly and firmly wound by the film.

[0016] The structure of the machine, which enables the containing casing to be moved along a movement direction parallel to the axis of wrapping of the film around the group of products, is particularly compact and functional. In addition to wrapping the group of products, the machine enables the empty containing casing to be moved and managed, making the empty containing casing available for subsequent use.

[0017] The invention can be better understood and implemented with reference to the attached drawings that illustrate some embodiments thereof by way of non-limiting example, in which:

Figure 1 is a frontal schematic view of a wrapping machine according to the invention associated with a group of products to be wrapped that are inserted into a containing casing in an operating step, the containing casing being represented as a dashed line in another operating step;

Figure 2 is a side view of the wrapping machine in Figure 1, with groups of products inserted into the respective containing casings and wrapped in various operating steps;

Figure 3 is a top plan view of the wrapping machine in Figure 2;

Figure 4 is an enlarged detail of Figure 2, showing in particular carriage means supporting rotating ring means and a movement unit of a containing casing in one operating configuration;

Figure 5 is an enlarged perspective view of the wrapping machine in Figure 1, in which some parts have been eliminated to show better the carriage means, the rotating ring means and the movement unit;

Figure 6 is a plan and enlarged view of the movement unit of Figure 5;

Figure 7 is an enlarged detail of Figure 5, illustrating gripping means of the movement unit;

Figure 8 is a frontal view of supporting and movement means of the machine in Figure 1, showing closing means in an active position;

Figure 9 is a perspective view of the supporting and movement means of Figure 8;

Figure 10 is a perspective view of a containing casing of a group of products provided with abutting means in an open position;

Figures 11 is a front view of the containing casing in Figure 10;

Figure 12 is a bottom plan view of the containing casing of Figure 10 showing the abutting means in a closed position;

Figures 13 to 21 illustrate successive operating steps of a procedure for wrapping the group of products in the containing casing with a film of plastic material.

[0018] With reference to figures 1 to 9, there is illustrated the wrapping machine 1 of the invention arranged for wrapping with a film 50 of stretch plastic material a plurality or group of products 100 arranged on a pallet 101 and housed inside a containing casing 200. In particular, the products 100 are products (objects, manufactured products, articles, etc) having an irregular and/or variable shape and/or dimensions and/or having little consistency or compactness, i.e. products that for being stacked or superimposed in a stable manner onto a pallet 101 require an external supporting and stabilising containing casing 200.

[0019] As illustrated in figures 10 to 12, the containing casing 200 comprises a pair of longitudinal walls 201 connected at opposite ends by a pair of transverse walls 202, in such a manner as to form a quadrangular structure that is open above and below to stack the products 100 onto a pallet 101, in a step of composing the group of products 100, and to extract the aforesaid containing casing 200 from the group of products 100, during a step of wrapping with the film, as explained in greater detail further on in the description. The longitudinal walls 201 and transverse walls 202 of the casing are made, for example, of sheet metal with reinforcing ribs and tubular sections. The longitudinal walls 201 are substantially parallel to a substantially horizontal advancement direction B, along which the groups of products 100, housed in the respective containing casings 200 are moved inside the machines 1 and along which the groups of products 100 wrapped in the film and the empty containing casings 200 are moved outside of the wrapping machine 1 (Figure 2).

[0020] The wrapping machine 1 comprises carriage means 3 that is movable linearly along a movement direction A, for example a direction that is vertical and orthogonal to the advancement direction B, slidably supported by frame means 2 and rotatably supporting ring means 4, comprising a horizontal ring rotating with respect to a wrapping axis Z of the film 50 around the group of products 100. The wrapping axis Z is, for example, vertical and parallel to the movement direction A.

[0021] To the rotating ring 4 a reel of film 50 and an unwinding unit 5 are rotatably fixed comprising, for example, a pair of prestretching rollers 6, one or more deviating or idler rollers, and possibly a roller, a so-called dancing roller, for controlling the unwinding and/or tensioning of the film.

[0022] To the rotating ring 4 a gripping, cutting and welding unit 7 is also fixed that is arranged for grasping the film 50 at the end of wrapping and cutting the film 50 in such a manner as to retain a first end connected to the reel and weld a second end to the film already wound on the group of products.

[0023] The wrapping machine 1 further comprises a movement unit 10 slidably supported by the carriage means 3 in such a manner as to be linearly movable along the movement direction A to raise and disengage the containing casing 200 from the group of products 100 and enable simultaneous wrapping thereof with said film 50, according to the operating procedure disclosed in greater detail below in the description.

[0024] The carriage means 3 substantially comprises a rectangular-shaped supporting structure, slidingly fixed to two vertical columns 9 of the frame means 2 and driven along the movement direction A by movement means that is known and is not illustrated in the figures. The carriage means 3 enables the rotating ring 4 to be moved, and thus the reel of film and the unwinding unit 5 to be moved between a respective minimum elevation position L1, in which the film 50 can be wound around the pallet 101 and around a lower portion of the group of products 100, and a respective maximum elevation position H1, to enable the groups of products 100 and the corresponding containing casings 200 to enter and exit the wrapping machine 1.

[0025] To the carriage means 3 a cover unit can be fixed, which is optional and is not illustrated in the figures, which is arranged for laying over the group of products 100 a covering sheet on which the film 50 is then wrapped.

[0026] The machine 1 comprises further frame means 8 fixed to the carriage means 3 and arranged for slidably supporting and guiding the movement unit 10 along the movement direction A.

[0027] The further frame means 8 in particular comprises a portal structure provided with two parallel and spacedapart uprights 11, fixed below to the carriage means 3 and connected at opposite upper free ends by a crosspiece 12. Reinforcing tie rods 13 connect the crosspiece 12 to connecting plates 14 of the carriage means 3.

[0028] The movement unit 10 comprises a respective frame structure 15 with a substantially rectangular shape that is slidably connected to the uprights 11 of the further frame means 8 and is moved along the latter and along the movement direction A, by first driving means 31, 32. In particular, the movement unit 10 comprises sleeves 16 for the cable sliding, provided with wheels 17, fixed to the frame structure 15 and engaged in the respective uprights 11.

[0029] The first driving means comprises, for example, chain means 31 driven by a first motor 32 fixed to the further frame means 8.

[0030] The movement unit 10 further comprises gripping means 20 arranged for engaging hooking means 203, 202 provided on the containing casing 200 in such a manner as to be able to lift the containing casing 200.

[0031] The gripping means 20 includes first gripping means 21 comprising two pairs of gripping arms fixed rotatably on opposite transverse sides the frame structure 15. In particular, each pair of arms 21 is connected rotatably to a respective supporting beam 22 fixed to the frame structure 15 (Figure 7). Each gripping arm 21 is rotated around a respective axis, for example a vertical axis, between a disengaged position, in which an operating end 21a thereof, in the form of a hook, is spaced away from the longitudinal wall 201 of the containing casing 200, and an engaged position, in which said operating end 21a faces a respective first hooking means 203 provided on said longitudinal wall 201 (Figures 10 and 11). The gripping arm 21 is driven by a respective linear actuator 23. The first hooking means 203 comprises, for example, a plate fixed to the longitudinal wall 201 and provided with a shaped seat that is suitable for being engaged by the operating end 21a when the movement unit 10 is raised, as explained better further on in the description.

[0032] The gripping means 20 further includes second gripping means 25 comprising a pair of locking arms fixed rotatably on opposite transverse sides of the frame structure 15. In particular, each locking arm 25 is rotatably connected by brackets 26 to the frame structure 15 and to a respective sliding sleeve 16. The locking arm 21 is rotated around a respective axis, for example vertical axis, between a non-operating position, in which an operating end 25a thereof is spaced away from the transverse wall 202 of the containing casing 200, and a locking position, in which said operating end 25a is inserted inside a respective second hooking means 204 provided on said transverse wall 202. The locking arm 25 is driven by a respective linear actuator 27.

[0033] The second hooking means 204 comprises, for example, an opening made on an anchoring plate fixed to the transverse wall 202. The locking arms 25 prevent possible oscillations of the containing casing 200 during movement thereof along the movement direction A.

[0034] The wrapping machine 1 comprises supporting and movement means 41, 42, 43 arranged for supporting and moving the groups of products 100 and the containing casings 200 along an advancement plane M. In particular, the machine 1 comprises first supporting and movement means 41 that includes, for example, a first motorized roller conveyor located inside the frame means 2 below the rotating ring 4 to support the group of products 100 during wrapping. As illustrated in figures 8 and 9, the first roller conveyor 41 comprises closing means 44 arranged for acting on abutting means 205 of the containing casing 200. The abutting means 205 comprises a pair of stiff flat and elongated straps or slats or flaps fixed rotatably freely to respective lower portions of the walls, for example longitudinal walls 201, of the containing casing 200. The abutting means 205 allows the pallet 101 which supports the products 100 to be centred and/or supported with respect to the walls 201, 202.

[0035] During the composition of the group of products 100 inside the containing casing 200 and during movement of the latter, the abutting means 205 is folded inside, in a closed position, substantially parallel to the advancement plane M of the products, defined by the rollers 47 of the first roller conveyor 41. As explained in greater detail further on in the description, in the steps of wrapping the group of products 100, when the containing casing 200 is lifted by the movement unit 10, the abutting means 205, being free to rotate outwards to the open position, enables the aforesaid casing to be disengaged from the group of products 100.

[0036] The closing means 44 comprises a plurality of levers 45 arranged in opposite pairs and rotated around respective fulcrums by respective linear actuators 46, for example pneumatic or hydraulic cylinders, between an inactive and an active position. In the inactive position, the levers 45 are rotated and positioned inside the first roller conveyor 41 below the advancement plane M to enable a group of products to move freely. In the active position, the levers 45 protrude outside the first roller conveyor, in particular tilted by a set angle with respect to the advancement plane M, to abut on the abutting means 205 and rotate the abutting means 205 to the closed position. The wrapping machine 1 further comprises second supporting and movement means 42 and third supporting and movement means 43 that include, for example, respectively a second motorized roller conveyor and a third motorized roller conveyor placed on opposite sides of, and adjacent to, said first roller conveyor 41.

[0037] The second roller conveyor 42 enables groups of products 100 inserted inside respective containing casings 200 to be supported and moved into the machine 1.

[0038] The third roller conveyor 43 enables groups of products 100 wrapped by the film 50 and disengaged from the respective containing casings 200 and empty containing casings 200 to be supported and moved outside the machine 1.

[0039] In one embodiment of the machine that is not illustrated, the supporting and movement means 41, 42, 43 can comprise a single motorized roller conveyor, or comprise equivalent means such as, for example, separate or integrated conveyor belts or mats.

[0040] The wrapping machine 1 is provided with sensor means, that is of known type and is not illustrated in the figures, that detects at least one longitudinal and/or transverse position of the group of products 100 housed in the containing casing 200. The sensor means comprising, for example photocell barriers, is connected to a control unit, which is not shown, of the wrapping machine 1 such as to enable the latter to control the position of the group of products acting on the supporting and movement means 41, 42, 43. The sensor means also detects the lack or incorrect positioning of the groups of product 100 and/or of containing casings 200 on the supporting and movement means 41, 42, 43. Guiding means, that is of known type and is not illustrated in the figures, can be associated with the supporting and movement means 41, 42, 43 to arrange the groups of products 100 in the corresponding containing casings 200 in the desired transverse position, substantially orthogonal to the movement direction A, during the longitudinal movement, along the advancement direction B, entering the wrapping machine 1.

[0041] The wrapping process actuated by the wrapping machine 1 of the invention disclosed above involves the following operating steps, schematically illustrated in Figures 13 to 21.

[0042] In a first step (Figure 13), the wrapping machine 1 is ready to start the cycle: the carriage means 3 is in a respective maximum elevation position H1 and the movement unit 10, with respect to the carriage means 3, is arranged in a respective maximum elevation position H2. In this operating configuration of the machine 1, the group of products 100 housed in the containing casing 200 can be introduced on the first roller conveyor 41 inside the machine 1 along the advancement direction B.

[0043] In a second step (Figure 14) the carriage means 3 is moved to a respective minimum elevation position L1 and the movement unit 10, with respect to the carriage means 3, is moved to a respective minimum elevation position L2 to enable the gripping means 20 to hook the containing casing 200. In particular, the gripping means 20 is driven to engage the hooking means 203, 204 of the containing casing 200.

[0044] In a third step (Figure 15) the movement unit 10 is raised partially to a position that is intermediate with respect to the carriage means 3, maintained in the respective minimum elevation position L1, to hook and then lift the containing casing 200 and disengage a lower portion of the group of products 100 and the corresponding pallet 101 to enable wrapping thereof with the film 50. For this purpose, the ring 4 is rotated around the wrapping axis Z and the film 50 is unwound from the unwinding unit 6.

[0045] In a fourth step (Figure 16), the carriage means 3 is lifted to disengage from or progressively taking the containing casing 200 off the group of products 100 and simultaneously enable the film 50 to wrap the latter. The carriage means 3, and thus the containing casing 200, are lifted at a lifting speed that is correlated with a wrapping speed of the film 50 around the group of products 100, in such a manner as to ensure correct binding with the film 50 without compromising the stability of the group of products 100. In particular, the lifting speed of the carriage means 3, and/or of the movement unit 10, is calculated in function of one between: rotation speed of the rotating ring 4, speed of unwinding of the film 50 from the reel, elongation or prestretching of the film 50. During the wrapping step, the products 100 are maintained stable, correctly stacked or superimposed, as they are supported above by the containing casing 200 (which is gradually taken off upwards) and below from the already applied bands or strips of film 50. These latter progressively wrap external portions or surfaces of the group of products 100 left uncovered by the outer casing 200. The final raised position of the carriage means 3 at the end of wrapping is a function of the height of the group of products 100.

[0046] In a fifth step (Figure 17), the movement unit 10 is arranged, with respect to the carriage means 3, in the respective maximum elevation position H2 to enable the covering unit to lay a covering sheet on the group of products 100.

[0047] In a sixth step which is not shown, the carriage means 3 is thus lowered and subsequently lifted to enable the covering sheet to be bound to and immobilised on the group of products 100 with the film 50. For this purpose, the ring 4 is rotated and the film 50 is unwound from the unwinding unit 5. When the carriage means 3 is returned to the raised position reached at the end of wrapping, the gripping, cutting and welding unit 7 is driven to grasp and cut the film 50, retaining the first flap connected to the reel and welding the second free flap to the film 50 already wrapped on the group of products 100. If a covering sheet has not been positioned, the fifth step and the sixth step are replaced by a single step that arranges the movement unit 10 in the respective maximum elevation position H2 and the subsequent driving of the gripping, cutting and welding unit 7 to terminate the wrapping.

[0048] In a seventh step (Figure 18), after arranging carriage means 3 in the respective maximum elevation position H1, the group of products 100 wrapped with the film 50, and possibly with the covering sheet, is moved outside the machine 1 along the advancement direction B.

[0049] In an eighth step (Figure 19) the carriage means 3 and the movement unit 10 are moved to the respective minimum elevation position L1, L2 in such a manner as to deposit the empty containing casing 200 on the first roller conveyor 41. The gripping means 20 of the movement unit 10 is thus disengaged from the hooking means 203, 204 of the containing casing 200.

[0050] In a ninth step (Figure 20) the carriage means 3 and the movement unit 10 are moved to the respective maximum elevation positions H1, H2.

[0051] In a tenth step (Figure 21) whilst the empty containing casing 200 is moved outside the machine 1, a new group of products 100 inserted into a respective containing casing 200 is introduced onto the first roller conveyor 41 inside the machine 1 along the advancement direction B. At this point, the wrapping process can be repeated for the new group of products according to the ten operating steps disclosed above.

[0052] It should be noted that owing to the machine and to the wrapping method of the invention it is possible to wrap and bind with a stretch plastic film, and possibly with an upper covering sheet, groups of products having a shape, dimensions and consistency such as to be difficult to stack and group safely and stably on flatbeds or pallets. As disclosed above, by gradually lifting the containing casing 200, at a suitably calculated speed (function of the rotation speed of the ring 4, unwinding speed and prestretching value of the film 50) and at the same time by wrapping with the film 50 external portions or surfaces of the group of products 100 left uncovered by the aforesaid outer casing 200, by binding and stabilising the corresponding products 100, it is possible to maintain stable, correctly stacked or superimposed the products 100 and obtain groups of products that are correctly and firmly wrapped by the film 50.

[0053] It should be further noted that by virtue of the structure of the carriage means 3 and of the movement unit 10 that move linearly along the movement direction A, parallel to the wrapping axis Z, it is possible to make a very compact and functional wrapping machine. This in fact enables not only the group of products 100 to be wrapped with the film but also the empty containing casing 200 to be moved and handled, thus making the empty containing casing 200 available for subsequent use.

Claims

1. Machine for wrapping with a film (50) a group of products (100) arranged inside a containing casing (200) that is open that in upper and lower parts, comprising carriage means (3) that is slidably supported by frame means (2) along a movement direction (A) and rotatably supporting ring means (4), which rotates around a wrapping axis (Z), in particular parallel to said movement direction (A), said ring means (4) supporting a reel of said film (50) and an unwinding unit (5) for unwinding said film (50), said machine (1) comprising a movement unit (10) that is slidably connected to said carriage means (3) and is movable along said movement direction (A) at least for hooking, lifting and progressively disengaging said containing casing (200) from said group of products (100), in a wrapping step, such as to enable said film (50), unwound by said unwinding unit (5), to wrap portions of said group of products (100) left uncovered by said containing casing (200).

2. Machine according to claim 1, wherein said carriage means (3) and/or said movement unit (10) is lifted, in said wrapping step, at a defined lifting speed that is calculated in function of one or more among: rotation speed of said ring means (4), unwinding speed of said film (50) from said reel, prestretching value of said film (50).

3. Machine according to claim 1 or 2, comprising further frame means (8) fixed to said carriage means (3) and arranged for supporting and guiding said movement unit (10), the latter being movable with respect to said carriage means (3) by first driving means (31, 32) at least between a respective maximum elevation position (H2) and a respective minimum elevation position (L2).

4. Machine according to any preceding claim, wherein said movement unit (10) comprises gripping means (20) arranged for engaging, in a gripping condition (P), respective hooking means (203, 204) of said containing casing (200).

5. Machine according to claim 4, wherein said gripping means (20) includes first gripping means (21) acting, in said gripping condition (P), on first hooking means (203) provided on longitudinal walls (201) of said containing casing (200), in particular said first gripping means (21) comprising two pairs of gripping arms that are rotatably fixed to opposite transverse sides of a frame structure (15) of said movement unit (10), in particular each pair of arms (21) being rotatably connected to a respective supporting beam (22) fixed to said frame structure (15).

6. Machine according to claim 4 or 5, wherein said gripping means (20) includes second gripping means (25) acting, in said gripping condition (P), on second hooking means (204) provided on transverse walls (202) of said containing casing (200), in particular said second gripping means (25) comprising a pair of locking arms that are rotatably fixed to opposite transverse sides of a frame structure (15) of said movement unit (10).

7. Machine according to any preceding claim, comprising supporting and movement means (41, 42, 43) for supporting and moving at least along an advancement direction (B) said group of products (100) and said containing casing (200).

8. Machine according to claim 7, comprising closing means (44) associated with said supporting and movement means (41) and arranged for acting on abutting means (205), which is rotatably connected to lower portions of walls (201) of said containing casing (200) and which is movable between a closed position, in which said abutting means (205) is substantially orthogonal to said walls (201) to centre and/or support a pallet (101) that supports said group of products (100), and an open position, in which said abutting means (205) is substantially parallel to said walls (201) to enable said containing casing (200) to be disengaged from said group of products (100).

9. Machine according to claim 8, wherein said closing means (44) comprises a plurality of levers (45) driven by respective actuators (46) between an inactive position, in which said levers (45) are positioned inside said supporting and movement means (41) to enable a free movement of said group of products (100), and an active position, wherein said levers (45) protrude outwards said supporting and movement means (41), in particular tilted, to abut on said abutting means (205) and rotate said abutting means (205) in said closed position.

10. Method for wrapping with a film (50) a group of products (100) arranged inside a containing casing (200) that is open in upper and lower parts, by using a wrapping machine (1) according to any preceding claim, comprising:

- hooking said containing casing (200) by gripping means (20) of a movement unit (10) that is slidably connected to carriage means (3) of said machine (1);

- lifting said movement unit (10) and/or said carriage means (3) along a movement direction (A) in order to disengage progressively said containing casing (200) from said group of products (100) and, at the same time,

- wrapping with said film (50) portions of said group of products (100) left uncovered by said containing casing (200).

11. Method according to claim 10, wherein it is provided, before said hooking, moving said carriage means (3) and said movement unit (10) from respective maximum elevation positions (H1, H2) to respective minimum elevation positions (L1, L2) along said movement direction (A).

12. Method according to claim 10 or 11, wherein said lifting comprises lifting partially said movement unit (10) with respect to said carriage means (3), in an intermediate position, to disengage a lower portion of said group of products (100) from said containing casing (200) so as to enable said film (50) to wrap said lower portion, and further lifting said carriage means (3) to complete a wrapping of said group of products (100).

13. Method according to any one of claims 10 to 12, comprising after said wrapping:

- moving said group of products (100) wrapped with said film (50) outside of the machine (1) by supporting and movement means (41, 42, 43);

- moving said carriage means (3) and said movement unit (10) in respective minimum elevation positions (L1, L2) along said movement direction (A) to put down and release said containing casing (200) on said supporting and movement means (41, 42, 43);

- moving said empty containing casing (200) outside of the machine (1) by said supporting and movement means (41, 42, 43).

14. Method according to any one of claims 10 to 13, wherein said lifting said movement unit (10) and/or said carriage means (3) comprises lifting along said movement direction (A), substantially parallel to a wrapping axis (Z) of said film (50) around said group of products (100), at a defined lifting speed that is calculated in function of one or more among: rotation speed of a film reel around said group of products (100), unwinding speed of said film (50) from said reel, prestretching value of said film (50).

15. Method for wrapping with a film (50) a group of products (100) arranged inside a containing casing (200) that is open in upper and lower parts, comprising:

- hooking, lifting and progressively disengaging said containing casing (200) from said group of products (100) and at the same time

- wrapping with said film (50) portions of said group of products (100) left uncovered by said containing casing (200),
in particular said lifting comprising lifting along a movement direction (A), substantially parallel to a wrapping axis (Z) of said film (50) around said group of products (100), at a defined lifting speed that is calculated in function of one or more among: rotation speed of a film reel around said group of products (100), unwinding speed of said film (50) from said reel, prestretching value of said film (50).

Drawing