The invention relates to movable or self-propelled wrapping machines arranged to wrap a film of extensible plastic material around a load consisting of a product or a plurality of products arranged on a pallet.

The self-propelled wrapping machines, also called self-propelled wrapping robots, are machines generally used to wrap loads of variable shapes and sizes and in limited productions, typically in environments or rooms where fixed or static wrapping machines cannot be used because of the dimensions and/or available spaces. The loads are generally formed by pallets on which a plurality of products and/or objects, also of different sizes and formats, superimposed in a more or less regular manner, is arranged.

In other cases, the wrapping, normally for protective purposes, directly concerns the product which is generally large in size.

The self-propelled wrapping machines include a cart or carriage that supports a vertical post along which a film unwinding or dispensing unit, which houses a plastic film reel and is provided with a plurality of rollers for unwinding and pre-stretching the film, is movable with alternating rectilinear motion. More precisely, the unwinding unit is provided with a pair of pre- stretching rollers suitable for unwinding the film from the reel and pre-stretching or extending it by a predefined percentage, and with one or more return rollers to divert the film towards the load.

The carriage is generally provided with motorized rear drive wheels and a front guide device which includes one or more steering wheels, operated by a steering. The steering can be operated via a guide bar by an operator to manually drive the machine in a manoeuvring configuration, or by a feeler element capable of following the profile or external shape of the load in an operational working configuration, in which the self-propelled machine turns autonomously and automatically around the load to wrap it with the film.

The combination of the alternating linear movement of the unwinding unit along the vertical post and the rotation of the self-propelled machine around the load allows the film to be wrapped around the load so as to form a series of intertwined strips or bands. The plastic film is wrapped to completely wrap the load on all its sides.

The feeler element comprises an arm which extends externally and laterally with respect to the carriage and is provided at the end with an idler wheel capable of following the external contour of the load to be wrapped. The feeler element exerts a predefined elastic compression or thrust force on the load, so as to maintain contact with the aforementioned load and allow the machine to move reliably around the load according to a path determined by the contour of the load.

Self-propelled wrapping machines are also known which, in place of the feeler element, include sensors e.g. ultrasonic, capable of detecting the external surfaces and edges of the load and processing related signals that allow the control unit of the wrapping machine to calculate a wrapping path around the load to avoid collisions. More precisely, the control unit on the basis of the external surfaces and edges of the load detected by the sensors controls the steering wheels and/or the driving wheels of the carriage so as to steer and guide the latter around the load.

In both types of known self-propelled wrapping machines described above, although the wrapping phase takes place in a substantially automatic way, i.e. without manual intervention by an operator, the latter is necessary both in an initial phase of the winding process to fix an initial flap of the film to the load or to the underlying pallet, both in a final phase to cut the film and separate it from the reel.

The aforesaid known self-propelled wrapping machines therefore have the disadvantage of not allowing to carry out winding processes in a completely automated way, that is, without any manual intervention by operators.

EP 3070003 describes an unwinding apparatus for a self-propelled wrapping machine comprising frame means for supporting a film reel, roller means for unwinding and pre stretching the film, at least one folding element movable along a narrowing path to find a first longitudinal edge of the film and push it towards a second longitudinal edge of the film so as to reduce a band width of the film exiting the apparatus and actuating means for moving the folding element along the narrowing path.

WO 2013/050832 describes a self-propelled wrapping machine which includes a motorized self-propelled carriage capable of moving on the ground by means of at least two drive wheels, a control unit for controlling the drive wheels, means supported by the carriage to dispense a wrapping material and a distance sensor positioned on the machine and suitable for measuring the distance between the machine and the load.

WO 99/42367 describes an apparatus for wrapping a load with a wrapping material comprising a load supporting surface for supporting the load during wrapping, a dispenser for dispensing the wrapping material, means for performing the relative rotation between dispenser and load so as to wrap the latter with the wrapping material, gripping means for retaining or releasing an end flap of the wrapping material, and a movable support arm above the load supporting surface for radially moving the gripping means between an external position away from the load and an internal position close to the load. US 5450711 describes a machine for wrapping a load with a film of plastic material comprising means for supporting the load, means for supporting a film reel, first means for rotating the film reel with respect to the load around a first axis of rotation, second means for rotating the film reel with respect to the load around a second axis of rotation and actuating means acting on said first and second rotation means of the film reel to control and coordinate their operation.

An object of the invention is to improve the known self-propelled wrapping machines arranged to wrap a load with an extensible plastic film.

Another object is to provide a self-propelled wrapping machine which allows to wrap a load with a film in a completely automatic way, that is, without requiring any manual intervention by an operator.

A further object is to provide a self-propelled wrapping machine which allows to make firm and stable windings.

These objects and others are achieved by a self-propelled wrapping machine according to claim 1.

The invention can be better understood and implemented with reference to the attached drawings which illustrate some exemplifying and non-limiting embodiments thereof, wherein:

- figure 1 is a plan view of the self-propelled wrapping machine of the invention associated with a load and in a wrapping phase;

- figure 2 is an enlarged and partial side view of the wrapping machine of figure 1 ;

- figure 3 is a perspective view of the wrapping machine of figure 1 ;

- figure 4 is an enlarged detail of figure 3 illustrating an inserting arm and a cutting arm in respective folded configurations;

- figure 5 is a front perspective view of the wrapping machine in an initial phase of the wrapping cycle, which illustrates the inserting arm in a release position of an anchor element inside the load pallet;

- figure 6 is an enlarged, partial, bottom perspective view of the machine of figure 5;

- figure 7 is a perspective view of the wrapping machine in the wrapping phase with the inserting arm and the cutting arm in respective folded configurations;

- figure 8 is a perspective view of the wrapping machine in a terminal phase of the wrapping cycle wherein the inserting arm fixes an anchor element to the wrapping film;

- figure 9 is an enlarged detail of figure 8;

- figure 10 is a front perspective view of the wrapping machine in the terminal phase of the wrapping cycle while the cutting arm grasps and cuts the film;

- figure 11 is a front perspective view of the wrapping machine in a waiting phase of the wrapping cycle;

- figure 12 is an enlarged front view of an anchor element fixed to an initial flap of the film;

- figure 13 is a plan view of the anchor elements of figure 12;

- figure 14 is a perspective view of the anchor elements of figure 12.

With reference to figures 1 to 11, a self-propelled wrapping machine 1 according to the invention is shown, movable around a load 100 to wrap it with a plastic film 50, in particular of the cold-extensible type. The load 100 is formed by a group of products 101, that is, by one or more products 101, arranged on a pallet 102. The aforesaid pallet 102, of a known type, is provided with a plurality of side openings 103, opening on the sides, in particular on the longer ones. In particular, the side openings 103 are made on longitudinal supports 104 which support a plane 105 of the pallet 102 and which form longitudinal supports or compartments 106 suitable for receiving the forks of a forklift so as to allow the lifting and handling of the pallet 102 itself.

The self-propelled wrapping machine 1 comprises a self-propelled carriage 2 and a post 3 fixed to the latter and slidably supporting an unwinding unit 4 provided with a reel 51 of film 50 and roller means 41, 42, 43 for the unwinding and pre- stretching of the film 50.

The self-propelled wrapping machine 1 further comprises a magazine 5, fixed to the carriage 2 and arranged to contain a plurality of anchor elements 30, each thereof arranged to retain a portion of film, more precisely an initial flap 50a of the film 50 unwound from the unwinding unit 4. In particular, each anchor element 30 is provided with hooking means 35 arranged to receive and retain the initial flap 50a of film.

The self-propelled wrapping machine 1 also includes an inserting arm 6, supported by the carriage 2 and provided with gripping means 8 suitable for gripping and retaining firmly an anchor element 30. The inserting arm 6 is movable for taking an anchor element 30 from the magazine 5, associating the aforesaid anchor element 30 to a portion of the film 50 unwound from the reel 51 and intended to form the initial flap 50a after cutting the film 50 at the end of the wrapping cycle of the load 100, inserting and then releasing the anchor element 30 connected to the initial flap 50a inside a side opening 103 of the pallet 102. The anchor element 30 is configured so as to get engaged and restrained in a side opening 103 during the phase of wrapping the load 100 so as to firmly restrain the initial flap 50a of film to the pallet 102.

The inserting arm 6 includes a first end 6a fixed to a rear portion of the carriage 2 adjacent to the post 3 and a second end 6b to which the gripping means 8 are fixed.

In the embodiment shown in the figures, the inserting arm 6 comprises an articulated arm, formed by a plurality of members rotatably and/or slidably connected to each other and therefore having a plurality of degrees of freedom so as to be movable in different operating positions during the operation of the self-propelled wrapping machine 1. More precisely, and as better specified in the description that follows, the inserting arm 6 can be moved between a picking position A, wherein it is in a folded configuration and adjacent to the carriage 2 so as not to interfere with the winding of the film 50 around the load 100 and to allow the gripping means 8 to grasp and then extract from the magazine 5 an anchor element 30 (figures 1-4), a release position R wherein the inserting arm 6 is in an extended configuration for inserting and then releasing an anchor element 30, to which the initial flap 50a is fixed, inside one of the side openings 103 of the pallet 102 (figures 5 and 6), an insertion position F wherein the inserting arm 6 is in a partially folded configuration and the gripping means 8 fix the anchor element 30 taken from the magazine 5 to the portion of film interposed between the unwinding unit 4 and the load 100 (figures 8-10), and a waiting position B wherein the inserting arm 6 is in a folded configuration adjacent to the carriage 2 so as not to interfere with the movement of the self-propelled wrapping machine 1 and the gripping means 8 support the anchor element 30 to which the initial flap 50a of film is fixed (figure 11).

The self-propelled wrapping machine 1 also comprises a cutting arm 7 supported by the carriage 2 and provided with gripping and cutting means 9 arranged to cut the film 50 at the end of the wrapping phase and make an end flap 50b and the initial flap 50a. The gripping and cutting means 9 comprise, for example, a cutting plier capable, in addition to cutting the film 50, of retaining the end flap 50b thus obtained, while the initial flap 50a is retained by the anchor element 30 which is in turn supported by the gripping means 8 of the inserting arm 6.

The cutting arm 7 includes a respective first end 7a fixed to a rear portion of the carriage 2 adjacent to the post 3 and a respective second end 7a to which the cutting plier 9 is fixed.

In the embodiment shown in the figures, the cutting arm 7 comprises a respective articulated arm, formed by a plurality of members rotatably and/or slidably connected to each other and having a plurality of degrees of freedom so as to be movable in different operating positions during the operation of the self-propelled wrapping machine 1. More precisely and as better illustrated in the following description, the cutting arm 7 can be moved between a cutting position T, in which the cutting plier 9 grasps and cuts the film 50 at the end of the load wrapping phase and retains the end flap 50b thus obtained (figure 10), an abutting position (not shown) wherein the cutting plier 9 presses and makes the end flap 50b of film adhere to the load 100, and a rest position C (figures 1-9, 11) wherein the cutting arm 7 is in a folded configuration adjacent to the carriage 2, in particular so as not to interfere with the wrapping of the film 50 around the load 100.

The magazine 5 comprises a compartment 15 suitable for housing a plurality of anchor elements 30, in particular arranged superimposed to form at least a substantially vertical stack or column, and provided with an access opening 16 which allows the gripping means 8 of the inserting arm 6 to grasp one of the anchor elements 30, in particular the one partially protruding from the access opening 16, for example provided on a lower portion of the magazine 5.

The carriage 2 comprises two or more drive wheels 21, a directional wheel 22 and guiding means 10 for guiding the self-propelled wrapping machine 1 along a wrapping path around the load 100. More precisely, the self-propelled wrapping machine 1 is provided with a pair of rear drive wheels 21 driven by motor means and a front directional wheel 22.

In the illustrated embodiment the guiding means 10 comprise a feeler arm 11, of a known type, arranged to follow an external profile of the load 100 during the wrapping phase and connected to the directional wheel 22 to steer the latter and move the carriage 2 along the wrapping path.

Alternatively, in a variant not shown of the self-propelled wrapping machine 1, the latter can comprise sensors capable of detecting external surfaces and edges of the load 100 and processing related signals and a control unit suitable for receiving the aforementioned signals from the sensors, calculating a wrapping path such as to avoid collisions with the load 100 and controlling the guiding means 10 so as to guide the self-propelled wrapping machine 1 along the wrapping path. In this variant, the guiding means 10 comprise actuating means controlled by the control unit and arranged to steer the directional wheel 22 or actuating means also controlled by the control unit and arranged to vary the speed of the drive wheels 21.

The unwinding unit 4 comprises frame means 13 adapted to support the reel 51 and the roller means 41, 42, 43 which are arranged to unwind the film 50 from the reel 51, pre-stretch it and divert it towards the load 100. More precisely, the roller means comprise a pair of pre stretching rollers 41, 42 and one or more guiding rollers 43. The pair of pre- stretching rollers comprises a first pre- stretching roller 41 and a second pre- stretching roller 42, rotating around respective longitudinal axes with different speeds so as to stretch or extend the film 50 during the unwinding from the reel 51 and before the wrapping on the load 100.

The unwinding unit 4 further comprises folding means 14 for transversely rolling and/or narrowing the film 50 exiting from the roller means 41, 42, 43 so as to reduce its width or band width and, in particular, make a film rolled portion or cord. Such cord is obtained by progressively rolling on itself at least one of the longitudinal flaps of the film, transversely to the unwinding direction. The film rolled-up as a cord can be more firmly grasped by the cutting plier 9 of the cutting arm 7 and therefore more easily cut to form the two rolled up initial and end flaps. Furthermore, the film rolled-up in a cord can be fixed more effectively to the hooking means 35 of the anchor element 30.

The folding means 14, of a known type and not described and illustrated in detail, comprise at least one folding element moved by respective actuating means transversely to a direction of unwinding of the film 50 so as to intercept and find a first longitudinal edge of the film 50 and to push it and roll it progressively towards an opposite second longitudinal edge of the film 50 thus forming a cord.

With particular reference to figures 12 to 14, each anchor element 30 has a cup or glass shape and comprises a bottom wall 31, for example slightly concave inside and circular in shape, to which a side wall 32 is connected, for example, of truncated cone shape, provided with a peripheral annular edge 33. The peripheral annular edge 33 is provided with an appendix or lateral extension 34 which can be grasped and held by the gripping means 8 of the inserting arm 6 to support the entire anchor element 30. The hooking means 35 comprise a first through opening 35a made on the side wall 32, on the side opposite to the lateral extension 34 and which extends from the peripheral edge 33, interrupting it, to the bottom wall 31, and a second through opening 35b which is made on the bottom wall 31 and connected to the first through opening 35a so as to form a single through opening suitable for receiving and retaining the initial flap 50a of film, preferably in the form of a cord. To facilitate the insertion and locking thereof, the first through opening 35a has decreasing width in the direction of the bottom wall 31 and similarly the second through opening 35b has decreasing width in the direction of the centre of the bottom wall 31 and forms in correspondence with the aforesaid centre a seat 35c suitable for housing and retaining the film.

It should be noted that the particular cup shape of the anchor element 30 allows not only an easy stacking of the anchor elements 30 inside the magazine 5, but also that the anchor element 30 can abut and engage the internal walls of the side opening 103 and/or of the longitudinal support 106 of the pallet 102 and remain locked and constrained to the latter when the film 50 is wrapped around the load 100. In a variant not shown, the anchor element 30 can also comprise hooking means which can be operated in opening so as to meet the inner walls of the side opening 103 and/or of the longitudinal support 106 of the pallet 102 when the anchor element 30 is released by the first gripping means 8 of the cutting arm 7.

The operation of the self-propelled wrapping machine 1 of the invention provides that it is previously brought closer to the load 100 to be wrapped in an operating configuration wherein the cutting arm 7 is in the folded position C and the inserting arm 6 is in the waiting position B wherein it is folded adjacent to the carriage 2 and supports an anchor element 30 to which the initial flap 50a of film is fixed (figure 11). The anchor element 30 was fixed to the initial flap 50a in a previous wrapping cycle at the end of the wrapping phase of the load, as it is explained in detail in the following description.

The self-propelled wrapping machine 1 in the above-mentioned configuration is activated, makes a turn around the load 100 and stops in a defined position, in particular at a longer side of the latter wherein the side openings 103 open.

The inserting arm 6 is then moved to the release position R wherein the anchor element 30 and the initial flap 50a of film fixed to it are inserted by the same inserting arm 6 under the pallet 102 through one of the side openings 103 of its long side. The gripping means 8 then release the anchor element 30 inside the side opening 103 and the inserting arm 6 is moved in the picking position A for grasping and taking a new anchor element 30 from the magazine 5. In the picking position A the inserting arm 6 is folded to allow the film 50 to be wrapped around the load 100, the gripping means 8 supporting the anchor element 30 extracted from the magazine 5.

The self-propelled wrapping machine 1 then begins the wrapping phase which involves its rotation around the load 100 with the unwinding unit 4 delivering and pre- stretching the film 50, moved with alternate motion along the post 3. With the movement of the self-propelled wrapping machine 1 around the load 100, the anchor element 30 is dragged and moved by the film 50 which is being wrapped inside the side opening 103 until it encounters and engages the internal walls of the latter and/or the relative longitudinal support 106, locking and fitting inside the pallet 102. The blocking of the anchor element 30 is more firm and stable as tensile strength exerted by the film 50 grows.

At the end of the wrapping phase, the film 50 is transversely shrunk and rolled by the folding means 14 so as to form a cord.

The self-propelled wrapping machine 1 is then stopped and the inserting arm 6 is moved to the insertion position F to secure the anchor element 30 to the portion of rolled film (cord). More precisely, the inserting arm 6 moves the anchor element 30 so that the cord is progressively inserted into the through openings 35a, 35b up to the seat 35c of the hooking means 35.

At this point the cutting arm 7 is moved to the cutting position T so that the cutting plier 9 can grasp and cut the film cord and make the two flaps, the initial flap 50a being fixed to the anchor element 30 supported by the inserting arm 6 and the end flap 50b being held by the cutting arm 7.

The latter is then moved to the abutment position in which the cutting plier 9 presses and leads the end flap 50b of film to adhere to the load 100.

Subsequently the inserting arm 6 and the cutting arm 7 are moved respectively to the picking position A and to the rest position C wherein the aforesaid arms are folded and adjacent to the carriage 2 so as not to interfere with the movements of the self-propelled wrapping machine 1 which, having finished wrapping the load 100 with the film, can be positioned at a new load 100 to be wrapped.

The self-propelled wrapping machine 1 of the invention therefore allows to wrap a load 100 with a film 50 completely automatically, that is, without requiring any manual intervention by the operator, either in an initial phase of the wrapping cycle, wherein it is required fixing an initial flap 50a of the film to the pallet 102, both in a terminal phase, wherein the film 50 must be cut and the film flaps retained.

The inserting arm 6 provided with the gripping means 8 in fact allows to insert an anchor element 30, to which the initial flap 50a of film has been previously fixed, in one of the side openings 103 of the pallet 102 inside which said anchor element 30 remains blocked or stuck due to its conformation.

Thanks to the firm and secure restrain of the initial flap 50a of the film to the pallet 102 it is therefore possible for the self-propelled wrapping machine 1 of the invention to achieve firm and stable windings.

Operations performed completely automatically by the self-propelled wrapping machine 1 are also those at the end of the wrapping cycle which provide the fastening of a new anchor element 30 to the portion of rolled film and cutting the latter to make the two flaps of film.