50 folded or rolled to form a cord or strip can be grasped more firmly by the second gripping means 8.

In particular, the folding means 13 comprise a linearly movable folding element 13a so as to abut transversely, in particular substantially orthogonally, one longitudinal edge of the film and push it, folding it and/or rolling it towards the opposite longitudinal edge. The folding means 13 further comprise a perforating element of known type and not illustrated in the figures, associated with the folding element 13a and intended to partially tear the film when said folding element 13a is moved, to facilitate the complete tearing of the film by the second gripping unit 7 at the end of the wrapping cycle.

The carriage 2 comprises two or more traction wheels, a directional wheel and guide means for guiding the self-propelled wrapping machine 1 along a wrapping path around the load 100. For example, the self-propelled wrapping machine 1 is provided with a pair of rear traction wheels, at least one of which driven by the motor means, and a front directional wheel.

In the embodiment the self-propelled wrapping machine 1 comprises sensors capable of detecting external surfaces and corners of the load 100 and processing related signals, and a control unit adapted to receive the aforementioned signals from the sensors, calculating a wrapping path such as to avoid collisions with the load 100 and controlling the guide means so as to guide the self-propelled wrapping machine 1 along the wrapping path. The guide means 10 comprise in particular driving means controlled by the control unit and arranged to steer the directional wheel or driving means also controlled by the control unit and arranged to vary the speed of the traction wheels.

Alternatively, the guide means 10 comprise a feeler arm, of known type, arranged to follow an external profile of the load 100 during the wrapping step and connected to the directional wheel to steer the latter and move the carriage 2 along the wrapping path.

The control unit of the self-propelled wrapping machine 1 is also arranged to command and control in a coordinated way the movement of the carriage 2 around the load 100, the dispensing of the film 50 from the unwinding unit 4, the movement thereof along the upright 3, the actuation of the gripping units 5, 7 in the different steps of the wrapping cycle.

The self-propelled wrapping machine 1 is also provided with sensor means, of the known type, for example comprising photocells or capacitive sensors, or the like, capable of detecting the overall dimensions and sizes of the load 100 and the distances between the latter and the self-propelled wrapping machine 1 during operation. The signals of the sensor means are sent to the control unit of the machine to allow the proper execution of the different steps of the wrapping cycle.

In operation, the self-propelled wrapping machine 1 of the invention performs wrapping cycle of the load 100 according to the following steps.

In a first initial step the self-propelled wrapping machine 1 is positioned adjacent to the load 100, and thus activated so as to move around the load 100 for at least one turn in order to calculate and identify a defined initial position W at the beginning of the wrapping cycle, for example at a side along the load 100 having a rectangular plan shape. More precisely, thanks to the sensor means which detect the overall dimensions and sizes of the load 100, the control unit is able to stop the self-propelled wrapping machine in the defined initial position W. The first gripping unit 5 is arranged in the retracted configuration R, in which the gripping means 6, 16 are capable of engaging and interacting with the anchoring element 30 positioned in the housing 22 of the supporting frame 20 of the carriage 2. More precisely, in such a retracted configuration R of the first gripping unit 5, the first arm 15 is arranged in the retracted angular position R and in the first lowered linear position D1 so that the first gripping means 6 abut the upper plate 32 and the second gripping means 16 do not abut the intermediate plate 36. In such a configuration, the initial flap 50a of film unwound from the reel 51, for example obtained by cutting the film 50 at the end of a previous wrapping cycle, is locked between the locking element 35 and the base 33 of the anchoring element 30 arranged abutted in the closed configuration C. As explained above, when the anchoring element 30 is released and disengaged from the first or second gripping means 6, 16 or when it is gripped and lifted by the first gripping means 6 acting on the upper plate 32, the locking element 35 is brought and/or kept abutting the base 33 by the force of gravity acting thereon so as to lock and retain the initial flap 50a of film.

In a second step, the electromagnetic means of the first gripping means 6 are operated so as to interact with the upper plate 32 and grasp the anchoring element 30 and the first gripping unit 5 is moved from the retracted configuration R to the gripping/releasing configuration G, in which the supporting end 15a of the first arm 15 is adjacent to the load 100 and to the supporting plane P to release on the latter the anchoring element 30 to which the initial flap 50a of film is fastened.

More in detail, the electromagnet means of the first gripping means 6 are activated so as to grasp and lock the upper plate 32 of the anchoring element 30 and the first arm 15 is moved by the second driving means 25 along the first movement direction V1 from the first lowered linear position D1 to the raised linear position S so as to lift the anchoring element 30 from the housing 22.

The first arm 15 is then moved by the first driving means 24 between the retracted angular position F and the extended angular position E and then again moved by the second driving means 25 along the first movement direction V1 from the raised linear position S to the second lowered linear position D2 to deposit the anchoring element 30 on the supporting plane P.

In a third step, the anchoring element 30 retaining the initial flap 50a of film is released from the first gripping unit 5. More precisely, the electromagnet means of the first gripping means 6 are deactivated to allow their disengagement from the upper plate 32 and the first arm 15 is rotated away to also disengage the second gripping means 16 from the anchoring element 30 and thus lifted.

The first gripping unit 5 disengaged from the anchoring element 30 is brought from the gripping/release configuration G to the retracted configuration R.

In a fourth step, the self-propelled wrapping machine 1 is moved around the load 100 for at least one turn so as to wrap the latter with the film 50 dispensed from the unwinding unit 4. The film 50, whose initial flap 50a is fixed to the anchoring element 30, is thus wrapped, and adheres and fastens firmly to the load 100. The film 50 is dispensed from the unwinding unit 4 at full height, i.e., not rolled or narrowed transversely.

In a fifth step, the self-propelled wrapping machine 1 is stopped in the defined initial position W.

Preferably before the stop of the self-propelled wrapping machine, the folding means 13 are operated to narrow and/or roll the film so as to form a stretch of reduced height at the anchoring element 30.

The first gripping unit 5 is then moved from the retracted configuration R to the gripping/release configuration G to grip and lift the anchoring element 30 from the supporting plane P. More precisely, in the extended angular position E and in the second lowered linear position D2 of the first arm 15 the electromagnet means of the first gripping means 6 are activated so as to engage and lock the upper plate 32. Thereby, the locking element 35 and the base 33 remain abutted in the closed configuration C continuing to lock the initial flap 50a of film.

The first gripping unit 5 then lifts the anchoring element 30 from the supporting plane P, which still locks and retains the initial flap 50a of film. More precisely, the first arm 15 is moved by the second driving means 25 along the first movement direction V1 from the second lowered linear position D2 to the raised linear position S, in particular to a greater height of the restricted/rolled stretch of film comprised between the unwinding unit 4 and the load 100.

In a sixth step the first gripping unit 5 is moved in rotation towards the carriage 2 by a defined stretch so that the anchoring element 30 passes the portion of the film comprised between the load 100 and the unwinding unit 4 and the initial flap 50a of film can be released and can fall back on the portion of the film. More precisely, the first arm 15 is rotated by the first driving means 24 from the extended angular position E towards the retracted angular position R by a defined stretch and then stopped.

The electromagnet means of the first gripping means 6 are deactivated and the anchoring element 30 released by the latter is engaged and supported by the second gripping means 16. More precisely, the fork element 16 underlying the electromagnet means of the first gripping means 6 receives and engages the intermediate plate 38 when the anchoring element 30 detaches from the first gripping means 6. Thereby, as shown in FIG. 14, while the anchoring element 35 is supported by the fork element 16, the base 33 with the upper plate 32 is free to slide downwards by virtue of the force of gravity and detach from the locking plate 36 in the open configuration A.

The initial flap 50a of film thus released and disengaged from the anchoring element 30 can fall back, depositing on the underlying portion of the film comprised between the load 100 and the unwinding unit 4.

It is also possible, before moving the first gripping unit 5 in rotation by a defined stretch towards the carriage 2, to move the self-propelled wrapping machine 1 around the load 100 by a respective defined stretch to increase the length of the restricted portion of film between the load 100 and the unwinding unit 4 and lift the latter, moving it along the upright 3 to decrease a distance between the first gripping unit 5 and the underlying portion of film to ensure that the initial flap 50a of film falls thereon once released.

In a seventh step, the first gripping unit 5 transfers and positions the anchoring element 30 in the housing 22 of the supporting frame 20 of the carriage 2. For this purpose, the first arm 15 is rotated by the first driving means 24 in the retracted position F and is then moved along the first movement direction V1 by the second driving means 25 from the raised position S to the first lowered position D1 to deposit the anchoring element 30 in the housing 22. In such a first lowered position D1 the anchoring element 30 is positioned in the housing 22 disengaged from the first and the second gripping means 6, 16 and thus with the locking plate 36 and the base 33 abutting in the closed configuration C.

In an eighth step, the self-propelled wrapping machine 1 is activated again to move around the load 100 for a defined number of turns so as to wrap the latter with the film 50 according to a defined wrapping configuration.

The initial flap 50a of film that was arranged transversely above the portion of the film comprised between the load 100 and the unwinding unit 4, substantially “straddling” such portion is thus fixed to the nearest wall of the load 100, in particular wrapped and covered by one or more bands of film 50 superimposed thereon. Thereby, advantageously the initial flap 50a of film completely adheres to the load, covered by other bands of film, and does not remain exposed and lying on the supporting plane P.

The wrapping step envisages, during the rotation of the carriage 2 around the load 100, moving the unwinding unit 4 with alternate motion along the upright 3 and the simultaneous dispensing of the film 50, possibly pre-stretched or lengthened from the unwinding unit 4. During the wrapping of the load 100, in particular when the unwinding unit 4 is lifted and farther from the supporting plane P, the second gripping unit 7 is moved by the third driving means 26 from the transfer position T to the gripping position B.

In a ninth step, at the end of the wrapping, the self-propelled wrapping machine 1 is stopped in a defined final position Z, possibly coincident with the initial position W, and the second gripping unit 7 is operated to grasp a portion of the film 50 comprised between the unwinding unit 4 and the load 100, stretch it and then shear it so as to make a new initial flap 50a of film retained by the same second gripping unit 7 and a final flap or end 50b of film associated with the load 100.

Before moving the second gripping unit 7, the folding means 13 of the unwinding unit 4 are operated to roll and/or transversely narrow the film 50 and at the same time partially tear it. For this purpose, during the descent of the folding element 13a, which engages and pushes for example an upper longitudinal edge of the film 50 towards the lower longitudinal edge, the perforating element is activated to intercept and tear the film. The film 50 is transversely narrowed in width and partially torn so as to be grasped and held more firmly by the second gripping means 8 of the second gripping unit 7 and more easily completely torn from the latter.

At the same time, the first arm 15 of the first gripping unit 5, arranged in the retracted angular position F and in the first lowered linear position D1, is moved along the first movement direction V1 by a defined section upwards so that the second gripping means 16 are capable of abutting and then lifting the intermediate plate 38 of the locking element 30 and the locking plate