Automatic device for strapping bales in fibrous material and automatic method for strapping bales in fibrous material

A system for making bales of fibrous material comprising a bale press for bales of fibrous material associated with an automatic strapping device configured to tie a plurality of straps around a pressed bale formed and pressed by the bale press, wherein said automatic strapping device comprises:

• a launching and welding assembly adapted to be arranged at a first side of said bale press, said launching and welding assembly comprising a plurality of launching and welding heads arranged side by side along an axis parallel to said first side of said bale press and orthogonal to a pressing direction of a first pressing plate of said bale press, each of said launching and welding heads comprising:
• a first launching and blocking unit configured to receive and block a portion of a strap from a feeding assembly and to wind said portion of said trap around said pressed bale;
• a second launching and blocking unit configured to receive, move and block a first end of said portion of said strap following the winding by said first launching and blocking unit;
• a welding unit configured to join said first end and a second end of said portion of said strap following their overlapping actuated by a joint action of said first launching and blocking unit and of said second launching and blocking unit, said welding unit being interposed between said first launching and blocking unit and said second launching and blocking unit;
• a first arched channel and a second arched channel which develop respectively from said first launching and blocking unit and from said second launching and blocking unit, on opposite sides of said welding unit, in a direction of said bale press;
• said launching and welding assembly being configured to assume, with respect to said bale press, when arranged at said first side of said bale press, at least a first position according to which said first arched channel and said second arched channel of each of said launching and welding heads are at least partially inserted in relative through grooves defined respectively along the first pressing plate and a second pressing plate of said bale press;
• a rear assembly adapted to be arranged at a second side of said bale press, opposite to said first side, said rear assembly being provided with a plurality of third arched channels equal to a number of said plurality of launching and welding heads, said rear assembly being configured to assume, with respect to said bale press, when arranged at said second side, at least a first position according to which each of said third arched channels has each of its ends at least partially inserted in said through grooves;
• when said rear assembly and said launching and welding assembly are arranged in the relative first positions with respect to said bale press, each of said launching and welding heads is coupled to one of said third arched channels so as to define a strapping path around said pressed bale;
• said feeding assembly is a single feeding assembly configured to be moved with respect to said launching and welding assembly along an axis, parallel to said first side of said bale press and orthogonally to said pressing direction of said bale press, so that said feeding assembly can be selectively arranged at each of a plurality of inlet ducts of each of said launching and welding heads to feed each of said launching and welding heads with a portion of a strap of predefined length and which is different from or equal to the lengths of the portion of straps supplied to the other launching and welding heads.