Patent ID: 8734144

Claim:
A device for selectively depositing molten plastic materials comprising a support ( 3 ), an ultrasonic transducer ( 1 ), a sonotrode ( 2 ), a nozzle ( 4 ), integral at an end part of said sonotrode ( 2 ), opposite to the transducer, and a melting chamber ( 5 ) in communication with a deposition outlet ( 4 a ) through a discharging channel ( 6 a ) wherein: said melting chamber ( 5 ) is placed at the end part of said sonotrode; an internal channel ( 6 ) is provided extending at least in part through said sonotrode allowing the passage of plastic material in solid state (F) fed therethrough towards said melting chamber ( 5 ); wherein: a) said internal channel ( 6 ) has a cross section that allows a loose passage of said plastic material in solid state (F); b) said internal channel ( 6 ) extends along a section with a progressive reduction of its clearance area through a truncated conical section providing said discharging channel ( 6 a ) leading to said deposition outlet ( 4 a ) and containing within said melting chamber ( 5 ); c) the angle of said truncated section is chosen in order that the plastic material in solid state (F) reaches a point of the interior wall of said frustum conical section in the proximity of said deposition outlet ( 4 a ); d) said melting chamber ( 5 ) of a truncated cone shape extends from the point of contact of the plastic material in solid state (F) with the interior wall of the conical section to approximately said deposition outlet; and e) at least two longitudinal profiles or ribs ( 10 ), located as a cone generator and angularly offset are protruding from said interior wall of the conical section corresponding to the melting chamber ( 5 ) area, having a multifaceted end ( 11 ) facing and opposed to an entrance to said melting chamber ( 5 ), so that that said melting chamber ( 5 ) is located at the end part of the sonotrode itself ( 2 ).