Ultrasonic head and transducer for ultrasonic soldering of plastics

A head for the ultrasonic welding of plastics of the type comprising an ultrasonic transducer provided to generate a vibration at a predetermined ultrasonic frequency, to which there is coupled or joined least one end part forming or including at least one sonotrode, said end part and said ultrasonic transducer being sized, depending on the respective materials from which they are manufactured, so that they resonate at said predetermined ultrasonic frequency, vibrating such that they transmit a vibration of one wavelength or of a multiple of one wavelength, said end part being provided to vibrate at said predetermined ultrasonic frequency according to a direction which can be oriented in relation to a working surface where there are plastics to be welded arranged under a free end of said end part, which is at least one in number, said head having a connection to an external cooling fluid source, said end part internally defining at least one first conduit running through the inside of at least part of the end part, through the inside of which said cooling fluid circulates, and which exits to the exterior through at least said free end so that the cooling fluid circulating therethrough is projected at least onto the welding area of said plastics, wherein said head comprises a second conduit communicating said first conduit with said connection, the inlet of said second conduit being arranged at a distance from the free end of the end part, taken according to an axis defining said vibration direction, greater than length of said end part or from an end segment or sector of said end part provided to vibrate such that it transmits a vibration of one wavelength at said predetermined ultrasonic frequency.