Abstract: Large vibration tool, vibrating at ultrasonic frequency, especially for applications in the welding, joining or cutting of materials, especially thermoplastics, in cleaning or emulsifying by the activation of a liquid medium, in gas spraying or in shot blasting by blasting any kind of medium, made in the form of a circular sonotrode hollowed out at its center so as to produce a cavity allowing a shape approaching that of a bell to be obtained, said tool having a linking mass providing surface coupling with a vibrational excitation element; at least one circular membrane vibrationally excited at its center or at one end; and at least one tube-shaped final element, the end of which defines the working area of the sonotrode, linked to the linking mass via the said membrane, the latter transmitting the vibration to the said final element whose length is defined by a longitudinal vibration mode tuned to the said excitation frequency.

Abstract: A compound sonotrode for an ultrasonic welding tool includes a carrier block or adaptor mounted on an ultrasonic machine, and secondary sonotrodes or concentrators fixed to the carrier block by pins tuned to the resonance frequency of the assembly, so as not to disturb the vibratory mode of operation of the compound sonotrode.