A converter having a converter base part, a bolt connected to the converter base part, a tensioning element and at least one piezo element with a through-opening, the bolt penetrating the through-opening and the tensioning element tensioning the at least one piezo element in the direction of the converter base part, wherein that the bolt is connected to the converter base part in a material bond.

Methods of mitigating current overload of an ultrasonic system having an ultrasonic stack under load at startup are provided. The methods include beginning an ultrasonic cycle in the ultrasonic system having the ultrasonic stack that runs a closed loop phase control through the weld cycle by ramping up the power of the ultrasonic stack under load. During ramping up of the power of the ultrasonic stack under load, a controller lowers the phase to a negative phase. After ramping up the power of the ultrasonic stack under load is complete, the controller raises the phase to 0 degrees and the ultrasonic stack is operating at steady state and with the phase at 0 degrees.

Methods and devices are described for driving ferroelectric perovskite oxide crystals to achieve polarization inversion with reduced coercivity. In some embodiments, the anisotropy in the potential energy surface of a ferroelectric material is employed to drive polarization inversion and switching with a reduced coercive field relative to uniaxial excitation. In some embodiments, polarization inversion with reduced coercivity is produced via the application of an electric field that exhibits a time-dependent orientation, in contrast with conventional uniaxial electrical excitation, thereby causing the central ion (and the crystal structure as a whole) to evolve along a lower-energy path, in which the central ion is driven such that it avoids the potential energy maximum. This may be achieved, for example, by applying at least two non-parallel time-dependent voltages (e.g. bias, potential) such that orientation of the electric field changes with time during the switching cycle.

There is disclosed a sonotrode comprising: a head which defines a sealing surface elongated along a first direction orthogonal to a second direction and at least one first slot which extends through the head transversally to the first direction; the first slot extends parallel to a third direction inclined to both the first direction and the second direction; the first direction defines an acute angle with the second direction.

The present invention relates to a method for determining at least one physical characteristic value of an electromechanical oscillatory system, which comprises a piezoelectric element and at least one additional element coupled, with respect to oscillation, to the piezoelectric element, the piezoelectric element having an electrode and a counter electrode. The method comprises the following steps: (a) applying an electrical alternating voltage between the electrode and the counter electrode for the duration of an excitation interval in order to induce mechanical oscillation of the oscillatory system or of a sub-system of the oscillatory system, so that after the excitation interval has expired, the oscillatory system or the sub-system performs a free oscillation without excitation, (b) after the end of the excitation and during the free oscillation of the oscillatory system or of the sub-system without excitation: (i) measuring a time curve of a voltage U between the electrode and the counter electrode, or (ii) short-circuiting the electrode and the counter electrode with a line and measuring a time curve of a current I through the line, and (c) determining the at least one physical characteristic value of the electromechanical oscillatory system from the time curve of the voltage U, which time curve was measured in step b) i), or the time curve of the current I, which time curve was measured in step b) ii).

An ultrasonic horn is provided with: a vibration generating unit configured to generate longitudinal vibration having a frequency in the ultrasonic band on the basis of a signal having a frequency in the ultrasonic band input from an oscillator; a vibration amplifying unit configured to amplify the vibration generating unit while transmitting the longitudinal vibration from the vibration generating unit; and a longitudinal-torsional vibration conversion slit unit having slits formed in a groove-like shape on the surfaces of the vibration amplifying unit and configured to convert the longitudinal vibration into torsional vibration. The vibration amplifying unit has a polygonal shape in a plane view, and has a plurality of surfaces provided with slits along with a surface not provided with slits.

The particle impregnating device includes a placing body for placing a nonwoven fabric having a surface on which particles are sprayed; a vibrating member which is provided above the placing body and extends in the width direction of the nonwoven fabric placed on the placing body; a vibrator which applies ultrasonic vibration to the vibrating member; a lifting mechanism which lifts up and down the vibrating member; and a moving mechanism which relatively moves the nonwoven fabric and the vibrating member in a surface direction orthogonal to the width direction of the nonwoven fabric. When the nonwoven fabric and the vibrating member are relatively moved by the moving mechanism, the vibrating member is lowered by the lifting mechanism, so that the nonwoven fabric is pressed and compressed by the vibrating member and ultrasonic vibration is applied to the vibrating member by the vibrator.

A novel mode of ultrasonic oscillation is generated in a Langevin ultrasonic transducer comprising a metal block, a metal block provided with a supporting means protruding in a ring shape on its side surface, and polarized piezoelectric elements fixed between these metal blocks, by connecting the ultrasonic transducer to a base via the supporting means, whereby supporting the ultrasonic transducer on the base in a restrained state, and applying to the piezoelectric elements a voltage having such frequency that the ultrasonic transducer generates an ultrasonic oscillation with back-and-forth motion in a direction perpendicular to plane surfaces of the piezoelectric elements which has no oscillation node within the ultrasonic transducer; this novel ultrasonic oscillation mode is utilized for performing ultrasonic machining methods as well as for ultrasonic transmission method.

An ultrasonic tool comprising a first end face and a second end face, which is opposite the first end face, as well as a tool cover surface connecting the first end face and the second end face, wherein the ultrasonic tool is elongated in a longitudinal direction of the tool, wherein at least the first end face is formed as a connecting contact surface, which is arranged for pressing the ultrasonic tool against a connecting component, and wherein the ultrasonic tool comprises an end region comprising the connecting contact surface, which extends from the connecting contact surface in the longitudinal direction of the tool over 15 mm, but at most extends one third of the length of the ultrasonic tool in the direction of the opposite end face, and wherein in the end region, a first partial surface of the tool cover surface is formed as a surface-structured absorption surface.

To provide a vibration conversion apparatus capable of reducing occurrence of cracks although using a longitudinal vibration converter for obtaining a torsional vibration. The vibration conversion apparatus comprises: a first longitudinal vibration converter and a longitudinal-torsional transducer having a one-wavelength torsional vibrator portion and a first flexural resonator portion. The first flexural resonator portion is interposed between the first longitudinal vibration converter and the one-wavelength torsional vibrator portion. The first flexural resonator portion is configured such that when a longitudinal vibration generated by at least the first longitudinal vibration converter is received from one end of the first flexural resonator portion, the first flexural resonator portion is bent and imparts a rotational force from the other end of the first flexural resonator portion to the one-wavelength torsional vibrator portion.