Abstract: A DC switching device has at least one switching unit which is arranged between two terminals. Further, the DC switching device has a control unit for controlling the at least one switching unit. The switching unit has a first and a second semiconductor switching element, which are arranged in parallel with one another, the first switching element being a high-voltage switching element and the second switching element being a low-power-loss switching element. The switching unit is controllable by the control unit in such a way that, when the switching unit is switched off, initially the second switching element is switched to be non-conductive, and subsequently the first switching unit is switched to be non-conductive, and when the switching unit is switched on, initially the first switching element is switched to be conductive and subsequently the second switching element is switched to be conductive.

Abstract: A DC switching device has at least one switching unit which is arranged between two terminals. Further, the DC switching device has a control unit for controlling the at least one switching unit. The switching unit has a first and a second semiconductor switching element, which are arranged in parallel with one another, the first switching element being a high-voltage switching element and the second switching element being a low-power-loss switching element. The switching unit is controllable by the control unit in such a way that, when the switching unit is switched off, initially the second switching element is switched to be non-conductive, and subsequently the first switching unit is switched to be non-conductive, and when the switching unit is switched on, initially the first switching element is switched to be conductive and subsequently the second switching element is switched to be conductive.

Abstract: A drive system for a helicopter includes a main drive for driving a rotor the helicopter, a flywheel mass battery including at least one flywheel, a first transmission coupling the flywheel mass battery with the main drive such that, during operation of the main drive, output can be transferred from the main drive to the flywheel mass battery, and a second, variable transmission connecting the flywheel mass battery to the rotor of the helicopter such that a predetermined output can be transferred to the rotor through adjustment of a transmission ratio of the variable transmission.

Abstract: A drive system for a helicopter includes a main drive for driving a rotor the helicopter, a flywheel mass battery including at least one flywheel, a first transmission coupling the flywheel mass battery with the main drive such that, during operation of the main drive, output can be transferred from the main drive to the flywheel mass battery, and a second, variable transmission connecting the flywheel mass battery to the rotor of the helicopter such that a predetermined output can be transferred to the rotor through adjustment of a transmission ratio of the variable transmission.

Abstract: A rotor blade comprises an inner rotor blade root area, a rotor blade main area disposed adjacent to the inner rotor blade root area along a length of the rotor blade and having an aerodynamically effective rotor blade profile, the profile including a nose area and a rear edge area, and a rotor blade tip disposed adjacent to the rotor blade main area along the length of the rotor blade. The rotor blade tip is configured to be deformable relative to the rotor blade main area and is operatively connected to a first actuator device. The first actuator device is configured to initiate a vertical movement of the rotor blade tip upwards or downwards relative to the lift direction. The vertical movement starts from a neutral position relative to the rotor blade main area.

Abstract: A friction-welding device for the integral joining of components, having an oscillator, which generates a periodic movement of a component and a welding surface provided thereon relative to another, static component and a welding surface provided thereon, with directions of movement parallel to the welding surfaces, having a compression device which presses the welding surfaces together, and a cartridge which accommodates the moved component. The oscillator includes two or a greater, even number of piezoactuators, which are arranged in pairs on a line of application and are able to be prestressed with respect to the cartridge from opposite sides under pressure generation and are able to be moved in a synchronous, oscillating manner together therewith and the component.

Abstract: A deformable aerodynamic profiled member has a front profile area and a rear profile area in the outflow area. It is bounded by shells on the pressure side and/or on the suction side, converging in a rear profile edge (6). D33 piezo actuators are provided in at least some locations for deformation of the profiled member. The piezo actuators are aligned such that their length changes essentially in the direction of the planes of the shells when acted upon by electricity.

Abstract: A rotor blade comprises an inner rotor blade root area, a rotor blade main area disposed adjacent to the inner rotor blade root area along a length of the rotor blade and having an aerodynamically effective rotor blade profile, the profile including a nose area and a rear edge area, and a rotor blade tip disposed adjacent to the rotor blade main area along the length of the rotor blade. The rotor blade tip is configured to be deformable relative to the rotor blade main area and is operatively connected to a first actuator device. The first actuator device is configured to initiate a vertical movement of the rotor blade tip upwards or downwards relative to the lift direction. The vertical movement starts from a neutral position relative to the rotor blade main area.

Abstract: A piezoelectric expansion actuator for d33 piezoelements, which allows vibrations in structures to be suppressed. An expansion actuator (1) includes a piezoelectric stack (2), which consists of d33 piezoelectric elements and is arranged between output elements (4), which are attached to the surface of the structure (7). The invention applies to a piezoelectric extension actuator, which is used to control vibrations in structures. Alternatively, in order to damp vibrations between the main gearbox of a helicopter rotor and the cellular structure of the cockpit, a power application point of the output element (18, 19, 180, 190; 35, 36) is arranged at a distance from the corresponding end plate of the piezoelectric stack (22, 220; 31, 32, 33) in the axial direction (X).

Abstract: A friction-welding device for the integral joining of components, having an oscillator, which generates a periodic movement of a component and a welding surface provided thereon relative to another, static component and a welding surface provided thereon, with directions of movement parallel to the welding surfaces, having a compression device which presses the welding surfaces together, and a cartridge which accommodates the moved component. The oscillator includes two or a greater, even number of piezoactuators, which are arranged in pairs on a line of application and are able to be prestressed with respect to the cartridge from opposite sides under pressure generation and are able to be moved in a synchronous, oscillating manner together therewith and the component.

Abstract: A deformable aerodynamic profiled member has a front profile area and a rear profile area in the outflow area. It is bounded by shells on the pressure side and/or on the suction side, converging in a rear profile edge (6). D33 piezo actuators are provided in at least some locations for deformation of the profiled member. The piezo actuators are aligned such that their length changes essentially in the direction of the planes of the shells when acted upon by electricity.

Abstract: The invention relates to a linear, hydraulic pivot drive, especially for the flap control system of aerodynamic structures. Said pivot drive comprises a housing provided with ports for introducing a hydraulic medium, a piston which is arranged inside the housing and can be axially displaced by the effect of the hydraulic medium, and an output shaft which is provided with coarse threads and interacts with the piston in order to cover the axial displacement of the piston into a rotational movement. The invention is characterized in that the output shaft is integrated into the piston, the coarse threads running in the same direction and engaging in the piston, and the cross-section of the piston has a spline profile for effectively preventing a rotational movement of the piston.

Abstract: The invention relates to a linear, hydraulic pivot drive, especially for the flap control system of aerodynamic structures. Said pivot drive comprises a housing provided with ports for introducing a hydraulic medium, a piston which is arranged inside the housing and can be axially displaced by the effect of the hydraulic medium, and an output shaft which is provided with coarse threads and interacts with the piston in order to cover the axial displacement of the piston into a rotational movement. The invention is characterized in that the output shaft is integrated into the piston, the coarse threads running in the same direction and engaging in the piston, and the cross-section of the piston has a spline profile for effectively preventing a rotational movement of the piston.

Abstract: It is the object of the invention to create a piezoelectric expansion actuator for d33 piezoelements, which allows vibrations in structures to be suppressed. This object is achieved pursuant to a solution of the invention in that the expansion actuator (1) comprises a piezoelectric stack (2), which consists of d33 piezoelectric elements and is arranged between output elements (4), which are attached to the surface of the structure (7). The invention applies to a piezoelectric extension actuator, which is used to control vibrations in structures.

Abstract: A piezoelectric actuating device for controlling a flap on a rotor blade of a helicopter includes a piezo element arrangement including at least one piezoelectric stack actuator. A power transmission frame is coupled to the piezo element arrangement, the power transmission frame including an abutment and a driven element and generating a force therebetween from a change in length of the piezo element arrangement upon an excitation thereof, the force acting transversely to a direction of a centrifugal force of the rotor blade. A first holding device is provided including a pair of first flexible straps configured to fix the power transmission frame relative to the rotor blade in the direction of the centrifugal force and to allow the power transmission frame to move relative to the rotor blade transversely to the direction of the centrifugal force within a limited range.

Abstract: The invention relates to a piezoelectric actuating device for controlling the flaps on the rotor blade of a helicopter. The inventive device comprises a piezo element arrangement (2) and a power transmission frame (10) which is coupled therewith, is fixed to the rotor blade and generates a force between an abutment (14) and a driven element (13) by changing the length of the piezo element arrangement (2). Said force is effective crosswise in relation to the direction of the centrifugal force of the rotor blade. According to the invention, a first holder (11, 12) which fixes the power transmission frame (10) to the rotor blade in the direction of the centrifugal force and is flexible crosswise in relation to the direction of the centrifugal force and a second holder (15, 16) which fixes the abutment (14) that is provided on the power transmission frame (10) crosswise in relation to the direction of the centrifugal force and is flexible in the direction of the centrifugal force are provided.

Abstract: A ligand layer on a metal surface is capable of being reversibly switched between adhesion and deadhesion. The ligand layer includes substituted pyridine dimers and/or pyridine trimers which are selected from the group consisting of: with R1 through R6 being able to be equal or different and being selected from the group consisting of —R—CH(O)CH2, OH, —O—R, NR2, NHR, NH2, CO2H, CO2R, R and H. R is selected from the group consisting of alkyl and aryl residues with the proviso that not all residues R1 through R6 are hydrogen atoms at the same time. R7 is selected from the group consisting of —R—CH(O)CH2, OH, —O—R, NR2, NHR, NH2, CO2H, CO2R, CONHR, R and H, with R being selected from the group consisting of alkyl and aryl residues. Y is selected from the group consisting of silicon, carbon, nitrogen, phosphorus and oxygen atoms, and X is an oxygen, sulfur or phosphorus atom, and n having the value 0 or 1.

Abstract: Body or structural noise transmitted through a connector such as a strut, that connects a noise source, such as an engine, to an enclosure, such as a passenger cabin or cell of a helicopter, is suppressed by at least one piezoactuator which is excited to counteract any vibrations of the strut caused by body noise so that body noise vibrations are cancelled or at least substantially suppressed. The excitation of the piezoactuator is controlled in closed loop fashion in response to feedback signals from a sensor secured to the connector.

Abstract: A method for reversibly switchable cross-linking of monomers includes cross-linking the monomers by adding complexable metal ions to form a polymer, and bond-breaking the polymer formed by applying a direct voltage, by changing the pH value or by changing the temperature. The monomers include compounds of the general formulas R1 through R6 may be equal or different and are selected from the group consisting of H, OH, —NX2, —OX, —SH, and —SX, with X being selected from alkyl and/or aryl groups which are terminally substituted by reactive residues selected from the group consisting of OH, —CH(O)CH2, —NCO, —COOH and NZ2. Z is selected from the group consisting of alkyl groups, aryl groups and a hydrogen atom, one of the groups Z being a hydrogen atom with the proviso that not all residues R1 through R are hydrogen atoms at the same time.

Abstract: A piezoelectric actuator has at least two piezoelectric actuator elements connected in series with each other mechanically and electrically and form a half bridge in an amplifier bridge circuit having a further half bridge formed by two series connected electronic switches which are operated or clocked by a control circuit such as a pulse modulator circuit for periodically energizing the piezoelectric actuators in push-pull fashion. A choke (22) is connected between the junction point (JP1) of the two piezoelectric actuators and the junction point (JP2) between the two electronic switches (23, 24) for assuring a loss free reverse charging of the two piezoelectric actuators functioning as electrical capacitors in the energizing bridge circuit (21). The choke 22 functions as an energy storage and the stored energy is used in the push-pull charging of the capacitors (19, 20) formed by the piezoelectric elements.