Abstract: An apparatus for protecting an electrical network of an aircraft includes a power switch, an activation means coupled with the power switch, and a detection circuit connectable to the electrical network for detecting a voltage. The detection circuit is coupled with the activation means. The activation means is adapted for opening the power switch once the detected voltage is lower than a predetermined voltage. This is particularly advantageous for high voltage direct current networks temporarily, primarily or permanently powered by a fuel cell system.

Abstract: The invention relates to an air volume flow and pushing force control device for a vacuum cleaner that has at least a motor, a dust receptacle and a suction nozzle, comprising a controller for controlling the motor power, a first sensor for detecting the air volume flow, which in conjunction with the controller forms a first control loop in order to maintain the air volume flow at a prescribed air volume flow value on the basis of the signal of the first sensor. The control device further comprises a second sensor for detecting a pushing force that is required for pushing the suction nozzle, and in conjunction with the controller, forms a second control loop in order to maintain the pushing force below a prescribed value on the basis of the signal of the second sensor, and a control loop selection device that activates one of the two control loops as a function of the signals of the two sensors.

Abstract: The invention relates to a method and a device for a concentrator/solar collector for splitting solar radiation into various spectral colours by means of colour-selective mirrors, and for concentrating the same onto a plurality of semiconductor-photovoltaic cells optimised for various light colours. The inventive device is used to convert the energy of the solar radiation into an electrical current and heat with a high efficiency.

Abstract: The invention relates to an apparatus for power control by phase gating of an AC voltage, which supplies an electrical load (14), and for reduction of harmonics which are created by the phase gating, in particular up to a region of 4 kHz, preferably in the region of the third harmonic, having a first circuit element (12) (TRIAC) which is connected in series with the load (14) and is driven by a control device (20) in order to carry out phase gating. The apparatus is distinguished in that a second circuit element (34) is provided in series with a resistance element (32), with the series circuit being arranged in parallel with the first circuit element (12) and with the control device (20) being designed such that it drives the second circuit element (34) shortly before the first circuit element (12) and switches it to the on state for a short time period. The invention also relates to a method for harmonic reduction in the range up to 4 kHz, preferably of the third harmonic, for power control by phase gating.

Abstract: An apparatus for controlling the power of an AC voltage supplying an electrical consumer (14) by phase control and for reducing harmonics caused by said phase control, particularly within a range of 4 kHz, preferably within a range of the third harmonic, comprising a first switching element (12) (TRIAC) connected in series with the consumer (14) and driven by a control device (20) for performing a phase control. A second switching element (34) connected in series with a resistor element (32) is provided in parallel to the first switching element (12). The control device (20) is adapted to drive the second switching element (34) shortly before the first switching element (12) into its conducting state for a short time period.

Abstract: The invention relates to an apparatus for power control by phase gating of an AC voltage, which supplies an electrical load (14), and for reduction of harmonics which are created by the phase gating, in particular up to a region of 4 kHz, preferably in the region of the third harmonic, having a first circuit element (12) (TRIAC) which is connected in series with the load (14) and is driven by a control device (20) in order to carry out phase gating. The apparatus is distinguished in that a second circuit element (34) is provided in series with a resistance element (32), with the series circuit being arranged in parallel with the first circuit element (12) and with the control device (20) being designed such that it drives the second circuit element (34) shortly before the first circuit element (12) and switches it to the on state for a short time period. The invention also relates to a method for harmonic reduction in the range up to 4 kHz, preferably of the third harmonic, for power control by phase gating.

Abstract: The invention relates to a headrest (10) for a motor-vehicle seat that is fixed on the backrest of a vehicle seat by means of at least one support rod and that has a head cushion (13), the headrest being provided with a base element (15) on which the support rod (11) is provided. Object of the invention is to provide a headrest (10) that allows movable adaptation to the adjustment and equipment requirements of the individual vehicle types. A solution to this object is provided by the fact that the base element (15) has holding means (16, 17, 18, 23, 32, 33, 44) that are independent of each other and can be optionally used in a module-like manner for a respective application which allow the mounting of supporting elements for the connecting element (11a, 11b) as well as the mounting of adjusting elements (22, 34, 35), in particular for the vertical, horizontal and angle adjustment.

Abstract: The invention relates to thermal energy converters and a method for increasing the efficiency thereof. Said method is based on thermodynamic phase transformation of some solid materials within a very narrow temperature range, e.g. the shape memory effect (SME) or the magnetocaloric effect (MCE). According to the invention, a gradient-type shift of the transformation temperature is set in a fixed manner along the axis of thermal flow by modifying the material properties, and the partial segments having a higher transformation temperature are arranged on the hot side while the partial segments having a lower transformation temperature are arranged on the cold side, said arrangement being as linear as possible or finely graduated.

Abstract: The present invention relates to an apparatus for controlling the power of an AC voltage supplying an electrical consumer (14) by phase control and for reducing harmonics caused by said phase control, particularly within a range of 4 kHz, preferably within a range of the third harmonic, comprising a first switching element (12) (TRIAC) connected in series with said consumer (14) and driven by a control device (20) for performing a phase control. The apparatus is characterized in that a second switching element (34) connected in series with a resistor element (32) is provided, said series connection is provided parallel to the first switching element (12), and said control device (20) is adapted such that it drives the second switching element (34) shortly before the first switching element (12) and switches it in its conducting state for a short time period.

Abstract: The invention relates to a pressure sensor comprising a housing (12), a membrane (26) arranged in said housing and which can be deflected by the pressure to be measured, a light source (LED) having an optical axis, a light detector having an optical axis and a light blocker (36) that is coupled to the membrane and that can be deflected thereby, the blocker being arranged in the beam path of the light source. The light source and the light detector are arranged inside the housing (12), wherein their optical axes lie parallel to one another. A first prism (40) is assigned to the light source and a second prism (42) is assigned to the light detector in such a way that an uninterrupted beam path from the light source through both prisms to the light detector is obtained. To this end, the light blocker (36) is arranged between the two prisms.

Abstract: The invention refers to an apparatus for generating a reference frequency depending on a timing information extracted from a data stream. In order to generate a carrier frequency in a user station of a satellite TDMA network at low costs which is accurate and stable and which meets stringent phase noise requirements, it is suggested to use at least one free-running oscillator. The frequency deviation with regard to the timing information extracted from the data stream is estimated by an estimation means. At least two oscillation signals are derived from the at least one oscillation means and are linked together by a linking means yielding said reference frequency. A frequency correction value is applied to at least one of the oscillation signals such that the timing information given by the reference frequency corresponds to the timing information extracted from said data stream.

Abstract: The invention relates to a pressure sensor comprising a housing (12), a membrane (26) arranged in said housing and which can be deflected by the pressure to be measured, a light source (LED) having an optical axis, a light detector having an optical axis and a light blocker (36) that is coupled to the membrane and that can be deflected thereby, the blocker being arranged in the beam path of the light source. The light source and the light detector are arranged inside the housing (12), wherein their optical axes lie parallel to one another. A first prism (40) is assigned to the light source and a second prism (42) is assigned to the light detector in such a way that an uninterrupted beam path from the light source through both prisms to the light detector is obtained. To this end, the light blocker (36) is arranged between the two prisms.

Abstract: A joining assembly for mounting a fastening element of thermoplastic material to an external surface of a structural member of thermoplastic material. The fastening element and the structural member are provided with a joining projection and, respectively, a joining extension have matingly shaped joining surfaces which are integrally joined to each other by melting.

Abstract: The invention refers to an apparatus for generating a reference frequency depending on a timing information extracted from a data stream. In order to generate a carrier frequency in a user station of a satellite TDMA network at low costs which is accurate and stable and which meets stringent phase noise requirements, it is suggested to use at least one free-running oscillator. The frequency deviation with regard to the timing information extracted from the data stream is estimated by an estimation means. At least two oscillation signals are derived from the at least one oscillation means and are linked together by a linking means yielding said reference frequency. A frequency correction value is applied to at least one of the oscillation signals such that the timing information given by the reference frequency corresponds to the timing information extracted from said data stream.

Abstract: A joining assembly for mounting a fastening element of thermoplastic material to an external surface of a structural member of thermoplastic material. The fastening element and the structural member are provided with a joining projection and, respectively, a joining extension have matingly shaped joining surfaces which are integrally joined to each other by melting.

Abstract: A ferrite component is provided for forming a ferrite bobbin about which an electric conductor is wound. The component is formed with an enlarged flange portion from which extends a shaft portion that defines a free end. The free end of the shaft portion has at least one outwardly extending projection and at least one recessed hollow which are similarly shaped and dimensioned. Two of the ferrite components are mated together to form the bobbin with the projection of one component extending into the hollow of the other component and vice versa.

Abstract: A method and arrangement for controlling the output of electrical consumers connected to ac line voltage, especially of electric motors and the like, in which the output is changed by changing the phase control of the electric alternating magnitude supplied to the consumer. The extent of the firing angle determining the extent of the phase control is varied toward larger or smaller values around the given reference value of the firing angle, which reference value corresponds to the desired power consumption, so that asymmetry of the firing angle is produced with respect to time between two successive full waves, whereby odd-numbered harmonics are sharply reduced as even-numbered harmonics slowly increase.

Abstract: A method for controlling the output of electrical consumers connected to ac voltage, especially ohmic loads such as hot-plates, fans, hot-air blowers, electric heaters and the like, wherein an electric or electronic circuit component which conducts ac voltage in both directions, preferably a triac, is connected in series with the consumer, and the output control is effected at the consumer by the given angle of the phase control. An additional electric or electronic circuit component is arranged in parallel to the first series switching element, however, the additional component is controlled first so as to conduct in a controlled manner at the trigger time determined by the device control. The current flow of the additional component is substantially taken over by the first circuit component at the latest when reaching a predetermined threshold current through the load or a threshold voltage at the load or triac.

Abstract: There is disclosed a direction-changing roller for suspension frames of photographic material developing machines, over which the photographic material to be developed is guided in a meandering path. The roller has a cylindrical roller body on each end of which there is arranged a respective collar-shaped flange. There are further rollers inserted in the roller body. The surfaces of the further rollers are flush with the outline or surface of the roller body. Each further roller is mounted to be freely rotatable about an axis extending perpendicular to the axis of rotation of the direction-changing roller and radially offset from this axis of rotation.