Abstract: The invention relates to a generating unit driven by a combustion engine. Control of the engine speed is carried out in a known manner via a mechanical control device which controls a throttle valve in the carburetor system of the engine. In case of a failure of the mechanical control device and, consequently, in case of a change in the engine speed outside a predetermined range, an electronic control system takes over to activate a firing element of the engine and control the engine speed, independently from the mechanical control system, in such a way that the engine speed is maintained within the predetermined range.

Abstract: The invention relates to a protective device for an electric consumer. A residual-current circuit-breaker is located in an electrical supply line between a mains connection and a switch device of the consumer. Said residual-current circuit-breaker has a detection device for recognizing a residual current and a first interrupter for interrupting the supply of electricity from the mains connection to the switch device in accordance with a switching signal from a detection device. If an electrical energy storage device is provided in the switching device, a second interrupter is provided, this second interrupter being controlled by the residual-current circuit-breaker.

Abstract: The invention relates to a frequency converter (8) for an immersion vibrator (1), comprising a mobile converter housing (9), and a converter circuit disposed in said converter housing (9) and adapted to convert an electrical supply voltage to a special voltage. The converter is further provided with a feed line (10) that is mechanically linked with the converter housing (9) and electrically connected to the converter circuit. At the end of said feed line facing away from the converter housing (9) a plug part (11) is disposed. The converter circuit feeds a connector (12) with the special voltage, a plug part (7) of the immersion vibrator (1) being insertable into said connector.

Abstract: A method and apparatus for improving microprocessor data acquisition. Noise in analog signals is removed by a low pass filter with a variable cutoff frequency controlled to cut off all frequencies above a frequency range of interest. The filtered signal is sampled by an analog-to-digital converter at a sampling rate which is variable and controlled to sample at a rate that is at least two times the low pass filter cutoff frequency thereby reducing the rate at which data is passed to a microprocessor and reducing the need for speed in the microprocessor's processing.

Abstract: The invention relates to a motor-driven operating device that comprises a guide handle (1). Two sensor elements are provided on the guide handle and in two handle areas (2, 3) for detecting the hands of an operator. An ignition device (7) of the motor is controlled by means of a security control device (6) in such a way that the speed can only be increased beyond a security speed when the guide handle (1) is held with both hands, whereby said security control device evaluates the sensor signals. The motor speed is limited to the security speed when the two sensor signals are missing.

Abstract: An optical resonator receives a light beam having a first state of polarization. The resonator comprises a polarization modifying device (40) and a polarization dependent coupling device (30) for coupling light having the first state of polarization into a first path and for coupling light having a state of polarization perpendicular to the first state of polarization into a second path. The polarization dependent coupling device (30) is arranged to receive from a first propagation direction the light beam having the first state of polarization and to couple the light beam from the first propagation direction in the first path to the polarization modifying device (40). The polarization modifying device (40) is arranged for modifying the state of polarization of the light beam before reentering the first path of the polarization dependent coupling device (30) from a second propagation direction in order to couple into the second path a portion of the light beam traveling into the second propagation direction.

Abstract: A device for controlling the speed of an internal combustion engine in a working tool including a device for recognizing a special operating state of the working tool. By way of example, a special operating state can be taken to mean the start-up of the internal combustion engine or a danger that can occur when the user lets go of said working tool or the tool tips over. An adjustment device adjusts the engine speed of the internal combustion engine to a safety speed that is below the operating speed of the internal combustion engine when the special operating state is recognized.

Abstract: A method and apparatus for improving microprocessor data acquisition. Noise in analog signals is removed by a low pass filter with a variable cutoff frequency controlled to cut off all frequencies above a frequency range of interest. The filtered signal is sampled by an analog-to-digital converter at a sampling rate which is variable and controlled to sample at a rate that is at least two times the low pass filter cutoff frequency thereby reducing the rate at which data is passed to a microprocessor and reducing the need for speed in the microprocessor's processing.

Abstract: A vibrating plate consists of an upper mass with a drive unit and a lower mass with a ground contact plate and a vibration exciter. The upper mass and lower mass are coupled with each other at several points with spring-and-damper units. According to the invention, the spring properties and/or damping properties of the particular spring-and-damper unit in at least one of these points can be modified via a steering device which makes it possible to steer the vibrating plate.

Abstract: A soil compacting machine has a receiver unit that can receive control signals from a transmitter unit to a receiver unit. The transmitter unit can be operated by a user and is separate from the machine. The control signals are then processed into commands and sent to a control mechanism of the machine. Signals originating from the transmitter unit and reflected by the machine are received as safety signals by a receiver connected to the transmitter unit and are tested in relation to at least one distance-dependent parameter. If the parameter which is tested shows that a predetermined safety distance between the machine and the receiver is not respected, the transmission of the control signals or the operation of the machine is interrupted.

Abstract: A cable drum has a rotating winder fitted in a mounting and a frequency converter fitted on the winder. At least one socket outlet of the winder is electrically coupled to the frequency converter and is supplied with an electrical spatial frequency. The integration of the cable drum and frequency converter makes it easier to transport the equipment by reducing weight and the number of pieces.

Abstract: A soil compacting device has a damping system which couples an upper mass and a lower mass together with a spring system in a vibration system. The damping properties of the damping system can be modified while the device is in operation. Therefore, when the soil compacting device passes over soils having different properties, it can constantly be adjusted in an optimal manner to the ground underneath it by acting on the vibration properties of the overall vibration system.

Abstract: In a hand-held electric tool driven by an electric motor (2) and capable of being connected to a single-phase alternating current (4a), the electric motor (2) has no collector or slip ring, and its driving energy is supplied by control electronics (5) which are powered at their input by the single-phase alternating current (4a) and which supply at their output the type of current (4b) suitable for the motor. The control electronics (5) are arranged in a handle (1a) of the electric tool and are cooled by the cooling air flow (7) which also cools the motor (2).

Abstract: An internal vibrator for compacting concrete and having a vibrator housing in which is disposed an eccentric mass and an electric motor for driving the eccentric mass. The electric motor is supplied via a power supply cord with electric current having a frequency that is greater than line frequency. The vibrator comprises a switch for controlling the electric motor, and also includes a transformer for supplying to the electric motor the electric current having the frequency that is greater than line frequency. The switch and the transformer are combined in a common housing to form a miniaturized built-in unit on the power supply cord.

Abstract: An infrared remote-controlled soil compacting device is controlled such that the device cannot be set into operation as long as the operator with the sending unit is within close vicinity of the soil compacting device so that an accidental operation or propelling in the wrong direction is prevented. This is achieved by providing an infrared close range radiation in addition to the infrared control radiation required for the operational control of the device. The close range radiation has a substantially reduced intensity relative to the control radiation so that the close range radiation can be received within the receiving unit only within close vicinity of the sending unit. When the close range radiation is received within the receiving unit the generation or release of electric signals affecting propelling of the soil compacting device is suppressed.

Abstract: A method of determining and displaying during operation an actual degree of soil compaction achieved with a soil compacting device includes the steps of driving the soil compaction device with a motor and compacting the soil with the soil compacting device. The motor is secured against surpassing a predetermined maximum rpm limit by providing a protective rpm limiting circuit. The ignition impulse is delayed with the protective rpm limiting circuit, when the predetermined maximum rpm limit is surpassed. Within a time interval the average of the delay of the ignition impulse is determined as a base value for a display value of the actual degree of compaction. For a large surface area to be compacted it is possible to compact the soil within a test portion to the desired degree of compaction and save the corresponding display value as a reference value to be used during compaction of the remaining portions.

Abstract: In order to be able to position the cutter blades (A, B, C) of a cutter head so that they are radially adjustable in a simple manner in the smallest possible axial space, toothing, (10) is formed in an elongated hole (7) in the area of the blade root (6) at its parallel opposite internal longitudinal edges, whereby toothing (11) at parallel opposite external longitudinal edges of a shaft mounting plate (8) engages with this toothing (10), the shaft mounting plate having a central opening (9), the shape of which corresponds to the cross section of a driven shaft (9'). In this arrangement the thickness of the shaft mounting plate (8) is not greater than the depth of the elongated hole (7), although the length of the shaft mounting plate (8) is smaller than the longitudinal extension of the elongated hole (7).