Abstract: A power tool has an internal combustion engine with an injection valve through which fuel is supplied to the internal combustion engine; a crankcase; and a crankshaft arranged in the crankcase so as to be rotatable about an axis of rotation. A fan wheel housing is provided and a fan wheel is arranged in the fan wheel housing and conveys cooling air to the internal combustion engine. In the fan wheel housing a connecting opening is formed. The injection valve is arranged in a cooling area, wherein cooling air is supplied by the fan wheel through the connecting opening to the cooling area.

Abstract: A power tool has a drive motor with an actuating element. The power tool has a power tool housing with a first subassembly and a second subassembly that is connected with the first subassembly. An operating element is supported on the first subassembly. A Bowden cable is disposed within the power tool housing and has a Bowden cable housing and a Bowden cable inner wire arranged in the Bowden cable housing. The actuating element is a part of the second subassembly. The Bowden cable inner wire has a first end connected to the operating element and a second end connected to the actuating element, wherein the operating element acts on the actuating element through the Bowden cable. The Bowden cable housing has a first end and a second end and the first and second ends are secured on the same one of the first and second subassemblies.

Abstract: A hand-operated implement has a guide bar on which is fitted a cutting chain for cutting mineral and metal materials. The cutting chain is driven around the guide bar by a chain sprocket. The chain sprocket is arranged in a chain sprocket chamber which is delimited by a chain sprocket cover. A cutting element has an outer side facing a sidewall of the chain sprocket cover which lies in a first notional plane. The distance between the sidewall and the first notional plane measured perpendicular to the first notional plane and centrally between the top of the cutting element and the peripheral wall is less than approximately 0.8 cm over at least 30% of the section between a second notional plane containing the central axis of a fixing bolt on the guide bar and the exit opening at which the cutting chain leaves the chain sprocket chamber.

Abstract: A cutting chain for a hand-operated implement for cutting metal and mineral materials such as a stone cutter has central connecting links which are connected to one another by lateral connecting links. The central connecting links comprise first central connecting links which each have a drive tooth. The cutting chain has two central connecting links with drive teeth shaped differently to the drive teeth on the first central connecting links; or located a different distance from the leading drive teeth; or having no drive teeth. A hand-operated implement for cutting mineral materials has a drive motor which drives the cutting chain around a guide bar by a drive sprocket. The cutting chain is guided round part of the circumference of the drive sprocket and round a nose sprocket on the guide bar. The drive sprocket or nose sprocket have different first and second areas matched to the cutting chain.

Abstract: An electric motor in a work apparatus has a power characteristic line which runs between a lower rotational speed of the electric motor and an upper rotational speed of the electric motor. The power characteristic line has a power characteristic with a pronounced maximum (M) and an operating plateau (AP) which lies in a working rotational speed range (AD) of the work apparatus. A method for operating the electric motor provides for configuring the position of the operating plateau (AP) to be variable with respect to the rotational speed of the electric motor to achieve stable operating points over a wide rotational speed range.

Abstract: A handheld work apparatus has a combustion engine (4) for driving a tool. The combustion engine (4) has an ignition device, a device for metering fuel and a control device (31). The control device (31) engages when an engagement speed (nE1, nE2) is reached, in order to limit the speed (n) of the combustion engine (4). In order to allow the speed (n) to be set in an easy manner at full throttle, the work apparatus has a device for setting the engagement speed (nE2) by the user.

Abstract: A cutter head of an implement, comprising a cutting blade rotatabiy drivable about an axis of rotation and provided with at least two blade wings that extend along a longitudinal axis in a radial direction relative to the axis of rotation. The cutting blade is clamped between two contact or pressure pieces, at least one of which is provided with at least one radially extending dampening projection that rests against at least one of the blade wings and has a longitudinal axis that is angularly offset relative to the longitudinal axis of the blade wing. A protection against rotation that acts in at least one direction of rotation is provided between cutting blade and the contact or pressure piece that is provided with the at least one radially extending dampening projection. The protection against rotation is in the form of a positive connection between the angularly offset dampening projection and an outer edge of an associated blade wing.

Abstract: An electric work apparatus having an electric load which is fed from a rechargeable battery pack. The battery pack is accommodated in a housing with the electric load being connected to the battery pack via an electric connecting cable. To provide cable guidance for the connecting cable that is ergonomically suitable for a user, cable ducts are molded in a housing wall of the backpack-type battery pack that is separate from the electric load. The cable duct opens in the edge of the housing as cable outlets.

Abstract: A protective circuit for an arrangement includes a multiplicity of individual cells in a rechargeable battery pack. A predefined number of individual cells are connected in series in a cell row and at least two cell rows are mutually parallel, and at least one cell connector situated between the individual cells at a location of one cell row is electrically connected via a compensation line to the cell connector situated at an identical location of the parallel cell row, and the potential of the cell connector connected to the compensation line at one location of one cell row and the potential of the cell connector electrically connected to the compensation line at the same location of the parallel cell row are detected and the detected potentials are fed to an evaluation unit.

Abstract: A protective circuit for an arrangement which includes a plurality of individual cells in a rechargeable battery pack with a predefined number of individual cells being connected in series in a cell row and at least two cell rows being situated parallel to one another. The component current flowing in a first cell row when the rechargeable battery pack is subject to loading is compared with the component current flowing in a second cell row to generate a signal when there is an implausible deviation in the component currents with respect to one smother. The signal is used to disconnect a defective cell row or to switch off the entire rechargeable battery pack in order to protect the latter.

Abstract: The invention is directed to a rechargeable battery pack for an electrical load with the load being connected to the rechargeable battery pack by a connection cable. A housing of the rechargeable battery pack has an inner space for accommodating a large number of rechargeable individual cells which are electrically connected to one another and supply the load via the connection cable. To provide the housing with a high level of stability, provision is made for the receiving space in the housing to be subdivided into individual receptacles by partition walls. A cell pack includes a predefined number of the individual cells and is arranged in a corresponding individual receptacle. Each cell pack forms an independent unit which is held in the individual receptacle. The individual cells of a cell pack are electrically and mechanically connected to one another by cell connectors.

Abstract: The invention is directed to a protective circuit for a multiplicity of individual Cells arranged in a rechargeable battery pack, wherein a predefined number of individual cells forms a cell network. A monitoring circuit for the state of charge of the individual cells in the cell network is provided. Wherein the voltage at an individual cell is detected and the detected voltages of a plurality of individual cells are compared among one another to output a signal when an unbalancing limit is exceeded unbalancing limit indicates a permissible voltage difference between two selected individual cells of the cell network. The unbalancing limit of the cell network is provided as a characteristic curve variable over its state of charge. To alter the unbalancing limit, the characteristic curve is altered in dependence on a correction value.

Abstract: An ignition circuit for a combustion engine has an ignition coil and a control unit for the coil. The coil and the control unit are included in a common component as an ignition module. The module is supplied with voltage by a generator driven by the engine. A spark plug and the coil form a power circuit which includes a line segment to a reference potential outside the module. A sensor detects data of the engine and the output of the sensor is supplied to the module. The sensor is supplied with voltage via a sensor circuit. The sensor circuit and the power circuit use the line segment as a common connection to the reference potential, so that for a defect of the line segment, a missing connection to the reference potential in the high voltage circuit is recognized via the change of the sensor output signals.

Abstract: An internal combustion engine has a fuel supply device, wherein the fuel supply device includes a fuel pump, a fuel pressure damper, an injection valve, and a fuel pressure regulator. The fuel pressure damper has a damper membrane separating a damper chamber and a damper back chamber from each other. The damper chamber of the fuel pressure damper is loaded with a first reference pressure. The fuel pressure regulator regulates a pressure of fuel supplied by the fuel pump to the injection valve based on a second reference pressure of the fuel pressure regulator. The first reference pressure and the second reference pressure are adjusted relative to each other.

Abstract: A handheld work apparatus includes a fuel tank (8), into which a flexible fuel line (9) projects. A suction head (12, 46, 56, 66) is arranged at the free end (45) of the fuel line (9). The suction head is connected via the fuel line (9) to a fuel supply device (10) of an internal combustion engine (5) of the work apparatus. The suction head (12, 46, 56, 66) has at least, one weight member (16, 17, 47, 57, 67). The weight member (16, 47, 57, 67) is formed at least partially as a magnet to achieve good cleaning of the fuel without a substantial increase in the weight of the work apparatus.

Abstract: The invention relates to an ignition device for triggering an ignition spark at a spark plug by way of an ignition generator. The latter includes a magnet wheel, which has two permanent magnets arranged at a spacing from each other in the peripheral direction and a magnetic yoke. The magnetic yoke carries a charging coil which charges an ignition capacitor, a primary coil and a secondary coil, connected, to the spark plug. During every passing of a permanent magnet, a voltage is induced in the coils, wherein, in order to trigger the ignition spark, the ignition capacitor is discharged via a switch element. In order to avoid an unwanted ignition at the bottom dead center of the piston, a device for reducing the voltage that occurs at the spark plug is provided.

Abstract: A handheld work apparatus such as a stone cutter (1) having a housing (2) in which a drive motor (5) is arranged. The work apparatus has a tool driven by the drive motor (5) for cutting mineral or metallic materials. The housing (2) has a housing front end (16) facing the workpiece to be cut and arranged adjacent to the workpiece. The tool projects beyond the housing front end (16). In order to avoid damage on the housing front end (16), it is provided that an elastic guard (17, 47), which extends over at least 50% of the width (b) of the housing front end (16), is arranged on the housing front end (16).