Andreas Stihl

Other

Andreas Stihl Ag & Co.

Andreas Stihl Ag Co. Kg

Roland Schierling

Werner Geyer

Hans Nickel

Michael Wissmann

Roland Adam

Norbert Apfel

Bernd Andress

Helmut Zimmermann

Johannes Menzel

Joachim Hoffmann

Heinrich Leufen

Wolfgang Weissert

Eberhard Schieber

Reinhard Friedrich

Kai-Ulrich Machens

Ernst Gorenflo

Peter Bauer

Hans-Peter Dohse

David Mitrega

Walter Sattelmaier

Klaus Wieninger

Tilo Deichl

Manfred Thaiss

Horst Eckhardt

Helmut Köstner

Norbert Rehbein

Udo Bartmann

Karsten Schone

In a method for providing in a hand-held power tool electric energy for an engine control unit before start of an internal combustion engine of the power tool that is to be started by a rope starter, a voltage source is provided that generates electric energy electro-dynamically or photovoltaically before starting the internal combustion engine. The thus generated electric energy is stored in a rechargeable energy storage device arranged within the power tool. The electric energy stored in the energy storage device is supplied to the engine control unit upon first rope starter pull for start of the internal combustion engine. The device for performing the method has an electro-dynamic or photovoltaic voltage source and an energy storage device electrically conductingly connected to the voltage source, wherein the energy storage device has an output that is electrically conductingly connected to the engine control unit.

Method and device for providing electric energy for an engine control unit

A protective shield () is provided for a free-cutting tool (). The free-cutting tool has a cutterhead () rotatable about a rotational axis () and carries a cutting filament (). For a rotating cutterhead (), the cutting filament () rotates in a rotational direction (), aligns itself approximately radially to the rotational axis () and defines a cutting circle () having a constructively pregiven nominal radius (R). The cutting radius () is at least partially covered by the protective shield (). A cut-to-length knife () having a cutting edge () for cutting the cutting filament () to length is mounted on the protective shield () in the peripheral region thereof. The cut-to-length knife () is mounted on the protective shield () to be moveable back and forth between a cutting position () and a rest position (). The cutting edge () lies in the plane of the cutting circle () in the cutting position () and has the nominal radius (R) to the rotational axis () and, in the rest position (), the cutting edge () lies outside of the cutting circle ().

Protective shield for a free-cutting tool

A cutting blade for a motor-driven implement is provided. The cutting blade has a main body having a central fastening opening and blade sections that extend approximately radially from the main body. The blade sections have edges that extend in a radial direction and form cutting edges. Each blade section is provided with at least one bead-like embossment having a longitudinal axis that extends at an angle of between 0 and 45&#xb0; relative to a longitudinal direction of the blade section.

Cutting blade for a motor-driven, manually-guided implement

A tool head for a motor-driven, manually guided implement for receiving a rotatable cutter tool is provided. The tool head comprises a housing in which is provided a tool shaft that is rotatably mounted via bearings. Secured on the tool shaft so as to turn with it is a tool carrying mechanism for the cutter tool. This tool carrying mechanism includes an engagement plate having an engagement surface, which is oriented perpendicular to the axis of the shaft, and a centering shoulder. The engagement plate and a centering element having the centering shoulder are embodied as separate components. The engagement plate is of light weight construction and is positively connected with the tool shaft. The centering element is made of a material, the hardness of which is adapted to the cutter tool.

Tool head

A guide bar for a saw chain of a motor chain saw has a single member steel plate having a center plane and a circumferential guide groove for guiding a saw chain extending in the center plane. The steel plate has a longitudinal extension and a height perpendicular to the longitudinal extension. The steel plate has a cutout extending over a portion of the longitudinal extension and over a portion of the height. A filling member, consisting of a casting material having a smaller density than the steel plate, is cast into the cutout. The cutout has a circumferential edge facing the filling member. The circumferential edge has undercuts uniformly distributed along the circumferential edge. The filling member has a shrinkage rate of at least 0.5% for engaging positive-lockingly the undercuts upon solidification of the casting material to thereby create a uniformly distributed pretension within the center plane of the guide bar in the unloaded state of the guide bar.

Guide bar for a motor chain saw

A clamping device for axially clamping a disk-shaped tool member on a shaft of a working tool has a pressure member for force-lockingly clamping the tool member between a radial surface of the shaft and the pressure member. A ring mount for force-loading the clamping member is provided for clamping and releasing the tool. An engaging device acting between the shaft and the pressure member is provided for positive-lockingly engaging the shaft upon actuation of the ring mount in a clamping direction of the clamping device.

Clamping device for axially clamping a disk-shaped tool

The invention is directed to a fuel pump for an internal combustion engine such as a two-stroke engine in a portable handheld work apparatus such as a motor-driven chain saw or the like. A pump chamber is connected via a suction valve to a fuel feed and via a pressure valve to a pressure line. A pump membrane delimits the pump chamber and is driven by the fluctuating crankcase pressure of the engine which is present in the work chamber. Pump operation free of disturbances over a wide rpm range is attained with the suction valve to the pump chamber being configured essentially as a valve having the shape of a part circle, The pressure valve is disposed approximately at the center of the suction valve and delimits the pump chamber in the stroke direction of the pump membrane.

Fuel pump for an internal combustion engine

The invention is directed to a fuel-injection arrangement for a two-stroke engine in a portable handheld work apparatus such as a motor-driven chain saw or the like. Fuel is drawn by suction from a fuel tank by a fuel-feed pump and is made available at the suction connection of an injection pump. The injection pump has a pressure connection which is connected to an injection line through which the engine is supplied with fuel. A rapid start of a two-stroke engine provided with this fuel-injection arrangement is achieved by providing a bypass line which conducts fuel and bypasses the injection pump. A switchable flow valve is mounted in the bypass line. The bypass line opens directly into the intake channel conducting combustion air to the engine so that even without the pump action of the injection pump, adequate fuel is made available to the engine for starting the same.

Fuel-injection arrangement for an internal combustion engine

A cutterhead for a string trimmer having a rotatable drive shaft is adapted to hold and meter a cutting filament during operational use thereof. The cutterhead includes a disc-like carrier fixedly connected to one end of the drive shaft to permit the carrier to rotate about a rotational axis. The carrier has a peripheral edge and a peripherally extending outer wall approximately perpendicular to the carrier along the peripheral edge. The outer wall defines a space for accommodating the cutting filament in the cutterhead and has a guide eyelet disposed therein to define a pass-through opening for guiding the filament from the space to the outside of the cutterhead where a segment of the filament extends radially outwardly from the outer wall to define a cutting plane when the drive shaft rotates. The guide eyelet is made of wear-resistant material and is adapted to the diameter of the cutting filament. A stop is disposed in the cutting plane for receiving the segment of the cutting filament thereagainst when the segment strikes an obstacle and is deflected during operation of the string trimmer. The stop is disposed radially forward of the outer wall next to the pass-through opening.

Cutterhead for a string trimmer

The invention is directed to a fuel-injection arrangement for a two-stroke engine in a motor-driven chain saw. An injection pump is mounted in a base housing with the injection pump including a pump piston axially displaceable in a pump cylinder. The pump piston delimits a pump chamber. The pump chamber is connected via a suction valve to a fuel tank. The fuel drawn by suction is pumped by the pump piston via a pressure valve, an injection line and an injection valve to the engine. For driving the pump piston, the latter is connected at one end to a membrane via a membrane plate. The membrane delimits a work chamber charged with fluctuating crankcase pressure. A simple assembly is provided by arranging the pump chamber, the suction valve and the pressure valve in a common valve housing which, in turn, is seated in the base housing of the injection pump in a seal-tight manner. The injection line is connected directly to the valve housing. This permits a preassembly of the valve housing with the valves provided therein which facilitates the manufacture of the fuel-injection arrangement.

The invention is directed to a pump for pumping a viscous fluid. The pump includes a stator body and a rotor body rotatably mounted in the stator body so as to be coaxial therewith. The stator body has a wall structure having a spiral slot formed therein which communicates with a suction connection formed in the stator body for conducting the viscous fluid to be pumped into the slot. A pressure connection is formed in the stator body for conducting the viscous fluid out of the slot. The suction connection and the pressure connection open into respective peripheral annular slots which are formed between a total of at least three sealing rings on the outer surface of the stator body. The channels for liquids provided in a housing can be disposed in any rotational position relative to the stator. This affords the advantage that the pump stator can be seated with any rotational position in a receiving cylinder of the housing. The sealing rings are injection molded on the stator body to define a tight seat in the receiving cylinder of the housing without additional seals. By a simple insertion of the pump rotor, a connection between the connections of the pump and the channels in the housing is provided which is tight with respect to the medium under pressure.

Pump for viscous fluids

The invention is directed to a guide bar for guiding the saw chain of a motor-driven chain saw. The guide bar of the invention has a lamellar configuration and is not made of three parts as are conventional guide bars. Instead, the guide bar of the invention is made of two side parts. The two side parts are connected by means of spacers which are configured as projections on at least one of the two side parts. The side parts can be frames having large inner openings and are preferably stiffened. The connected frames define a composite frame which can be filled with plastic. The spacers determine the spacing of the side parts and therefore the width of the guide groove for the saw chain. The invention is also directed to a method of making the guide bar.

Guide bar having a lamellar assembly and method of making the same

The invention relates to a motor-driven chain saw having a motor mounted in a housing for driving a saw chain on a guide bar. The guide bar extends forwardly in the longitudinal direction of the chain saw from a forward housing end face. The housing is held by a grab handle for holding and guiding the chain saw. The handle has an upper segment projecting over the housing transversely to the longitudinal center axis of the guide bar. The upper segment extends at one end with a transition segment into a lateral segment lying approximately parallel to the plane of the guide bar and next to the housing. The cross section of the upper segment and the cross section of the lateral segment are configured in a shape which departs from the circular shape and are approximately the same. This affords an ergonomically advantageous hold and increases the operational safety. The major cross-sectional axis of the lateral segment lies approximately perpendicularly to the plane of the guide bar and the same cross-sectional axis in the upper segment lies at an angle of less than 90.degree. to a reference plane which extends at right angles in the longitudinal center axis of the guide bar at right angles to the plane of the guide bar.

Motor-driven chain saw having a grab handle

The invention is directed to a starter arrangement for an internal combustion engine wherein a manual starter device is combined with an electrical starter. Handheld portable tools such as motor-driven chain saws, brushcutters and the like are driven by two-stroke engines which can be started with a suitable manual starter device such as a pull-rope starter. Pull-rope starters require a forceful yank on the pull rope which is difficult for persons having inadequate physical strength. For this reason, electrical starters are provided to facilitate starting such handheld portable tools. The invention combines an electric starter and a manual starter device wherein the overrun clutch of the manual starter device includes a latching device and a drive member and is combined with a further latching device which coacts with a drive member driven by the electric starter. The engagement with the overrun clutch of the manual starter device makes possible a compact configuration so that the overall volume of the unmodified engine is not significantly increased notwithstanding the arrangement of the electric starter.

Starter arrangement for an internal combustion engine

The invention relates to a handheld portable tool driven by a two-stroke engine equipped with a pneumatically actuated injection pump. Injection pumps for two-stroke engines are generally rigidly connected to the engine so that the injection line can be rigid and as short as possible. This, however, leads to operational disturbances in the injection pump. To eliminate these disturbances, the injection pump is mounted in a thermally insulated handle housing portion of the tool which is damped with respect to the vibrations of the engine and is connected to the latter via flexible connecting lines.

Growing community of inventors

Affalterbach, Germany

Roland Schierling