Abstract: A portable handheld lawn edger includes a cutterhead (2) at the end (16) of a guide tube (4) as well as an internal combustion engine (3) at the other end (17). The engine is connected to the cutter blade (5) via a drive shaft (20) in the guide tube (4) and in the cutterhead (2). The cutter blade is mounted for rotation about an axis (6), which lies parallel to the ground during cutting operation, and is guided along the edge. A guide wheel (27) is provided on the end of the cutterhead (2) facing toward the engine (3). The cutterhead (2) can be rolled over the ground with the aid of the guide wheel (27). The service life of the edge cutter (1) is increased and the manufacturing costs are reduced in that the cutterhead (2) is provided with a spacer (7, 9) approximately at the elevation of the drive axis (6) of the cutter blade (5). The spacer (7, 9) projects from the cutterhead and is set on the ground and prevents abrasion of the cutterhead (2).

Abstract: A two-stroke engine having charge stratification for portable, manually guided implements is provided. Formed in a cylinder is a combustion chamber that is delimited by a reciprocating piston that by means of a connecting rod drives a crankshaft in a crankcase. The combustion chamber has an exhaust port for exhaust gases and an intake port for rich mixture. The intake port forms one end of a feed channel, the other end of which opens into the crankcase. Between its ends, the feed channel is connected with a mixture-forming device. The crankcase has an air inlet for pure combustion air, which passes via a transfer channel from the crankcase into the combustion chamber. The intake port of the feed channel into the combustion chamber is, in the stroke direction of the piston, provided above the air inlet into the crankcase. At least a portion of the feed channel is embodied as an external component of the engine.

Abstract: An internal combustion engine, for example a two-stroke engine having scavenging collection, is provided. The combustion chamber formed in the cylinder is delimited by a reciprocating piston. A fuel/air mixture prepared in the Venturi section of a diaphragm carburetor is supplied to the engine. The air portion of the mixture is conveyed to the Venturi section via an intake channel, and the fuel portion is conveyed to the Venturi section via a main nozzle path that branches off from a fuel-filled control chamber to which fuel is supplied via a fuel line and a feed valve that is controlled by a control diaphragm that delimits the control chamber. A device is provided for varying the air portion and/or the fuel portion at full load. Connected to the device is a control unit that receives, as an input variable, an operating parameter of the engine that varies as a function of engine speed. The device is actuated as a function of the output signal of the control unit.

Abstract: A two-stroke engine for a portable two-stroke engine in a portable handheld work apparatus includes a combustion chamber (3) formed in a cylinder (2). The combustion chamber (3) is delimited by the piston (5) which drives the crankshaft (7) via a connecting rod (6). The two-stroke engine includes several transfer channels (14), which, referred to a symmetry plane (49), lie on opposite sides (47, 48) with the plane partitioning approximately the outlet (10). The transfer channels (14) connect the crankcase (4) to the combustion chamber (3). A first end (20) of each transfer channel (14) opens via an entry window (12, 15) into the combustion chamber (3) and the second end (19) of each transfer channel opens to the crankcase (4). Each transfer channel (14) is connected, between its ends (19, 20), to an air channel (22a, 22b) via a membrane valve (21). Air is supplied by the air channel (22a, 22b) via an adjustable throttle (31, 32).

Abstract: The invention is directed to a method for operating a two-stroke engine in a portable handheld work apparatus. The engine includes a cylinder (12) and a combustion chamber (26) which is delimited by a reciprocating piston (14). The combustion chamber includes an outlet (28) discharging exhaust gases and an inlet (30) of a storage channel (34). The inlet (30) lies approximately opposite the outlet (28) and the other end of storage channel (34) opens via a controlled end (38) into the crankcase (18). Between its ends, the storage channel (34) is connected to a first fuel metering device (20) of a first fuel path; whereas, the crankcase (18) has a crankcase inlet (24) which is connected to a second fuel metering device (19) of a second fuel path. In the case of an acceleration, additional fuel is metered to one or both fuel paths via an acceleration unit (22).

Abstract: The invention relates to a two-stroke engine for a portable handheld work apparatus such as a motor chain saw. The combustion chamber (3), which is configured in a cylinder (2), is delimited by a piston (5) which drives a crankshaft (7) rotatably journalled in a crankcase (4). The crankcase (4) is connected to the combustion chamber (3) via a transfer channel (14). A first end (20) of the transfer channel (14) opens into the combustion chamber (3) via an entry window (12, 15) lying in the cylinder wall (16); whereas, the second end (19) of this transfer channel (14) is open toward the crankcase (4). The transfer channel (14) is connected between its ends (19, 20) to an air channel (22a, 22b) via a check valve (21). The air channel (22a, 22b) supplies essentially fuel-free gas via a throttle (31) having an adjustable throttle element (33). A mixture-preparation device (8) is provided for the air/fuel mixture downstream of an air filter (42) in the flow direction of the combustion air.

Abstract: The invention relates to a two-stroke engine in a portable handheld work apparatus. A combustion chamber (3) is formed in a cylinder (2) and the chamber is delimited by a piston (5). At least one transfer channel (14) is provided which connects the crankcase (4) to the combustion chamber (3). An air channel (22) opens into the transfer channel (14) and this channel supplies essentially fuel-free gas, preferably air. The intake channel (28) of a carburetor (8) is connected to an intake opening (45) in the housing base (41) of the air filter housing (43) upstream of a carburetor throttle flap. The intake channel (28) connects downstream of the carburetor throttle flap to an intake channel (9) to the crankcase (4).

Abstract: The invention relates to an internal combustion engine and especially to a drive motor in a portable handheld work apparatus such as a motor-driven chain saw, cutoff machine or the like. The engine is formed from a cylinder (7) with a combustion chamber (34) which is delimited by the reciprocating piston (35). The piston (35) drives a crankshaft (38) which is rotatably journalled in a crankshaft housing (37) via a connecting rod (36). In the combustion chamber (34) an outlet (29) is provided through which the oxygen-rich exhaust gases (16) and oxygen-poor exhaust gases (18) flow out. Transfer channels (40) are configured in the cylinder (7) for supplying an air/fuel mixture prepared by a mixture preparation device (39) and gas-feeding channels (41) are configured for supplying fuel-poor, oxygen-rich gases in the combustion chamber (34). An exhaust-gas muffler (2) is assigned to the outlet (29) according to the invention to obtain an exhaust-gas quality which remains the same.

Abstract: The invention relates to a two-stroke engine for a portable handheld work apparatus such as a motor-driven chain saw, cutoff machine, brushcutter or the like. A crankcase (4) is formed below the engine cylinder (2). A piston (5) moves up and down in the cylinder (2) and drives a crankshaft (7) rotatably journalled in the crankcase (4). A fuel-containing mixture is supplied via a membrane carburetor (8) to the combustion chamber (3) delimited between the piston (5) and the cylinder (2). A bypass channel (22) is provided parallel thereto and supplies essentially fuel-free air to the combustion chamber (3). The bypass channel (22) opens into a channel segment (21) via a connecting piece (24) fixedly attached to the cylinder (2). The channel segment (21) is formed in the cylinder wall (16). A spark plug (20) and an ignition control device (34) are assigned to the combustion chamber (3).

Abstract: The invention relates to a cylinder which can be produced of die cast metal. The cylinder is for a two-stroke engine in a portable handheld work apparatus such as a motor chain saw. A combustion chamber (3) is formed in the cylinder (2) and this combustion chamber is delimited by a piston (5). In the cylinder wall (16), there is an outlet (10) for conducting away the combustion gases from the combustion chamber (3). Furthermore, transfer channels (14a, 14b) are provided which open into the combustion chamber (3) via transfer windows (12, 15) and supply the operating medium from the crankcase (4) needed for operating the two-stroke engine. The transfer channels (14a, 14b) are configured in the cylinder wall (16) as channels opening radially to the outside. These channels are closed by a seated cover (23).

Abstract: The invention relates to a two-stroke engine for a portable handheld work apparatus such as a motor chain saw. The combustion chamber (3), which is configured in a cylinder (2), is delimited by a piston (5) which drives a crankshaft (7) rotatably journalled in a crankcase (4). The crankcase (4) is connected to the combustion chamber (3) via a transfer channel (14). A first end (20) of the transfer channel (14) opens into the combustion chamber (3) via an entry window (12, 15) lying in the cylinder wall (16); whereas, the second end (19) of this transfer channel (14) is open toward the crankcase (4). The transfer channel (14) is connected between its ends (19, 20) to an air channel (22a, 22b) via a check valve (21). The air channel (22a, 22b) supplies essentially fuel-free gas via a throttle (31) having an adjustable throttle element (33). A mixture-preparation device (8) is provided for the air/fuel mixture downstream of an air filter (42) in the flow direction of the combustion air.

Abstract: The invention relates to a two-stroke engine in a portable handheld work apparatus such as a motor chain saw. A combustion chamber (3) is formed in a cylinder (2) and is delimited by a piston (5). The piston (5) drives a crankshaft (7) via a connecting rod (6). The crankshaft is journalled in a crankcase (4). Air is supplied to the combustion chamber (3) via a first outlet-near transfer channel (15); whereas, the air/fuel mixture, which is needed for operation, flows in via a second outlet-remote transfer channel (12) from the crankcase (4). The constructive volume of the outlet-near transfer channel (15) is designed to approximately 20% to 60% of the volumetric total air input of the engine (1) in order to achieve a complete charge of the combustion chamber while having low scavenging losses.

Abstract: The invention relates to a two-stroke engine in a portable handheld work apparatus. A combustion chamber (3) is formed in a cylinder (2) and the chamber is delimited by a piston (5). At least one transfer channel (14) is provided which connects the crankcase (4) to the combustion chamber (3). An air channel (22) opens into the transfer channel (14) and this channel supplies essentially fuel-free gas, preferably air. The intake channel (28) of a carburetor (8) is connected to an intake opening (45) in the housing base (41) of the air filter housing (43) upstream of a carburetor throttle flap. The intake channel (28) connects downstream of the carburetor throttle flap to an intake channel (9) to the crankcase (4).

Abstract: The invention relates to a two-stroke engine in a portable handheld work apparatus such as a motor-driven chain saw or the like. A combustion chamber (3) is formed in the cylinder (2) of the two-stroke engine (1). The combustion chamber (3) is delimited by the piston (5). The piston (5) drives the crankshaft (7) via a connecting rod (6) and the crankshaft (7) is rotatably journalled in the crankcase (4). The two-stroke engine includes several transfer channels (14), which, referred to a symmetry plane (49), lie on opposite-lying sides (47, 48) with the plane partitioning approximately the outlet (10). The transfer channels (14) connect the crankcase (4) with the combustion chamber (3). A first end (20) of each transfer channel (14) opens via an entry window (12, 15) into the combustion chamber (3); whereas, the second end (19) of each transfer channel opens to the crankcase (4). Each transfer channel (14) is connected, between its ends (19, 20) to an air channel (22a, 22b) via a membrane valve (21).

Abstract: The invention relates to a two-stroke engine which operates as a drive motor in a portable work apparatus such as a motor-driven chain saw. The two-stroke engine has a combustion chamber (3) which is formed in a cylinder (2) and is delimited by a piston (5) which moves up and down in the cylinder. The piston drives via a connecting rod (6) a crankshaft (7) which rotates in a crankcase (4). The crankcase (4) is connected to the combustion chamber (3) via a transfer channel (14). A first end (20) of the transfer channel (14) opens via an entry window (12) into the combustion chamber (3) and the second end (19) of the transfer channel (14) opens into the crankcase (4). The entry window (12) lies in the cylinder wall (16) and is controlled by the piston (5). The transfer channel (14) is connected to a gas channel (22) between its ends (19, 20). An essentially fuel-free gas flow (40) flows via a check valve (21) from the gas channel (22) and flows into the transfer channel (14).

Abstract: The invention relates to a two-stroke engine having a combustion chamber (3) configured in a cylinder (2). The combustion chamber is delimited by a piston (5) which moves upwardly and downwardly. The crankcase (4) is connected to the combustion chamber (3) via an transfer channel (14). A first end (20) of the transfer channel (14) opens into the combustion chamber (3) via an entry window (12) lying in the cylinder wall (16) and controlled by piston the (5). Between its ends (19, 20), the transfer channel (14) is connected to a gas channel (22) via a valve (21). The gas channel (22) essentially supplies fuel-free gas. The air/fuel mixture, which is necessary for the operation of the two-stroke engine, is supplied to the crankcase (4) via an inlet (11). In order to ensure a full charge of the transfer channel (14) with fuel-free gas, the entry window (12) of the transfer channel (14) is held open to the crankcase (4) in a stroke position of the piston (5) in the region of top dead center.