Abstract: A power tool has an internal combustion engine with a cylinder. An injection valve supplies fuel to the internal combustion engine. A fuel pump conveys fuel from a fuel tank to the injection valve. A fan wheel is provided that is driven by the internal combustion engine. The cylinder is arranged in a first cooling zone of the power tool and the fan wheel conveys cooling air through the first cooling zone. The fuel pump is arranged in a second cooling zone of the power tool. Between the first cooling zone and the second cooling zone a buffer zone is arranged. The buffer zone is separated by at least one first partition from the first cooling zone and by at least one second petition from the second cooling zone.

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 power tool has an internal combustion engine with a cylinder. An injection valve supplies fuel to the internal combustion engine. A fuel pump conveys fuel from a fuel tank to the injection valve. A fan wheel is provided that is driven by the internal combustion engine. The cylinder is arranged in a first cooling zone of the power tool and the fan wheel conveys cooling air through the first cooling zone. The fuel pump is arranged in a second cooling zone of the power tool. Between the first cooling zone and the second cooling zone a buffer zone is arranged. The buffer zone is separated by at least one first partition from the first cooling zone and by at least one second petition from the second cooling zone.

Abstract: A cylinder housing (1) is cast with a cylinder wall (2) in the making of a cylinder for an internal combustion engine. The cylinder wall delimits an interior space (3) for accommodating a reciprocating piston and, thereafter, a control window (5) is machined into the cylinder wall (2) as an opening of a transfer channel (4) into the interior space (3). A two-stage machining for forming the control window (5) is provided in order to make possible a rapid and cost effective manufacture of the cylinder. In a first step with a work tool (7) having a rotating primary movement (11), a breakthrough (10) is machined into the cylinder wall (2) and, in a second step with a work tool, the breakthrough (10) is widened to the wanted dimensions of the control window (5).

Abstract: A mixture lubricated two-stroke engine includes a cylinder (4) having a cylinder head (3) and a cylinder bore (5) open to the crankcase (6). A piston (7) is displaceably arranged in the cylinder bore (5). The piston (7) and the cylinder (4) conjointly delimit a combustion chamber (8). A mixture is led into the crankcase (6) via a mixture inlet (12). The crankcase (6) is flow connected to the combustion chamber (8) via transfer channels (14, 15). The transfer channels (14, 15) are open at their ends (16) toward the crankcase (6) and are connected to bypass channels (18, 19) between the ends (16) of the transfer channels facing toward the crankcase and their ends (17) facing toward the combustion chamber. The bypass channels (18, 19) supply air and open via a membrane valve (20) into the transfer channels. The membrane (21) of the membrane valve (20) is held on a wall part of the transfer channel (14, 15).

Abstract: A cylinder housing (1) is cast with a cylinder wall (2) in the making of a cylinder for an internal combustion engine. The cylinder wall delimits an interior space (3) for accommodating a reciprocating piston and, thereafter, a control window (5) is machined into the cylinder wall (2) as an opening of a transfer channel (4) into the interior space (3). A two-stage machining for forming the control window (5) is provided in order to make possible a rapid and cost effective manufacture of the cylinder. In a first step with a work tool (7) having a rotating primary movement (11), a breakthrough (10) is machined into the cylinder wall (2) and, in a second step with a work tool, the breakthrough (10) is widened to the wanted dimensions of the control window (5).

Abstract: A portable, manually-guided implement, such as a cut-off machine, is provided and has an internal combustion engine, a cylinder of which has a combustion chamber with an exhaust gas outlet. The combustion chamber is delimited by a piston that, via a connecting rod, drives a crankshaft rotatably mounted in a crankcase. Disposed on both sides of a central plane of the cylinder are transfer channels that respectively connect the crankcase with the combustion chamber. The first end of a transfer channel is connected via an inlet window with the combustion chamber, while the second end of the transfer channel is open toward the crankcase. The transfer channels are connected with an air duct that, via a control member, supplies essentially fuel-free combustion air from an air filter. A duct section of the air duct is formed in a housing wall disposed between the carburetor and the engine cylinder.

Abstract: A mixture lubricated two-stroke engine includes a cylinder (4) having a cylinder head (3) and a cylinder bore (5) open to the crankcase (6). A piston (7) is displaceably arranged in the cylinder bore (5). The piston (7) and the cylinder (4) conjointly delimit a combustion chamber (8). A mixture is led into the crankcase (6) via a mixture inlet (12). The crankcase (6) is flow connected to the combustion chamber (8) via transfer channels (14, 15). The transfer channels (14, 15) are open at their ends (16) toward the crankcase (6) and are connected to bypass channels (18, 19) between the ends (16) of the transfer channels facing toward the crankcase and their ends (17) facing toward the combustion chamber. The bypass channels (18, 19) supply air and open via a membrane valve (20) into the transfer channels. The membrane (21) of the membrane valve (20) is held on a wall part of the transfer channel (14, 15).

Abstract: A method is provided for producing a cylinder in a two-cycle engine. The cylinder bore is first machined as a preparation for the provision of a coating. The thereby resulting window edges that surround an inlet window are then at least partially chamfered. The cylinder bore is consequently provided with the coating, which at least partially overlaps the chamfered window edge. There thereby results in the region of the window edge a location of least spacing relative to the axis of the transfer channel. The piston liner or gliding surface is finally machined to a finished dimension such that in the region of the chamfered and coated window edge or corner there is formed a coating edge having a wall spacing relative to the location of least spacing, which such wall spacing having a maximum value of 0.7 mm.

Abstract: A portable, manually-guided implement, such as a cut-off machine, is provided and has an internal combustion engine, a cylinder of which has a combustion chamber with an exhaust gas outlet. The combustion chamber is delimited by a piston that, via a connecting rod, drives a crankshaft that is rotatably mounted in a crankcase. Disposed on both sides of a central plane of the cylinder are transfer channels that respectively connect the crankcase with the combustion chamber. The first end of a transfer channel is connected via an inlet window with the combustion chamber, while the second end of the transfer channel is open toward the crankcase. The transfer channels are connected with an air duct that, via a control member, supplies essentially fuel-free combustion air from an air filter. A duct section of the air duct is formed in a housing wall that is disposed between the carburetor and the cylinder of the engine.

Abstract: A mixture lubricated two-stroke engine includes a cylinder (4) having a cylinder head (3) and a cylinder bore (5) open to the crankcase (6). A piston (7) is displaceably arranged in the cylinder bore (5). The piston (7) and the cylinder (4) conjointly delimit a combustion chamber (8). A mixture is led into the crankcase (6) via a mixture inlet (12). The crankcase (6) is flow connected to the combustion chamber (8) via transfer channels (14, 15). The transfer channels (14, 15) are open at their ends (16) toward the crankcase (6) and are connected to bypass channels (18, 19) between the ends (16) of the transfer channels facing toward the crankcase and their ends (17) facing toward the combustion chamber. The bypass channels (18, 19) supply air and open via a membrane valve (20) into the transfer channels. The membrane (21) of the membrane valve (20) is held on a wall part of the transfer channel (14, 15).

Abstract: A method is provided for producing a cylinder in a two-cycle engine. The cylinder bore is first machined as a preparation for the provision of a coating. The thereby resulting window edges that surround an inlet window are then at least partially chamfered. The cylinder bore is consequently provided with the coating, which at least partially overlaps the chamfered window edge. There thereby results in the region of the window edge a location of least spacing relative to the axis of the transfer channel. The piston liner or gliding surface is finally machined to a finished dimension such that in the region of the chamfered and coated window edge or corner there is formed a coating edge having a wall spacing relative to the location of least spacing, which such wall spacing having a maximum value of 0.7 mm.

Abstract: A cylinder is produced of die cast metal and 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). 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 and are closed by a seated cover (23).

Abstract: A mixture lubricated two-stroke engine includes a cylinder (4) having a cylinder head (3) and a cylinder bore (5) open to the crankcase (6). A piston (7) is displaceably arranged in the cylinder bore (5). The piston (7) and the cylinder (4) conjointly delimit a combustion chamber (8). A mixture is lead into the crankcase (6) via a mixture inlet (12). The crankcase (6) is flow connected to the combustion chamber (8) via transfer channels (14, 15). The transfer channels (14, 15) are open at their ends (16) toward the crankcase (6) and are connected to bypass channels (18, 19) between the ends (16) of the transfer channels facing toward the crankcase and their ends (17) facing toward the combustion chamber. The bypass channels (18, 19) supply air and open via a membrane valve (20) into the transfer channels. The membrane (21) of the membrane valve (20) is held on a wall part of the transfer channel (14, 15).

Abstract: The invention relates to a radial blower for a work apparatus and especially for a suction/blower apparatus. The radial blower has a blower wheel (2) and a blower housing (1) which at least partially surrounds the blower wheel (2). The blower housing (1) includes a peripheral wall (3) and a side wall (4). The housing includes an intake opening (6) in the region of the blower wheel axis (5) as well as a discharge stub (7) peripherally of the blower wheel (2) in the region of the peripheral wall (3). The peripheral wall (3) and the side wall (4) are lined on the side facing toward the blower wheel (2) with a wear insert (8) configured as one piece.

Abstract: The invention relates to a filter element of at least two filter layers (10, 20) wherein the one filter layer (20) is formed from a non-woven fabric (21) and the other filter layer (10) is of an open-pore foam (11) which is attached to the one filter layer (20). Furthermore, a carrier is provided which supports the filter element (1). In order to properly mount the filter element in the filter housing, the non-woven fabric is a felt (21) stiffened by impregnation with a curing liquid. The felt (21) imparts rigidity as a carrier to the filter element (1).

Abstract: The invention relates to a radial blower for a work apparatus and especially for a suction/blower apparatus. The radial blower has a blower wheel (2) and a blower housing (1) which at least partially surrounds the blower wheel (2). The blower housing (1) includes a peripheral wall (3) and a side wall (4). The housing includes an intake opening (6) in the region of the blower wheel axis (5) as well as a discharge stub (7) peripherally of the blower wheel (2) in the region of the peripheral wall (3). The peripheral wall (3) and the side wall (4) are lined on the side facing toward the blower wheel (2) with a wear insert (8) configured as one piece.

Abstract: The invention is directed to a pull-rope starter for an internal combustion engine of a portable handheld work apparatus such as a motor-driven chain saw, cutoff machine or the like. The work apparatus has a housing defining cooling air openings for conducting cooling air and the pull-rope starter includes a rope disc rotatably journalled in the housing in the region of the cooling air openings. A carrier is disposed adjacent the rope disc and seated in the housing so as to close a space in the housing for accommodating a spiral spring mounted on the carrier. The carrier is so configured that its outer periphery is greater than the rope disc. The carrier has a wall section on its side facing toward the rope disc and this wall section extends essentially over the width of the rope slot and over essentially the entire periphery of the rope disc.