Abstract: A guide bar for motor chainsaws has side plates and a middle section between the side plates connected fixedly and non-movably to the side plates. The side plates form a clamping section and a deflection section opposite the clamping section. A guide groove extends circumferentially about the guide bar. The middle section forms the guide groove bottom in the deflection section. A guide bar tip is located where the longitudinal center axis of the guide bar intersects the deflection section. The side plates each have a guide surface extending continuously across a first longitudinal side of the guide bar, the deflection section, and a second longitudinal side of the guide bar. The guide surfaces of the side plates have hardened regions at the first and second longitudinal sides and at the guide bar tip with a hardness greater than a hardness of a middle region of the side plates.

Abstract: A guide bar for motor chainsaws has side plates and a middle section between the side plates connected fixedly and non-movably to the side plates. The side plates form a clamping section and a deflection section opposite the clamping section. A guide groove extends circumferentially about the guide bar. The middle section forms the guide groove bottom in the deflection section. A guide bar tip is located where the longitudinal center axis of the guide bar intersects the deflection section. The side plates each have a guide surface extending continuously across a first longitudinal side of the guide bar, the deflection section, and a second longitudinal side of the guide bar. The guide surfaces of the side plates have hardened regions at the first and second longitudinal sides and at the guide bar tip with a hardness greater than a hardness of a middle region of the side plates.

Abstract: An internal combustion engine has a cylinder liner arranged in the cylinder. A piston moves reciprocatingly in a direction of the longitudinal cylinder axis in the cylinder and is guided within the cylinder liner across a section of a movement path of the piston in the cylinder. A combustion chamber disposed in the cylinder is delimited by the piston. In a crankcase, a crankshaft is rotatably supported by a crankshaft bearing, wherein the crankshaft is driven in rotation by the piston about an axis of rotation of the crankshaft. A position of the cylinder liner relative to the crankcase is secured with form fit by a securing element located at an end face of the cylinder liner that is facing the crankcase. No loads are transmitted into the cylinder liner from the crankshaft bearing through the end face of the cylinder liner that is facing the crankcase.

Abstract: A two-stroke engine has a cylinder with a combustion chamber and a piston reciprocatingly supported in the cylinder. A crankshaft is rotatably supported in a crankcase and driven by the piston. At least one transfer passage connects the crankcase in at least one position of the piston with the combustion chamber and has a piston-controlled transfer port that opens into the combustion chamber and an opening that opens into the crankcase. A mixture inlet opens into the crankcase. An outlet is provided at the combustion chamber. The transfer port and the opening are displaced relative to each other in a circumferential direction of the cylinder. At least one wall section of the transfer passage forms an undercut when viewed from the crankcase in a direction of a longitudinal cylinder axis of the cylinder and is delimited by a separate component inserted into the cylinder from a side facing the crankcase.

Abstract: An arrangement forms control windows (5) in a cylinder wall (2) of a cylinder housing (1) for a two-stroke internal combustion engine as openings of flow channels (4) in the interior space (3) of the cylinder delimited by the cylinder wall (2). The arrangement includes a driveable tool (7) which can be introduced at a free end (16) of a rotatable tool holder (17) into the interior space (3). The tool (7) can be brought into engagement with the cylinder wall (2) in the position in which the control window (5) is to be formed by transverse movement (13) with reference to a rotational axis (11) of the tool holder (17). A milling tool having a drive axis (19) is provided which lies essentially orthogonally to the rotational axis (11) of the tool holder (17) in order to provide a rapid and cost effective manufacture of a cylinder housing (1) with a precise manufacture of the control windows (5) in the cylinder wall (2).