Abstract: This disclosure is directed to a portable handheld power-driven tool such as a cutoff machine. The cutoff machine includes an engine having a drive shaft. A drive wheel for the work tool is provided at one end of the drive shaft and a fan wheel for moving cooling air to the engine is mounted at the other end of the drive shaft. A pull rope starter is mounted at the power takeoff end of the drive shaft so that it lies outside of the flow of cooling air. In this way, abrasive dust is prevented from accumulating on the pull rope starter and its operational service life is significantly increased.

Abstract: A portable handheld motor-driven tool such as a brushcutter or the like drives a work tool via a drive shaft. The drive shaft is coupled to the motor shaft and is journalled in the motor housing by means of damping member. The respective longitudinal axes of the motor shaft and drive shaft are displaced with respect to each other to prevent vibrations during operation of the motor-driven tool.

Abstract: A portable tool such as a motor-driven chain saw is disclosed which includes a cylinder, a piston, a connecting rod and a crankshaft. The crankshaft is rotatably journalled in crankshaft bearings and a crankcase made of plastic is provided. The bearing shells of the crankshaft bearings are releasably connected only to the cylinder and independently of the plastic crankcase. The plastic crankcase is likewise attached to the cylinder in such a manner that a housing arrangement is provided which is free of transmitted forces and is fully independent of the crankshaft bearings.

Abstract: A crankcase assembly for the engine of a portable tool such as chain saw or the like is disclosed. A plastic crankcase is connected to the cylinder of the engine and an annular insulating member is mounted between the cylinder and the crankcase. The annular insulating member is made of a firm temperature-resistant plastic thereby protecting the crankcase from the temperature developed in the cylinder during the operation of the engine.

Abstract: A single-cylinder motor having a crankshaft mounted or journalled in the crankcase by means of roller-bearing sets. A crank web or lobe with a crankshaft pin is arranged at one end of the crankshaft. The crankshaft pin is drivingly connected via a connecting rod with the piston of the piston-cylinder unit. The other end of the crankshaft, in the region of the end segment thereof, carries the rotor of a magneto ignition device, whereby an end journal of the crankshaft can be coupled with a power take-off or output member. To journal or mount the crankshaft, the roller-body sets are arranged axially nondetachable in a sleeve which coaxially surrounds the crankshaft, whereby the sleeve is pressed or forced into a recess of the crankcase. The sleeve, the roller body sets, and the crankshaft form a structural unit capable of being preassembled.