Portable handheld motor-driven tool

摘要

The invention is directed to a handheld, portable tool such as a chain saw equipped with an internal combustion engine mounted in an engine housing. The engine has a carburetor defining an air-intake channel. A heating element is provided which is electrically connected to the generator of the chain saw and mounted on the carburetor in the region of the air-intake channel. The heating element has a positive temperature coefficient and a predetermined temperature region thereby preventing the carburetor housing and the throttle flap from heating to a temperature above a predetermined value. The heating element and the way it is mounted prevents icing at the carburetor in cold weather thereby enabling the engine to run uninterruptedly and uniformly especially when the engine idles.