Portable handheld motor-driven tool

US4816192A · kind A · utility

Assignee

• Andreas Stihl AG & Co. KG · DE

Inventors

• Mohamed Abou-Aly · Waiblingen, DE
• Eberhard Bohnacker · Waiblingen, DE
• Bernhard Kiefel · Schorndorf, DE
• Reinhard Gerhardy · Bad Marienberg, DE
• Reinhard Friedrich · Waiblingen, DE
• Erich Krauter · Winnenden, DE

Key dates

• Filing date: Nov 20, 1987
• Grant date: Mar 28, 1989
• Expiry date: Nov 20, 2007

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S261/20
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

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.