The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 03, 1993
Filed:
Feb. 10, 1993
Helmut Lux, Waiblingen-Bittenfeld, DE;
Lothar Ulrich, Schwaikheim, DE;
Andreas Stihl, Waiblingen, DE;
Abstract
The invention is directed to a portable handheld work apparatus including a motor-driven chain saw, cutoff machine and the like. The work apparatus includes a housing and an internal combustion engine mounted in the housing for driving a work tool. The housing defines a space from which said engine draws combustion air and a fan wheel is disposed in the housing for generating a cooling-air flow which leaves the fan wheel in a direction tangential to the periphery of the fan wheel for cooling the engine. The housing has a U-shaped channel for conducting the cooling-air flow. The U-shaped channel is disposed so as to face toward the fan wheel with the base wall thereof being disposed at a predetermined spacing from the periphery of the fan wheel. The U-shaped channel has a pass-through formed in the base wall at a pregiven spacing downstream from the fan wheel for passing a portion of the cooling-air flow to the space as combustion air for the engine. The pass-through defines a plane and a center axis perpendicular to the plane. The U-shaped channel is configured to impart a predetermined direction of flow to the cooling-air flow at the region of the pass-through and the center axis and the predetermined direction of flow conjointly define an angle .beta. having a value in a range of approximately 70.degree. to 180.degree..