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:
Jun. 28, 1977
Filed:
Aug. 08, 1975
Donald Earl Fleigle, Frostburg, MD (US);
The Black and Decker Manufacturing Company, Towson, MD (US);
Abstract
In a cordless electric rotary lawnmower, for example, of the type having two counter-rotating blades, a blade configuration providing substantially improved efficiency and performance is disclosed. The lawnmower is battery operated and each blade in a twin blade mower, or the single blade of a single blade mower, is provided with a configuration to maximize cutting effectiveness, air flow and blade life. The blade comprises a generally rectangular strip of metal having a cross section defined by two parallel spaced flat surfaces joined at their ends by generally tapering surfaces. The flat surfaces extend across approximately 50 to 70% of the total width of the blade adjacent the blade ends and preferably extend across about 60%. In addition, the blade deviates from a rectangular strip in that its outer portions are twisted downwardly from a planar portion at the center to define a lift angle to obtain axial air flow. On the bottom surface of the outer portions, the tapering surface comprises a flat to provide a sharp cutting edge.