Rotary lawn mower cutting blade

Abstract

A rotary lawn mower cutting blade with reduced drag and improved cutting ability includes a central mounting section, intermediate sections, and outboard sections along a common longitudinal axis and disposed about a common center of rotation. The outboard sections include downward and inward projecting sections. The cutting blade also preferably includes cutting edges on the full extent of the leading edge of the outboard section including the downward and inward projecting sections. Additionally, the outer section can be twisted slightly to enhance airflow upward.

1 . A rotary lawn mower cutting blade comprising:
 a center portion joined to respective intermediate portions which in turn are joined to respective first and second outer portions;   first and second inwardly extending cutting portions, the first inwardly extending cutting portion being joined to said first outer portion through a first downwardly extending end portion extending downwardly from said first outer portion, the second inwardly extending cutting portion being joined to said second outer portion through a second downwardly extending end portion extending downwardly from said second outer portion;   wherein said first cutting portion has an inwardly extending leading cutting edge and an inwardly extending trailing edge, the leading cutting edge of said first cutting portion facing forward of said rotary lawn mower cutting blade, the trailing edge of said first cutting portion facing rearward of said rotary lawn mower cutting blade; and   wherein said second cutting portion has an inwardly extending leading cutting edge and an inwardly extending trailing edge, the leading cutting edge of said second cutting portion facing rearward of said rotary lawn mower cutting blade, the trailing edge of said second cutting portion facing forward of said rotary lawn mower cutting blade.   
     
     
         2 . The rotary lawn mower cutting blade of  claim 1 , wherein said leading cutting edge of said first cutting portion extends contiguously along said first cutting portion and said first downwardly extending end portion. 
     
     
         3 . The rotary lawn mower cutting blade of  claim 1 , wherein said leading cutting edge of said first cutting portion extends contiguously along said first cutting portion, said first downwardly extending end portion, and said first outer portion. 
     
     
         4 . The rotary lawn mower cutting blade of  claim 1 , wherein the intermediate portions are twisted so as to cause the trailing edges of said first and second cutting portions to be slightly higher than their respective leading cutting edges. 
     
     
         5 . The rotary lawn mower cutting blade of  claim 1 , wherein said cutting blade includes a center of rotation, and wherein the plane or axis of said first and second end portions are skewed causing a first edge of each of said first and second end portions to be closer to said center of rotation than a second edge of each of said first and second end portions. 
     
     
         6 . The rotary lawn mower cutting blade of  claim 1 , wherein each of said first and second outer portions has a leading cutting edge. 
     
     
         7 . The rotary lawn mower cutting blade of  claim 1 , wherein said leading cutting edge of each of said first and second inwardly extending cutting portions is beveled to define said inwardly extending leading cutting edge. 
     
     
         8 . The rotary lawn mower cutting blade of  claim 1 , wherein said center portion includes mounting means. 
     
     
         9 . The rotary lawn mower cutting blade of  claim 1 , wherein said center portion is adapted to be mounted to an external body. 
     
     
         10 . The rotary lawn mower cutting blade of  claim 1 , wherein said rotary lawn mower cutting blade is adapted to be mounted to an external body.