Cutter blade for pneumatically transporting grass clippings

Abstract

Disclosed herein is a cutter blade for a rotary lawn mower, which cutter blade is generally of elongated rectangular outline and includes a leading edge, a trailing edge, a longitudinal axis extending lengthwise between the leading and trailing edges, a generally planar outer end portion including a cutting edge forming a part of the leading edge and an outer tip, and a sail portion extending from outer end portion along a form line extending between the outer tip and the trailing edge at a form angle within the range of 25 degrees to 35 degrees to the longitudinal axis. The sail portion also has an upper edge which is spaced above a horizontal plane containing the cutting edge at a height of between 0.65 inches and 0.75 inches and which extends continuously concavely arcuately outwardly and upwardly from the form line at a uniform radius between 1.00 inches and 1.40 inches measured in a plane perpendicular to the form line.

I claim: 
     
       1. A cutter blade for a rotary lawn mower, said cutter blade being generally of elongated rectangular outline and including a leading edge, a trailing edge, a longitudinal axis extending lengthwise between said leading and trailing edges, a generally planar outer end portion including a cutting edge forming a part of said leading edge and an outer tip which travels at a speed between 14,000 fpm and 19,000 fpm when rotated by the lawn mower, and a sail portion extending from said outer end portion along a form line extending from said outer tip to said trailing edge at a form angle within the range of 25 degrees to 35 degrees to said longitudinal axis, said sail portion having an upper edge spaced above a horizontal plane including said cutting edge at a height of between 0.65 inches and 0.75 inches, and said sail portion extending continuously concavely arcuately outwardly and upwardly from said form line. 
     
     
       2. A cutter blade in accordance with claim 1 wherein said form angle is 30 degrees. 
     
     
       3. A cutter blade in accordance with claim 1 wherein said sail portion extends concavely arcuately outwardly and upwardly from said form line at a uniform radius measured in a plane perpendicular to said form line. 
     
     
       4. A cutter blade in accordance with claim 3 wherein said radius is between 1.00 inches and 1.40 inches. 
     
     
       5. A cutter blade in accordance with claim 4 wherein said radius is 1.20 inches. 
     
     
       6. A cutter blade in accordance with claim 1 wherein said sail portion has a chord length of between 2.20 inches and 3.00 inches measured in a plane perpendicular to said longitudinal axis and from said leading edge to said sail upper edge. 
     
     
       7. A cutter blade in accordance with claim 1 wherein said sail portion has an angle of attack of between 13 degrees and 18 degrees measured in a plane perpendicular to said longitudinal axis and between a horizontal line and a line extending from the said cutting edge to said sail upper edge. 
     
     
       8. A cutter blade for a rotary lawn mower, said cutter blade being generally of elongated rectangular outline and including a leading edge, a trailing edge, a longitudinal axis extending lengthwise between said leading and trailing edges, a generally planar outer end portion including a cutting edge forming a part of said leading edge, and an outer tip which travels at a speed between 14,000 fpm and 19,000 fpm when rotated by the lawn mower, and a sail portion extending from said outer end portion along a form line extending from said outer tip to said trailing edge at a form angle within the range of 25 degrees to 35 degrees to said longitudinal axis, said sail portion having an upper edge spaced above a horizontal plane containing said cutting edge at a height of between 0.65 inches and 0.75 inches and said sail portion extending continuously concavely arcuately outwardly and upwardly from said form line at a uniform radius between 1.00 inches and 1.40 inches measured in a plane perpendicular to said form line, and said sail portion also having a chord length of between 2.20 inches and 3.00 inches measured in a plane perpendicular to said longitudinal axis and from said cutting edge to said sail upper edge, and having an angle of attack of between 13 degrees and 18 degrees measured in a plane perpendicular to said longitudinal axis and between a horizontal line and a line extending from said cutting edge to said sail upper edge. 
     
     
       9. A cutter blade for a rotary lawn mower, said cutter blade being generally of elongated rectangular outline and including a leading edge, a trailing edge, a longitudinal axis extending lengthwise between said leading and trailing edges, a generally planar outer end portion including a cutting edge forming a part of said leading edge, and an outer tip which travels at a speed between 14,000 fpm and 19,000 fpm when rotated by the lawn mower, and a sail portion extending from said outer end portion along a form line extending in the plane of said outer end portion from said outer tip to said trailing edge at a form angle of 30 degrees to said longitudinal axis, said sail portion having an upper edge spaced above a horizontal plane containing said cutting edge at a height of 0.70 inches and extending continuously concavely arcuately outwardly and upwardly from said form line at a uniform radius of 1.20 inches measured in a plane perpendicular to said form line, said sail portion having a chord length of between 2.20 inches and 3.00 inches measured in a plane perpendicular to said longitudinal axis and from said cutting edge to said sail upper edge and having an angle of attack of between 13 degrees and 18 degrees measured in a plane perpendicular to said longitudinal axis and between a horizontal line and a line extending from said cutting edge to said sail upper edge. 
     
     
       10. A rotary lawn mower comprising a housing supported for travel over the ground and including a top deck and a depending skirt, an engine mounted on said top deck and including an output shaft extending veritcally downwardly through said top deck, and a cutter blade located within said housing and driven by said output shaft, said cutter blade being generally of elongated rectangular outline and including a leading edge, a trailing edge, a longitudinal axis extending lengthwise between said leading and trailing edges, a generally planar outer end portion including a cutting edge forming a part of said leading edge, and an outer tip which travels at a speed between 14,000 fpm and 19,000 fpm, and a sail portion extending from said outer end portion along a form line extending from said outer tip to said trailing edge at a form angle within the range of 25 degrees to 35 degrees to said longitudinal axis, said sail portion having an upper edge spaced above a horizontal plane including said cutting edge at a height of between 0.65 inches and 0.75 inches and extending continuously concavely arcuately outwardly and upwardly from said form line. 
     
     
       11. A rotary lawn mower in accordance with claim 10 wherein said form angle is 30 degrees. 
     
     
       12. A rotary lawn mower in accordance with claim 10 wherein said sail portion extends concavely arcuately outwardly and upwardly from said form line at a uniform radius measured in a plane perpendicular to said form line. 
     
     
       13. A rotary lawn mower in accordance with claim 12 wherein said radius is between 1.00 inches and 1.40 inches. 
     
     
       14. A rotary lawn mower in accordance with claim 13 wherein said radius is 1.20 inches. 
     
     
       15. A rotary lawn mower in accordance with claim 10 wherein said sail portion has a chord length of between 2.20 inches and 3.00 inches measured in a plane perpendicular to said longitudinal axis and from said cutting edge to said sail upper edge. 
     
     
       16. A rotary lawn mower in accordance with claim 10 wherein said sail portion has an angle of attack of between 13 degrees and 18 degrees measured in a plane perpendicular to said longitudinal axis and between a horizontal line and a line extending from the said cutting edge to said sail upper edge. 
     
     
       17. A rotary lawn mower comprising a housing supported for travel over the ground and including a top deck and a depending skirt, an engine mounted on said top deck and including an output shaft extending vertically downwardly through said top deck, and a cutter blade located within said housing and driven by said output shaft, said cutter blade being generally of elongated rectangular outline and including a leading edge, a trailing edge, a longitudinal axis extending lengthwise between said leading and trailing edges, a generally planar outer end portion including a cutting edge forming a part of said leading edge and an outer tip which travels at a speed between 14,000 fpm and 19,000 fpm, and a sail portion extending from said outer end portion along a form line extending from said outer tip to said trailing edge at a form angle within the range of 25 degrees to 35 degrees to said longitudinal axis, said sail portion having an upper edge spaced above a horizontal plane including said cutting edge at a height of between 0.65 inches and 0.75 inches and extending continuously concavely arcuately outwardly and upwardly from said form line at a uniform radius between 1.00 inches and 1.40 inches measured in a plane perpendicular to said form line, and said sail portion also having a chord length of between 2.20 inches and 3.00 inches measured in a plane perpendicular to said longitudinal axis and from said cutting edge to said sail upper edge and having an angle of attack of between 13 degrees and 18 degrees measured in a plane perpendicular to said longitudinal axis and between a horizontal line and a line extending from said cutting edge to said sail upper edge. 
     
     
       18. A rotary lawn mower comprising a housing supported for travel over the ground and including a top deck and a depending skirt, an engine mounted on said top deck and including an output shaft extending vertically downwardly through said top deck, and a cutter blade located within said housing and driven by said output shaft, said cutter blade being generally of elongated rectangular outline and including a leading edge, a trailing edge, a longitudinal axis extending lengthwise between said leading and trailing edges, a generally planar outer end portion including a cutting edge forming a part of said leading edge and an outer tip which travels at a speed between 14,000 fpm and 19,000 fpm, and a sail portion extending from said outer end portion along a form line extending in the plane of said outer end portion from said outer tip to said trailing edge at a form angle of 30 degrees to said longitudinal axis, said sail portion having an upper edge spaced above a horizontal plane including said cutting edge at a height of 0.70 inches and extending continuously concavely arcuately outwardly and upwardly from said form line at a uniform radius of 1.20 inches measured in a plane perpendicular to said form line, said sail portion having a chord length of between 2.20 inches and 3.00 inches measured in a plane perpendicular to said longitudinal axis and from said cutting edge to said sail upper edge and having an angle of attack of between 13 degrees and 18 degrees measured in a plane perpendicular to said longitudinal axis and between a horizontal line and a line extending from the said cutting edge to said sail upper edge. .Iadd. 
     
     
       19.  A cutter blade for a rotary lawn mower, said cutter blade being generally of elongated rectangular outline and including a leading edge, a trailing edge, a longitudinal axis extending lengthwise between said leading and trailing edges, a generally planar outer end portion including a cutting edge forming a part of said leading edge and an outer tip which travels at a speed between 14,000 fpm and 19,000 fpm when rotated by the lawn mower, and a sail portion extending from said outer end portion along a form line extending from said outer tip to said trailing edge at a form angle within the range of 25 degrees to 35 degrees to said longitudinal axis, said sail portion having an upper edge spaced above a horizontal plane including said cutting edge at a height of at least 0.65 inches, and said sail portion extending continuously concavely arcuately outwardly and upwardly from said form line..Iaddend. .Iadd.20. A cutter blade in accordance with claim 19 wherein said form angle is 30 degrees..Iaddend. .Iadd.21. A cutter blade in accordance with claim 19 wherein said sail portion extends concavely arcuately outwardly and upwardly from said form line at a uniform radius measured in a plane perpendicular to said form 
     
     
        line..Iaddend. .Iadd.22.  A cutter blade in accordance with claim 21 wherein said radius is between 1.00 inches and 1.40 inches..Iaddend. .Iadd.23. A cutter blade in accordance with claim 22 wherein said radius is 1.20 inches..Iaddend. .Iadd.24. A cutter blade in accordance with claim 19 wherein said sail portion has a chord length of between 2.20 inches and 3.00 inches measured in a plane perpendicular to said longitudinal axis and from said leading edge to said sail upper edge..Iaddend. .Iadd.25. A cutter blade in accordance with claim 19 wherein said sail portion has an angle of attack of between 13 degrees and 18 degrees measured in a plane perpendicular to said longitudinal axis and between a horizontal line and a line extending from said cutting edge to said sail upper edge..Iaddend. 
     
     
        .Iadd.26.  A rotary lawn mower comprising a housing supported for travel over the ground and including a top deck and a depending skirt, an engine mounted on said top deck and including an output shaft extending vertically downwardly through said top deck, and a cutter blade located within said housing and driven by said output shaft, said cutter blade being generally of elongated rectangular outline and including a leading edge, a trailing edge, a longitudinal axis extending lengthwise between said leading and trailing edges, a generally planar outer end portion including a cutting edge forming a part of said leading edge, and an outer tip which travels at a speed between 14,000 fpm and 19,000 fpm, and a sail portion extending from said outer end portion along a form line extending from said outer tip to said trailing edge at a form angle within the range of 25 degrees to 35 degrees to said longitudinal axis, said sail portion having an upper edge spaced above a horizontal plane including said cutting edge at a height of at least 0.65 inches and extending continuously concavely arcuately outwardly and upwardly from said form line..Iaddend. .Iadd.27. A rotary lawn mower in accordance with claim 26 
     
     
        wherein said form angle is 30 degrees..Iaddend. .Iadd.28.  A rotary lawn mower in accordance with claim 26 wherein said sail portion extends concavely arcuately outwardly and upwardly from said form line at a uniform radius measured in a plane perpendicular to said form line..Iaddend. .Iadd.29. A rotary lawn mower in accordance with claim 28 wherein said radius is between 1.00 inches and 1.40 inches..Iaddend. .Iadd.30. A rotary lawn mower in accordance with claim 29 wherein said radius is 1.20 inches..Iaddend. .Iadd.31. A rotary lawn mower in accordance with claim 26 wherein said sail portion has a chord length of between 2.20 inches and 3.0 inches measured in a plane perpendicular to said longitudinal axis and from said cutting edge to said sail upper edge..Iaddend. .Iadd.32. A rotary lawn mower in accordance with claim 26 wherein said sail portion has an angle of attack of between 13 degrees and 18 degrees measured in a plane perpendicular to said longitudinal axis and between a horizontal line and a line extending from said cutting edge to said sail upper edge..Iaddend.