NZ782637B2

NZ782637B2 - High efficiency lawn mower blade

Info

Publication number: NZ782637B2
Application number: NZ782637A
Authority: NZ
Inventors: John Southwell
Original assignee: Husqvarna Ab
Filing date: 2020-10-20
Publication date: 2025-01-28

Abstract

cutting blade (100) for a lawn mower may include a mounting portion (130) and a plurality of cutting elements (102,104,106,108). The mounting portion (130) may include a plurality of mounting arms (136) and a mounting orifice (132) formed at an axis of the cutting blade. The mounting orifice (132) may be configured to interface with a shaft of the lawn mower. Each of the cutting elements (102,104,106,108) may be operably coupled to a corresponding one of the mounting arms (136). Each of the cutting elements may include a wing portion (110) at a distal end thereof, and a transition region (120) configured to operably couple the wing portion (110) to a respective one of the mounting arms (136). The cutting elements may further include a first cutting edge (140) disposed at the wing portion (110), and a second cutting edge (142) disposed at the transition region (120). The transition region (120) is configured to taper in width from a leading edge to a trailing edge thereof from the constant chord length of the wing portion (110) at a distal end of the transition region (120) to the width of the mounting arm (136) at a proximal end of the transition region (120). The transition region (120) further comprises an aerodynamic orifice (300). Turning the mower blade can be one of the main sources of power consumption in a battery powered lawnmower. The invention provides a tapered cutting blade with an aerodynamic orifice to reduce power consumption and increase usage time.

Claims

THAT WHICH IS CLAIMED:

1. A cutting blade when used on a lawn mower, the cutting blade comprising: a mounting portion comprising a plurality of mounting arms and a mounting orifice formed at an axis of rotation of the g blade, the mounting e being configured to interface with a shaft of the lawn mower, and each of the plurality of mounting arms having a constant width; and a plurality of cutting elements, each of the cutting elements operably d to a corresponding one of the mounting arms, wherein each of the g ts comprises a wing portion at a distal end f, the wing portion having a nt chord length in a distal direction, and a transition region configured to operably couple the wing portion to a respective one of the mounting arms, wherein the transition region broadens and twists in the distal direction such that a width of a proximal end of the transition region is equal to the width of the respective one of the mounting arms and a chord length at a distal end of the transition region is equal to the chord length of the wing portion, wherein the cutting elements further comprise a first cutting edge disposed at the wing portion, and a second cutting edge disposed at the transition region; wherein the transition region is configured to taper in width from a leading edge to a trailing edge thereof from the constant chord length of the wing portion at a distal end of the transition region to the width of the mounting arm at a proximal end of the transition region; and further wherein the transition region comprises an aerodynamic orifice disposed at a portion thereof.

2. The cutting blade of claim 1, n the first cutting edge of each of the cutting elements extends linearly across a leading edge of the wing portion from a proximal end of the wing portion to a distal end of the wing portion, and wherein the first cutting edge of each of the cutting ts lies in a cutting plane.

3. The cutting blade of claim 2, n the wing portion further comprises a trail edge disposed opposite the first cutting edge on the wing portion and extending substantially el to the first cutting edge, and wherein the trail edge of each of the g elements lies in a trail edge plane.

4. The cutting blade of claim 3, wherein the mounting n lies in a plane about half way between the trail edge plane and the cutting plane.

5. The cutting blade of claim 3, n the trail edge is chamfered.

6. The cutting blade of claim 3, wherein the second cutting edge extends across a g edge of the transition region from a proximal end of the transition region to a distal end of the transition region.

7. The cutting blade of claim 6, n the second cutting edge and the first cutting edge form a continuous cutting surface, and wherein the second cutting edge extends away from the cutting plane as the second cutting edge moves away from the distal end of the transition region toward the proximal end of the transition region.

8. The cutting blade of claim 7, wherein the second cutting edge bends away from the trail edge as the second cutting edge moves away from the distal end of the transition region toward the proximal end of the transition region.

9. The cutting blade of claim 3, wherein the constant chord length of the wing n from the first cutting edge to the trail edge is more than twice a width of the mounting

10. The cutting blade of claim 1, wherein the aerodynamic orifice has a square shape with rounded corners.

11. The cutting blade of claim 1 or 10, wherein the aerodynamic orifice is disposed at a center of the tion region.

12. The cutting blade of claim 1, wherein the wing portion is configured to curve from the first cutting edge to a trail edge defining an attack angle of n about 15 degrees and 20 degrees.

13. The cutting blade of claim 1, wherein the wing portion is swept ve to the mounting arm at a swept angle of between about 20 degrees and 40 degrees.

14. The cutting blade of claim 13, wherein the swept angle is about 30 s.

15. The cutting blade of claim 1, wherein the cutting blade comprises four cutting elements equidistantly spaced apart from each other.

16. The cutting blade of claim 1, wherein the wing n is curved and the mounting portion is flat, and wherein the transition region is flat at a proximal end thereof and curved at a distal end thereof to transition from the ng portion to the wing portion.

17. The cutting blade of claim 16, wherein the distal end of the transition region includes a first portion that extends downward from a plane in which the mounting portion lies to the first cutting edge, and a second portion that extends upward from the plane to a trail edge of the wing portion. SUBSTITUTE SHEET (RULE 26) SUBSTITUTE SHEET (RULE 26) iiuiiu‘:3.... SUBSTITUTE SHEET (RULE 26) SUBSTITUTE SHEET (RULE 26) SUBSTITUTE SHEET (RULE 26)