Blade guard for a robot lawnmower

Patent metadata

Field	Value
Publication number	US-11058053-B2
Application number	US-201916369702-A
Country	US
Kind code	B2
Filing date	Mar 29, 2019
Priority date	Mar 30, 2018
Publication date	Jul 13, 2021
Grant date	Jul 13, 2021

Abstract

An autonomous robot lawnmower includes a blade assembly including blades, a drive system to drive the blades through a cutting area having a cutting width, and a lateral blade guard including at least four bars spaced apart from one another by no less than 1 mm and no more than 15 mm. The at least four bars are positioned between the blades and a mowable area when the robot lawnmower is supported on the mowable area. The at least four bars extend across a portion of the cutting width and extending rearward and forward of the cutting area.

First claim

What is claimed is:

1. An autonomous robot lawnmower comprising:
a first blade assembly comprising blades;
a second blade assembly comprising blades;
a first drive system to drive the blades of the first blade assembly through a first cutting area, the first cutting area extending across a first portion of a cutting width of the robot lawnmower;
a second drive system to drive the blades of the second blade assembly through a second cutting area, the second cutting area extending across a second portion of the cutting width; and
first and second lateral blade guards, the first lateral blade guard covering the first blade assembly and the second lateral blade guard covering the second blade assembly,
wherein the first lateral blade guard comprises at least four bars spaced apart from one another by no less than 1 mm and no more than 15 mm, the at least four bars positioned between the blades of the first blade assembly and a mowable area when the robot lawnmower is supported on the mowable area, the at least four bars extending at least partially across the first portion of the cutting width and extending rearward and forward of the first cutting area.

2. The robot lawnmower of claim 1 , wherein each of the at least four bars comprises a front portion, a bottom portion, and a back portion, the bottom portion being generally parallel to a cutting deck to which the at least four bars are mounted, and the front portion and the back portion angled toward the bottom portion such that a distance between a top end of the front portion and a top end of the back portion is greater than a distance between a bottom end of the front portion and a bottom end of the back portion.

3. The robot lawnmower of claim 2 , wherein the front portion of the at least four bars are attached to the cutting deck.

4. The robot lawnmower of claim 2 , wherein the at least four bars of the front portion define a plurality of front facing openings such that grass on the mowable area pass through the front facing openings toward the blades of the first blade assembly when the robot lawnmower moves in a forward drive direction.

5. The robot lawnmower of claim 1 , wherein the at least four bars are substantially parallel to one another.

6. The robot lawnmower of claim 5 , wherein the at least four bars are substantially parallel to a forward drive direction of the robot lawnmower.

7. The robot lawnmower of claim 5 , wherein an angle between any two of the at least four bars is no more than 5 degrees.

8. The robot lawnmower of claim 1 , wherein each of the at least four bars comprises:
a bottom portion parallel to the mowable area, and
a rear portion angled upward relative to the bottom portion.

9. The robot lawnmower of claim 1 , wherein an outermost of the at least four bars is a shortest of the at least four bars, and an innermost of the at least four bars is a longest of the at least four bars.

10. The robot lawnmower of claim 1 , wherein a width of each of the at least four bars is no greater than 1 mm to 10 mm.

11. The robot lawnmower of claim 1 , wherein:
the first drive system is configured to rotate the first blade assembly to sweep the blades of the first blade assembly through the first cutting area, the first cutting area being defined by a first circumference swept by tips of the blades of the first blade assembly,
wherein ends of the at least four bars are positioned along a second circumference offset from the first circumference.

12. The robot lawnmower of claim 11 , wherein a diameter of the second circumference is 3 to 12 cm greater than a diameter of the first circumference swept by the blades of the first blade assembly.

13. The robot lawnmower of claim 1 , wherein each of the at least four bars comprises:
a bottom portion parallel to the mowable area, and
a front portion connected to the bottom portion, the front portion being angled upward relative to the bottom portion.

14. The robot lawnmower of claim 1 , wherein a height between the blades of the first blade assembly and a bottom portion of each of the at least four bars is no less than 2 to 14 mm.

15. The robot lawnmower of claim 1 , wherein a minimum distance between an outer perimeter of the robot lawnmower and the first lateral blade guard is no more than 4 cm to 6 cm.

16. The robot lawnmower of claim 1 , wherein an innermost of the at least four bars is at least 2 to 10 cm from an outer perimeter of the robot lawnmower.

17. The robot lawnmower of claim 1 , wherein:
the second lateral blade guard comprises at least four bars spaced apart from one another by no less than 1 mm and no more than 15 mm, the at least four bars of the second lateral blade guard positioned between the blades of the second blade assembly and the mowable area when the robot lawnmower is supported on the mowable area, each of the at least four bars of the second lateral blade guard extending across the second portion of the cutting width and extending rearward and forward of the second cutting area of the blades of the second blade assembly.

18. The robot lawnmower of claim 17 , wherein the first lateral blade guard and the second lateral blade guard cover between 10% and 30% of the cutting width of the first blade assembly and the second blade assembly.

19. The robot lawnmower of claim 17 , further comprising a central blade guard between the first lateral blade guard and the second lateral blade guard, the central blade guard detachably connected to a cutting deck to which the first lateral blade guard and the second lateral blade guard are mounted.

20. The robot lawnmower of claim 19 , wherein the central blade guard comprises a plurality of bars extending along a forward drive direction of the robot lawnmower and a plurality of transverse bars transverse to the forward drive direction of the robot lawnmower.

21. The robot lawnmower of claim 1 , wherein each of the blades of the first blade assembly and the second blade assembly comprises a sharpened edge, an entirety of the sharpened edge being positionable directly between the first lateral blade guard or the second lateral blade guard and the mowable area.

Assignees

• Irobot Corp

Inventors

• Patel Shaan
• Doughty Brian

Classifications

• A01D75/20 Primary

  Devices for protecting men or animals · CPC title

• A01D2101/00

  Lawn-mowers · CPC title

• A01D34/81 Primary

  Casings; Housings (A01D34/71 takes precedence) · CPC title

• A01D34/828

  Safety devices · CPC title

• A01D34/66

  with two or more cutters · CPC title