Robotic mower with secured screw-nut interface for adjustable cutting height

Patent metadata

Field	Value
Publication number	US-9357699-B2
Application number	US-201214412471-A
Country	US
Kind code	B2
Filing date	Jul 4, 2012
Priority date	Jul 4, 2012
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

A robotic mower includes a chassis, a cutting motor driving at least one cutting blade, and a height adjustment assembly. The cutting motor is mounted on a motor bracket. The motor bracket provides structural support for the cutting motor at an adjustable level relative to the chassis. The height adjustment assembly includes a biasing element, a screw engagement nut, and a height adjustment screw. The screw engagement nut is operably coupled to the motor bracket to enable adjustment of a height of the motor bracket via rotation of the height adjustment screw. The height adjustment screw rotates to translate the screw engagement nut vertically along the height adjustment screw based on an engagement of teeth on the screw engagement nut with threads of the height adjustment screw. The teeth of the screw engagement nut are urged toward the threads of the height adjustment screw via the biasing element.

First claim

That which is claimed:

1. A robotic mower comprising:
a chassis;
a cutting motor mounted on a motor bracket, the cutting motor driving at least one cutting blade, the motor bracket providing structural support for the cutting motor at an adjustable level relative to the chassis; and
a height adjustment assembly comprising a biasing element, a screw engagement nut, and a height adjustment screw, the screw engagement nut being operably coupled to the motor bracket to enable adjustment of a height of the motor bracket via rotation of the height adjustment screw, the height adjustment screw rotating to translate the screw engagement nut vertically along the height adjustment screw based on an engagement of teeth on the screw engagement nut with threads of the height adjustment screw, the teeth of the screw engagement nut being urged toward the threads of the height adjustment screw via the biasing element,
wherein the height adjustment screw is arranged to extend along a first direction to enable adjustment of the height of the motor bracket responsive to translation of the screw engagement nut along the first direction in response to rotation of the height adjustment screw,
wherein the biasing element is disposed to urge the screw engagement nut in a second direction that is substantially perpendicular to the first direction, and
wherein the screw engagement nut is suspended from a pivot point disposed at a portion of a nut housing at least partially surrounding the screw engagement nut.

2. The robotic mower of claim 1 , wherein the teeth of the screw engagement nut comprise at least one top partial tooth disposed above, and at least one bottom partial tooth disposed below, a tooth that is wider than the top partial tooth and the bottom partial tooth.

3. The robotic mower of claim 2 , wherein the height adjustment screw comprises a top stop disposed at one end of a threaded portion of the height adjustment screw and a bottom stop disposed at the other end of the threaded portion, the top and bottom stops extending along a direction substantially parallel to an axis of the height adjustment screw.

4. The robotic mower of claim 3 , wherein a range of motion of the screw engagement nut is defined between a first cutting height at which the top partial tooth engages the top stop and a second cutting height at which the bottom partial tooth engages the bottom stop.

5. The robotic mower of claim 1 , wherein the screw engagement nut includes at least two portions that each extend substantially along the first direction parallel to an axis of the height adjustment screw, and wherein one of the at least two portions lies in a plane that is substantially parallel to and closer to the axis of the height adjustment screw than the other of the at least to portions in order to define a space between the motor bracket and the one of the at least two portions to house the biasing element.

6. The robotic mower of claim 1 , wherein the biasing element comprises an elastic element disposed to urge the screw engagement nut in the second direction.

7. The robotic mower of claim 1 , wherein the biasing element comprises a spring disposed to urge the screw engagement nut away from the motor bracket and toward the height adjustment screw.

8. A height adjustment assembly for a robotic mower comprising a chassis, a cutting motor mounted on a motor bracket, the cutting motor driving at least one cutting blade, the motor bracket providing structural support for the cutting motor at an adjustable level relative to the chassis, the height adjustment assembly comprising:
a biasing element;
a screw engagement nut; and
a height adjustment screw,
wherein the screw engagement nut is operably coupled to the motor bracket to enable adjustment of a height of the motor bracket via rotation of the height adjustment screw, the height adjustment screw rotates to translate the screw engagement nut vertically along the height adjustment screw based on an engagement of teeth on the screw engagement nut with threads of the height adjustment screw, and the teeth of the screw engagement nut are urged toward the threads of the height adjustment screw via the biasing element,
wherein the height adjustment screw is arranged to extend along a first direction to enable adjustment of the height of the motor bracket responsive to translation of the screw engagement nut along the first direction in response to rotation of the height adjustment screw,
wherein the biasing element is disposed to urge the screw engagement nut in a second direction that is substantially perpendicular to the first direction, and
wherein the screw engagement nut is suspended from a pivot point disposed at a portion of a nut housing at least partially surrounding the screw engagement nut.

9. The height adjustment assembly of claim 8 , wherein the teeth of the screw engagement nut comprise at least one top partial tooth disposed above, and at least one bottom partial tooth disposed below, a tooth that is wider than the top partial tooth and the bottom partial tooth.

10. The height adjustment assembly of claim 9 , wherein the height adjustment screw comprises a top stop disposed at one end of a threaded portion of the height adjustment screw and a bottom stop disposed at the other end of the threaded portion, the top and bottom stops extending along a direction substantially parallel to an axis of the height adjustment screw.

11. The height adjustment assembly of claim 10 , wherein a range of motion of the screw engagement nut is defined between a first cutting height at which the top partial tooth engages the top stop and a second cutting height at which the bottom partial tooth engages the bottom stop.

12. The height adjustment assembly of claim 8 , wherein the screw engagement nut includes at least two portions that each extend substantially along the first direction parallel to an axis of the height adjustment screw, and wherein one of the at least two portions lies in a plane that is substantially parallel to and closer to the axis of the height adjustment screw than the other of the at least to portions in order to define a space between the motor bracket and the one of the at least two portions to house the biasing element.

13. The height adjustment assembly of claim 8 , wherein the biasing element comprises an elastic element disposed to urge the screw engagement nut in the second direction.

14. The height adjustment assembly of claim 8 , wherein the biasing element comprises a spring disposed to urge the screw engagement nut away from the motor bracket and toward the height adjustment screw.

15. A height adjustment assembly for a robotic mower comprising a chassis, a cutting motor mounted on a motor bracket, the cutting motor driving at least one cutting blade, the motor bracket providing structural support for the cutting motor at an adjustable level relative to the chassis, the height adjustment assembly comprising:
a biasing element;
a screw engagement nut; and
a height adjustment screw,
wherein the screw engagement nut is operably coupled to the motor bracket to enable adjustment of a height of the motor bracket via rotation of the height adjustment screw, the height adjustment screw rotates to translate the screw engagement nut vertically along the height adjustment screw based on an engagement of teeth on the screw engagement nut with threads of the height adjustment screw, and the teeth of the screw engagement nut are urged toward the threads of the height adjustment screw via the biasing element,
wherein the height adjustment screw is arranged to extend along a first direction to

Assignees

• Elonsson Martin
• Husqvarna Ab

Inventors

• Elonsson Martin

Classifications

• A01D34/74 Primary

  Cutting-height adjustment · CPC title

• A01D34/008

  for automated or remotely controlled operation · CPC title

• Y10T74/18728

  Backlash · CPC title

• F16H25/24

  Elements essential to such mechanisms, e.g. screws, nuts (F16H25/22 takes precedence) · CPC title