Modular Robotic Lawnmower Fence with Adjustable Depth Anchoring

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Solution Overview

Problem

Existing methods for delimiting the operating area of robotic lawn mowers are costly and time-consuming, particularly when temporary restrictions are needed to avoid obstacles like gardens or freshly sown grass within the working area.

Innovation Solution

A physical robotic lawnmower fence with a bracket and support elements that can be easily anchored in the ground, featuring a crossbar for collision detection and a design that allows for uniform collision behavior and stability, enabling the fence to be easily assembled and disassembled.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If boundary wire is modified or expanded to delimit operating area, then the robotic lawnmower can be restricted from entering specific zones, but the process becomes costly and time consuming

Engineering Contradiction:
Improveability to delimit operating areaVSAvoidtime for boundary wire modification
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The fence is divided into modular components: a bracket with two legs, a crossbar, and separate support elements. This segmentation allows the fence to be easily assembled and disassembled, enabling quick deployment and relocation without time-consuming modifications to boundary wires or permanent installations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fence design allows for dynamic reconfiguration - the support elements can be moved along the legs to adjust the maximum depression depth, and the entire fence can be easily relocated. This dynamic adaptability provides flexible delimitation of operating areas without the permanent commitment of boundary wire modifications.

Inventive Principle:
Principle #15Dynamics

2Strength

If fence is anchored deeper into the ground to ensure stability, then the fence can withstand robotic lawnmower collision, but the installation becomes more complex and time consuming

Engineering Contradiction:
Improvewithstand collision forceVSAvoidanchoring complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The support elements are pre-configured with apertures that guide the legs through them during installation. The maximum depression depth is pre-defined by the support element positioning, eliminating the need for complex measurement and adjustment processes during anchoring. This preliminary configuration simplifies the installation while ensuring adequate anchoring depth for collision resistance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The friction between the leg and support element aperture provides self-retaining functionality, automatically holding the support element in place at the correct depth without requiring additional fastening mechanisms or complex anchoring procedures. The system anchors itself through the friction-based retention mechanism.

Inventive Principle:
Principle #25Self-service

3Strength

If crossbar is made with protruding parts for structural strength, then the fence resists impact better, but the robotic lawnmower body part may hook into the crossbar at impact

Engineering Contradiction:
Improveresist impactVSAvoidbody part hooking into crossbar
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The crossbar has a uniform, smooth surface without protruding parts, creating a consistent local quality throughout. This uniformity ensures that the collision interface is predictable and prevents the robotic lawnmower body from hooking into the crossbar, while the overall structural strength is maintained through the bracket and support element configuration rather than crossbar protrusions.

Inventive Principle:
Principle #3Local quality

4Ease of operation

If fence is designed for easy placement and disassembly, then the installation process is simplified, but the anchoring strength may be reduced

Engineering Contradiction:
Improveplacement and disassembly easeVSAvoidanchoring strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The fence transitions from a static anchoring system to a dynamic one where support elements can be easily moved along the legs to adjust depth. The friction-based retention mechanism provides sufficient anchoring strength while allowing easy disassembly by simply pulling the support element along the leg to overcome the friction and release it from the aperture.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4057792B1Robotic lawnmower fence
Publication Date: 2025.03.26 HUSQVARNA AB
  • EP4057792B1 patent drawingFigure 1A~1B
  • EP4057792B1 patent drawingFigure 2A~2B
  • EP4057792B1 patent drawingFigure 3A

AI summary

The present disclosure relates to a robotic lawnmower fence (1) comprising a bracket (3) with two legs (9', 9''), which are essentially straight and parallel, and a crossbar (11), which extends between upper ends (9'a, 9''a) of the two legs (9', 9'') and perpendicular to the legs (9', 9''). Opposite free ends (9'b, 9''b) of the legs (9', 9'') are adapted to be anchored in the ground (17) and two support elements (5), each adapted to be arranged along respective leg (9', 9'') in the extension direction (L) thereof to define a maximum depression depth (D) of the legs (9', 9'') into the ground (17). The disclosure also relates to a fence system (49) comprising at least two fences (1).