Automatic Lawn Mower Movable Guard for Child Safety and Grass Clearance

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Solution Overview

Problem

Existing autonomous lawn mowers lack an effective protecting assembly that prevents accidental injuries to children while maintaining the ability to pass over grass effectively.

Innovation Solution

The autonomous lawn mower incorporates a protecting assembly with a movable protecting member and a mechanism protecting member, ensuring a child's arm cannot enter the cutting mechanism by maintaining a safe distance and adjusting to obstacles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the protecting member is disposed excessively close to the ground to prevent child injury, then safety is improved, but the ability to pass over grass deteriorates

Engineering Contradiction:
ImprovesafetyVSAvoidability to pass over grass
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The protecting member is designed to be movable rather than fixed. It can dynamically adjust its position: staying close to the ground during normal operation to prevent child injury, and lifting upward when encountering obstacles or raised ground to maintain the mower's ability to pass over grass effectively.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The vertical position parameter of the protecting member is made variable. By changing the distance between the protecting member and the ground based on operating conditions, the system achieves both safety (when close) and grass-passing capability (when elevated).

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the protecting member is disposed higher to maintain grass-passing ability, then adaptability is improved, but safety deteriorates as children can reach the cutting mechanism

Engineering Contradiction:
Improveability to pass over grassVSAvoidsafety
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The protecting member transitions from a static high position to a dynamic system that can lower itself during normal mowing operations, creating a safe barrier against child access while maintaining the capability to raise when needed for obstacle clearance.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a fixed protecting member is used to prevent injury, then safety is improved, but the device complexity increases and grass-passing ability is reduced

Engineering Contradiction:
ImprovesafetyVSAvoidprotecting assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The protecting member is designed to automatically respond to obstacles through its movable mechanism, lifting when encountering raised ground or stones and returning to its protective position afterward, without requiring complex control systems or user intervention.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3987914B1Automatic lawn mower
Publication Date: 2025.09.03 POSITEC POWER TOOLS (SUZHOU) CO LTD
  • EP3987914B1 patent drawingFigure 1
  • EP3987914B1 patent drawingFigure 2
  • EP3987914B1 patent drawingFigure 3

AI summary

An autonomous lawn mower includes: a housing, provided with a bottom shell, a movement module, a cutting mechanism with a cutting element, and a control module. The autonomous lawn mower further includes a protecting assembly provided with a protecting wall. In a horizontal direction, the protecting wall is disposed on an outer side of the cutting mechanism. The protecting assembly at least includes a movable protecting member. The protecting wall at least includes a movable protecting wall that is disposed at the movable protecting member and is located on the outer side of the cutting mechanism in the horizontal direction. When the cutting mechanism is at any cutting height and the movable protecting member is in a free state under no external force, a ground clearance of a lower end of the movable protecting wall is an initial distance. The initial distance remains less than M. 38 mm ≤ M ≤ 40 mm. The movable protecting member is movable in a vertical direction relative to the bottom shell under the action of an external force, to change the ground clearance of the lower end of the movable protecting wall.