Multi-Height Lawn Mower Cutting Assembly for Repeated Grass Cutting

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Solution Overview

Problem

Existing lawn mowers often leave long grass stems and large pieces of cut grass on the lawn due to the design of cutting blades, which do not effectively cut grass into smaller pieces.

Innovation Solution

A lawn mower design with multiple cutting element groups at different heights on the cutting deck, forming distinct cutting trajectories with varying diameters and staggered distribution, allowing for repeated cutting of grass into smaller pieces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single cutting blade is used, then the structure is simple, but long grass is not cut into small pieces

Engineering Contradiction:
Improvecutting efficiencyVSAvoidcutting assembly structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The cutting assembly is segmented into multiple cutting element groups (at least two) distributed at different heights on the cutting deck. Each group contains cutting elements that operate at different vertical levels, enabling multi-stage cutting of grass. This segmentation allows long grass to be cut into smaller pieces through repeated cutting actions, directly resolving the contradiction between cutting efficiency and structural simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-plane cutting approach to a multi-height spatial arrangement. Cutting element groups are positioned at different heights (vertical dimension) and different radial distances from the center, creating three-dimensional cutting trajectories. This dimensional expansion enables repeated cutting of long grass without requiring a single complex blade design.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If multiple cutting elements are added to cut grass into smaller pieces, then cutting effectiveness improves, but the risk of collisions between cutting elements increases

Engineering Contradiction:
Improvegrass cutting effectivenessVSAvoidcollision risk between cutting elements
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Cutting elements are arranged in three-dimensional space with different heights and radial distances from the center of the cutting deck. This spatial distribution ensures that cutting trajectories of different element groups do not intersect, eliminating collision risk while maintaining multiple cutting elements for effective grass cutting.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Each cutting element group is positioned at specific local positions (different heights and radial distances) optimized for its function. The staggered circumferential distribution within each group further refines the local arrangement, ensuring that cutting paths are separated while maintaining cutting effectiveness across different grass heights.

Inventive Principle:
Principle #3Local quality

3Productivity

If cutting elements are distributed at different heights, then repeated cutting of long grass is achieved, but the device complexity increases

Engineering Contradiction:
Improverepeated cutting capabilityVSAvoidcutting element arrangement
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The cutting assembly is divided into discrete cutting element groups positioned at different heights, each group functioning as an independent cutting stage. This modular segmentation achieves repeated cutting capability while keeping each group's structure relatively simple and manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple cutting element groups serve the universal function of cutting grass, but at different heights and trajectories. This multi-functional arrangement allows a single cutting deck to handle various grass lengths and types, achieving repeated cutting capability without proportionally increasing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4018807B1Lawn mower
Publication Date: 2026.01.28 POSITEC POWER TOOLS (SUZHOU) CO LTD
  • EP4018807B1 patent drawingFigure 1~3
  • EP4018807B1 patent drawingFigure 4~5

AI summary

The present invention relates to a cutting assembly and a lawn mower. The cutting assembly is mounted on the lawn mower to perform cutting work. The cutting assembly includes a cutting deck and at least two cutting element groups disposed at different heights of the cutting deck. Each cutting element group includes at least one cutting element. The cutting deck responds to driving of the lawn mower to rotate and drive the cutting elements to rotate, to form at least two cutting trajectories at the different heights of the cutting deck. In the cutting assembly and the lawn mower, the at least two cutting element groups are disposed at the different heights of the cutting deck, to enable the cutting assembly to be driven by an electric tool to form the at least two cutting trajectories, and the cutting trajectories are distributed at the different heights of the cutting deck, so that long grass is cut repeatedly into smaller pieces.