Air Cushion Mower Chassis Deflector Profile for Lift Optimization

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Solution Overview

Problem

Hover mowers suffer from low energy efficiency, high vibration, noise, and reduced lifting force due to high impeller rotation speeds, leading to suboptimal performance and user discomfort.

Innovation Solution

The design incorporates a body with a converging deflector profile and adjustable axial distance between the impeller and opening, optimizing airflow to reduce rotation speed, enhance lifting force, and improve fluid dynamics, using a monoblock body made of plastic or metallic material with a specific detachment angle and shape to enhance the floating effect and grass expulsion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the impeller rotates at high speed to generate sufficient lifting force, then the device can maintain floating effect, but energy consumption increases and vibrations and noises are generated

Engineering Contradiction:
Improvelifting forceVSAvoidenergy consumption
Core Design Contradiction:
ForceVSUse of energy by moving object

Solution Approach 1:

The patent modifies the geometric parameters of the body, specifically the detachment angle of the inner surface and the shape of the opening edge, to optimize airflow patterns. This allows the impeller to operate at lower rotational speeds while maintaining sufficient lifting force, thereby reducing energy consumption and minimizing vibrations and noises.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a specific three-dimensional configuration of the body's inner surface with defined detachment angles and opening edge shapes. This spatial arrangement optimizes the airflow dynamics in multiple dimensions, enabling efficient lift generation at reduced impeller speeds and improving overall energy efficiency.

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

2Force

If the impeller rotates at high speed to generate sufficient lifting force, then the device can maintain floating effect, but vibrations and noises are generated

Engineering Contradiction:
Improvelifting forceVSAvoidvibrations and noises
Core Design Contradiction:
ForceVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the geometric parameters of the body, specifically the detachment angle of the inner surface and the shape of the opening edge, to optimize airflow patterns. This allows the impeller to operate at lower rotational speeds while maintaining sufficient lifting force, thereby reducing energy consumption and minimizing vibrations and noises.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the body has a simple geometry, then the device is easier to manufacture, but the floating effect and grass expulsion are suboptimal

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidfloating effect
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The patent specifies precise geometric parameters including detachment angles between 15°-85° and particular opening edge configurations. These defined parameters can be directly implemented in mold design and manufacturing processes, allowing complex aerodynamic shapes to be produced efficiently through conventional molding techniques while optimizing floating effect and grass expulsion.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If the impeller rotates at high speed to improve grass expulsion, then cutting efficiency increases, but energy consumption increases

Engineering Contradiction:
Improvegrass expulsion efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent introduces a specific three-dimensional configuration of the body's inner surface with defined detachment angles and opening edge shapes. This spatial arrangement optimizes the airflow dynamics in multiple dimensions, enabling efficient lift generation at reduced impeller speeds and improving overall energy efficiency.

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

Solution Approach 2:

The patent modifies the geometric parameters of the body, specifically the detachment angle of the inner surface and the shape of the opening edge, to optimize airflow patterns. This allows the impeller to operate at lower rotational speeds while maintaining sufficient lifting force, thereby reducing energy consumption and minimizing vibrations and noises.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4124229A1Mobile device for cutting grass of the air cushioned type having an improved chassis
Publication Date: 2023.02.01 STIGA S P A IN BREVE ANCHE ST SPA
  • EP4124229A1 patent drawingFigure 1
  • EP4124229A1 patent drawingFigure 2
  • EP4124229A1 patent drawingFigure 3

AI summary

The present invention relates to a device (1; 1*) for cutting grass, comprising a payload (7), an impeller (8) and a body (9). An inner surface (18) of the body (9) defines a cavity (10) for housing the payload (7) and the impeller (8). The cavity (10) of the body (9) is in fluid communication with the external environment through an opening (12) delimited by an edge (28) of the body (9). According to the invention, at least one stretch (28p, 28s) of the edge (28) is the terminal edge of a respective wall (23p, 23s) of the inner surface (18) of the body (9), which is shaped so as to form a deflector profile which confers to an airflow exiting the cavity (10) at least one radial component oriented towards the axis (C-C) of the body (9).