Lawnmower Shutter Mechanism for Bagging and Mulching Mode Switching

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Solution Overview

Problem

Existing rotary lawnmowers face inefficiencies in both bagging and mulching modes, with kickers in the housing affecting storage performance in bagging mode and incomplete discharge in mulching mode.

Innovation Solution

A rotary lawnmower with a shutter mechanism and a kicker on moveable components that can be switched between bagging and mulching modes, allowing efficient discharge below the housing in mulching mode and unhindered storage in bagging mode by positioning the kicker away from the cut grass conveyor passage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If kickers are positioned on the internal periphery of the housing to guide cut grass to the bottom in mulching mode, then cut grass discharge efficiency is improved, but storage performance in bagging mode is deteriorated due to interference with the revolving movement of cut grass

Engineering Contradiction:
Improvecut grass discharge efficiencyVSAvoidstorage performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The kicker is made movable between a first position (for mulching mode) and a second position (for bagging mode). This dynamic repositioning allows the kicker to guide cut grass to the bottom in mulching mode while being removed from the cut grass conveyor passage in bagging mode, thus resolving the contradiction between discharge efficiency and storage performance.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a shutter mechanism is added to switch between bagging mode and mulching mode, then versatility is improved, but device complexity increases

Engineering Contradiction:
Improvemode switching capabilityVSAvoidhousing structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The shutter mechanism and kicker positioning are combined into a single integrated system. The shutter mechanism controls both the opening/closing of the cut grass conveyor passage and the positioning of the kicker, allowing mode switching without requiring separate independent mechanisms, thus reducing overall complexity while maintaining versatility.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2258162B1Lawnmower
Publication Date: 2012.04.04 HONDA MOTOR CO LTD
  • EP2258162B1 patent drawingFigure 1
  • EP2258162B1 patent drawingFigure 2
  • EP2258162B1 patent drawingFigure 3

AI summary

A lawnmower (10) capable of being switched between a bagging mode and a mulching mode is disclosed. The lawnmower includes a shutter mechanism (40) provided on an internal peripheral surface of a housing (11) which opens downward for storing a cutting blade (14). The shutter mechanism (40) is switched, by the operation of the shutter mechanism (40), between a bagging mode for delivering cut grass from the housing (11) to a cut grass storage container (22) and a mulching mode for discharging the cut grass out below the housing (11). The shutter mechanism (40) has a kicker (47) on a shutter body (42) positioned in the interior of the housing (11). The kicker (47) guides the cut grass to the bottom of the housing (11) during the mulching mode.