Work Machine Safe Mode for Blade Locking Damage

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Solution Overview

Problem

Engine-driven work machines, such as lawn mowers, can experience blade locking due to abrupt load applications, leading to engine and work portion damage when restarted with obstacles present, as existing systems lack effective mechanisms to mitigate damage during restarts.

Innovation Solution

A control system that determines the reason for engine stoppage and sets the operation mode to a safe mode if blade locking is detected, featuring a slow start mechanism, clutch management, and lifting device control to minimize damage by reducing engine speed increase rate and avoiding obstacle contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the engine is restarted immediately after stoppage, then productivity is improved, but damage to the work portion and engine occurs due to blade locking

Engineering Contradiction:

Improveengine restart speedVSAvoiddamage prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The control portion performs preliminary detection of blade locking state before engine restart. The storing portion records stop information indicating blade locking, and the determination portion checks this information before allowing restart, preventing damage while enabling quick recovery

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts restart behavior based on detected conditions. When blade locking is detected, the engine restart is controlled to a safe mode with limited power output, transitioning between normal and protected operation states based on real-time conditions

Inventive Principle:

Principle #15Dynamics

2Reliability

If the engine speed increase rate is reduced during restart, then damage is lessened, but productivity decreases

Engineering Contradiction:

Improvedamage reductionVSAvoidrestart speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The safe mode implements partial action by limiting engine power output to a predetermined level during restart after blade locking. This partial power delivery is sufficient to clear the locked condition and resume operation while preventing excessive forces that cause damage

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If the work portion is raised to maintain safe distance from obstacles, then damage is prevented, but work capability is reduced

Engineering Contradiction:

Improveprotection from obstaclesVSAvoidwork performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The lifting device operates periodically to raise and lower the work portion based on detected obstacle conditions. During blade locking events, the work portion is raised to a safe height; when normal operation is restored, it returns to working position, creating a rhythmic protect-work cycle

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS11363756B2Work machine for lessening damage resulting from an object coming into contact with work portion

Publication Date: 2022.06.21 HONDA MOTOR CO LTD

AI summary

A work machine determines, when a request to restart an engine is made, whether or not a reason indicated by stop information stored in a memory is a reason related to locking of the work portion. The machine sets an operation mode of the engine and a work portion to a safe mode if it determines that the reason indicated by the stop information is a reason related to locking of the work portion. The safe mode is an operation mode for lessening damage resulting from causing the engine and the work portion to work during the work portion locked or damage resulting from an object coming into contact with the work portion during the engine and the work portion working.