Electric Shovel Rotation Limits Against Internal Component Contact

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Solution Overview

Problem

Existing construction machines with infinitely rotating electric motors risk unintentional contact between the working portion and internal components, potentially causing damage.

Innovation Solution

A work machine equipped with a restricting member that limits the rotation range of the working portion, using sensors and control devices to prevent contact with other machine components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the electric motor enables infinite rotation of the working portion, then the working portion can perform continuous operations, but the working portion may unintentionally contact other machine components causing damage

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoiddamage prevention
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The restricting member is positioned in advance to prevent the working portion from rotating beyond the safe range. This preliminary protective measure stops the working portion before it can contact other machine components, thereby preventing damage while allowing continuous operation within the restricted range.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The restricting member acts as an intermediary between the electric motor and the working portion, mediating the rotation to ensure it remains within safe limits. This intermediary component prevents direct contact between the working portion and other machine components that would cause damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a restricting member is added to limit rotation range, then contact with other components is prevented, but device complexity increases

Engineering Contradiction:
Improvedamage preventionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The rotation restriction function is segmented as a separate component (restricting member) rather than integrating it into the motor or working portion. This segmentation allows the restricting member to be a simple, standalone element that prevents damage without significantly complicating the overall device structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The restricting member is designed as a simple, inexpensive component that can be easily replaced if needed. This approach minimizes the complexity and cost added to the system while effectively preventing damage through a straightforward mechanical limitation.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP4640960A1Work machine
Publication Date: 2025.10.29 YANMAR HLDG CO LTD
  • EP4640960A1 patent drawingFigure 1
  • EP4640960A1 patent drawingFigure 2
  • EP4640960A1 patent drawingFigure 3

AI summary

[Problem] To provide a work machine capable of avoiding contact of a working portion with a member different from the working portion by limiting a rotation range of the working portion. [Solution] An electric shovel as a work machine includes an electric motor, a working portion rotated by the electric motor, and a restricting member that restricts rotation of the working portion.