Telescopic Rod Detection for Electric Pruner Safety

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Solution Overview

Problem

Existing electric bush cutters have a fixed rod length, making them rigid and difficult to store compactly, and lack a detection system for the extending state of the rod, which can lead to unsafe operation and sudden motor start-ups when the rod is extended.

Innovation Solution

An electric working machine with a contracting rod and a detection unit that ensures the rod is fully extended before allowing motor operation, featuring a control unit that prevents motor rotation when the rod is not extended and improves wiring from the detection unit to the control unit for enhanced safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the rod length is made constant to achieve rigidity, then the structural stability is improved, but the storage compactness deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidstorage volume
Core Design Contradiction:
Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The rod is divided into multiple telescopic sections that can slide relative to each other, allowing the rod to be extended to a long length for work and retracted to a short length for storage, thus resolving the contradiction between structural stability and storage compactness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rod transitions from a static fixed length to a dynamic adjustable length through telescopic sections, enabling the rod to adapt between extended and retracted states to satisfy both operational stability and storage compactness requirements

Inventive Principle:
Principle #15Dynamics

2Volume of moving object

If the rod is made telescopic to reduce storage size, then the storage compactness is improved, but the structural stability deteriorates

Engineering Contradiction:
Improvestorage volumeVSAvoidstructural stability
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The rod is segmented into telescopic sections with locking mechanisms that maintain structural stability when extended and allow compact retraction when not in use, balancing storage compactness with operational stability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The detection unit detects the rod extension state before allowing motor operation, and the control unit pre-prevents motor rotation when the rod is not fully extended, ensuring safety before operation begins

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If no detection unit is provided to simplify the system, then the device complexity is reduced, but the operational safety deteriorates

Engineering Contradiction:
Improvesystem complexityVSAvoidoperational safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The detection unit provides real-time feedback on the rod extension state to the control unit, which then controls motor rotation accordingly, creating a closed-loop safety system that prevents operation when the rod is not properly extended

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2814641B1Electric working machine
Publication Date: 2019.09.04 KOKI HLDG CO LTD
  • EP2814641B1 patent drawingFigure 1
  • EP2814641B1 patent drawingFigure 2
  • EP2814641B1 patent drawingFigure 3

AI summary

An electric working machine (1) including: a motor; a control unit configured to control rotation of the motor; a fixed part (3) provided with a handle having a grip portion (43); a movable part (4) held by the fixed part (3) and is configured to be extendible by sliding relative to the fixed part (3); and a cutting blade (155) provided to a end portion of the movable part (4) and is configured to be driven by the motor; characterized in that the electric working machine (1) further includes a detection unit which is connected to the control unit and is configured to detect whether or not the movable part (4) is positioned at a predetermined extended position relative to the fixed part (3).