Top Handle Power Switch Arrangement for Electric Chain Saw

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Solution Overview

Problem

Conventional electric chain saws require operators to use one hand to manipulate the power switch, making it difficult to securely grip the tool and reducing working efficiency, as the design lacks a suitable thumb rest and positions the power switch in an inconvenient location.

Innovation Solution

An electric power work device with a top handle featuring a thumb rest and power switch on its upper surface, allowing the operator to stably grip the handle and easily switch the power on/off with their thumb while holding the device with both hands, with the thumb rest and power switch positioned on a recessed surface for improved ergonomics and accessibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the power switch is arranged on the front side of the gripping part, then the operator can access the power switch, but there is no space for placing the pad of the thumb, causing poor gripping stability

Engineering Contradiction:
Improvepower switch accessibilityVSAvoidgripping stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The power switch is relocated from the front surface to the right side surface of the top handle, utilizing the lateral dimension. This allows the thumb to rest on the front surface while the index finger reaches across to operate the power switch on the side, resolving the conflict between thumb placement space and power switch accessibility.

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

Solution Approach 2:

The side surface of the top handle serves as an intermediary space that accommodates both the thumb rest function and the power switch function. By positioning the power switch on the right side surface, the design creates a functional zone that doesn't interfere with thumb placement on the front surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the operator uses one hand to manipulate the power switch, then the power switch can be operated, but the operator cannot securely grip the tool with both hands, reducing working efficiency

Engineering Contradiction:
Improvepower switch manipulationVSAvoidworking efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

By moving the power switch to the right side surface, the operator can use the index finger of the right hand to reach across and operate the switch while the thumb remains on the front surface for gripping. This dimensional separation allows dual-hand operation without compromising power switch accessibility.

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

3Reliability

If the power switch is positioned away from the thumb rest, then the thumb can securely rest, but the operator cannot easily switch the power on/off during operation

Engineering Contradiction:
Improvethumb rest stabilityVSAvoidpower switch accessibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The power switch is positioned on the right side surface adjacent to the front surface where the thumb rests. This lateral proximity allows the operator to easily reach the power switch with the index finger while the thumb maintains a stable position on the front surface, achieving both stability and accessibility.

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

Data Source

PatentEP3718697B1Electric power work device with power switch arrangement
Publication Date: 2024.10.09 YAMABIKO CORP
  • EP3718697B1 patent drawingFigure 1
  • EP3718697B1 patent drawingFigure 2
  • EP3718697B1 patent drawingFigure 3

AI summary

Provided is an electric power work device (1) which includes: a body case (10); a work tool (20) protruding forward from a front side with respect to the body case (10); a motor (30); and a battery (90) supplying power to the motor (30). The motor (30) is accommodated in the body case (10) and the battery (90) is detachably attached to a rear side with respect to the body case (10). A top handle (40) is extended in a longitudinal direction at an upside with respect to the body case (10). The top handle (40) includes, on an upper surface of a front part thereof, a thumb rest (45) and a power switch (46). The power switch (46) is arranged on a side in a lateral direction of the thumb rest (45).