Chainsaw Fuel Tank Integrated With Top Handle

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Solution Overview

Problem

Chainsaws require reduction in size and weight for improved operability, as they are typically cumbersome for operators to carry during use.

Innovation Solution

The fuel tank is integrated with the top handle, reducing the body case size and weight, with the carburetor and fuel tank positioned close to each other to minimize piping length, and the body case is supported by the top handle via elastic members at multiple points to reduce vibration and enhance stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the fuel tank is integrated with the top handle, then the body case size and weight are reduced, but the fuel tank position changes to the top handle side

Engineering Contradiction:
Improvechainsaw weightVSAvoidfuel tank positioning complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The fuel tank is integrated with the top handle as a single unit, combining two previously separate components (fuel tank and top handle) into one. This merging reduces the overall number of parts, simplifies the structure, and directly contributes to weight reduction while maintaining functionality.

Inventive Principle:
Principle #5Merging (Combining)

2Length of moving object

If the carburetor and fuel tank are positioned close to each other, then the piping length is reduced, but the spatial arrangement becomes more constrained

Engineering Contradiction:
Improvepiping lengthVSAvoidspatial arrangement flexibility
Core Design Contradiction:
Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The carburetor and fuel tank are arranged in a three-dimensional space within the top handle assembly, utilizing vertical and lateral dimensions rather than just linear extension. This spatial optimization allows the components to be positioned close together, minimizing piping length while accommodating the constrained geometry of the integrated handle design.

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

3Object-affected harmful factors

If the body case is supported by the top handle via elastic members at multiple positions, then the vibration is reduced, but the number of connection points increases

Engineering Contradiction:
ImprovevibrationVSAvoidconnection structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Elastic members (springs) are installed at multiple connection positions between the body case and top handle to provide vibrational damping. These elastic elements act as vibration isolators, absorbing and attenuating vibrations transmitted between the heavy body case and the handle, thereby reducing the harmful vibrations affecting the operator while maintaining structural support.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

4Productivity

If the fuel tank is disposed near the carburetor, then the fuel supply efficiency is improved, but the center of gravity shifts toward the top handle

Engineering Contradiction:
Improvefuel supply efficiencyVSAvoidchainsaw balance
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The dense fuel tank is strategically positioned within the top handle assembly to optimize the center of gravity location. By carefully selecting the placement coordinates and orientation of the fuel tank, the design achieves a balance between improving fuel supply efficiency (through proximity to the carburetor) and maintaining acceptable handling characteristics, accepting a shift in center of gravity as a trade-off for overall system performance.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design results in a lighter, more compact chainsaw with improved operability due to reduced vibration and enhanced visual perception of downsizing, allowing easier handling and operation.

Implementation Method 1

the body case is supported by the top handle via an elastic member... vibration of the top handle can be suppressed

Methodology Applied
Scientific EffectVibration isolation: Damping

Implementation Method 2

the top handle and the body case are coupled to each other via the elastic member

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

The fuel tank is heavy due to the amount of the fuel contained therein. Accordingly, by providing the heavy fuel tank on the top handle side, vibration of the body case can be considerably decreased

Methodology Applied
Scientific EffectMass distribution for vibration reduction: Inertia

Data Source

PatentEP1952959B1Chain saw
Publication Date: 2018.02.21 HUSQVARNA ZENOAH CO LTD
  • EP1952959B1 patent drawingFigure 1
  • EP1952959B1 patent drawingFigure 2
  • EP1952959B1 patent drawingFigure 3

AI summary

A chainsaw includes: a body case 20 in which an engine for driving the chainsaw is accommodated; and a top handle 41 provided on an upper side of the body case 20. A fuel tank 7 for storing fuel of the engine is integrally provided to the top handle 41. A carburetor 6 is also provided to the top handle 41. The fuel tank 7 is disposed near the carburetor 6.