Lateral Air Filter Geometry for Compact Hand-Held Tool Ergonomics

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing hand-held work tools, such as motor chainsaws, suffer from bulkiness due to wide handles designed to accommodate air filters, leading to ergonomic issues and ingress of dirt through cooling air inlets, compromising tool design and functionality.

Innovation Solution

A hand-held tool design with an air filter component positioned on the side surface, featuring a longitudinal extension bounded by specific planes, allowing for a compact and ergonomic layout with minimal dirt ingress and efficient cooling, incorporating a battery compartment and handle placement for improved ergonomics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the air filter is positioned on the side surface with longitudinal extension, then the tool achieves compact and ergonomic design, but the handle width must be reduced which may affect user comfort

Engineering Contradiction:
Improvetool compactnessVSAvoiduser comfort
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The air filter is repositioned from a conventional location to the side surface of the tool, utilizing the lateral dimension. The filter's longitudinal extension is arranged such that it does not protrude beyond a tangential plane, effectively using three-dimensional space optimization to achieve compactness without compromising handle ergonomics

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

2Temperature

If the cooling air inlet is oriented upwards for sufficient cooling, then cooling efficiency is improved, but dirt enters the motor through the inlet under gravity

Engineering Contradiction:
Improvecooling efficiencyVSAvoiddirt ingress
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The air filter component is positioned at the cooling air inlet on the side surface, providing localized filtration exactly where cooling air enters the tool. This targeted approach ensures that the filtration function is applied precisely at the point of air ingress, blocking dirt while maintaining cooling efficiency

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the handle is designed wide to accommodate air filter and ensure user comfort, then user comfort is improved, but the tool becomes bulky and unwieldy

Engineering Contradiction:
Improveuser comfortVSAvoidtool bulkiness
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The air filter is extracted from the conventional handle integration and repositioned to the side surface of the tool. This separation allows the handle to be designed with optimized dimensions for user comfort without the additional width requirement, thereby reducing overall tool bulkiness while maintaining ergonomics

Inventive Principle:
Principle #2Taking out (Extraction)

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

The design achieves a compact and ergonomic tool with reduced dirt entry, ensuring effective cooling and enhanced user comfort by positioning the air filter laterally and optimizing handle placement near the tool's center of gravity, thereby reducing pivoting forces.

Implementation Method 1

an air filter component (12) for filtering the cooling air

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

cooling air can flow longitudinally through the inlet opening (4) into the hand-held tool (1)... the cooling air flows along a filter surface of the air filter component (12)

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP4491340B1Hand-held work device
Publication Date: 2026.03.18 ANDREAS STIHL AG & CO KG
  • EP4491340B1 patent drawingFigure 1~2
  • EP4491340B1 patent drawingFigure 2a
  • EP4491340B1 patent drawingFigure 3

AI summary

The invention relates to a hand-held tool (1) comprising a tool (6) and a control handle (34). The tool (1) includes a motor (7) for driving the tool (6). A longitudinal direction (50) extends from the control handle (34) towards the tool (6). The tool (6) has a tool plane (E). The tool (1) includes an air filter component (12) for filtering cooling air to cool the motor (7). The tool (1) can be placed in a storage position on a horizontal plane. The tool (1) has a base (17) which, in the storage position, faces the horizontal plane. The tool (1) has a housing top (20) opposite the base (17). The tool (1) has a side surface (21) that connects the housing top (20) and the base (17) and limits the tool (1) along the longitudinal direction (50) in a direction perpendicular to the tool plane (E).The air filter component (12) is arranged on the side surface (21) of the working tool (1) and has a filter extension (70) in the longitudinal direction (50) with a front half (71) which is located in front of a rear half (72) of the filter extension (70) with respect to the longitudinal direction (50). An imaginary tangent plane (T) extending perpendicular to the horizontal plane in the parked position is tangent to the side surface (21) in the region of the filter extension (70) only in the region of the rear half (72) of the filter extension (70) of the air filter component (12). The tangent plane (T) intersects the tool plane (E) with respect to the longitudinal direction (50) in front of the region of the filter extension (70).