Cylindrical Blade Guide Centering for Jigsaw Stability

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Solution Overview

Problem

Existing blade mounting devices in cutting tools, such as jigsaws, face instability due to the flat plate configuration of the blade guide, which leads to incorrect centering of the blade, resulting in unstable reciprocating movement and potential misalignment.

Innovation Solution

A blade mounting device with a cylindrical blade guide and V-shaped guide recess, allowing for reliable centering and stable reciprocation, featuring a lock device and blade guide that moves axially to lock and release the blade, preventing rotation and ensuring proper alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flat plate configuration is used for the blade guide, then the construction is simple, but the blade centering is incorrect and reciprocating movement becomes unstable

Engineering Contradiction:
Improveconstruction simplicityVSAvoidblade centering accuracy
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The blade guide is changed from a flat plate configuration to a cylindrical configuration. This curvature allows the V-shaped guide recess to properly center the blade head during reciprocating movement, ensuring stable operation while maintaining manufacturing simplicity through standard cylindrical forming processes

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of manufacture

If a flat plate configuration is used for the blade guide, then the manufacturing process is simple, but the reciprocating movement stability deteriorates

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidreciprocating movement stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The cylindrical configuration of the blade guide provides a stable geometric foundation that ensures consistent blade centering throughout reciprocating movement. The curved surface maintains stable contact with the blade head, preventing lateral displacement and ensuring reliable reciprocating motion

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Device complexity

If the blade guide is made as a thin flat plate, then the device complexity is reduced, but the blade alignment precision worsens

Engineering Contradiction:
Improveblade guide structure complexityVSAvoidblade alignment precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The cylindrical blade guide with V-shaped recess provides inherent geometric alignment features that ensure precise blade centering. The curved configuration naturally guides the blade head to the correct position, achieving high alignment precision without complex adjustment mechanisms

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 cylindrical blade guide design enhances blade centering and stability, improving the reciprocating movement and cutting ability of the tool, while simplifying the construction and maintenance of the device.

Implementation Method 1

a compression spring (16) which biases the blade guide (12) toward the restricting position

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

a torsion spring (18) which biases the operation member (14) toward the blade mounting position

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP2394768B1Blade mounting device in cutting tools
Publication Date: 2015.08.05 MAKITA CORP
  • EP2394768B1 patent drawingFigure 1
  • EP2394768B1 patent drawingFigure 2~3
  • EP2394768B1 patent drawingFigure 4~5

AI summary

A blade mounting device (10) of a cutting tool (1) includes a lock device (13, 14) and a blade guide (12). The lock device (13, 14) is configured to releasably lock a blade (B) against a rod (11) of a cutting tool (1). The blade guide (12) is movable relative to the rod (11) in an axial direction of the rod (11) and is coupled to the lock device (13, 14), so that the lock device (13, 14) locks and releases the blade (B) in response to position of the blade guide (12) in the axial direction. The blade guide (12) has a guide recess (12c) capable of guiding and engaging the blade (B), so that the blade guide (12) can be moved by the blade (B) in the axial direction through engagement of the guide recess (12c) with the blade (B). The blade guide (12) has a configuration other than a thin flat plate configuration.