Foldable Hand Tool Bracket Locking for Low-Force Blade Adjustment

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Solution Overview

Problem

Existing foldable hand-held tools, such as handsaws, face challenges with high force requirements for blade adjustment and premature wear of locking mechanisms due to direct force transfer during operation.

Innovation Solution

A hand-held tool design featuring a pivotably coupled blade with a spring-biased bracket member and a locking mechanism that engages with apertures on the blade, allowing for adjustable angular positions while dissipating forces across multiple components to reduce wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring-biased projection engages with orifices to secure the blade, then the blade can be retained at selected angular positions, but a high force is required to keep the projection disengaged during adjustment

Engineering Contradiction:
Improveblade retentionVSAvoidblade adjustment force
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A bracket member is introduced as an intermediary between the blade and the locking mechanism. The bracket member includes a locking member that engages with apertures in the blade, while the bracket itself is biased by a spring. This distributes the retaining force across the bracket structure rather than concentrating it on a single projection, reducing the force needed to disengage the locking mechanism during adjustment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If a single projection is used for locking, then the structure is simple, but the area of force dissipation is limited leading to increased wear

Engineering Contradiction:
Improvelocking mechanism structureVSAvoidforce dissipation area
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The bracket member is designed with two lateral portions that extend in opposite directions, effectively adding a dimensional aspect to the force distribution. Instead of a single-point projection, the locking system now distributes forces across multiple contact points on the blade's apertures and the bracket's lateral portions, increasing the area of force dissipation without significantly increasing overall structural complexity.

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

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 solution reduces the force required for blade adjustment and minimizes wear on the tool's components by distributing operational forces across a broader area, enhancing the tool's durability and user convenience.

Implementation Method 1

The bracket member is spring biased such that the locking member engages with one of the plurality of the apertures to retain the blade at an angular position relative to the handle

Methodology Applied
Scientific EffectSpring bias: Spring

Data Source

PatentEP2976189B3Foldable hand-held tool
Publication Date: 2025.05.28 HUSQVARNA AB
  • EP2976189B3 patent drawingFigure 1
  • EP2976189B3 patent drawingFigure 2
  • EP2976189B3 patent drawingFigure 3

AI summary

A hand-held tool (100) includes a handle (104), and a blade (102) pivotably coupled to the handle at a proximal end (105). The blade includes a plurality of apertures (116, 118, 120, 122). The hand-held tool further includes a locking member (438) is configured to detachably engage with one of the plurality of the apertures to retain the blade at an angular position relative to the handle. The locking member is provided on a bracket member coupled to the handle, the bracket member being configured to at least partially enclose the proximal end of the blade. The bracket member is spring biased such that the locking member engages with one of the plurality of the apertures to retain the blade at an angular position relative to the handle. Further, the bracket member is movable such that the locking member disengages from one of the plurality of the apertures to allow the blade to pivot relative to the handle.