Folding Knife Blade Unlocking Mechanism for Safe One-Handed Operation

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Solution Overview

Problem

Folding blade knives with existing locking systems often require two hands to unlock and can be dangerous due to sudden blade deployment, making them difficult to open and pose a risk of injury.

Innovation Solution

A knife design with a handle incorporating a locking mechanism, a user-actuable unlocking mechanism, and a spring system that allows partial rotation of the blade for easy grasping and unfolding, along with a braking mechanism to control the blade's speed and amplitude, ensuring safe and ergonomic operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a strong locking mechanism is used to secure the blade in the closed position, then the blade can be safely carried and prevented from untimely removal, but the blade becomes difficult to unlock and may require two hands or complex operations

Engineering Contradiction:
Improveblade retention in closed positionVSAvoidblade unlocking operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The spring-loaded strip is pre-loaded and held in a blocked position by the push button mechanism. When the user presses the push button, the block is retracted and the strip automatically advances to unlock the blade, performing the unlocking action in advance of the user's intent and enabling one-handed operation.

Inventive Principle:
Principle #10Preliminary action

2Extent of automation

If an opening spring is compressed to automate blade opening, then the blade opening is automated and accidental folding is prevented, but the blade opens abruptly causing safety hazards and classification as a weapon

Engineering Contradiction:
Improveblade opening automationVSAvoidsudden blade deployment risk
Core Design Contradiction:
Extent of automationVSObject-affected harmful factors

Solution Approach 1:

The system uses a spring-loaded strip that can be progressively advanced in controlled increments. The push button mechanism allows the user to control the timing and speed of blade deployment by advancing the strip step-by-step, transforming the abrupt static spring release into a dynamic, user-controlled motion sequence.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring-loaded strip acts as an intermediary between the user's push button action and the blade movement. Instead of the spring directly propelling the blade, the strip transmits the force in a controlled manner, mediating the energy transfer and enabling gradual, safe deployment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the blade is locked in the closed position using a spring or locking points, then the blade is securely retained, but removing the blade from the handle becomes difficult despite the presence of a groove for fingernail insertion

Engineering Contradiction:
Improveblade retention in closed positionVSAvoidblade removal from handle
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The push button mechanism is pre-configured to retract the block that holds the spring-loaded strip. When activated, this preliminary action automatically advances the strip to disengage the locking engagement, preparing the system for easy blade removal without requiring the user to manually manipulate the groove or apply excessive force.

Inventive Principle:
Principle #10Preliminary action

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 enables safe and easy opening of the blade by allowing partial rotation, optimizing user safety and reducing the risk of injury during deployment, while maintaining secure locking in both closed and open positions.

Implementation Method 1

a spring-loaded strip (12), equipped with a lug (14), designed to cooperate with a recess (18) provided for this purpose within the base of the blade to hold it in a locked position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a spiral spring mounted coaxially with the blade's articulation axis and cooperating with it, the spring's action being released when the unlocking mechanism is activated by the user, thereby causing the blade to rotate and come out of the handle slot

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

This washer is capable of braking the blade's rotation through friction by the spring

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3429808B1Folding-blade knife
Publication Date: 2023.05.10 LEPAGE FRANCIS
  • EP3429808B1 patent drawingFigure 1~3
  • EP3429808B1 patent drawingFigure 4
  • EP3429808B1 patent drawingFigure 5~6

AI summary

This folding-blade knife comprises a handle (2) defining a recess within which a blade (1), articulated close to one of the ends of the handle, can be stowed. Integrated into the handle (2) are: – a first means for locking the blade (1) in the folded position in order to prevent unintended egress of the blade from the handle (2); – close to the region where the blade is articulated to the handle, ∙ a second means (6, 22) for unlocking said first locking means, said second means being actuable by the user, ∙ a third means to cause the blade to rotate about its articulation axis once unlocked.