Folding Knife Locking Mechanism With Rotatable Safety Switch
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Solution Overview
Problem
Folding knives often experience lock failure or inadvertent unlocking, and existing locking mechanisms can be 'sticky' due to material properties, posing safety risks.
Innovation Solution
A locking folding knife design featuring a handle lock and a rotatable safety switch arranged around the pivot axis, with a spring-based rotational bias to securely engage or disengage the lock, preventing accidental closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-biased locking mechanism is used to secure the blade in the extended position, then the blade can be reliably locked during use, but the lock may fail or be inadvertently released due to material wear and metal fatigue over time
Solution Approach 1:
The patent applies beforehand cushioning by designing the locking mechanism to account for future wear and material fatigue. The handle lock is positioned and dimensioned to maintain effective engagement even as materials degrade over time, cushioning against the anticipated loss of locking force from wear and fatigue before they cause failure.
Solution Approach 2:
The patent implements preliminary action by positioning the handle lock to engage the blade tang at an optimized location that anticipates wear patterns. The lock is pre-positioned to maintain reliable engagement throughout the service life of the knife, compensating for expected material degradation before it affects locking reliability.
2Force
If the handle lock directly contacts the blade tang with high friction materials, then the lock provides strong holding force, but the interaction becomes 'sticky' making the lock difficult to engage and disengage
Solution Approach 1:
The patent applies parameter changes by optimizing the contact parameters between the handle lock and blade tang. The handle lock is positioned and dimensioned to change the friction characteristics of the interaction, reducing stickiness while maintaining adequate holding force through optimized geometric and material parameters.
Solution Approach 2:
The patent implements local quality by creating a specific interaction zone between the handle lock and blade tang with optimized local properties. The handle lock is positioned to engage at a specific location on the tang where the local geometry and material properties provide the right balance between holding force and smooth operation.
3Force
If the handle lock is positioned closer to the pivot axis, then the locking force is improved, but the risk of accidental disengagement increases due to proximity to the rotating blade
Solution Approach 1:
The patent implements preliminary action by pre-positioning the handle lock at an optimized distance from the pivot axis that anticipates the trade-off between locking force and safety. The position is determined in advance to provide sufficient locking force while maintaining a safe margin from the blade's rotation path to prevent accidental disengagement.
Solution Approach 2:
The patent applies beforehand cushioning by designing the handle lock position to cushion against the harmful effect of accidental disengagement. The lock is positioned to maintain effective engagement force while being far enough from the pivot axis to avoid interference with blade rotation, providing a safety buffer against unintended unlocking.
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 enhances safety by preventing accidental disengagement of the handle lock, even when the bias tension is diminished due to wear or metal fatigue, and reduces the 'stickiness' issue by optimizing the interaction between handle materials and the blade tang.
Implementation Method 1
A spring, such as a wire form spring, can be arranged within a pocket of the switch, and when the switch is moved between engaged and disengaged positions the spring can be compressed generating a rotational bias on the switch urging the switch toward either the engaged or disengaged position.
Implementation Method 2
the spring can be compressed generating a rotational bias on the switch urging the switch toward either the engaged or disengaged position
Implementation Method 3
certain metals and other materials experience greater dynamic friction when surface movement between two objects occurs. In the case of a handle lock on a folding knife, the handle and thus the handle lock is often formed from aluminum or titanium, metals that feel 'sticky' when moved across the tang of a steel blade.
Data Source
AI summary
This disclosure describes systems, methods, and apparatus for a locking folding knife having a handle lock and a safety switch arranged around and rotatable around a pivot axis of the knife. In an engaged position the switch overlaps at least a portion of the handle lock and prevents it from moving into an unlocked position. A spring, such as a wire form spring, can be arranged within a pocket of the switch, and when the switch is moved between engaged and disengaged positions the spring can be compressed generating a rotational bias on the switch urging the switch toward either the engaged or disengaged position.