Folding Knife Button Lock Mechanism for Safe One-Handed Operation
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Solution Overview
Problem
Conventional folding knives, such as liner lock and button lock flipper knives, require fingers to be in the path of the closing blade for closure and suffer from unreliable blade opening due to weak detent retention, leading to unsafe deployment.
Innovation Solution
A folding knife design featuring a button lock element, a detent element with a biased ball, and a tension adjustment screw, allowing for one-handed closure without finger interference and ensuring reliable blade opening by controlling the resistance and energy deployment through a spring plate and groove mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a liner lock mechanism is used, then one-handed operation is enabled, but fingers must be placed in the path of the closing blade
Solution Approach 1:
The locking function is extracted from the blade closure path. The lock bar engages with a lock surface on the blade tang that is positioned away from the closing path, allowing the lock to be disengaged without fingers being in the blade's closure trajectory. This separates the locking mechanism's engagement point from the harmful closure path.
Solution Approach 2:
The lock bar acts as an intermediary element that transfers the locking force from a safe position (lock surface on blade tang) to the blade retention function. The user presses the lock bar laterally to disengage it from the lock surface, and this lateral motion is transmitted through the lock bar mechanism to release the blade without requiring fingers in the closure path.
2Reliability
If a ball detent is made strong to securely hold the blade closed, then closed position retention is improved, but the knife becomes difficult to open
Solution Approach 1:
The lock bar is designed with lateral mobility rather than fixed positioning. When the user applies lateral force to the lock bar, it shifts position to disengage from the lock surface. This dynamic, movable design allows the same mechanism to provide strong retention when locked (ball detent holds lock bar in place) while enabling easy release through lateral motion, solving the contradiction between strong closed retention and easy opening.
3Speed
If a flipper tab is used to build energy for blade deployment, then opening speed is improved, but poor technique or weak detent can cause unsafe underpowered opening
Solution Approach 1:
The lock bar is positioned and pre-loaded against the lock surface on the blade tang before opening occurs. The ball detent is pre-positioned to engage with the lock bar's detent surface. When the user actuates the flipper tab, the pre-positioned lock bar and ball detent mechanism ensures that sufficient force is accumulated and transmitted to reliably deploy the blade, preventing underpowered opening even with varying user technique.
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
Enables safe and reliable one-handed closure and opening of the blade, with adjustable resistance to prevent unintended opening and ensure consistent deployment, enhancing user safety and convenience.
Implementation Method 1
a spring plate and groove mechanism. The groove is an arcuate track centered on a pivot axis
Implementation Method 2
a ball detent to releasably secure the blade in the closed position
Data Source
AI summary
A folding knife has an elongated frame defining a major plane and having a pivot element at a pivot end and defining a pivot axis and the frame defining a blade receptacle, an elongated blade occupying the major plane having a tip end and a base end, a spine edge and a cutting edge, and opposed major faces, the base end connected to the pivot element, the blade being operable to pivot between a stowed position in which the blade is received in the blade receptacle and an extended position in which the tip end of the blade extends away from the frame, and the blade having a lock feature proximate the base end, a button lock element connected to the frame proximate the pivot element and operable to selectably engage the lock feature when the blade is in the extended position.