Folding Knife Blade Opening Mechanism With Threshold Spring Activation
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Solution Overview
Problem
Existing folding knives with automatic or opening assist mechanisms lack a reliable mechanism to ensure the blade remains closed until intentionally opened, posing safety concerns, especially when dropped or subjected to unintended motion.
Innovation Solution
A folding knife design utilizing a pair of torsion springs axially positioned on the blade axis pin within stationary bushings, where the springs are loaded in the closed position and apply force to the blade only after a predetermined rotational threshold is reached, driving the blade into the open position and locking it securely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a spring mechanism is used to provide opening assist, then the blade can be automatically driven open, but the blade may unintentionally open when dropped or subjected to strong motions
Solution Approach 1:
The spring mechanism is pre-loaded in the closed position but designed with a threshold activation point. The spring force is stored and only begins to act on the blade after the blade rotates past a predetermined angle, ensuring the blade remains securely closed until intentionally opened by the user.
Solution Approach 2:
The mechanism changes the activation parameter from continuous spring pressure to threshold-based activation. The spring force is applied only when the blade rotation exceeds a specific angular threshold, transforming the blade from a passive spring-loaded system to an actively controlled opening assist system that distinguishes between accidental and intentional opening motions.
2Ease of operation
If the spring force is applied continuously, then the blade opens easily, but the blade cannot remain securely closed without additional retaining mechanisms
Solution Approach 1:
The spring is pre-loaded during blade closure but its force is temporarily contained. The mechanism is designed so that the spring force is only released after the blade passes the threshold angle, eliminating the need for separate retaining mechanisms while maintaining secure closed position and easy intentional opening.
Solution Approach 2:
The invention extracts the retaining function from a separate mechanism and integrates it into the threshold-based spring activation system. The spring force itself serves dual purposes: providing opening assist when activated and implicitly retaining the blade closed when below the activation threshold, simplifying the overall device structure.
3Reliability
If a latch or trigger mechanism is used for automatic opening, then the blade can be reliably held closed, but the mechanism complexity increases
Solution Approach 1:
The invention removes the latch and trigger components entirely, replacing them with a threshold-based spring activation system. The spring mechanism alone provides both reliable closed position retention and automatic opening assist, eliminating the complexity of separate latching and triggering mechanisms while maintaining safety and functionality.
Solution Approach 2:
The spring mechanism is designed to perform multiple functions: it retains the blade in the closed position through threshold control, provides opening assist once activated, and eliminates the need for separate latching and triggering mechanisms. This multi-functional design simplifies the overall device while maintaining reliability.
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 mechanism ensures the blade is securely locked in both the open and closed positions, preventing unintended opening and providing a safe and efficient automatic opening assist, even when the knife is dropped or subjected to strong motions.
Implementation Method 1
The present invention relies upon a pair of torsion springs held axially on the blade axis pin and within a pair of bushings that are stationary relative to the knife handle
Implementation Method 2
When the blade is in the closed position the torsion springs are 'loaded' but do not apply their spring force to the blade
Implementation Method 3
the paired springs, which act on the blade and thereby impart sufficient rotational kinetic energy to the blade that the inertia drives the blade into the fully open position
Data Source
AI summary
A folding knife incorporates an opening assist mechanism that functions to drive the blade from the closed to the open position. A torsion spring is retained axially on the blade axis pin and within a bushing that is stationary relative to the knife handle. One leg of the spring is fixed relative to the handle. The opposite leg of the spring extends through and rides in a partial annular groove in the bushing and acts on the blade as it is moved between the open and closed positions.