Folding Knife Assisted Opening Mechanism With Bar Spring
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Solution Overview
Problem
Folding knives with assisted opening mechanisms often require additional components that affect the 'lock-up' of the blade in both open and closed positions, and existing designs may not effectively balance the forces for smooth operation and safety.
Innovation Solution
An assisted opening mechanism featuring a bar spring seated within the handle and a contact pin extending from the blade, which engages with the bar spring as the blade moves between open and closed positions, providing a bias to assist in opening and holding the blade in the closed position without affecting the lock-up in either state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bar spring is seated within the handle and engaged by a contact pin on the blade, then the blade is securely held in the closed position and assisted in opening, but the mechanism complexity increases by adding two components
Solution Approach 1:
A contact pin serves as an intermediary element between the blade and the bar spring. The contact pin extends from the blade through an arcuate slot in the handle side and engages with the bar spring, transferring the bias force from the spring to the blade without requiring direct attachment of the spring to the blade. This intermediary approach allows the spring to remain enclosed in the handle while still effectively influencing blade movement.
Solution Approach 2:
The bar spring is nested within a recessed cavity formed in one side of the knife handle, completely enclosed and protected within the handle structure. The contact pin extends through an arcuate slot in the same handle side, allowing the spring to be hidden within the handle while still engaging the blade through the pin. This nesting approach integrates the spring mechanism into the existing handle geometry without adding external complexity.
2Reliability
If the bar spring exerts bias force on the blade during closing, then the blade is held in closed position, but the spring may cause material wear on the blade
Solution Approach 1:
The contact pin acts as a mediator that transfers the bias force from the bar spring to the blade. Instead of the spring directly contacting and wearing the blade, the force is transmitted through the contact pin, which is positioned radially from the pivot axis. This intermediary approach protects the blade from direct spring contact and associated wear while still achieving the desired holding effect.
Solution Approach 2:
The bar spring is extracted from direct contact with the blade and repositioned within the handle cavity. The spring's function is maintained through the contact pin mechanism, but the spring itself is removed from the path that would cause wear on the blade. This extraction separates the spring's biasing function from any harmful contact with the blade.
3Ease of operation
If the bar spring engages the contact pin during blade movement, then the blade is assisted in opening, but the mechanism affects the lock-up in open and closed positions
Solution Approach 1:
The contact pin is positioned radially from the pivot axis of the blade, allowing it to travel along the length of the arcuate slot as the blade moves between open and closed positions. This dynamic positioning ensures that the contact pin engages the bar spring during closing to provide holding force, but does not interfere with the lock-up mechanism in either the open or closed position. The arcuate slot guides the pin through the appropriate engagement zone.
Solution Approach 2:
The bar spring is positioned to engage the contact pin at a specific location radially from the pivot axis, creating a localized engagement zone. This local engagement provides the necessary bias force for holding the blade closed without creating continuous contact that would affect the lock-up mechanism. The arcuate slot is designed with specific geometry to allow engagement only in the appropriate angular range.
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 enhances the safety and reliability of folding knives by ensuring the blade is securely held in the closed position until manually opened, while assisting in the opening process without adding material wear or affecting the lock-up in either position, and can be easily integrated into various folding knife designs.
Implementation Method 1
a bar spring seated within one of the handle sides and a contact pin extending from the blade. The bar spring is seated within a recessed cavity formed on one side of the knife handle. The contact pin extends outward from one side of the blade through an arcuate slot in the handle side
Data Source
AI summary
An assisted opening mechanism for folding knives, which helps hold the blade in the closed position, as well as, assists in moving the blade toward the open position. The mechanism includes a bar spring seated within one of the handle sides and a contact pin extending from the blade. The bar spring is seated within a recessed cavity formed on one side of the knife handle and engages the contact pin, which extends outward from one side of the blade through an arcuate slot in the handle side.