Double-pivot folding knife blade extension mechanism
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Solution Overview
Problem
Prior art folding knives are limited by the constraint that the blade length cannot exceed the handle length due to the mechanism of folding, which restricts the overall length of the blade when in use.
Innovation Solution
The design incorporates a pivotable blade mechanism with specific pivot members and arcuate openings that allow the blade to extend beyond the handle length by rotating and sliding, utilizing a liner lock to secure the blade in the open position, enabling a longer effective blade length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the blade length is increased beyond the handle length, then the cutting capability and effectiveness are improved, but the folding mechanism cannot accommodate the longer blade
Solution Approach 1:
The pivot mechanism is divided into two separate pivot members (first pivot member and second pivot member) instead of using a single pivot point. This segmentation allows the blade to rotate in two distinct stages: first rotating on the first pivot member, then on the second pivot member, enabling the blade to extend beyond the handle length while maintaining a compact folded state
Solution Approach 2:
The invention introduces a second rotational dimension by adding the second pivot member with its arcuate opening. The blade transitions from rotating around a single axis to rotating around two different axes sequentially, effectively using another dimension of motion to achieve extended blade length without increasing the folded profile
2Device complexity
If the blade length is limited to the handle length, then the folding mechanism remains simple, but the overall length of the blade when in use is restricted
Solution Approach 1:
The first arcuate opening is positioned within or alongside the second arcuate opening, creating a nested arrangement where the blade rotates on the first pivot member within the confines of the second arcuate opening, then transitions to rotate on the second pivot member. This nesting allows the complex two-stage rotation to be contained within a compact structure that folds neatly into the handle
3Length of moving object
If a single pivot mechanism is used, then the device is simpler, but the blade cannot extend beyond the handle length
Solution Approach 1:
The mechanism transitions from a static single-pivot design to a dynamic two-stage rotational system. The blade's motion is divided into two dynamic phases: initial rotation on the first pivot member, then transition to rotation on the second pivot member. This dynamic progression allows smooth operation while achieving extended blade length, with each pivot member optimized for its specific rotational phase
Data Source
AI summary
A folding knife having a handle, a blade pivotably coupled to the handle, and a liner includes a liner lock and a first pivot member that is a post, pin, rod, or other structure having a shape adapted to be slidably received in the second arcuate opening of the blade. The liner further includes a first arcuate opening that has an enlarged end portion and an axis approximately perpendicular to the longitudinal axis of the handle adapted for slidably receiving the second pivot member of the blade. A tang of the blade includes the second pivot member, and the second arcuate opening that has an enlarged end portion and an axis approximately parallel to the longitudinal axis of the blade. An extended tang portion, or flipper, extends downward from the tang. The handle also includes an opposing liner arranged alongside the liner in the handle with the blade positioned therebetween.