Folding Knife Blade Release Hidden Until Carrier Rotation

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Solution Overview

Problem

Conventional folding knives with removable blades often require the blade carrier to be positioned at a specific angle for blade removal, but users may mistakenly believe the mechanism is broken if they attempt to release the blade while in the cutting position, leading to frustration and potential misuse.

Innovation Solution

A folding knife design that prevents blade removal when in the cutting position by hiding the blade release mechanism, making it accessible only when the blade carrier is rotated to a specific angle, typically 45 degrees, ensuring intuitive operation and preventing accidental detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the blade release mechanism is always accessible, then the user can easily remove the blade, but the user may accidentally detach the blade while in the cutting position

Engineering Contradiction:
Improveblade removal accessibilityVSAvoidaccidental blade detachment
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The blade release mechanism transitions from a static always-accessible state to a dynamic state that changes position based on blade carrier orientation. The mechanism moves between accessible and hidden states as the blade carrier rotates, allowing easy access during blade removal while preventing accidental activation during cutting operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The blade release mechanism is moved from a two-dimensional surface on the handle to a third-dimensional position that is spatially separated when the blade carrier is in the cutting position. This dimensional relocation ensures the mechanism is physically inaccessible during cutting while remaining accessible when the blade carrier is in the removal position.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If the blade release mechanism is hidden when not in use, then accidental detachment is prevented, but the user may be confused about how to access it

Engineering Contradiction:
Improveaccidental blade detachmentVSAvoiduser awareness of release mechanism location
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The blade release mechanism incorporates visual indicators that change appearance or become visible based on the blade carrier position. This visual feedback system maintains user awareness of the mechanism's location and accessibility state without requiring the mechanism to be constantly visible, thus preventing accidental detachment while avoiding user confusion.

Inventive Principle:
Principle #32Color changes

3Object-affected harmful factors

If the blade carrier must be positioned at a specific angle for blade removal, then accidental detachment is prevented, but the user may mistakenly believe the mechanism is broken

Engineering Contradiction:
Improveaccidental blade detachmentVSAvoiduser understanding of operation requirements
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The system provides immediate visual and tactile feedback to confirm the blade carrier is in the correct position for blade removal. This feedback mechanism reassures users that the system is functioning properly and guides them to the correct operational state, eliminating confusion about whether the mechanism is broken or if they are using it incorrectly.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4015166B1Folding knife with selectively hidden blade release
Publication Date: 2026.01.28 STANLEY BLACK & DECKER INC
  • EP4015166B1 patent drawingFigure 1~2
  • EP4015166B1 patent drawingFigure 3~4
  • EP4015166B1 patent drawingFigure 5~6

AI summary

Certain embodiments of a folding knife 100 are disclosed. In one embodiment, an example knife may include a handle 102 and a blade carrier 104. The blade carrier may be rotatable about the handle and may include a left and a right cap 114, 116. A blade 106 may be removably disposed within the blade carrier. The knife may further include a blade release mechanism 110. In one embodiment, the blade release mechanism may include a compression spring 118 and a lift bar 120. In another embodiment, the blade release mechanism may further include a wheel 1122. In yet another embodiment, the blade release mechanism may include a leaf spring 718 and a slide bar 720. When the blade carrier is rotated such that the knife is not in a cutting position, at least a portion of the blade release mechanism is exposed. When the blade release mechanism is activated, the blade may be removed from within the blade carrier.