Folding Knife Assembly With Full-Length Tang Locking Strength
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Solution Overview
Problem
Current folding knives have a weak point at the interface of the single blade member and the handle due to the blade being secured only at one end by a pivot structure, lacking strength for tasks requiring prying forces and not designed for side loads, making them unsuitable for heavy-duty applications like bushcraft or outdoor tasks.
Innovation Solution
A fixed blade folding knife assembly with a handle assembly and blade member featuring a central steel member and pivot pin, where the blade tang extends through the handle for enhanced strength, and a lock pin mechanism ensures secure locking in both open and closed positions, allowing for compact carry and use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single blade member is secured only at one end by a pivot structure, then the knife can be folded for compact carrying, but the interface between blade and handle becomes a weak point lacking strength for prying forces and side loads
Solution Approach 1:
The blade is segmented into a blade portion and a tang portion, where the tang portion extends into the handle assembly. This segmentation allows the tang to be securely retained within the handle structure, distributing mechanical loads across multiple attachment points rather than relying solely on a single pivot structure, thereby strengthening the blade-handle interface while maintaining foldability.
Solution Approach 2:
The tang of the blade is nested within the handle assembly, with the tang extending into and being retained by the handle structure. This nesting arrangement provides internal support and strengthens the connection between blade and handle, creating a more robust interface that can withstand prying forces and side loads while still allowing the blade to fold for compact carrying.
2Strength
If a fixed blade knife is used for heavy-duty applications, then sufficient strength for prying and side loads is achieved, but the knife cannot be folded for safe and compact carrying
Solution Approach 1:
The knife assembly transitions between two dynamic states: a deployed state where the blade is extended and locked for heavy-duty applications, and a folded state where the blade is retracted for compact carrying. The lock pin mechanism enables this dynamic transformation, allowing the same structure to provide fixed-blade strength when needed and compact portability when not in use.
Solution Approach 2:
The lock pin acts as an intermediary mechanism that enables the blade to achieve fixed-blade stability during heavy-duty tasks. When engaged, the lock pin secures the blade in the extended position, providing the necessary strength for prying and side loads, while allowing the blade to be folded back for compact carrying when the lock is disengaged.
3Reliability
If a lock pin mechanism is added to secure the blade, then strength and stability in locked position is improved, but device complexity increases
Solution Approach 1:
The spring component provides self-service by automatically applying force to engage or disengage the lock pin based on the blade's position. When the blade is moved to the extended position, the spring automatically pushes the lock pin into the locked position, and when the blade is folded, the spring facilitates automatic unlocking, reducing the need for complex manual locking mechanisms.
Solution Approach 2:
The spring mechanism replaces more complex mechanical locking systems with a simpler elastic force-based system. The spring provides the necessary locking and unlocking forces through elastic deformation, eliminating the need for multiple springs, cam mechanisms, or complex linkage systems, thereby achieving reliable locking with minimal complexity.
Data Source
AI summary
A folding knife assembly includes a handle assembly and a blade member having a primary blade portion with a sharpened cutting edge and a rear portion defining a blade tang. The handle assembly includes a central steel member having a forward tang geometry that is structured and disposed for cooperative, keyed engagement with the opposing blade tang within the handle assembly to effectively achieve a blade tang that extends substantially the length of the handle. A lock pin is movable between a locked position and a release position in relation to a pivot pin to allow pivotal movement of the blade member between the open and closed positions and, together with blade and handle tang geometry, creates a fixed blade to handle structure in the open locked position.