Folding Knife Lock Back Mechanism Space Optimization
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Solution Overview
Problem
Existing folding hand tools, particularly multi-blade knives like the Whittler Pattern, face challenges in implementing reliable locking mechanisms for the primary cutting blade due to structural constraints, which affect safety and functionality.
Innovation Solution
A lock back-type locking mechanism is introduced, utilizing spring members and a lock bar with oversized bores to apply biasing force, allowing secure locking of the primary blade in the open position and easy release for folding, while minimizing space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional lock back mechanism is used, then the blade can be securely locked in the open position, but a significant amount of space is required to house the springs and associated structures
Solution Approach 1:
The locking mechanism components are nested within each other to minimize space. The lock bar is received within the handle assembly, and the spring is contained within a cavity formed by the lock bar and handle. The oversized bore in the lock bar allows the pin to move freely while the spring occupies minimal space within the nested structure.
Solution Approach 2:
The locking mechanism utilizes the thickness dimension of the handle rather than requiring additional lateral space. The lock bar extends through the handle thickness, and the spring operates in the thickness direction, allowing the mechanism to be integrated into the existing handle profile without increasing overall handle volume.
2Reliability
If a cross-bolt mechanism is used, then the blade can be locked in the open position, but the mechanism requires a locking body with tapered side wall portions and compression springs that increase structural complexity
Solution Approach 1:
The complex tapered locking body and compression spring system is extracted and replaced with a simpler lock bar design. The lock bar directly engages the blade tang without requiring a separate locking body with tapered surfaces, eliminating the need for compression springs and reducing the number of components.
Solution Approach 2:
Instead of using a locking body that actively wedges against the blade with tapered surfaces, the lock bar uses a flat surface that simply contacts the blade tang. The locking action is achieved through the geometric relationship between the lock bar opening and blade tang notch rather than through forced wedging action.
3Device complexity
If a resilient lever liner lock is used, then the blade can be locked in the open position, but the mechanism relies on a resilient lever formed as part of the handle liner which may not provide sufficient locking force for multi-blade tools
Solution Approach 1:
The locking function is merged with the handle structure itself. The lock bar is received within the handle assembly and uses the handle's own structural strength to provide the locking force, rather than relying on a separate resilient lever. The combined structure of handle and lock bar creates a more robust locking system suitable for multi-blade tools.
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 provides a reliable and space-efficient locking solution for the primary blade, enhancing safety and usability by ensuring the blade remains securely locked in the open position and easily foldable back into the closed position.
Implementation Method 1
springs mounted in the rearward portion of the handle (between the handle halves) applies upwardly directed pressure on the latch bar rearward of the pivot, urging the forward end of the latch bar into a locking engagement with the blade
Data Source
AI summary
A hand tool such as a multi-bladed folding knife incorporates a lock back mechanism t hat is interconnected with springs extending parallel to the knife body and with pins that interconnect the springs. The springs apply biasing force via the pins to the lock back mechanism associated with the primary blade, and also on secondary blades if used.