Pivoting Lockbar in Folding Knife Mechanism
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Solution Overview
Problem
The existing side locking liner mechanism in folding knives faces issues with lockbar stiffness and resilience, leading to potential blade disengagement and safety concerns due to the need for resilient materials that are either too flexible or too stiff, and the risk of metal fatigue in springs.
Innovation Solution
The lockbar is constructed using a rigid material with a hinge-type joint instead of a bending joint, eliminating the need for resilient materials and allowing the use of thick, non-resilient materials, which provides strength and stability while enabling the lockbar to pivot securely, with optional biasing springs for convenience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resilient material is used for the lockbar to allow it to function as a spring, then the lockbar can automatically lock the blade in the open position, but the lockbar becomes too flexible and may bend inappropriately under downward force
Solution Approach 1:
The lockbar is divided into two functional segments: a rigid locking portion that maintains strength and rigidity for reliable locking, and a separate resilient portion or alternative mechanism that provides the spring function. This segmentation allows each part to optimize its properties without compromising the other.
Solution Approach 2:
The spring function is extracted from the lockbar itself and implemented as a separate resilient component or mechanism. This allows the lockbar to be made of rigid material while the spring function is performed by a dedicated component designed for resilience.
2Strength
If thicker resilient material is used to strengthen the lockbar, then the lockbar becomes stronger, but the flexibility required for the spring function is reduced
Solution Approach 1:
The lockbar system is segmented into a thick rigid lockbar for strength and a separate thin resilient component for flexibility. This allows the rigid portion to be optimized for strength while the resilient portion maintains the necessary flexibility for easy operation.
Solution Approach 2:
The locking mechanism uses a composite structure combining rigid material (for the lockbar) with resilient material (for the spring function). This composite approach allows both strength and flexibility requirements to be met simultaneously through material combination rather than relying on a single material property.
3Strength
If the lockbar is made of rigid material with a hinge joint, then the lockbar strength and stability are improved, but a separate biasing spring is needed to provide automatic lockup
Solution Approach 1:
The spring function is extracted as a separate, simple component rather than being integrated into the lockbar structure. This separate resilient portion or biasing spring is a straightforward element that provides the automatic locking function without adding significant complexity to the overall mechanism.
4Adaptability or versatility
If resilient material is used for the lockbar, then the lockbar can function as a spring, but the material is mechanically weaker compared to non-resilient materials
Solution Approach 1:
The spring function is extracted from the primary lockbar structure and implemented as a separate resilient component. This allows the main lockbar to be made of strong non-resilient material while the separate spring component provides the necessary elasticity and spring function.
Solution Approach 2:
The system uses composite material construction where the lockbar is made of strong rigid material and the spring function is provided by a separate resilient material component. This combination leverages the strengths of both material types without compromising overall performance.
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
This design enhances the safety and functionality of the folding knife by ensuring the blade remains locked securely without relying on springs, reducing the risk of metal fatigue, and allowing for the use of various materials for improved aesthetics and durability.
Implementation Method 1
The lockbar is made of non resilient material and is adapted with a hinge type joint that allows the lockbar to pivot
Data Source
AI summary
A locking mechanism for a tool or knife blade based on the locking liner lock. A hinge replaces the typical flex point at the base of the lockbar which allows the lockbar to be made of materials other than those required to be resilient. This allows materials that are lightweight, non metallic, and many other possibilities. As well very strong non resilient materials can be used which would avoid some of the mechanical failures that resilient materials have shown by bending due to downward force on the top of the tool or knife. This mechanical failure will not only destroy the ability of a knife to lock in the open position but the event will cause the blade to rotate toward the closed position and can cut the operators hand. That is a safety issue.