OTF Knife Locking Mechanism Using Nested Tang Design
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Solution Overview
Problem
Out-the-front automatic knives face challenges such as limited space for mechanisms, inadequate locking that allows blade movement, high activation force requirements, complex and costly precision parts, leading to unreliable and unwieldy designs with weak and wobbly lockups.
Innovation Solution
A double action OTF knife design featuring a locking mechanism with a lock bar, rocker bar, and ball system, along with a shuttle plate and thrust blocks, that allows the blade to be securely locked in both open and closed positions using a compound angle wedge system, reducing internal space requirements and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is added to restrict blade movement, then reliability is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is nested within the blade tang itself, with the lock bar and ball contained inside the tang's internal cavity. This integration eliminates the need for separate locking components and reduces overall mechanism complexity while maintaining reliable blade lockup in both open and closed positions.
Solution Approach 2:
The locking function is segmented into distinct components (lock bar, ball, control pin) that work together through a simple rotational motion. The lock bar rotates about a pin, with the ball engaging different positions to lock the blade in either open or closed state, providing reliable locking through functional segmentation.
2Ease of operation
If the handle size is reduced to improve blade-to-handle ratio, then ease of operation is improved, but volume available for mechanism decreases
Solution Approach 1:
The locking mechanism components are nested within the blade tang's internal cavity, utilizing space that would otherwise be structural. This allows for a more compact handle design while maintaining all necessary locking functions, improving the blade-to-handle ratio without sacrificing mechanism volume.
Solution Approach 2:
The locking mechanism utilizes the internal three-dimensional space of the blade tang, transitioning from a two-dimensional surface layout to a three-dimensional volumetric arrangement. This allows efficient packing of locking components within minimal handle volume.
3Reliability
If precision parts are used to achieve reliable locking, then reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
The locking mechanism is segmented into simple, discrete components (lock bar, ball, control pin, rocker bar) that can be manufactured using standard machining processes. Each component has simple geometries that are easy to fabricate and assemble, avoiding the need for complex precision parts while maintaining reliable locking through their coordinated arrangement.
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 design provides a secure and robust locking system that restricts blade movement in all six degrees of freedom, reducing play and enhancing the handle-to-blade ratio, while being easier to manufacture and more cost-effective.
Implementation Method 1
spring-loaded locking mechanism
Implementation Method 2
locking mechanism with a lock bar, rocker bar, and ball system
Data Source
AI summary
A knife include a handle, button, blade with an integral tang, locking mechanism within the tang, and thrust mechanism. The blade moves between closed and open positions. The button may axially slide along the handle. When the blade is in the closed position and locked, movement of the button towards the first handle end releases the locking mechanism and the thrust mechanism moves the blade to the open position. A knife includes a stop pin connected to a tang of a blade and a stop plate positioned within a knife handle. The stop plate has two angled surfaces. The stop pin mates with both angled surfaces and the blade is constrained from movement in two planes.