Pocket Knife Blade Stop Pin Chassis Alignment
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Solution Overview
Problem
Single and double action out-the-front pocket knives experience slight longitudinal and/or axial movement or play between the blade and the chassis when the blade is locked in the deployed position, reducing precision and usefulness compared to folding or fixed blade knives.
Innovation Solution
Incorporating a stop pin connected to the blade that extends to engage with an insert surface inside the chassis, providing a higher hardness than the chassis surface, to prevent movement of the blade when deployed, and utilizing a lock mechanism to secure the blade in both retracted and deployed positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a spring-assisted single or double action mechanism is used to enable one-handed operation, then ease of operation is improved, but manufacturing precision deteriorates due to movement or play between the blade and chassis when locked
Solution Approach 1:
A stop pin is introduced as an intermediary component between the blade and chassis. The stop pin extends from the blade and engages with a recess in the chassis to prevent movement or play between these components when the blade is locked in the deployed position, thereby improving alignment precision without affecting the spring-assisted operation mechanism
Solution Approach 2:
The patent modifies the physical parameters of the engagement interface by adding the stop pin structure that changes the positional parameters of the blade relative to the chassis. This structural modification eliminates the play or movement that occurs with standard manufacturing tolerances, achieving tighter effective tolerances through geometric constraint rather than requiring tighter manufacturing precision
2Ease of manufacture
If standard manufacturing tolerances and clearances are used for spring mechanism components, then ease of manufacture is improved, but reliability deteriorates due to blade movement or play when locked
Solution Approach 1:
The stop pin serves as a mediator that compensates for tolerances and clearances in the spring mechanism components. By introducing this additional geometric constraint, the system achieves reliable blade locking stability without requiring tighter manufacturing tolerances on the spring mechanism components themselves
Data Source
AI summary
A pocket knife includes a chassis and an insert engaged with the chassis, wherein the insert defines an insert surface. A blade has a retracted position in which the blade is inside of the chassis and a deployed position in which at least a portion of the blade is outside of the chassis. An actuator is slidingly engaged with the chassis to reposition the blade between the retracted and deployed positions. A lock is pivotally connected to the chassis and engaged with the blade in the deployed position to lock the blade in the deployed position. A stop pin is connected to the blade, and an end of the stop pin extends a predetermined distance from the blade to engage with the insert surface when the blade is in the deployed position to prevent movement of the blade with respect to the chassis.