Pocket Knife Blade Play Reduction via Stop Pin
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Solution Overview
Problem
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 a predetermined distance to engage with the chassis surface when the blade is deployed, preventing movement between the blade and the chassis, and using a lock pivotally connected to the chassis to secure the blade in the deployed position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a double action out-the-front pocket knife uses a spring-assisted mechanism to enable one-handed operation, then the ease of operation is improved, but manufacturing tolerances and clearances cause slight longitudinal and/or axial movement or play between the blade and chassis when locked, reducing precision
Solution Approach 1:
A stop pin is introduced as an intermediary element between the blade and chassis. The stop pin extends from the blade and engages with a recess in the chassis when the blade is in the deployed position, preventing longitudinal and axial movement. This intermediary component eliminates the play and movement caused by manufacturing tolerances and clearances in the spring-assisted mechanism, while preserving the one-handed operation capability.
2Ease of operation
If manufacturing tolerances and clearances are designed to allow smooth operation of the double action mechanism, then the ease of operation is improved, but slight movement or play occurs between the blade and chassis when locked, reducing precision
Solution Approach 1:
The stop pin serves as a mediator that bridges the gap between the blade and chassis. It is designed to engage precisely with a recess in the chassis when the blade is deployed, eliminating movement and play while maintaining smooth operation. The stop pin compensates for the effects of manufacturing tolerances and clearances without compromising the ease of operation.
Solution Approach 2:
The invention changes the geometric parameters of the blade-chassis interface by introducing the stop pin with specific dimensional constraints. The stop pin extends a predetermined distance from the blade and engages with a recess of specific size and position in the chassis. This parameter change eliminates movement while preserving operational smoothness.
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 solution effectively reduces or eliminates movement between the blade and the chassis when locked, enhancing the precision and usability of the pocket knife by maintaining the blade's position securely in both retracted and deployed states.
Implementation Method 1
a spring that assists a user to deploy and/or retract the blade using a single hand
Data Source
AI summary
A pocket knife includes a chassis, a surface defined by the chassis, and a blade having a retracted position in which the blade is locked inside of the chassis and a deployed position in which at least a portion of the blade is locked outside of the chassis. An actuator is slidingly engaged with the chassis to reposition the blade between the retracted and deployed positions. A stop pin is connected to the blade. An end of the stop pin extends a predetermined distance from the blade to engage with the surface defined by the chassis when the blade is in the deployed position to prevent movement of the blade with respect to the chassis.