Adjustable Spring Tension Pocket Knife Mechanism
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Solution Overview
Problem
Double action switchblades often require excessive force to deploy and retract the blade due to varying manufacturing tolerances in spring length and elasticity, making operation difficult for some users and unreliable.
Innovation Solution
A pocket knife design with an adjustable connection between the spring and rear operator, allowing multiple positions to adjust tension between the front and rear operators, facilitating convenient and reliable one-handed operation by accommodating different spring characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring with higher tension is used to ensure reliable blade deployment and retraction, then the reliability of operation is improved, but the force required to move the actuator increases making operation difficult
Solution Approach 1:
The spring tension is made adjustable through an adjustable connection mechanism between the spring and rear operator. This allows the tension to be dynamically modified according to user needs, enabling reliable operation with manageable force requirements. The adjustable connection includes multiple positions that change the effective spring length and thus the tension applied to the blade mechanism.
Solution Approach 2:
The invention changes the physical parameter of spring tension by providing an adjustable connection that modifies the effective spring length. By varying the spring length, the tension force can be optimized to balance reliability of operation with ease of actuation. This parameter adjustment compensates for manufacturing tolerances in spring elasticity and length.
2Device complexity
If manufacturing tolerances in spring length and elasticity are not compensated, then the device complexity is reduced, but the ease of operation deteriorates due to varying force requirements
Solution Approach 1:
The adjustable connection introduces a dynamic element to the otherwise static spring mechanism. This adjustment capability compensates for manufacturing tolerances in spring length and elasticity without requiring precision manufacturing. The user can modify the spring tension to achieve consistent operation across different spring variations.
Solution Approach 2:
By providing an adjustable connection with multiple positions, the invention allows modification of the spring's effective length and tension. This parameter change compensates for variations in spring characteristics due to manufacturing tolerances, ensuring consistent ease of operation across different units without increasing manufacturing complexity.
3Reliability
If the spring tension is increased to compensate for shorter spring length or higher modulus of elasticity, then the reliability of blade deployment is improved, but the difficulty of operation increases
Solution Approach 1:
The adjustable connection enables dynamic modification of spring tension based on the specific spring characteristics and user requirements. This allows the system to maintain reliable blade deployment while adjusting the force required to operate the actuator to manageable levels.
Solution Approach 2:
The invention changes the spring tension parameter through an adjustable connection that modifies the effective spring length. This parameter adjustment ensures that even springs with shorter length or higher modulus of elasticity can provide reliable deployment without making operation excessively difficult.
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 adjustable tension mechanism ensures consistent and manageable force requirements for deploying and retracting the blade, enhancing user convenience and reliability across various manufacturing tolerances.
Implementation Method 1
A spring connected between the front operator and the rear operator provides a tension between the front and rear operators
Data Source
AI summary
A pocket knife includes a chassis that defines a cavity. A blade having a cutting edge has a retracted position in which the cutting edge is inside the cavity and a deployed position in which the cutting edge is outside of the cavity. A front operator inside the cavity engages with the blade to move the blade to the retracted position, and a rear operator inside the cavity engages with the blade to move the blade to the deployed position. A spring connected between the front operator and the rear operator provides a tension between the front and rear operators. An adjustable connection between the spring and the rear operator has a plurality of positions to adjust the tension between the front and rear operators.