Assisted-Opening Knife Spring Ejection and Stopper Locking
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Solution Overview
Problem
Conventional retractable knives have inefficient blade extension mechanisms, leading to insecure locking during cutting and stabbing, and pose safety risks due to sudden blade ejection and finger pinching.
Innovation Solution
An assisted-opening knife design featuring a spring mechanism for rapid blade expansion, combined with a stopper and slider assembly that ensures the blade remains extended during use and prevents accidental retraction, using a spring to eject the blade and a stopper to secure it in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a spring mechanism is used for rapid blade expansion, then blade extension speed is improved, but the risk of sudden blade ejection and safety hazards increases
Solution Approach 1:
A limiter component is introduced as an intermediary between the spring mechanism and the blade. This limiter restricts the blade's movement range, preventing it from ejecting too far while still allowing rapid extension. The limiter acts as a mediator that controls the spring's effect, enabling fast blade deployment without causing safety hazards from excessive ejection distance.
2Measurement precision
If a stopper and corrugated portion mechanism is used for stepwise blade locking, then blade positioning is improved, but the locking reliability during forceful cutting deteriorates
Solution Approach 1:
The locking mechanism utilizes a curved or rounded surface geometry where the stopper interacts with the corrugated portion. This curved interaction surface allows for smoother engagement and more reliable locking under forceful cutting conditions, compared to flat or angular surfaces. The curvature distributes forces more effectively during the locking engagement.
3Object-affected harmful factors
If the blade is made fully retractable for safety, then user safety is improved, but the ease of operation during cutting deteriorates
Solution Approach 1:
The blade mechanism transitions from a static locking position to a dynamic system that can rapidly extend and retract. The spring provides dynamic force to quickly extend the blade when needed, while the limiter and stopper mechanisms ensure it can be reliably retracted and locked when not in use. This dynamic behavior allows the blade to be fully retractable for safety while maintaining ease of operation during cutting through rapid deployment.
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 allows for rapid and secure blade extension without sudden ejection, ensuring safe operation during cutting and stabbing while maintaining the retractable feature for safety.
Implementation Method 1
using a spring to eject the blade and a stopper to secure it in place
Data Source
AI summary
An assisted-opening knife has a spring tied to a front of a blade carrier and a movable slider assembly within a slot formed through the blade carrier, so that a blade can be rapidly extended by the elastic force without going through stepwise movement. An expanded portion of the slot engaging the slider assembly allows the blade to be received in a holder and ejected only when the slider assembly fully disengages from the expanded portion, thereby generating no sudden ejection of the blade. Additionally, a safety latch securely locks the blade when the blade is fully retracted. When the blade is fully extended, a stopper engages the slider assembly to prevent the blade from being retracted during cutting and stabbing. Accordingly, the assisted-opening knife addresses a solution to rapidly extend the blade for cutting and stabbing without compromising the safety considerations.