Retractable Utility Knife Thumb-Actuated Blade Release Mechanism
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Solution Overview
Problem
Conventional retractable utility knives are complex in structure, inconvenient to use, and require extra tools for blade replacement, with complicated mechanisms that involve releasing a lock member and rotating a top cover.
Innovation Solution
A retractable utility knife with a sliding blade holder and a manually operable blade lock featuring a rotatable release member actuated by the user's thumb, utilizing a spring biasing mechanism for quick and convenient blade release, allowing one-hand operation and a slim profile for easy storage and transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional retractable utility knife uses a lock member and top cover mechanism for blade replacement, then the blade can be secured, but the structure becomes complex and blade replacement becomes inconvenient
Solution Approach 1:
The patent extracts the top cover and lock member components from the blade securing mechanism, replacing them with a simplified slot-and-button system. The release button directly disengages the blade from the slot without requiring separate locking or rotating operations, thereby maintaining blade security while eliminating structural complexity.
Solution Approach 2:
The patent merges the blade holder, securing mechanism, and release operation into a single integrated slot-and-button system. The button is rotatably mounted on the blade holder and directly controls blade retention through a simple disengagement motion, combining multiple functions into one compact mechanism that reduces overall device complexity.
2Reliability
If a conventional utility knife uses a lock member and top cover for blade replacement, then the blade can be secured, but the blade replacement process becomes complicated and time-consuming
Solution Approach 1:
The patent removes the multi-step lock member and top cover rotation process, replacing it with a single-button release mechanism. The button's rotational motion directly releases the blade from the slot, eliminating unnecessary intermediate steps and significantly reducing the time required for blade replacement while maintaining secure blade retention during use.
Solution Approach 2:
The release button is pre-positioned and spring-loaded to facilitate immediate blade release. The spring maintains the button in a position where minimal user effort is required to disengage the blade, allowing for rapid blade replacement without requiring the user to perform complex preparatory actions.
3Reliability
If a utility knife uses a bolt anchored in a fixing hole to secure the blade, then the blade can be firmly fixed, but extra tools are required for blade replacement
Solution Approach 1:
The patent implements a self-service blade replacement system where the release button on the blade holder allows users to easily remove the blade without requiring external tools. The button's rotational motion directly disengages the blade from the slot, making the blade replacement process as convenient as the initial blade installation while maintaining firm blade fixation during use.
4Ease of operation
If the release member is positioned to be actuated by the thumb while holding the handle, then one-hand operation is enabled, but the release member mechanism becomes more complex
Solution Approach 1:
The patent merges the release member into the blade holder structure, with the button rotatably mounted directly on the holder. This integration allows the thumb to easily access and actuate the button while maintaining a compact, simplified mechanism that does not require separate components or complex linkages, thus achieving one-hand operation without significantly increasing device complexity.
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
Enables simple, economical, and ergonomic operation with one-hand blade release, facilitating quick blade replacement and a compact design for easy storage and transport, improving user convenience and reducing complexity.
Implementation Method 1
Biasing means in the form of a spring is provided for normally rotating the release member to move the second portion to the locking position
Data Source
AI summary
A retractable knife includes an elongate handle and a blade holder slidingly mounted within the handle for sliding movements between a retracted position and an extended position. The blade holder is configured for receiving. A manually operable blade lock is formed on the holder and including a release member rotatably mounted on the blade holder. The release member having a first portion projecting beyond the handle and positioned to be actuated by a finger of a user while holding the handle. A second portion is movable with the first portion between a locking position in which the second portion is received with a notch of a blade and a releasing position in which the second position is removed from the blade notch to a position outside the notch of the blade. A spring normally rotates the release member to move the second portion to the locking position. Actuation of the release member by the finger of the user to overcome the spring moves the second portion to the releasing position and releases the blade.