Retractable Knife Blade Locking Mechanism
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Solution Overview
Problem
Existing retractable blade knives, such as cutters, require complex disassembly to change blades, making the process delicate and time-consuming.
Innovation Solution
A knife design featuring a blade holder that slides along a longitudinal axis with a locking mechanism using a blade blocker, pivot axis, and spring device, allowing for easy blade extension and retraction, and simple blade replacement by tilting the blocker to disengage the locking pin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional locking mechanism is used in retractable blade knives, then the blade can be securely locked in the extended position, but the blade replacement process becomes complex and time-consuming requiring disassembly of cheek components
Solution Approach 1:
The locking mechanism is segmented into distinct functional components: a blocker element that can be independently actuated, a pusher element for releasing the blocker, and a spring device for automatic resetting. This segmentation allows the blade to be released without disassembling the entire knife structure, resolving the contradiction between secure locking and easy replacement.
Solution Approach 2:
The blocker element serves as an intermediary component between the blade holder and the blade. It mediates the locking and releasing actions by being actuated through the pusher element, allowing blade replacement without direct manipulation of the blade holder or cheek components, thus simplifying the replacement process while maintaining secure locking.
2Reliability
If a secure blade locking mechanism is implemented, then the blade remains firmly in place during use, but the mechanism for releasing and replacing the blade becomes more complex
Solution Approach 1:
The spring device provides self-service functionality by automatically resetting the blocker element to the locked position after the pusher element releases it. This eliminates the need for additional manual steps to reset the locking mechanism, reducing overall complexity while maintaining secure blade holding during use.
Solution Approach 2:
The locking mechanism operates through periodic action: the blocker element alternates between locked and released positions. During normal use, the spring maintains the blocker in the locked position; during replacement, the pusher temporarily actuates the blocker to the released position. This periodic operation simplifies the mechanism compared to continuous control systems.
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
Simplifies the process of changing blades by allowing the blade to be easily extended, retracted, and replaced without the need for complex disassembly, enhancing user convenience and reducing operational time.
Implementation Method 1
a spring device returning the first arm to the blade locking position
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
[Claim 11] Knife comprising a knife body (1a, 1b), a blade holder (2) supporting a blade (4), said blade holder sliding in the knife body along a longitudinal axis (A) between a retracted position and an extended position in which the blade (4) comes out of a first end of the knife body, comprising a mechanism for locking the blade in the blade holder provided with a blade blocker (3, 3', 3") mounted on the blade holder, comprising: a. a pivot axis (B), received in the blade holder and transverse to a direction of movement of the blade holder between a position for retracting the blade into the knife and a position for extending the blade along said longitudinal axis (A), b. a first arm (3a), comprising a free end provided with a pin (33) for locking the blade (4) inserted into a hole (41) in the blade and, c.a spring device (5) returning the first arm (3a) to the blade locking position, said mechanism further comprising a pusher element (11) associated with the body and positioned opposite a support part (32) of the blade locker when the blade holder is in the blade exit position, said pusher element (11) being configured so that pressing on the pusher element pushes said support part (32) so as to tilt the locker (3) around said pivot axis (B) and release the blade by disengaging the pin (33) from the hole (41) in the blade.