Hinged Knife Blade Locking Ferrule Extraction Design
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Solution Overview
Problem
Existing knife designs with rotating ferrules for blade deployment and locking suffer from complex manufacturing, aesthetic, and handling issues, including increased cost, reduced grip convenience, and compromised structural integrity due to additional grooves and features.
Innovation Solution
Incorporation of a male guide element on the rotating ferrule and a complementary female guide element on the fixed ferrule, such as a circular groove, to facilitate smooth rotation and secure the rotating ferrule without adding manufacturing complexity or affecting aesthetics, along with a notch on the rotating ferrule to limit rotational travel and a proximal notch on the fixed ferrule for blade locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second groove is added to the rotating ferrule to prevent accidental removal, then the reliability of blade locking is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts the retention function from the rotating ferrule by moving it to the fixed ferrule. The fixed ferrule now includes a retention groove that engages with the rotating ferrule, preventing accidental removal while keeping the rotating ferrule simple and easy to manufacture.
Solution Approach 2:
Instead of adding features to the rotating ferrule to prevent removal, the invention inverts the approach by providing the retention groove in the fixed ferrule. This reverses which component carries the complexity, simplifying the rotating ferrule while maintaining reliability.
2Reliability
If additional grooves and features are added to the rotating ferrule, then the blade locking reliability is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The retention groove feature is extracted from the rotating ferrule and placed in the fixed ferrule. This allows the rotating ferrule to be manufactured simply as a basic ring, while the fixed ferrule incorporates the groove feature that is easier to add during its manufacturing process.
3Reliability
If the rotating ferrule is made with additional features for maintenance, then the reliability is improved, but the aesthetic appearance deteriorates
Solution Approach 1:
The retention groove is extracted from the rotating ferrule and placed in the fixed ferrule, which is typically hidden or less visible. This keeps the rotating ferrule aesthetically pleasing with its simple, clean appearance, while the functional groove is located in a less conspicuous position.
4Reliability
If the rotating ferrule includes additional grooves, then the blade locking reliability is improved, but the ease of operation deteriorates due to reduced grip convenience
Solution Approach 1:
The retention groove is extracted from the rotating ferrule surface, preserving its smooth, continuous outer surface that provides good grip convenience. The groove is instead provided in the fixed ferrule, where it does not interfere with the user's ability to grip and rotate the ferrule easily.
Data Source
Figure 1A~7
Figure 1B~9
AI summary
Knife 1 having a handle 2 and a blade hinged 3 on the handle, between a position of use and a position folded in the handle, a rotating ferrule 14 disposed at the level of the axis of rotation of the blade, and capable of rotating, said rotating ferrule being formed of a split ring and being provided with guiding means 18 and retaining the ferrule tending to oppose its accidental removal, and said guiding and retaining means comprising on the one hand a male guiding element 18, projecting and disposed on the rotating ferrule, directed towards the inside thereof, and on the other hand a fixed female guiding element 17, disposed on the handle or on a member fixed on the latter, the fixed female guiding element being of complementary shape and being capable of receiving and guiding said projecting guiding element.