Profiled Key Undercut Groove for Cylinder Lock Security
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Solution Overview
Problem
Existing profiled keys with undercut grooves, while secure, can be challenging to further distinguish and copy-resistant, as they can be replicated using conventional locksmith tools.
Innovation Solution
The innermost part of the undercut groove is extended into a longitudinal pocket with parallel lateral walls and a flat or slightly curved transverse end wall, requiring specialized tools like broaching for accurate reproduction, enhancing security and profile variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional locksmith tools are used to copy keys, then key duplication is easy and cost-effective, but security against unauthorized copying is insufficient
Solution Approach 1:
The key blade features an asymmetric profile groove with an undercut portion that creates an irregular, non-symmetric cross-sectional shape. This asymmetric geometry cannot be replicated by conventional symmetric copying methods, thereby enhancing security while maintaining manufacturability through standard key cutting processes
Solution Approach 2:
The profile groove extends into the key blade with an undercut portion that creates a three-dimensional complex geometry rather than a simple two-dimensional groove. This dimensional complexity requires specialized broaching tools and precise control, significantly increasing the difficulty of unauthorized copying while maintaining ease of manufacture through controlled manufacturing processes
2Reliability
If profile groove depth and complexity are increased to enhance security, then copying becomes more difficult, but manufacturing precision requirements increase
Solution Approach 1:
The profile groove is designed with specific dimensional parameters including a controlled undercut portion with defined depth and width ratios. By optimizing these parameters, the groove achieves sufficient complexity for security while remaining within the capabilities of standard broaching tools and manufacturing processes
Solution Approach 2:
The key blade is designed with the profile groove formed as an integral part of the manufacturing process rather than as a post-processing feature. This preliminary formation ensures precise dimensional control is built into the manufacturing process itself, reducing the need for additional precision operations while maintaining high security standards
Data Source
AI summary
A key for use in a cylinder lock with a rotatable key plug having an elongated key blade with a relatively wide lower portion and a relatively narrow upper portion. A step-like transition region between the wider lower portion and the narrow upper portion. The key blade includes a longitudinal profile groove located adjacent to the step-like transition region that extends along at least a portion of the length of the blade. An inner wall of groove is substantially parallel to a side surface of the lower portion of the key blade. The longitudinal profile groove includes an undercut portion adjacent to and inside a ridge portion of the key blade. The outside of ridge portion forms a part of the side surface of the blade in the relatively wide lower portion up to the step-like transition region and the inside of ridge portion facing inner wall of the groove.