Flat Key Undercut Groove Profile to Prevent Scanner Copying
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Solution Overview
Problem
Existing flat keys can be easily copied using laser scanners, and locksmiths can produce inferior keys with thicker profiles that compromise the security and precision of locking systems, making it difficult to maintain clear assignments between keys and locks.
Innovation Solution
A flat key design featuring symmetrical depressions in the grooves and corresponding elevations in the ribs, which are not visible from the side, combined with overlapping grooves and ribs, ensures that the key profile cannot be accurately captured by scanners, while allowing milling and maintaining conventional thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional flat key profiles are used, then keys can be easily copied using laser scanners and copy milling machines, but maintaining security and clear key-lock assignment becomes difficult
Solution Approach 1:
The patent applies asymmetry by providing undercut grooves where the groove bottoms are positioned asymmetrically relative to the groove openings. The groove bottoms are offset in the direction of the key front section, creating an asymmetric profile that cannot be accurately captured by conventional lateral scanning methods. This asymmetric configuration prevents unauthorized copying while maintaining manufacturability through standard milling processes.
Solution Approach 2:
The patent transitions from two-dimensional lateral grooves to three-dimensional undercut grooves by positioning groove bottoms at different depths and positions along the key profile. This dimensional change creates hidden features that are not visible from the side, preventing accurate scanning and copying while maintaining compatibility with existing milling equipment.
2Reliability
If complex broaching processes are used to create secure key profiles, then copying becomes difficult, but manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces complex broaching processes with standard milling operations. The undercut grooves are created using conventional milling cutters that move in straight lines, eliminating the need for complex broaching tools and processes. This substitution maintains security through asymmetric groove design while simplifying manufacturing and reducing equipment requirements.
3Reliability
If key profiles are made thicker to prevent copying, then security improves, but the key thickness deviates from conventional standards and may compromise locking system compatibility
Solution Approach 1:
The patent achieves enhanced security within conventional key thickness limits by creating three-dimensional undercut grooves. The groove bottoms are positioned at different depths and locations, creating hidden features that prevent accurate copying without increasing overall key thickness. This maintains compatibility with standard locking systems while providing robust security.
Data Source
AI summary
A flat key for a locking cylinder has substantially flat and approximately parallel flat key sides, a key rear section, and a key front section opposite thereto. The key front section has a toothing for positioning tumbler pins divided into core pins and housing pins and which are spring-loaded against the key front section in the direction of the key rear section and into corresponding bores. Grooves in the form of profiled variation elements and profiled guiding elements are provided in the flat sides of the flat key, wherein at least two grooves of one flat side of the flat key, which are preferably part of the profiled guide, overlap and are undercut in opposite directions. A depression is provided in the outer flank of at least one of the two grooves, preferably both grooves, at least one region of the depression not being visible from the side.