Flat Key Coding Recesses for Enhanced Security

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Solution Overview

Problem

Existing mechanical locking systems face challenges in providing robust protection against unauthorized key copying while maintaining efficient manufacturability, as the number of possible coding positions is limited by available space on the key, and copying is relatively easy using mechanical devices.

Innovation Solution

A flat key design featuring a key blade with coding recesses that have a monotonous slope from the flat side to the narrow side, which are less defined and harder to copy, combined with a method of creating these recesses using a rotating tool that can produce them in the same operation as coding holes, enhancing security and manufacturability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional coding holes are used on the key, then the key can be easily manufactured using mechanical copying devices, but the security against unauthorized key copying is reduced

Engineering Contradiction:
Improveease of key copyingVSAvoidsecurity against unauthorized copying
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces traditional cylindrical coding holes with conical coding recesses that have a monotonic slope. The conical shape with a continuous sloping surface from the flat side toward the narrow side makes it difficult for mechanical copying devices to accurately reproduce the precise 3D geometry, thereby enhancing security while remaining manufacturable using specialized milling processes

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention adds a new dimension to the coding system by creating recesses that extend into the key body with a monotonic slope toward the narrow side, rather than simple holes through the flat side. This creates a more complex three-dimensional coding structure that increases the difficulty of unauthorized copying while maintaining a manageable number of coding positions

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the number of coding positions is increased to enhance security, then the available space on the key is exhausted, but if the number is limited, then security is reduced

Engineering Contradiction:
Improvesecurity through coding positionsVSAvoidavailable space on key
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent places coding recesses at specific locations including the edges of the key in addition to the flat sides. By utilizing the edge areas and creating recesses with monotonic slopes, the design maximizes the use of available key space while maintaining a practical number of coding positions that provide sufficient security without exhausting the key's physical dimensions

Inventive Principle:
Principle #3Local quality

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

The design increases the number of coding positions and complicates unauthorized copying by requiring accurate 3D shape reproduction or knowledge of the manufacturing process, while allowing for efficient production of the key using standard tools.

Implementation Method 1

a method for producing a key of the type described herein, wherein the coding recesses are created using a subtractive tool in the same operation as the coding holes

Methodology Applied
Scientific EffectMaterial removal by rotating tool: Abrasion

Data Source

PatentEP4148212B1Key, locking system, locking cylinder and method for producing same
Publication Date: 2023.10.25 DORMAKABA AUSTRIA GMBH
  • EP4148212B1 patent drawingFigure 1~3
  • EP4148212B1 patent drawingFigure 4~7
  • EP4148212B1 patent drawingFigure 8~9

AI summary

The flat key (1) has a key bow (11) and a key shaft (12) extending along a key axis (10) from the key bow (11) to a front key tip (23), with two parallel flat sides (21) and two opposing narrow sides (22). Between the flat sides and the narrow sides, an edge (25) parallel to the key axis (10) runs. At least one of the flat sides has a row of coding holes (31) parallel to the key axis. The key also has at least one coding recess (35) in at least one of the edges (25). This coding recess forms a flank (43) extending from the flat side to the narrow side, which has a monotonic slope.