Key Blade Segmentation for Hierarchical Master Key Security

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Solution Overview

Problem

Existing lock cylinder systems lack the capability to maximize the number of unique keyway shapes, limiting the development of large and secure hierarchical lock systems, as most key blanks are manufactured with simple profiles using single pass formed milling cutters, making them vulnerable to unauthorized copying and lacking advanced security features.

Innovation Solution

The key blade is divided into three vertical sections with specific variations of ridges and grooves, including a registry groove, undercut longitudinal grooves, and curved or rectangular profiles, allowing for unique key profile shapes that create a structured hierarchical system, enhancing security by preventing unauthorized key copying and increasing the number of non-interchangeable key systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If single pass formed milling cutters are used to manufacture key blanks, then manufacturing simplicity and ease of production are improved, but security against unauthorized copying deteriorates

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

Solution Approach 1:

The key blade is divided into three vertical sections (first, second, and third sections) with distinct ridge and groove configurations in each section. This segmentation allows for complex key profiles that are difficult to copy while maintaining manufacturability through systematic formation processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the key blade have different ridge and groove configurations tailored to specific security requirements. The first section has ridges and grooves for basic identification, the second section has additional security features, and the third section provides further differentiation. This local variation in profile complexity enhances security while allowing standardized manufacturing approaches for each section.

Inventive Principle:
Principle #3Local quality

2Volume of moving object

If finite space in lock cylinder plug is used, then compactness is improved, but the number of unique keyway shapes that can be developed deteriorates

Engineering Contradiction:
Improvekeyway spaceVSAvoidnumber of unique keyway shapes
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The invention utilizes the vertical dimension of the key blade by creating three distinct vertical sections with different ridge and groove configurations. This dimensional approach allows multiple unique keyway shapes to be developed within the finite horizontal space of the lock cylinder plug, effectively increasing versatility without compromising compactness.

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

Solution Approach 2:

The key profile structure nests multiple levels of identification features within each other - ridges and grooves in the first section, additional features in the second section, and further variations in the third section. This nested arrangement maximizes the number of unique keyway shapes that can be accommodated within the limited space of the lock cylinder plug.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If hierarchical lock system with multiple levels is developed, then security and system control are improved, but device complexity deteriorates

Engineering Contradiction:
Improvesecurity and system controlVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hierarchical lock system is segmented into three vertical sections, where each section can independently contribute to the hierarchical structure. The first section provides basic level identification, the second section adds intermediate level differentiation, and the third section provides fine-grained control. This segmentation allows complex hierarchical security to be achieved through modular profile variations rather than monolithic system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different vertical sections of the key blade are assigned different levels of complexity and security function. The first section handles basic hierarchical level identification, the second section manages intermediate control levels, and the third section provides detailed access control. This local differentiation of function reduces overall system complexity by distributing security responsibilities across distinct structural zones.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2142731B1Key blank and key
Publication Date: 2017.06.28 ASSA ABLOY HIGH SECURITY GROUP INC
  • EP2142731B1 patent drawingFigure 1~2
  • EP2142731B1 patent drawingFigure 3~4
  • EP2142731B1 patent drawingFigure 5~6

AI summary

A key blank or key has a rectangular parallel metal shaped blade which has side edges formed with grooves for cooperating with a complementary shaped keyway; the sides of the blank having a portion grooved for registration, another portion grooved for top-level hierarchical master keying, and two other portions, one on each side of the blade, for further master key variations and different combinations. One of the two further sections being curvilinear and the other rectangular or angular cuts.