Lock Cylinder with Asymmetrical Attachment Element for Key Restriction

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Solution Overview

Problem

Conventional lock cylinders and keys are limited by requiring keys to be inserted in a single position, and reversible keys and cylinders have limited locking features due to symmetrical designs, necessitating high warehousing for manufacturing.

Innovation Solution

A lock cylinder with a point-symmetric key channel and an attachment element that partially covers the key channel, allowing only specific keys to be inserted, enabling multiple variants with reduced warehousing and increased security against tampering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a symmetrical key channel is used for reversible keys, then key handling convenience is improved, but the variety of locking features is limited and high warehousing is required

Engineering Contradiction:
Improvekey handling convenienceVSAvoidvariety of locking features
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The lock cylinder is segmented into two functional parts: a universal symmetrical cylinder core that accepts reversible keys, and an attachment element with an asymmetrical passage that restricts key insertion. This segmentation allows the base component to maintain versatility while the add-on component provides specialization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The attachment element introduces asymmetry through its passage design, which has specific geometric features (protrusions, cross-sectional shape) that only match certain key profiles. This asymmetrical design restricts key insertion to specific orientations and profiles, enabling differentiated locking features while maintaining the symmetrical cylinder core.

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If conventional lock cylinders are used with single-position key insertion, then manufacturing simplicity is maintained, but handling convenience is impaired

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidhandling convenience
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The symmetrical cylinder core serves multiple functions: it can accept both reversible keys (when used alone) and non-reversible keys (when combined with an attachment element). This multi-functionality allows a single base design to support different key types and locking configurations, simplifying manufacturing while improving handling convenience.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system dynamically adapts its key acceptance characteristics based on the presence or absence of an attachment element. The same cylinder core can provide different locking behaviors depending on whether an attachment element is installed, allowing flexibility in handling convenience without requiring multiple manufacturing variants.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If reversible keys are used, then key handling convenience is improved, but security against tampering is reduced due to symmetrical design

Engineering Contradiction:
Improvekey handling convenienceVSAvoidsecurity against tampering
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The attachment element's asymmetrical passage design with specific geometric features (protrusions, cross-sectional shape) prevents unauthorized key insertion. Only keys with matching asymmetrical profiles can be inserted, providing security against tampering while the symmetrical cylinder core maintains reversible key functionality when used alone.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3095931B1Lock cylinder and lock system with such a lock cylinder
Publication Date: 2019.10.09 BKS
  • EP3095931B1 patent drawingFigure 1
  • EP3095931B1 patent drawingFigure 2
  • EP3095931B1 patent drawingFigure 3(a)~3(b)

AI summary

A locking cylinder (10) comprising a rotatable cylinder core (12) with a symmetrical keyway (14) suitable for receiving a reversible key is designed and further developed to allow for a high degree of variety with reduced inventory, such that an attachment element (18) with a passage (20) adjoining the keyway (14) is arranged adjacent to and in the key insertion direction (16) in front of the cylinder core (12), and that the passage (20) is designed such that the keyway (14) is partially covered by the attachment element (18). A locking system with such a locking cylinder (10) and with a key (36) is specified.