Lock Key Shaft With Angled Scanning Surfaces Against Copying

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Solution Overview

Problem

Existing security keys lack effective mechanisms to prevent easy copying and manipulation, particularly in high-value systems, and require simpler, user-friendly designs.

Innovation Solution

A key design featuring angled query surfaces on the key shaft, which are symmetrically arranged relative to the longitudinal axis, providing additional query elements that are complex to replicate and enhance security while maintaining ease of use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If control surfaces are provided through recesses and slots in the key shaft, then manufacturing cost is reduced, but security against copying is insufficient

Engineering Contradiction:
Improvemanufacturing costVSAvoidsecurity against copying
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies asymmetry by providing query surfaces that are inclined at an angle to the longitudinal axis of the key shaft, rather than being perpendicular or parallel to it. This angular inclination creates an asymmetric feature that is difficult to replicate with standard drilling and milling machines, thereby enhancing security against copying while maintaining cost-effective manufacturing through simple angular machining operations

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If query surfaces are arranged perpendicular to the longitudinal axis, then manufacturing is simple, but security against manipulation is insufficient

Engineering Contradiction:
Improvesimplicity of productionVSAvoidvulnerability to copying
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent transforms the symmetric/perpendicular query surface arrangement into an asymmetric inclined arrangement. The query surfaces are deliberately angled relative to the longitudinal axis, creating a geometric feature that maintains manufacturing simplicity through basic angular machining while introducing complexity that resists copying by standard machining processes

Inventive Principle:
Principle #4Asymmetry

3Reliability

If additional control surfaces are added to the key shaft, then security is improved, but device complexity increases

Engineering Contradiction:
Improvesecurity levelVSAvoidkey structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent enhances security by adding query surfaces with specific angular orientations rather than adding multiple complex control surfaces. This approach increases security through the angular complexity of the query surfaces while keeping the overall key structure relatively simple, avoiding excessive complexity that would arise from multiple differently oriented control surfaces

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4047161B1Key, key and locking cylinder
Publication Date: 2026.05.06 ASSA ABLOY (SCHWEIZ) AG
  • EP4047161B1 patent drawingFigure 1~2
  • EP4047161B1 patent drawingFigure 3
  • EP4047161B1 patent drawingFigure 4

AI summary

A key (1) for a locking cylinder (2) comprising a key handle (3) and a key shaft (4) adjoining the key handle (3) and extending along a longitudinal axis (L), wherein the key shaft (4) has control recesses, in particular control bores, on its outside (5) for aligning tumblers on the locking cylinder (2), wherein the key (1) further comprises at least one key-side scanning surface (6) with which the key (1) abuts a locking cylinder-side scanning surface (7), and wherein at least one of the key-side scanning surfaces (6a) is inclined at an angle (a) to a reference line (G) oriented parallel to the longitudinal axis (L).