Reversible Flat Key with Accumulating Bevel for Cylinder Lock

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Solution Overview

Problem

Existing lock cylinder technologies face issues with key compatibility and security, particularly with core pins that are vulnerable to improper key usage and percussion methods, leading to potential unauthorized access or locking failures.

Innovation Solution

The design of a reversible flat key with specific rib and groove configurations, including high and low ribs, sloping walls, and a ramp, ensures precise engagement with core pins, preventing unauthorized access by adapting to the control zones and reducing wear, while maintaining cost-effective production and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If control flanks are extended to attack deeper control zones of core pins, then security against unauthorized access is improved, but wear on the key and core pin increases

Engineering Contradiction:
ImprovesecurityVSAvoidwear
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The control flanks are designed with rounded contours instead of sharp edges, and the control zones on the core pins are correspondingly shaped. This curvature distributes the contact pressure over a larger surface area during the unlocking motion, reducing stress concentration and minimizing wear on both the key and core pin while maintaining effective engagement for security.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Reliability

If the key design is made more complex with multiple ribs and grooves, then key compatibility and security are improved, but manufacturing cost increases

Engineering Contradiction:
Improvekey compatibilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The key is segmented into distinct functional elements: high ribs for initial engagement, low ribs for controlled displacement, and grooves defining control flanks. Each segment performs a specific function in the unlocking sequence. This segmentation allows for standardized manufacturing processes for each component type while achieving complex overall functionality and improved key compatibility.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the ramp extends over the entire thickness of the key, then controlled displacement of core pins is improved, but the key structure becomes more complex

Engineering Contradiction:
Improvecontrolled displacementVSAvoidkey structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The ramp feature is merged with the low rib structure, combining the displacement control function with the existing key geometry. The ramp extends as an integrated feature of the low rib rather than as a separate component, achieving controlled core pin displacement while minimizing additional structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2317040B1Key for a cylinder lock
Publication Date: 2012.06.20 DOM SICHERHEITSTECHN
  • EP2317040B1 patent drawingFigure 1~2
  • EP2317040B1 patent drawingFigure 3~4
  • EP2317040B1 patent drawingFigure 5

AI summary

The turning flat key has a key point forming a fork opening (19), which possesses two control flanks (21) at a distance from each other by a channel (12). The base of the channel forms an accumulating bevel (13) for a point of a nuclear pin. The control flanks are extended to the diagonal walls of a lower rib (5).