Key Blade Rib Stop Arrangement for Flexible Cylinder Lock Coding

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Solution Overview

Problem

Existing key blanks and coded keys have limited flexibility in selecting the length and location of the lateral extension of the key blade, restricting the variability of key combinations and making it difficult to create new or backwards-compatible lock and key systems.

Innovation Solution

The introduction of a longitudinal rib portion on the key blade, located at the lateral side of the upper narrow part, allows for variable length and location selection, enhancing flexibility and strength without expanding the key width, enabling new or backwards-compatible lock and key systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a key blank with a groove for receiving a stop is used, then the cylinder lock system achieves improved security and reliability, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvecylinder lock securityVSAvoidkey blank structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The stop is nested within the groove of the key blank, with the groove receiving and containing the stop. This nesting arrangement integrates the stop into the key blank structure without requiring separate mounting operations, thereby improving reliability while managing complexity through spatial integration rather than additive assembly steps.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The groove is pre-formed in the key blank during key blank manufacturing, preparing the structure in advance to receive the stop. This preliminary action ensures proper positioning and fit of the stop without requiring complex assembly operations later, thus improving reliability while keeping manufacturing processes manageable.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a groove is added to the key blank for stop reception, then the cylinder lock system achieves improved security, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvecylinder lock securityVSAvoidgroove dimensional accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The groove is designed with dimensions that provide sufficient tolerance for stop reception without requiring excessive precision. The groove dimensions are specified to be slightly larger than the stop, allowing for reasonable manufacturing tolerances while still achieving secure fit and proper function, thus balancing security requirements with manufacturing capability.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If the stop arrangement is modified to improve security, then the cylinder lock system achieves better reliability, but the ease of manufacture decreases

Engineering Contradiction:
Improvecylinder lock securityVSAvoidkey blank manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The key blank is segmented into functional zones: the groove portion for stop reception and the blade portion for cutting codes. This segmentation allows the groove to be formed as a distinct feature using standard manufacturing processes, maintaining ease of manufacture while enabling the security-enhancing stop arrangement.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4577711B1A key blank, a coded key and a cylinder lock and key system with improved stop arrangement
Publication Date: 2026.05.13 WINLOC
  • EP4577711B1 patent drawingFigure 1~2b
  • EP4577711B1 patent drawingFigure 3a~3e
  • EP4577711B1 patent drawingFigure 4a~4d

AI summary

A substantially flat key blade extends from a grip portion along a longitudinal axis and includes a connecting portion adjoining to the grip portion, a major longitudinal bitting portion provided with a row of coded cuts, and a free tip portion. The connecting portion of the key blade is provided with a first selectable abutment surface facing in the forward direction. The first abutment surface is formed as a forward end surface of a longitudinal rib portion located at a lateral side of the upper relatively narrow part of the key blade at a vertical level lying within a vertical range of the bitting portion of the key blade and extending in parallel to the longitudinal axis of the key blade and being confined longitudinally to the connecting portion of the key blade and confined also within the contour of or slightly laterally outside a rectangle of the key blank.