Dual-Bit Key Lock with Multifunctional Nut for Tumbler Conversion

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Solution Overview

Problem

Existing security locks have large openings that can be easily accessed with tools, requiring separate keys for locking and tumbler conversion, compromising security and compliance with certification standards.

Innovation Solution

A double-bit key is used to both operate the locking mechanism and change tumblers, with a multifunctional nut incorporating a bolt driver and changeover pin, allowing for secure and compact lock design with minimal keyhole size, enabling secure key changeover without additional tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate keys are used for locking and tumbler conversion, then the locking function and conversion function can be independently controlled, but the device complexity increases and multiple keys must be managed

Engineering Contradiction:
Improvefunctional separationVSAvoidkey management complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the locking function and tumbler conversion function into a single key system. The key features two different key bits: one for operating the locking mechanism and another for activating tumbler conversion. This merging eliminates the need to manage separate keys while maintaining functional distinction through the dual-bit design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single key serves multiple functions: it can operate the locking mechanism in normal position and activate tumbler conversion when inserted with the second key bit. This multi-functionality reduces the number of keys needed while preserving the ability to independently control both locking and conversion operations.

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

2Ease of operation

If large lock openings are provided, then tool access for manipulation is easier, but security is compromised and certification standards cannot be met

Engineering Contradiction:
Improvetool accessibilityVSAvoidsecurity level
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Instead of providing large openings that allow tool access, the patent inverts the approach by designing a small keyhole (9.5-11 mm diameter) that only accepts the specific dual-bit key. This inversion prevents tool manipulation while maintaining operational ease through the specialized key design that integrates both locking and conversion functions.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If the keyhole diameter is reduced to 9.5-11 mm, then security is enhanced and certification standards are met, but the key and opening dimensions must be precisely controlled

Engineering Contradiction:
Improvesecurity levelVSAvoiddimensional tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent specifies a precise keyhole diameter range of 9.5-11 mm, representing a parameter change from conventional larger openings. This dimensional parameter is optimized to balance security requirements with manufacturing feasibility. The dual-bit key design with specific coding patterns further refines the dimensional parameters to ensure only authorized keys can operate the lock.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If a multifunctional nut with bolt driver and changeover pin is used, then the device complexity is reduced and compactness is achieved, but the nut must perform multiple functions simultaneously

Engineering Contradiction:
Improvecomponent countVSAvoidfunctional integration
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent merges the bolt driver and changeover pin functions into a single multifunctional nut component. This nut integrates both the locking mechanism operation and the tumbler conversion activation, reducing the total component count while maintaining the ability to perform both functions through the dual-bit key system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The multifunctional nut serves dual purposes: it operates the bolt mechanism for locking/unlocking and simultaneously controls the tumbler conversion process. This multi-functionality reduces device complexity by consolidating components while maintaining the versatility needed for both security operations.

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

Data Source

PatentEP2483500B1Safety lock with a key for repositioning the tumblers and for actuating the locking mechanism
Publication Date: 2017.03.08 KABA MAUER GMBH
  • EP2483500B1 patent drawingFigure 1
  • EP2483500B1 patent drawingFigure 2~3
  • EP2483500B1 patent drawingFigure 4~5

AI summary

A key (7) serves for actuating a lock and has a grip, a shank (10) and a key bit (12), on which is arranged the coding of the key (7) in the form of key steps (13, 14, 18). The key bit (12) has key steps (13, 14, 18) on either side, wherein the diameter of their key bit (12), in relation to the key steps (13, 14), which project to the maximum extent in each case, is between 9,5 mm and 11 mm. A lock (1) for such keys (7), having a plurality of tumblers (24) arranged in a lock housing (2), has a rotatably mounted follower (3) which can be actuated via the key (7). This follower (3) is designed in the form of a multifunctional component, as a structural unit for repositioning the tumblers (24) and/or for controlling the locking function.