Lockdown Cylinder Lock Key Retention Mechanism

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Solution Overview

Problem

Current lockdown-type cylinder locks lack the ability to be operated by any key regardless of bitting profile and do not prevent key extraction when in a rotated position, posing security risks in emergency situations.

Innovation Solution

The development of a lockdown-type lock cylinder with a locking assembly that prevents rotation without a key and allows rotation with any key, while also preventing key extraction when the plug is in a rotated position, using mechanisms like knock-down pins, flexible members, rack pins, and rocker assemblies to ensure secure operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional lockdown systems use a thumb-turn or similar apparatus, then the door can be locked by any individual, but the lock cannot retain the key and prevent extraction

Engineering Contradiction:

ImproveAbility to lock by any individualVSAvoidKey retention capability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The locking assembly is divided into separate functional components: knock-down pins for enabling/disabling locking, rack pins for key retention, and rocker assemblies for operation control. Each component performs a specific function, allowing the system to achieve both ease of operation and key retention reliability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The lock cylinder acts as an intermediary mechanism between the key and the locking mechanism. The key operates the plug which controls the locking assembly, providing a reliable interface that maintains key retention while allowing authorized operation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the lock allows rotation with any key regardless of bitting profile, then ease of operation is improved, but security control is reduced

Engineering Contradiction:

ImproveUniversality of key operationVSAvoidKey bitting profile control

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The locking assembly is designed with universal functionality to accept any key regardless of bitting profile. The knock-down pins and rack pins are positioned and dimensioned to work with various key configurations, enabling any key to operate the lock while maintaining security through the locking mechanism itself

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the locking assembly prevents rotation when no key is inserted, then security is improved, but the mechanism complexity increases

Engineering Contradiction:

ImproveSecurity when no key is insertedVSAvoidLocking assembly structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The locking assembly is designed to be self-regulating through the interaction of knock-down pins, rack pins, and rocker assemblies. When no key is inserted, the knock-down pins automatically engage to prevent rotation. The system uses spring-loaded components that automatically return to their blocking positions, eliminating the need for additional control mechanisms

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS10808421B2Lockdown cylinder locks

Publication Date: 2020.10.20 SCHLAGE LOCK CO LLC

AI summary

An exemplary lock cylinder includes a shell, a plug positioned in the shell, and a locking assembly. The locking assembly is configured to prevent rotation of the plug when no key is inserted, and to permit rotation of the plug upon insertion of any of a plurality of keys having different bitting profiles. The locking assembly may further be configured to prevent key extraction when the plug is in a rotated position.