Lock Assembly Fire Resistant Spindle Linkage

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing lock assemblies in commercial buildings may not adequately inhibit the spread of fire due to open passageways through the lock mechanism, even when designed with internal fusible links that melt at fire temperatures.

Innovation Solution

A lock assembly with a spindle linkage that incorporates a fire compliant component made of a material with a lower melting temperature and a fire resistant component made of a material with a higher melting temperature, where the fire resistant component blocks the spindle bore to prevent fire spread after the compliant component melts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fusible links are used in the latch actuation linkage, then the door remains latched during fire, but open passageways through the lock mechanism may still allow fire spread

Engineering Contradiction:

Improvedoor latching reliabilityVSAvoidfire spread through passageways

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The spindle assembly is segmented into multiple functional components: an outer spindle providing structural support and a longitudinal bore, and an inner locking spindle assembly that can rotate within the outer spindle. This segmentation allows different portions to serve different fire safety functions while maintaining operational integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A fire-resistant barrier material is introduced as an intermediary substance within the longitudinal bore of the outer spindle. This barrier acts as a mediator that blocks fire and heat transmission through the spindle assembly while allowing the locking mechanism to function normally during non-fire conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a solid spindle structure is used to block fire spread, then fire resistance is improved, but the locking mechanism may become inoperable

Engineering Contradiction:

Improvefire spread preventionVSAvoidlocking mechanism operation

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The locking spindle assembly is designed to be rotatable within the outer spindle, transitioning between locked and unlocked positions. This dynamic capability ensures the mechanism remains operable during normal conditions while the fire-resistant barrier within the bore maintains fire blocking capability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The spindle assembly combines different materials with complementary properties: the outer spindle provides structural integrity, the inner locking spindle provides operational functionality, and the fire-resistant barrier material provides thermal protection. This composite structure achieves both operability and fire resistance.

Inventive Principle:

Principle #40Composite materials

3Object-affected harmful factors

If the spindle bore is completely blocked to prevent fire spread, then fire resistance is improved, but the coupling mechanism cannot function

Engineering Contradiction:

Improvefire spread through boreVSAvoidcoupling mechanism function

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The fire-resistant barrier is positioned specifically within the longitudinal bore of the outer spindle, providing fire protection only where needed for heat blocking. The coupling mechanism interfaces with the locking spindle assembly at different locations, allowing operational functionality to be maintained while fire resistance is provided in the critical bore area.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively renders the lock assembly inoperable during a fire and blocks potential fire paths through the spindle, thereby preventing the spread of fire and heat through the door.

Implementation Method 1

a fire compliant component made of a first material that melts during a fire to prevent operation of the latch assembly with the exterior operator assembly

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

a fire resistant component made of a second material having a higher melting temperature from that of the first material and configured to block the longitudinal bore of the outer spindle to aid in preventing the spread of the fire through the door via the longitudinal bore

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS9290964B2Lock assembly having fire resistant spindle linkage

Publication Date: 2016.03.22 DORMAKABA USA INC

AI summary

A lock assembly includes an exterior operator assembly, an interior operator assembly, and a latch assembly. An outer spindle is operatively coupled to a latch assembly, is drivably coupled to the interior operator assembly, and has a longitudinal bore. A coupling mechanism is coupled to the outer spindle. A locking spindle assembly is rotatably received in the longitudinal bore, and is configured to selectively operate the coupling mechanism to couple the exterior operator assembly to the outer spindle upon actuation of a drive assembly. The locking spindle assembly has a fire compliant component made of a first material that melts during a fire to prevent operation of the latch assembly with the exterior operator assembly, and has a fire resistant component made of a second material and configured to block the longitudinal bore of the outer spindle to aid in preventing the spread of the fire through the door.