Door Access Control Hardware with Fire-Rated Lockset Components
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Solution Overview
Problem
Access control hardware for doors often fails to provide full fire protection due to materials like zinc or aluminum melting, allowing flames to pass through the door opening, and existing steel plates have clearances that do not offer complete coverage.
Innovation Solution
Incorporating fire-rated components made of steel or bronze in the lockset components, such as fire cups and latches, with retention flanges that capture threaded fasteners to block spaces through which light or flames can pass, ensuring the components remain engaged even if the exterior trim melts away.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If trim components are made from zinc or aluminum, then ease of manufacture is improved, but fire resistance deteriorates as these materials melt away in fire
Solution Approach 1:
The patent combines zinc or aluminum trim components with steel plates to create a composite structure. The zinc or aluminum provides ease of manufacture and aesthetic appearance, while the steel plate provides fire resistance by blocking flame passage through the bore in the door.
Solution Approach 2:
The trim component is divided into separate functional segments: the zinc or aluminum portion for manufacturing ease and appearance, and the steel plate portion for fire protection. This segmentation allows each material to perform its optimal function without compromise.
2Reliability
If steel plates are provided to block flame passage, then fire resistance is improved, but device complexity increases due to additional components and clearances required
Solution Approach 1:
The steel fire-resistant plate is merged with the zinc or aluminum trim component into a single integrated assembly. This combining reduces device complexity by eliminating the need for separate installation steps and additional mounting hardware that would be required if the steel plate were a completely separate component.
3Ease of operation
If clearances are provided in steel plates for trim passage, then ease of operation is improved, but fire protection deteriorates due to gaps allowing flame passage
Solution Approach 1:
A flexible grommet or thin film material is used to fill the clearance between the steel plate and the passing trim component. This flexible element maintains the operational clearance needed for fastener passage while blocking the gaps that would otherwise allow flame passage, thus maintaining fire protection.
4Ease of manufacture
If exterior trim is made from melt-prone materials, then ease of manufacture is improved, but reliability deteriorates when exterior trim melts away during fire
Solution Approach 1:
The steel plate is installed beforehand as a protective cushioning layer behind the zinc or aluminum exterior trim. When the exterior trim melts away during fire, the steel plate remains in place to maintain fire resistance, providing a backup protection mechanism that compensates for the weakness of the exterior trim material.
Data Source
AI summary
Access control hardware for a door generally includes an exterior trim, an interior trim, and a plurality of lockset components housed within a cross-bore through the door. At least one of the plurality of the lockset components is a fire-rated component comprised of a fire-resistant material, such as steel or bronze. The fire rated component is configured so that at least one elongated component extending between the exterior trim and the interior trim extends through at least one fire-rated component. The fire-rated components interfaces with the at least one elongated component in order to reduce or eliminate space around the at least one elongated component through which light or flames may pass.