Surface-Mounted Door Frame for Flush Elevator-Lobby Installation
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Solution Overview
Problem
Conventional fire door frames for elevator shafts require a protruding wall for mounting, increasing construction costs and reducing space in elevator lobbies, while also being prone to deformation due to fire conditions.
Innovation Solution
A surface-mounted door frame system comprising a sub-buck and shell portion, allowing attachment to a single wall surface, enhancing rigidity and resistance to warpage with thicker gauge steel and reduced mechanical advantage, eliminating the need for a protruding wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional fire door frame is mounted to require a protruding wall, then the frame can be securely attached to withstand fire conditions, but construction costs increase and space in elevator lobbies is reduced
Solution Approach 1:
The door frame is divided into a sub-buck portion and a shell portion that can be assembled together. The sub-buck portion includes mounting arms with apertures for attachment, while the shell portion forms the protective enclosure. This segmentation allows the frame to be mounted flush to the wall surface without requiring a protruding structure, thereby reducing construction complexity while maintaining structural integrity for fire resistance.
Solution Approach 2:
The mounting mechanism transitions from requiring a three-sided protruding wall attachment to a two-dimensional flush mounting surface. The sub-buck portion's mounting arms extend perpendicular to the wall surface, allowing secure attachment through the wall face without creating a protruding structure. This dimensional change eliminates the need for additional wall construction while preserving the frame's ability to withstand fire conditions.
2Ease of manufacture
If the door frame uses thinner gauge steel to reduce costs, then construction costs decrease, but the frame becomes more prone to deformation under fire conditions
Solution Approach 1:
The frame is segmented into the sub-buck portion providing structural support and mounting function, and the shell portion providing protective enclosure. This segmentation allows optimization of material thickness in each component - the sub-buck can use sufficient gauge for structural integrity while the shell uses appropriate gauge for protection, overall reducing material costs while maintaining fire resistance through proper design rather than uniformly thick material.
Solution Approach 2:
The design changes the geometric parameters and structural configuration of the frame components rather than relying solely on increased material thickness. The sub-buck's mounting arm geometry, aperture placement, and connection to the shell portion create structural rigidity that resists warpage under thermal stress. This parameter optimization allows use of cost-effective material gauges while maintaining strength through intelligent structural design.
3Device complexity
If the door frame is surface mounted to a single wall surface, then construction costs are reduced and space is increased, but the frame may be more susceptible to torsional stress from door load
Solution Approach 1:
The sub-buck portion is segmented into multiple mounting arms extending from the wall surface, with each arm providing independent attachment points. This segmentation distributes the door load and torsional stress across multiple mounting locations rather than concentrating it at a single point, enhancing the frame's ability to resist torsional stress while maintaining the simple surface-mounted configuration.
Solution Approach 2:
The sub-buck portion and shell portion are merged through rigid connection, creating a unified structural assembly. The sub-buck's mounting arms are structurally integrated with the shell portion, forming a combined system that resists torsional stress more effectively than separate components. This merging ensures that loads are distributed throughout the entire frame structure while maintaining the flush-mounted design.
Data Source
AI summary
A door frame system comprises a wall and a door frame. The door frame comprises a sub-buck portion and a shell portion, coupled to the sub-buck portion. The sub-buck portion comprises a sub-buck mounting arm including at least one mounting aperture, a sub-buck rabbet arm coupled to one end of the sub-buck mounting arm and a sub-buck support arm coupled to the sub-buck mounting arm opposite the sub-buck rabbet arm. The sub-buck portion is surface mounted to a single surface of the wall through the at least one mounting aperture.