Flush In-Swing Door Jamb with Plaster Protrusions
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Solution Overview
Problem
Conventional door jambs for in-swing doors fail to provide a long-lasting flush finish due to cracking plaster and weak attachment to the wall, leading to unsightly gaps and cracking, as they are incompatible with wood and have insecure fastening.
Innovation Solution
A door jamb with a unitary body and specific geometry, formed using a roll forming process, which includes protrusions for plaster application and secure fastening to the wall stud, ensuring a strong and stable attachment and a flush finish with the surrounding wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If plaster is applied over the wall surface and door jamb surface to achieve a flush finish, then the aesthetic appearance is improved, but the plaster is susceptible to crazing and cracking due to incompatibility with wood
Solution Approach 1:
The patent introduces a metal door jamb as an intermediary component between the wood door and the wall finishing material. The metal jamb provides a stable, non-organic substrate that is compatible with plaster and other wall finishes, eliminating the crazing and cracking issues that occur when plaster is applied directly to wood. The jamb acts as a mediator that transfers the structural load while providing a suitable surface for finishing materials.
Solution Approach 2:
The patent employs a composite construction approach by using a metal door jamb (typically aluminum or steel) that combines the advantages of different materials: the strength and dimensional stability of metal, combined with the aesthetic qualities of wood doors and the finishability of metal surfaces. This composite structure allows for a flush finish that is both aesthetically pleasing and durable.
2Ease of manufacture
If a nail is used to secure the jamb to the wall stud, then the installation is simple, but the attachment is weak and may cause the jamb to move relative to the wall stud during door opening and closing
Solution Approach 1:
The patent extracts the fastening function from the main jamb body by using separate fasteners (screws or bolts) that extend through the jamb and into the wall stud. This separation allows the jamb to maintain its primary function of providing a flush finish while the fasteners provide dedicated structural attachment. The fasteners are positioned to engage the wall stud directly, providing strong anchoring that resists the forces generated during door operation.
Solution Approach 2:
The patent incorporates pre-drilled holes and predetermined fastening locations in the jamb design. These preliminary features guide the installation process and ensure that fasteners are positioned optimally for both strength and aesthetics. The jamb is designed with built-in attachment points that align with wall studs, eliminating the need for complex measurement and positioning during installation.
3Ease of operation
If the nail extends through the jamb in line with the direction of the wall, then the fastening is straightforward, but it creates a weak attachment point at the jamb-door interface that may cause intermittent and ultimately permanent separation
Solution Approach 1:
The patent changes the dimensional orientation of the fastening system by using fasteners that extend perpendicular to the wall surface rather than parallel to it. The fasteners are positioned at multiple locations along the jamb, creating a distributed attachment system that resists forces in multiple directions. This dimensional change allows the fasteners to anchor into the wall stud while maintaining alignment with the jamb structure, preventing separation at the jamb-door interface.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A door jamb configured to provide a flush in-swing door when viewed in the direction of door in-swing.