Entry Door Frame Reinforcement With Hidden Back-Mounted Strike Bar
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Solution Overview
Problem
Existing door frame reinforcement systems either require extensive machining, are visible and detract from appearance, or interfere with door closure, failing to provide effective resistance to forced entry.
Innovation Solution
A reinforcement assembly comprising a U-shaped bar and shaped plates secured within a slot in the door frame, reinforcing the strike side leg, with fasteners hidden by the weatherstrip, to distribute impact forces and enhance resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a shaped metal strip is mounted on the face of the frame to reinforce it, then the resistance to forced entry is improved, but the appearance of the door frame is detracted from and the gap for door closure is reduced
Solution Approach 1:
The reinforcement assembly is inverted from the traditional face-mounted approach by positioning the U-shaped bar and shaped plates on the back of the door frame instead of the face. This inversion allows the reinforcement to provide structural support while remaining hidden, thus maintaining appearance and preserving the door closure gap.
Solution Approach 2:
The reinforcement is moved from the two-dimensional face of the door frame to the three-dimensional space on the back of the frame. The U-shaped bar extends into the depth of the frame, and shaped plates are positioned at strategic locations on the back surface, utilizing the third dimension to provide reinforcement without visual impact.
2Strength
If significant sections of the door frame are machined away and replaced by a shaped metal bar, then the resistance to forced entry is improved, but the complexity of installation increases significantly
Solution Approach 1:
The reinforcement assembly is designed as pre-fabricated components (U-shaped bar and shaped plates) that can be prepared in advance with precise dimensions and features. This preliminary preparation eliminates the need for complex on-site machining operations, allowing installers to simply assemble the pre-made components onto the door frame.
Solution Approach 2:
The reinforcement system is segmented into separate, manageable components including the U-shaped bar, shaped plates, and fasteners. This segmentation allows each component to be independently manufactured and prepared, then assembled together during installation, significantly reducing the complexity compared to creating a single integrated reinforced structure.
3Strength
If sheet metal pieces wrap around the rabbeted edge and are secured with screws, then the resistance to forced entry is improved, but the door closure gap is reduced and appearance is compromised
Solution Approach 1:
Instead of wrapping metal pieces around the rabbeted edge from the front, the shaped plates are positioned on the back of the door frame. This inversion allows the reinforcement to engage with the frame structure effectively while remaining hidden, thus preserving both the door closure gap and the aesthetic appearance of the frame.
Data Source
AI summary
A door frame profile and reinforcement assembly to increase the resistance of an entry door and door frame to forced entry by an intruder. Increased resistance is achieved by either fitting and securing a U-shaped bar within a machined slot in the back of the door frame and attaching a shaped plate or plates that fits within the shaped bar or a rectangular bar and alternately shaped plates mounted directly on the back of the door frame which retains the door's throw bolt of the deadbolt and/or latch of the door lock. Optionally, with stronger door frames, the shaped plate alone may suffice, and the plate can be modified to a simple L-shaped form, a portion of which is inserted into a narrow groove which replaces the machined slot.