Hinged Metal Connectors for Drywall Joint Cracking
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Solution Overview
Problem
In construction, particularly with pitched ceilings and bay windows, drywall joints are prone to cracking and separation due to lumber shrinkage and warping, leading to costly repairs and quality issues.
Innovation Solution
A metallic connector with metallic wings and a flexible polymeric hinge is positioned between ceiling rafters and drywall, allowing for movement without disrupting the taped finish, and can be bent to fit various angles and framing irregularities, preventing joint cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If drywall is attached directly to rafters, then installation is simple, but the drywall joints crack when rafters shrink or warp
Solution Approach 1:
The connector is divided into two separate metallic wings that can be attached to different structural elements (rafter and drywall), with each wing independently positioned and secured. This segmentation allows the connector to bridge the gap between moving rafters and stationary drywall, maintaining joint integrity while accommodating rafter movement.
Solution Approach 2:
The metallic connector serves as an intermediary element between the rafter and drywall, providing a flexible connection that accommodates rafter movement while maintaining drywall joint stability. The connector absorbs the dimensional changes and warping of the rafter, preventing these movements from transferring to the drywall joint.
2Strength
If rigid connectors are used to secure drywall to rafters, then structural stability is improved, but the connector cannot accommodate rafter movement without causing joint failure
Solution Approach 1:
The connector incorporates flexible elements including a curved portion and slots that allow it to dynamically adapt to rafter movement. The curved portion can flex and the slots allow for positional adjustment, enabling the connector to maintain structural stability while accommodating dimensional changes and warping of the rafter over time.
Solution Approach 2:
The connector's geometry includes curved portions and slots that change its effective parameters (flexibility, range of motion) to accommodate rafter movement. These design features allow the connector to transition from a rigid to a more flexible state, maintaining strength while adapting to varying rafter positions and orientations.
3Productivity
If lumber is not adequately aged before installation, then construction time is reduced, but the lumber shrinks and warps causing drywall joint separation
Solution Approach 1:
The flexible metallic connector is installed beforehand to cushion and compensate for future lumber shrinkage and warping. By providing a flexible connection that can accommodate dimensional changes, the connector prevents drywall joint separation even when lumber is installed at higher moisture content and subsequently dries out.
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 connector maintains the integrity of drywall joints by accommodating rafter movement, reducing repair costs and ensuring a smooth, long-lasting finish, even in uneven framing conditions.
Implementation Method 1
a flexible polymeric hinge member... The connector can be folded into a V-shape... The connector has sufficient rigidity that it stays relatively straight during installation without collapsing or bending substantially
Implementation Method 2
The hinge member is glued to the metallic wings
Implementation Method 3
a series of corrugations on the wings including the tabs to allow the tabs to elongate and bend if the installer should not position the screw exactly on center in the tab opening. The corrugations strengthen the wings
Data Source
AI summary
A method of preventing disruption of a taped finished drywall board joint in a room having a center ridge member and angularly inclined ceiling rafters which involves a metallic connector positioned between the wallboard sections and the ridge member and rafters. The connector has two metallic wings with a center longitudinal bendable connection. The wings have flexible tabs at their free edges which are attached to the rafters and the connector itself is attached to the wallboard adjacent to the ridge member. The wallboard also is attached to the rafters 8-12 inches from the edges of the wings. Because the tabs can bend away from the wings, this construction allows the joint to flex if the rafters warp or shrink without disrupting the finish coating on the outside of the wallboard joint at the ridge member. The connector also can be applied to other critical joints in a home where the framing members are subject to movement such as flat ceilings to avoid truss uplift or rafter movement. The wings have longitudinal corrugations in the wings and tabs to strengthen the tape. In one embodiment two wings are connected by a polymeric tape. In another embodiment, the connector is a unitary metallic part with a longitudinal line of perforations connecting the wings along the centerline to allow the connector to be bent to form the two diverging wings.