Mitre Joint for Metallic Fenestration Frames
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Solution Overview
Problem
Existing fenestration unit frame assembly methods face challenges such as misalignment, high material costs, and complex assembly processes due to intricate components and uneven load distribution, which can lead to inadequate sealing and insulation.
Innovation Solution
A mitre joint design featuring frame members with hollow profiles and connector arms that support fasteners, allowing for secure and stable connection with reduced material usage, enabling easy assembly and adjustment, and facilitating uniform load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If frame members are connected one at a time to corner connectors using conventional fastening methods, then the assembly process is simple and requires minimal machinery, but misalignment occurs due to manufacturing inaccuracies and damage during transport, resulting in poor sealing and insulation
Solution Approach 1:
The connector arms are pre-configured with recesses that receive the ends of frame members before fastening. This preliminary location ensures proper alignment is established prior to securing the joint, compensating for manufacturing tolerances and transport damage without requiring complex alignment machinery
Solution Approach 2:
The connector acts as an intermediary component between frame members, providing a standardized interface with recesses that guide frame member ends into correct positions. This mediator absorbs alignment variations and ensures consistent positioning regardless of frame member manufacturing variations
2Productivity
If punches are used to deform frame members for mechanical engagement with connectors, then simultaneous connection of multiple frame members is achieved, but large investment in specialist machinery is required and no subsequent adjustment is possible
Solution Approach 1:
The connection function is segmented into two independent parts: the connector arms with recesses provide location and guidance, while separate fasteners provide securing. This segmentation eliminates the need for complex punch machinery that combines location and fastening in one operation, allowing simple tools to be used while maintaining simultaneous connection capability
Solution Approach 2:
The joint design transitions from rigid, irreversible punch deformation to a dynamic assembly process where frame members can be positioned and adjusted within the connector recesses before final fastening. This allows for correction of alignment issues and subsequent adjustment, unlike permanent deformation methods
3Reliability
If the end of the frame member has a particular internal profile to fit the connector, then secure connection is achieved, but substantial amounts of material are required, increasing cost particularly for aluminium frames
Solution Approach 1:
The complex internal profile requirement is extracted from the frame member and transferred to the connector arms. The connector arms are shaped with recesses that provide the necessary geometric constraints, allowing simple, extruded frame member ends to fit securely without requiring expensive complex-profiled frame members
Solution Approach 2:
Instead of shaping the frame member end to fit the connector (traditional approach), the solution inverts the approach by shaping the connector arm recesses to receive the simple frame member end. This reverses where the geometric complexity resides, reducing frame member material requirements while maintaining connection security
4Ease of manufacture
If conventional fastening methods are used without connector arm support, then the assembly process is simple, but uneven load distribution occurs and the connector is not well supported by the frame member
Solution Approach 1:
The connector arms are preliminarily positioned within the frame member hollow profiles before fastening occurs. This preliminary insertion ensures the connector is well-supported by the frame member structure, distributing loads evenly along the connection interface while maintaining simple fastening operations
Solution Approach 2:
The connector arms are nested within the hollow profiles of the frame members, with the arms extending inside the frame member cavities. This nesting arrangement provides structural support and ensures even load distribution while keeping the fastening process simple, as the nested configuration naturally aligns and supports the connection
Data Source
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AI summary
A mitre joint for a metallic frame of a fenestration unit, the joint comprising first and second frame members; a connector configured to locate the first and second frame members in relation to one another; and first and second fasteners configured to secure the first and second frame members to the connector. The connector comprises a first arm configured to extend within a hollow profile defined by the first frame member, and a second arm configured to extend within a hollow profile defined by the second frame member. A longitudinal axis of each of the first and second fasteners is configured to be parallel to a longitudinal axis of the respective connector arm. Each of the first and second fasteners is configured to engage the respective frame member when the respective connector arm extends within said frame member.