Sheet-Metal Clench Lock Corner Design to Eliminate Welding
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Solution Overview
Problem
Current methods for forming one-piece sheet-metal structures with corners, such as kitchen appliance doors, require labor-intensive processes like welding and metal finishing, and involve removing protective coverings, which increases costs and damage risks.
Innovation Solution
A method and structure that utilize clinch locks formed by bending tabs in a sheet metal to create weld-free corners, where a first bottom tab extends from one wall and a first top tab from another wall to engage and clench the bottom tab, eliminating the need for post-forming processing like welding and metal finishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is used to connect corners after forming, then structural integrity is improved, but manufacturing complexity and labor costs increase
Solution Approach 1:
The sheet metal structure connects its own corners using self-formed tabs and slots. The first tab extends from one wall and the second tab from another wall, where they engage with each other through bending and forming operations, eliminating the need for external welding processes or additional fastening components.
Solution Approach 2:
The corner connection is divided into discrete tab and slot elements that can be formed independently through bending operations. Each tab is a separate feature that can be precisely formed and positioned, allowing for modular assembly and simplified manufacturing compared to monolithic welding processes.
2Manufacturing precision
If manual scoring and removal of protective vinyl is performed, then surface quality is improved, but labor time and part damage risk increase
Solution Approach 1:
The tabs and slots are formed through automated bending and forming operations performed on the protective vinyl-covered sheet metal before the vinyl is removed. This preliminary formation ensures precise geometry and positioning while the protective vinyl is still in place, eliminating the need for manual scoring and reducing part damage risk.
3Manufacturing precision
If welding and metal finishing operations are performed, then corner seam quality is improved, but production cost and environmental impact worsen
Solution Approach 1:
The mechanical forming process replaces the thermal welding process and subsequent mechanical finishing operations. Tabs are formed through bending and engaging with slots through purely mechanical means, eliminating the need for welders, grinding wheels, and associated consumables, thereby reducing both cost and environmental impact.
4Device complexity
If one-piece structure is formed by bending single sheet, then manufacturing simplicity is improved, but corner connection reliability worsens
Solution Approach 1:
The tab and slot connection provides dynamic adaptability in the corner joint, allowing for slight variations in sheet metal thickness and bending tolerances while maintaining reliable connection. The interlocking geometry accommodates manufacturing variations better than rigid welded joints, improving reliability without sacrificing the one-piece forming simplicity.
Data Source
AI summary
A one-piece sheet-metal structure includes a first wall, a second wall perpendicularly extending from the first wall, and a third wall perpendicularly extending from the first wall. The second wall is perpendicular to the first wall and the third wall. An end edge of the second wall is adjacent an end edge of the third wall to form a corner. The corner is provided with a clench lock so that the corner is weld-free. The clench lock includes bottom and top tabs. The bottom tab perpendicularly extends from the end edge of the second wall at a bottom tab bend and engages an inner side of the third wall. The top tab perpendicularly extends from an outer edge of the third wall at a top tab bend and bends around the bottom tab and engages an inner side of the bottom tab to clench the bottom tab at the corner.