Abstract: 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.

Abstract: 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.