What mechanical element, patented by Elias Howe Jr. in 1846, formed the foundation of the modern sewing machine stitch?

Answer

The lockstitch mechanism

Elias Howe Jr. is credited with inventing the first truly practical sewing machine using the lockstitch mechanism, which created a far stronger and more durable seam than previous stitches.

What mechanical element, patented by Elias Howe Jr. in 1846, formed the foundation of the modern sewing machine stitch?
inventiondesignmachinesewing