Oblon, Fisher, Spivak, McClelland & Maier
Stitch forming mechanism of a sewing machine
An improved lockstitching mechanism for a sewing machine wherein the cylindrical bobbin case having a bobbin therein for supplying a lower thread has an upper thread guide for slidably guiding a loop of the upper thread across the lower thread and a lower thread guide hole in the side wall below the upper guide for guiding the lower thread being extracted from the bobbin, whereby the lower thread is placed ahead of the needle relative to the rotational direction of the shuttle body supporting the bobbin, such that the upper thread only crosses the lower thread once during each stitching operation to prevent gnarling of the seam commonly referred to as "hitchstitching".
Aisin Seiki Kabushiki Kaisha
D
D05B
inventional
Atsuo Tatsuo
Ohira Kozaki