Opening plate for attaching a lower thread bobbin of a sewing machine

摘要

An opening plate which closes a lower thread bobbin is provided with a drawing of a bobbin on its surface. A bobbin drawing is exactly overlapped with the bobbin when the plate is completely closed. Also a drawing of a thread tension adjusting device in a required position and a drawing of a lower thread normal path are provided on the opening plate. The drawings indicate to a machine operator the position of lower thread holding bobbin correctly inserted in a horizontal full rotation loop taker device and the path of drawing of the lower thread therefrom so as to enable the operator to insert the lower thread holding bobbin in the horizontal full rotation loop taker device correctly in place, and pass the lower thread wound on the bobbin through the thread tension adjusting device correctly.