Bobbin thread feeder of sewing machine

Abstract

The present invention provides a bobbin thread feeder of sewing machine of simple structure in which a lower thread can be reliably fed at an appropriate tension. A lower thread bobbin 21 can be removably contained through an opening for containing a lower thread bobbin 17 in a rotary hook 20 of a horizontal rotary hook 30 provided in a sewing machine frame. A thread tension plate and a thread tension spring are attached while overlapping along the inner circumference of the rotary hook 20, and function as a tension generating portion 22 for imparting resistance to pulling out a lower thread being guided through the gap between the thread tension plate and the thread tension spring. A needle plate 16 with an opening for taking the lower thread bobbin 21 in and out is provided above the rotary hook 20. The needle plate 16 comprises a guiding slit 27 that guides the lower thread formed thereon. The guiding slit 27 is formed substantially linearly in the extending direction of the overlapping portion of the thread tension plate and the thread tension spring.

Dependencies are inferred from the claim text.