1. Field of the Invention
This invention relates to a sewing machine, more particularly to a sewing machine with a thread cutting device for cutting both upper and lower threads in a sewing machine.
2. Description of the Related Art
Conventional sewing machines either include hooks rotating in a horizontal plane, such as those disclosed in U.S. Pat. Nos. 5,964,170 and 6,276,289 B1, or have hooks rotating in a vertical plane, such as those disclosed in U.S. Pat. Nos. 6,152,058 and 5,771,828.
The sewing machine disclosed in U.S. Pat. No. 6,152,058 includes a thread cutting device extending in a horizontal direction, and including a fixed knife and a movable knife which cooperate with each other to cut either one or both of upper and lower threads. The movable knife is operable to cut the upper thread at a first timing and to cut the lower thread at a second timing. In order to permit selective cutting of both the upper and lower threads or only the upper thread, the thread cutting device has a complicated construction, thereby resulting in high manufacturing costs and complicated operation.