| 摘要 |
This invention relates to an improved automatic sewing machine apparatus for sewing large articles, in lock-stitch or chain-stitch, employing two completely different upper and lower sewing mechanisms which are separately powered, wherein there is no continuous mechanical, electrical, hydraulic or other fixed connection between the upper and lower sewing mechanisms required. An open notched needle has a notch opening disposed near the needle end, the notch opening engages the needle thread, and carries the needle thread through the sewing material, and then leaves a loop extending through the sewing material as the notched needle raises above the sewing material. The notch opening in the needle is rethreaded during each cyclic, reciprocating actuation of the notched needle. A looper having two forked arms passes the thread loop around the bobbin case. The position of the open notched needle determines the timing of the looper actuation. The open notched needle position is sensed through the sewing material. The sewing material is advanced by pinching the material between adjacent wheels and rollers, or by a rotating belt.
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