Double-chain stitching method and apparatus

A method of double-chain stitching comprising the steps of sequentially:

• a) pushing a needle carrying a needle thread down through goods to be seamed to form below a lower face of the goods a needle-thread loop;
• b) passing a looper carrying a looper thread transversely to a stitching direction and generally parallel to the face through the loop below the lower face to pass the looper thread through the needle-thread loop;
• c) gathering the looper thread and needle-thread loop on a catching element below the lower face;
• d) moving the element with the gathered needle and looper threads away from the needle and looper generally parallel to the face while advancing the goods in the direction to form with the needle-thread loop and looper thread a window;
• e) repeating step a) with the needle passing through the window;
• f) releasing the gathered needle and looper threads from the element so that they engage around the needle loop formed in step e);
• and
• g) repeating steps b), c), d), e), f), and g).