Method and apparatus for tying threads

A thread tying apparatus, comprising:

• a first thread holding member that holds a tail end portion of a first thread;
• a latch needle having a hook at a tip thereof and a latch whose root is pivotally mounted to a stem thereof so as to open and close the latch with respect to the hook;
• a first loop controller that slidably makes contact with the stem of the latch needle and moves in a direction of an axis of the latch needle;
• a second thread holding member that holds a beginning end of a second thread and changes a position of the beginning end of the second thread so as to be close to the hook of the latch needle;
• and
• an interlock mechanism that performs the following steps:
• rotating the latch needle on the axis thereof to make a first loop at the hook by winding the first thread substantially around the hook;
• advancing the latch needle to place the first loop over the latch of the latch needle, which is away from the hook, on the stem of the latch needle and to place a portion extending from the first loop of the first thread inside the latch;
• moving the first loop controller and the latch needle relative to each other to make the first loop go over the hook, pass the portion extending from the first loop through the first loop to make a second loop at the hook, and make the second loop go over the latch to move the second loop toward the stem of the latch needle;
• bringing the second thread whose beginning end is held at the second thread holding member to the hook;
• operating the latch needle and the first loop controller together to move the second loop away from the hook and insert the second thread into the second loop;
• and
• reducing the second loop and the first loop until the beginning end of the second thread is stopped into the first loop.