Threading machine of a sewing machine and a threading method

A threading method for a sewing machine comprising the steps of:

• supplying pressurized gas from a pressurized gas supply means through a hollow thread guide means to a thread inlet of a tubular looper, which has a hollow structure extending from said thread inlet to a tip thread outlet;
• inserting a thread into a thread introduction portion of said thread guide means;
• closing a portion of said thread guide means and generating a negative pressure by a reverse operation of said pressurized gas supply means to draw said thread into said thread guide means;
• and
• conveying said pressurized gas through said thread guide means by a positive operation of said pressurized gas supply means to feed said thread from said tip thread outlet of said tubular looper by a flow of said pressurized gas.

A sewing machine comprising:

• at least one elongated looper with a thread inlet at one end and a thread outlet at its other end;
• an elongated hollow thread guide divided into at least two telescoping sections, one section being fixed in position and having a thread receiving end for receiving a thread and a second section mounted on the sewing machine for axial reciprocating movement and having a distal end for mating with the thread inlet of the one elongated looper;
• means for moving said second section of said thread guide linearly between an engaged position where said distal end is mated with said thread inlet of the one elongated looper and a disengaged position;
• and
• gas supply means for introducing a gas flow into said thread guide to feed the thread through said thread guide, through the one looper and out said thread outlet, when said thread guide is located in said engaged position.

A threading method for a sewing machine comprising the steps of:

• supplying pressurized gas through a hollow thread guide means to a thread inlet of a tubular looper, which has a hollow structure extending from said thread inlet to a tip thread outlet;
• inserting a thread into a thread introduction portion of said thread guide means;
• conveying said pressurized gas to said thread introduction portion to generate a negative pressure at said thread introduction portion;
• drawing said thread into said thread guide means, utilizing said negative pressure;
• and
• feeding said thread from said tip thread outlet of said tubular looper by a flow of said pressurized gas.