Gas carrying threading device of sewing machine

A gas carrying threading device of sewing machine comprising:

• at least one looper having a hollow structure from a looper thread inlet to a looper loop-taker point thread outlet,
• a thread introduction portion inserting a looper thread which is led to said looper,
• a hollow thread guide portion having a thread guide outlet which connects to said thread introduction portion and performs a contact/separation for the looper thread inlet of said looper,
• a connecting portion moving said thread guide portion between a threading state that said thread guide outlet of said thread guide portion contacts to said looper thread inlet of said looper and a sewing state that said thread guide outlet of said thread guide portion separates from said looper thread inlet of said looper, and
• a gas supply portion feeding said looper thread from said thread introduction portion to said looper loop-taker point thread outlet through said looper when said thread guide portion is moved to said threading state,
• further comprising, when moving said connecting portion to contact and separate said thread guide outlet of said thread guide portion and said looper thread inlet of said looper freely,
• a looper threading/sewing changeover mechanism including,
• a push button for a pressing operation of a push button shaft which protrudes a control pin,
• a control groove cam which includes plural control groove cam portions which receive said control pin,
• a connecting movement plate which supports said thread guide portion and which is elastically repelled toward said threading state that said thread guide outlet of said thread guide portion contacts to said looper thread inlet of said looper by a first spring, and
• a connecting positioning plate rotating together with a main shaft integrally and having a peripheral surface that a tip portion of said push button shaft contacts and having a notch portion that said tip portion of said push button shaft is fitted,
• said control groove cam of said looper threading/sewing changeover mechanism comprising
• a first control groove cam portion which latches together said control pin at the time of a non-pressing operation of said push button and holds said sewing state,
• a second control groove cam portion which is latched together at said control pin at the time of a pressing operation of said push button and holds said connecting movement plate in a threading preparatory state by contacting said tip portion of said push button shaft to a peripheral surface of said connecting positioning plate,
• a third control groove cam portion that said control pin is loosely fitted by rotating said main shaft manually and holds said threading state by fitting said tip portion of said push button shaft into said notch portion of said connecting positioning plate, and
• a fourth control groove cam portion which slides said control pin and holds said sewing state by latching together at said first control groove cam portion when returning said connecting movement plate from said threading state to said sewing state manually and forcibly after completing a threading to said looper.

A gas carrying threading device of sewing machine comprising:

• at least one looper having a hollow structure from a looper thread inlet to a looper loop-taker point thread outlet,
• a thread introduction portion inserting a looper thread which is led to said looper,
• a hollow thread guide portion having a thread guide outlet which connects to said thread introduction portion and performs a contact/separation for the looper thread inlet of said looper,
• a connecting portion moving said thread guide portion between a threading state that said thread guide outlet of said thread guide portion contacts to said looper thread inlet of said looper and a sewing state that said thread guide outlet of said thread guide portion separates from said looper thread inlet of said looper, and
• a gas supply portion feeding said looper thread from said thread introduction portion to said looper loop-taker point thread outlet through said looper when said thread guide portion is moved to said threading state,
• further comprising, when moving said connecting portion to contact and separate said thread guide outlet of said thread guide portion and said looper thread inlet of said looper freely,
• a looper threading/sewing changeover mechanism including,
• a push button for a pressing operation of a push button shaft which protrudes a control pin,
• a control groove cam which includes plural control groove cam portions which receive said control pin,
• a connecting movement plate which supports said thread guide portion and which is elastically repelled toward said threading state that said thread guide outlet of said thread guide portion contacts to said looper thread inlet of said looper by a first spring, and
• a connecting positioning plate which rotates together with a main shaft integrally and has a peripheral surface that a tip portion of said push button shaft contacts and has a notch portion that said tip portion of said push button shaft is fitted,
• said looper threading/sewing changeover mechanism comprising
• a threading preparatory function which holds said connecting movement plate from said sewing state to said threading preparatory state through a control groove cam which engages to said control pin by pressing said push button shaft by said push button and contacts said tip portion of said push button shaft to a peripheral surface of said connecting positioning plate which rotates together with said main shaft integrally,
• a threading function which fits said tip portion into said notch portion of said connecting positioning plate by rotating said main shaft manually and holds said threading state, and
• a return function which holds said sewing state through said control groove cam which slides at said control pin when returning said connecting movement plate from said threading state to said sewing state manually and forcibly after completing a threading to said looper.