Air-driven threading device for sewing machine

Abstract

Problem: To thread a looper with a one-touch operation. Solution: Provided is a looper threading and sewing switching mechanism (30) comprising a push-button (33) for push operation of a push-button shaft (32) from which a control pin (31) protrudes; a control groove cam (38) comprising first through fourth control groove cam sections (34 - 37) that receive the control pin; a link shift plate (40) that supports a thread guide section and that by using a first spring (39) is snapped toward a threading state in which a thread guide outlet of the thread guide section is in contact with a looper thread inlet; and a link positioning plate (82) comprising a peripheral surface (80) and an interlocking cutaway section (81) that rotate integrally with a main shaft (2) and with which a top section (41) of the push-button shaft comes into contact.

Description

technical field

[0001] The present invention relates to a gas delivery threading device for a sewing machine, and more particularly to a sewing machine for automatically passing a looper thread through a looper (ルパパ) of a hemming sewing machine, a double loop sewing machine, a flat stitch sewing machine, etc. by using pressurized gas Gas delivery threading device. Background technique

[0002] Conventionally, there is known an air delivery threading device in an overlock sewing machine, a double loop sewing machine, a flat stitch sewing machine, etc., by connecting a looper thread outlet from a thread introduction portion where the looper thread is inserted to the tip of the looper needle. The hollow looper thread guide that communicates with each other uses the flow of pressurized gas supplied into the hollow looper thread guide to transport the looper thread. Therefore, there is no need for complicated threading, and the threading can be performed with better operability,...

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