Sewing machine

Abstract

The sewing machine of the present invention has a needle bar crank linked to a main shaft, a vertical movement transmission mechanism linked to the needle bar crank, and a needle swing mechanism for swinging the needle bar. The up and down movement transmission mechanism includes: a ring-shaped member having a space defined by a ring-shaped inner peripheral surface, through which the needle bar passes; and a pair of upper and lower needle bar frame members, which are fixed on the outside of the needle bar, and Arranged on the upper and lower sides of the ring member. The ring member is journally connected to the needle bar crank. A clearance for swinging is ensured between the annular inner peripheral surface of the space of the annular member and the outer periphery of the needle bar. The needle bar can swing without being in contact with the annular inner peripheral surface within the swing gap.

Description

(1) Technical field [0001] The present invention relates to a sewing machine with a needle bar up-and-down movement mechanism and a needle zigzag mechanism for moving and swinging the needle bar up and down, in particular to a sewing machine with a needle bar that can reduce the effect on the needle bar during the up-and-down movement of the needle bar accompanied by the swing. bending stress mechanism of sewing machine. (2) Background technology [0002] In the past, in a round head buttonhole sewing machine for sewing round head buttonhole stitches composed of round head overlock stitches and a pair of left and right straight line overlock stitches connected thereto, a sewing mechanism is provided to drive the needle bar synchronously. and a looper facing the needle bar; a rotating mechanism to rotate the looper seat and the needle bar with the looper around the vertical axis; and a feeding mechanism to move the feeding table carrying the processing cloth in the X and Y di...

AI Technical Summary

Problems solved by technology

[0007] When sewing at a high speed with a buttonhole sewing machine, the heat generation becomes large, and the inclined groove and the guide pin wear rapidly, which not only lacks durability, but also the dimensional accuracy of the vertical movement stroke of the needle bar 8 and the needle swing amount. decline

As a result, problems such as confusion of the meeting time of the sewing needle 7 relative to the looper will occur.

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