Thread adjusting device of sewing machine

Abstract

This invention provides a thread adjusting device of sewing machine, which is capable of stably giving minute tension to the top thread provided to the needle through a balance, and is capable of sewing thin cloth, soft cloth with good quality but without generating stitch defect. The thread adjusting device comprises an auxiliary thread adjusting device for giving preparation tension to the top thread provided to a rotation resistance main thread adjusting device (4), including: a rotary cylinder (51) that winds and keeps several rings top threads in the peripheral width direction in a spaced way, an extruding spring (53) applying thrust to the rotary cylinder (51) and a regulating knob that adjusts the spring of the extruding spring (53). In addition, a guide groove is formed in a thread passage component (8) extending in the width direction of the rotation cylinder (41). The top thread (2) wound on the rotation cylinder (51) is hanged in the guide groove. The perimeter of the top thread (2) is gradually shortened from the thread supply source to the main thread adjusting device (4).

Description

technical field [0001] The present invention relates to a thread adjusting device equipped on a sewing machine for applying tension to an upper thread (needle thread) provided to a needle, and in particular to a thread adjusting device capable of imparting a slight tension suitable for sewing thin and soft fabrics. Background technique [0002] In sewing with a sewing machine, it is necessary to apply appropriate tension to the upper thread provided to the needle and the lower thread provided to the lower thread winding device such as a kettle and a looping device (ル-パ). In various sewing machines, in order to A thread adjustment device is installed to achieve this tension application. [0003] Most thread adjusting devices that apply tension to the upper thread have a pair of adjusting discs, and an energizing device (spring, solenoid) that causes these adjusting discs to push against each other, and the upper thread clamped between the adjusting discs when When pulled out...

AI Technical Summary

Problems solved by technology

[0004] In this thread adjusting device with a frictional resistance type thread adjusting device, the amount of tension imparted to the upper thread can be changed by adjusting the thrust of the energizing device and increasing or decreasing the pushing force of the thread adjusting disc. However, if the operation is performed under the state of reducing the thrust of the energizing device to apply a slight tension, the pushing state of the thread adjusting disc that is pushed with a weak force will be affected by the pulling of the upper thread. There is a problem that it is difficult to apply tension stably because it changes due to external factors such as vibration during operation and output.

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