Face thread holder for sewing machine

Abstract

The upper thread holding device (60) for the sewing machine (100) bends the upper thread with a projection part (2c) which is arranged in a pinching member, when the upper thread is held between the holding surface (1f) of a holding member and the pinching surface (2e) of the pinching member. A holding force for holding the upper thread by the upper thread holding device is adjusted in two steps, i.e., a resistance force in bending which is given to the projection part, and a pinching force for pinching the upper thread between the holding surface and the pinching surface. The upper thread is held after adjusting the length of the upper thread on the rear side surface of the fabric.

Description

technical field [0001] The present invention relates to a method for clamping the end of the upper thread passed through the needle under the needle plate at the start of sewing and moving the clamped end of the upper thread to a position separated from the up and down movement path of the needle Upper thread retaining device for sewing machines. Background technique [0002] In the past, it is well known that in order to reliably form the stitches at the beginning of sewing with a sewing machine and stabilize the length of the upper thread left on the needle point at the beginning of sewing, when the needle passes through the needle passage hole (needle hole) of the needle plate and pulls up, the The upper side of the needle plate holds the upper thread holding device that passes the end of the upper thread on the needle of the first stitch at the beginning of sewing and holds the upper thread at a predetermined position (for example, refer to Patent Document 1). [0003] ...

AI Technical Summary

Problems solved by technology

[0008] But, with regard to the situation of above-mentioned patent document 1, the clamping of upper thread is carried out when machine needle passed the machine needle passing hole of throat plate, and at this point of time, pull-up of upper thread with thread take-up lever has not yet finished, There may be a problem that the length of the thread remaining on the needle point becomes longer

[0009] In addition, in the case of the above-mentioned Patent Document 2, since the holding force of the needle thread holding device to hold the needle thread is changed and adjusted according to the adjustment of the pressure reducing valve, there is a problem that it is difficult to adjust the holding force.

In addition, the clamping of the upper thread is carried out with a holding force that allows the upper thread to be pulled up by the thread take-up lever. However, since the held time point is near the top dead center of the needle bar when the thread take-up lever has started to rise, Due to the inertial force of the upper thread lifted by the thread take-up lever, the upper thread will be loosened, and the length of the upper thread left in the fabric will be uneven, which will not stabilize the quality of the beautiful stitches.

[0010] In addition, since the end of the needle thread clamped by the needle thread holding device hangs down directly below the clamped position, it may easily come into contact with the machine shuttle below, or be caught in the machine shuttle, or stick to the needle thread. Contamination of shuttles

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