US 2002/0050240 A1Published application

Double chainstitch sewing machine

AssigneePegasus Sewing Machine Mfg. Co., Ltd.

InventorMasahiko Nishikawa

Life of this patent

Estimating the term…

Loading patent…

Abstract

In a double chainstitch sewing machine, a movable thread guide 37 is fixed to the lower end of a needle bar 1. A fixed thread guide 41 and a thread take-up cam 39 are fixed to a jaw 43a of a sewing machine arm 43. The thread take-up cam 39 has a cam section to be engaged with needle threads 51a, 51b from the fixed thread guide 41 to the movable thread guide 37, and takes up the needle threads oscillating up and down by vertical motion of the movable thread guide 37. Thread take-up members such as movable thread guide 37, fixed thread guide 41, and thread take-up cam 39 are disposed centrally at the lower end of the needle bar near the needle and in the jaw 43a of the sewing machine arm 43. As a result, there is no member for thread take-up moving at the upper side and front side of the sewing machine arm, and dangerous positions for the operator can be decreased. Further, the thread pathway length from the workpiece to the thread tension device is shortened, and the effects of thread stretch of properties can be decreased.

Claims7

Dependent claims

A double chainstitch sewing machine for forming a double chainstitch in a workpiece supplied onto a throat plate, comprising a needle bar moving vertically through a needle bar drive mechanism by rotation of an upper shaft, at least one needle attached to the lower end of the needle bar through a needle holder for moving vertically through the throat plate, a looper moving back and forth laterally toward the needle in cooperation with the rotation of a lower shaft, and a plurality of thread tension devices for adjusting the tension of the needle thread and looper thread threading in the needle and looper respectively, characterized in that said sewing machine further comprises a fixed thread guide fixed to a jaw of a sewing machine arm for leading a needle thread, a movable thread guide fixed at the lower end of the needle bar and having a thread eye for passing the needle thread, and a thread take-up cam fixed to the jaw of the sewing machine arm and having a cam section extended in a vertical direction by intersecting with the needle thread pathway between said fixed thread guide and movable thread guide, wherein the needle thread from the fixed thread guide to the movable thread guide is engaged with the cam section of the thread take-up cam by moving up and down by vertical motion of the movable thread guide accompanying the vertical motion of the needle bar, and the needle thread is taken up from the thread tension device to the needle by the interaction of the movable thread guide and the cam section of the thread take-up cam.

A double chainstitch sewing machine for forming a double chainstitch in a workpiece supplied onto a throat plate, comprising a needle bar moving vertically through a needle bar drive mechanism by rotation of an upper shaft, at least one needle attached to the lower end of the needle bar through a needle holder for moving vertically through the throat plate, a looper moving back and forth laterally toward the needle in cooperation with the rotation of a lower shaft, and a plurality of thread tension devices for adjusting the tension of the needle thread and looper thread penetrating through the needle and looper respectively, characterized in that said sewing machine further comprises a fixed thread guide fixed to a jaw of a sewing machine arm and having right and left thread eyes disposed oppositely to each other, a movable thread guide fixed at the lower end of the needle bar and having a thread eye for passing the needle thread, and a thread take-up cam fixed to the lower end of the needle bar and having a cam section disposed between the thread eyes of the fixed thread guide, wherein the needle thread from the fixed thread guide to the movable thread guide is oscillated up and down by vertical motion of the movable thread guide accompanying the vertical motion of the needle bar, and the needle thread between the thread eyes of the fixed thread guide is inflected by vertical motion of the thread take-up cam accompanying the vertical motion of the needle bar, and the needle thread is taken up from the thread tension device to the needle by the interaction of these motions.

Dependencies are inferred from the claim text.