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Abstract

A puckering preventing shuttle device of a sewing machine capable of providing high quality stitches without producing puckering by eliminating needle thread extraction resistance on the outer periphery of a rotating hook bobbin case holder to reduce the tension of a needle thread so as to keep a balance between the needle thread and a bobbin thread and also enabling the proper tightening of the threads even in an extra-soft fabric. The device comprises the rotating hook bobbin case holder (80) storing a bobbin case storing a bobbin around which the bobbin thread is wrapped and detachably fixed to a machine frame and locked to the machine frame by rotating hook bobbin case holder stopper (90) to stop its rotation and a rotating hook (70) in which the rotating hook bobbin case holder (80) is installed, having a sword tip (75), and rotated by a lower shaft. A needle thread inlet (EN1) and a needle thread outlet (EX1) are formed at circumferentially different positions between the rotating hook bobbin case holder stopper (90) and the rotating hook bobbin case holder (80) where the loop of the needle thread picked up by the sword tip (75) for each rotation of the rotatingly driven rotating hook (70) forms a clearance for guiding in and out the needle thread on the outer periphery of the rotating hook bobbin case holder (80) by eccentrically disposing the rotating center (O1) of the rotating hook (70) relative to the rotating center of the lower shaft.

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First Claim