Apparatus for adjusting timing of needle and looptaker of sewing machine

Abstract

An apparatus for adjusting a timing of a needle and a looptaker of a sewing machine provided at a zigzag sewing machine having an upper shaft for driving a needle bar, a lower shaft for driving a looptaker, a machine frame, and a timing belt for connecting and synchronizing the shafts includes a cam member including a first cam surface and a second cam surface, a first arm member and a second armmember supported by the machine frame and a first pulley and a second pulley mounted to the first arm member and the second arm member respectively and always contacting the timing belt, the first pulley following the first cam surface and the second pulley following the second cam surface.

Description

Technical field

[0001] The present invention generally relates to a device for adjusting the timing of a needle and a shuttle of a sewing machine, which adjusts the timing when the hook of the shuttle in the sewing machine meets the needle. Background technique

[0002] The conventional sewing machine disclosed in JP49-110450A includes an upper shaft driving a needle bar and a lower shaft driving a shuttle. The upper shaft is connected to a device for laterally moving the needle bar arm to control the width of the zigzag seam. A device for adjusting the timing of the needle and the shuttle is provided between the lower shaft and the shuttle (shuttle shaft). The lower shaft and the shuttle shaft are connected via a pulley and a belt, so that the rotation of the lower shaft is transmitted to the shuttle shaft via the belt. The belt is in contact with the four tension rollers, that is, with the two tension roller units. The sewing machine disclosed in JP49-110450A includes two te...

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