| 摘要 |
A buttonhole stitching device for a zigzag sewing machine, the buttonhole stitching device having a forked member which is arranged on a base plate. The forked member consists of a forked front portion which forms a long notch having a width corresponding to the amplitude of movement of a sewing machine needle and a rear portion provided with a shroud frame wall defining a nearly rectangular aperture. The base plate is provided with a hook at its front edge which is fitted into the long notch of the forked member and the forked member reciprocally moves along the base plate under the guidance of the hook provided thereto. A cam plate is removably fitted into a walled or framed aperture formed on the base plate, and the cam plate is provided with a loop channel surrounded by a rack at the under surface thereof. The shape of the loop channel corresponds to the shape of a buttonhole to be stitched. A rotative axis is arranged to penetrate the center portion of the base plate and the upper end of the rotative axis extends into the loop channel of the cam plate. A pinion is fixed to the upper portion of the axis and is engaged with the rack of the cam plate, while a ratchet is attached to the lower portion of the axis beneath the base plate so as to rotate the axis in cooperation with the up-and-down movement of the sewing machine needle. Therefore, when the sewing machine needle is axially and reciprocally moved, the pinion rotates so that the forked member moves forward and backward and also swings horizontally with the hook of the base plate as the central point. A cloth presser is pivotably connected to the extreme points of the forked member and is moved along the buttonhole formed on the cloth.
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