| 摘要 |
A sewing machine capable of forming a line of stitches along the edge of a workpiece, while the needle is reciprocated by a needle bar relative to the workpiece in a feeding movement. The needle bar is supported by an oscillator which is joggable in a lateral direction substantially perpendicular to the feeding direction. A sensor is provided to detect the fabric edge, by emitting a radiation toward a reflecting surface provided on the work bed of the machine. The sensor determines the position of the fabric edge by detecting an amount of the reflected radiation received. The reflecting surface has a concave shape in cross section taken in a vertical plane parallel to the feeding direction. The lateral jogging movement of the oscillator is controlled according to the amount of the reflected radiation received by the sensor, so that the line of stitches is spaced apart from the edge of the workpiece by a predetermined distance.
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