| 摘要 |
A measuring device for measuring the distance of feed of cloth in a sewing machine, comprising a wheel driven by the cloth without slippage and located at the presser foot. A plurality of slits on the wheel are arranged to cooperate with two slits in the bracket of the wheel, and thereby form two light gates producing two output signals in the form of a two bit binary code. This light is detected by photo transistors or photo diodes positioned to receive light through the slits from light emitting diodes or lamps. The output signals from the unit are applied to a data unit connected to compute a positive or negative feed of the cloth. The invention is especially useful when a buttonhole is to be sewn totally automatically. |
