| 摘要 |
A trimming pressure foot that can be interchangeably attached to a sewing machine includes one scissors blade fixedly attached to a pressure foot and one scissors blade pivotable about a shaft. The cutting motion is derived from the up-and-down motion of a needle drive rod. To this end, a pivot lever which is essentially in the shape of an inverted T is used. The pivot lever is pivotable about a shaft connected to the pressure foot, and its upwardly protruding arm rests with spring pressure on a needle securing screw. A flank of the arm resting on the screw forms an acute angle with the path of motion of the needle drive rod. In operation of the sewing machine, the up-and-down motion of the needle drive rod is converted into a pivoting motion of the pivot lever. The pivoting motion of the lever is transmitted onto the pivotable cutting blade by a tang secured to the pivot lever and by engaging the inside of a slit of the blade. The long needle drive rod stroke is thus elegantly and simply translated into a much shorter stroke of the trimming pressure foot.
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