| 摘要 |
An upper thread cutting unit in buttonhole sewing machines wherein a lever is provided for connecting and disconnecting the support of the thread cutting unit to and from a supporting member, connected via a lever and rod system, to the stop device of the sewing machine. Two appropriately set springs force the thread cutting unit, at the end of the sewing cycle, under the needle to catch and cut the upper thread and force the unit away from the needle to permit raising higher the work presser frame.
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