Buttonhole machine for forming eyelet button hole, has control unit reversely driving workpiece cutter drive unit for separating cutter and cutter retainer when control unit detects that gain rate of load is equal to reference value

摘要

The machine (1) has a cutter (50) for cutting a workpiece. A movement range detecting unit detects a movement range of the cutter and a cutter retainer (30). A control unit controls a workpiece cutter drive unit when a button hole is formed, where the workpiece cutter drive unit is provided with a pulse motor. The control unit reversely drives the workpiece cutter drive unit for separating the cutter and the cutter retainer when the control unit detects that a gain rate of a load is equal to a reference value with respect to the movement range of the cutter or the cutter retainer.