Mechanism for controlling the workpiece pressure grippers of buttonhole bar tacker sewing machines

摘要

There is disclosed mechanism for controlling the workpiece pressure grippers of buttonhole bar tacker sewing machines, such machines having means for selectively cutting the buttonhole either before or after the sewing operation. The controlling mechanism comprises a first disengaging member for controlling the pressure grippers, and a second disengaging member for selectively starting and stopping the machine. The two disengaging members are disposed in the path of rotary motion of at least one part coupled in the motion both with the device for driving the workpiece support plate of the machine and with the cam which controls the cutting knife of the machine.