Buttonhole sewing machine for sewing eye or straight buttonholes with or without a wedge bar tack

摘要

There is disclosed a machine for selectively sewing four different kinds of buttonholes, i.e. (1) with an eye, (2) without an eye, (3) with a wedge bar tack, and (4) without a wedge bar tack. The machine accomplishes all of these different types of sewing with the use of only two shaped cams permanently arranged in the machine, the first of such cams being for sewing the eye, and the second of such cams being for sewing the bar tack. The machine has a support plate for the workpiece, such support plate being coupled with one end of a first two-armed lever the second end of which is formed as a pivot of a second two-armed lever whose first end is disengageably connected with the first cam. The second end of the second two-armed lever is disengageably connected with the second cam by way of further members comprising a rod which is rendered immobile in the disengaged position with respect to the overarm of the sewing machine.