Abstract: A sewing machine for sewing buttonholes in a workpiece comprises a stationary lower part and an arm having one end pivotally mounted on the lower part and having an opposite end which carries a rotary hook which cooperates with a reciprocating needle carried in the lower part. The arm is pivotal relative to the base part to move the arm from a fixable sewing position with said hook spaced by a predetermined distance from the needle at a stitch-forming area to a rest position in which it is spaced away from the stitch-forming area. A thread-monitoring device is located adjacent the needle for monitoring the thread and detecting any breakage thereof. The machine includes a buttonhole cutting mechanism which is connected to the drive means so as to periodically cut the workpiece. A clamp is carried by the upper arm and it has a lower portion which rests on a resilient support which is biased upwardly by a spring.

Abstract: A sewing machine for sewing two material layers to each other in aligned positions, comprises a top feeding mechanism engageable with a top layer for feeding it and a bottom feed mechanism engageable with a bottom layer of material for feeding it. The top and bottom feeding mechanisms are connected to a synchronizing device which regulates the relative speed between the two. A sensor or measuring means is engageable with the material being fed and is connected to the synchronizing means in order to vary the relative speed of the top and bottom feeds in accordance with the actual feed of the material layers.