Abstract: A needle drive assembly for a sewing machine includes a drive shaft rotatable about a drive shaft axis and a needle drive cam operably connected to the drive shaft and rotatable therewith. A needle drive race is slidably connected to the needle drive cam via a cam pin secured to the needle drive cam and at least partially extending through the needle drive race. A needle is assembly affixed to the needle drive race and includes a needle bar and a needle secured to the needle bar. Rotary motion of the drive shaft and needle drive cam about the drive shaft axis is translated into a needle path via the needle drive race, the needle path including a substantially vertical downstroke from a stroke peak to a stroke depth, a horizontal carry portion from the stroke depth and a curvilinear or linear upstroke from the horizontal carry portion to peak.

Abstract: A sewing machine for leather or the like is provided with a flat needle holding bar supported for up/down movement. The needle holding bar is further supported for rotational movement and a control motor is provided to rotate the needle as required to cause the flat surface of the needle to be parallel to the direction in which the thread runs. To this end the needle is rotated after the needle penetrates the leather but before it reaches bottom dead center to a position in which the flat portion is in its normal position for the thread running direction and upper and lower threads are twisted together whereafter the needle is rotated again to be parallel to the thread running direction.