Sewing machine with thread-cutting device

Abstract

The device includes cutting of the needle and hook thread while forming short fabric-side thread ends in a double-thread lockstitch sewing machine with a hook rotating in a horizontal plane under a needle plate. A thread catch device with a cutting edge is provided. A knife is provided cooperating with the cutting edge and with a thread clamp for the hook thread. The process includes moving the catch thread device from a resting position into a movement reversal position, moving the knife and the thread clamp from a resting position into a cutting and pickup position located adjacent to the stitch hole of the needle plate, moving the catch thread device to grasp the hook thread and the fabric-side part of the needle thread loop in a first partial step into an intermediate position, in which the needle thread loop is then pulled up to the catch thread device, returning the catch thread device into its resting position in a second partial step, pulling the hook thread first off from the thread reserve by the catch thread device during the second partial step, then introducing the hook thread into the thread clamp, and cutting the needle thread and the hook thread in the vicinity of the stitch hole in cooperation with the knife and after the cutting of the threads, returning the knife and the thread clamp into their resting positions, while the thread clamp pulls off more hook thread from the thread reserve.