Abstract: A method and device applicable to a sewing machine which has a needle and a gripper with a horizontally positioned lower bobbin for executing a seam with stitches in a sewing material being sewn, for compensating a deficiency in a longitudinal shift of the needle during a stitch being caused by an arcuate movement of the needle when it shifts sideways in a stitch, wherein the method includes the material being advanced by a feeder a length yn in the longitudinal direction of the seam on the basis of the seam setting, and wherein the sewing machine has a control including an algorithm causing the feed motor to set the feeder, so that at each stitch which includes sideways shifts of the needle it advances the sewing material a correction length en in the longitudinal direction of the seam, thereby compensating a corresponding deficiency in the needle's longitudinal shift relative to the material during the stitch being caused by the needle's arcuate sideways movement.
Type:
Grant
Filed:
July 23, 2007
Date of Patent:
January 24, 2012
Assignee:
KSIN Luxembourg III, S. ar.l
Inventors:
Rolf Janeke, Fredrik Berglund, Lars Roos
Abstract: A sewing machine having a reciprocatory needle and a reciprocatory thread-take-up device to deliver thread to the needle employs a thread control device located between the thread take-up device and the needle to engage and apply light tension to the thread. The thread control device can have an opposed plate and spring wire between which the thread runs and which cooperate to apply spring pressure to the thread. Downstream thereof a thread brush can be employed through which the thread runs. The thread can be further lightly tensioned and laterally positioned by the thread brush. The guide plate or other device can include catcher structure to catch thread escaping the take-up device. The thread control device can help control premature descent of the thread and improperly tensioned stitches.