Patent ID: 8096250

Claim:
A thread tensioning device of a sewing machine, the sewing machine being operable to form a plurality of types of stitches using a plurality of threads, the thread tensioning device comprising: a plurality of thread tensioners disposed to correspond to the plurality of threads, each of the thread tensioners applying a tensional force to a respective one of the threads, an adjusting mechanism coupled to each of the thread tensioners, wherein the adjusting mechanism is configured to select a type of stitch from the plurality of types of stitches and to simultaneously adjust the tensional force applied from each of the thread tensioners to the corresponding thread such that, for each of the thread tensioners, the tensional force is selected from a plurality of reference tensional forces corresponding to the plurality of types of stitches so as to correspond to the selected type of stitch, a plurality of fine adjustment mechanisms disposed to correspond to the plurality of the thread tensioners, each of the fine adjustment mechanisms configured to be manually operable to finely adjust, from the selected reference tensional force, the tensional force applied from the corresponding one of the thread tensioners to the corresponding thread, and a reset mechanism coupled to each of the fine adjustment mechanisms, wherein the reset mechanism is configured to reset, at different timings and interlockingly with the adjusting mechanism, a respective amount of the tensional force that is finely adjusted by each of the fine adjustment mechanisms.