Thread tightening device for sewing machine, has spring disk bearing holding ends of drive axle on side that is conveniently detached from tightening disks that hold thread between pulleys, where permanent magnets are fastened to axle

摘要

The device has a pair of tightening disks (31, 32), which holds a thread between pulleys, and a drive mechanism (4) operable to actuate in order to move one disk to the other disk. A power source (5) is actuated to drive the mechanism. The source has an engine with a drive axle moving along an axial direction and permanent magnets (52-55) fastened to the axle. A stator has windings (57-60) wrapped around the magnets concerning the magnets with a pre-determined distance. A spring disk bearing (8) holds ends of the axle on a side that is conveniently detached from the disks.