Clutch for sewing machine thread winding mechanism

Claim 1

In a sewing machine having a main drive shaft rotated to vertically reciprocate a needle to penetrate a fabric for forming stitches thereon, a stop-motion mechanism comprising: (a) a rotation transmission member secured near one end part of said main drive shaft and having a plurality of grooves formed thereon; (b) a plulley rotated by driving means and having a knurled face applicable for thread winding operation and a central hollow axis, said pulley being secured to said end part of said main drive shaft and being prevented from axial movement but rotatable relative to said main drive shaft; (c) an operating member rotatable together with said pulley but axially displaceable with respect to said pulley between two positions, one position being close to said pulley and the other being away from said pulley; and (d) means for selectively transmitting rotation of said pulley to said rotation transmission member, said means being engaged with any of said grooves of said rotation transmission member so that rotation of said pulley is transmitted to said rotation transmission member for stitching operation, when said operating member is in the position close to said pulley, whereas said means being disengaged from said grooves so that said pulley alone is rotated for thread winding operation, when said operating member is in the position away from said pulley.