Needle positioning attachment for sewing machine

In a sewing machine comprising a head, a main drive shaft extending through the head and rotatably journaled thereon, a motor connected to the shaft for rotating same, and a needle positioning attachment, the improvement wherein the needle positioning attachment is connected to the shaft and arranged for accumulating energy from the rotation of the shaft for actuation when the shaft ceases rotation in order to turn the shaft a predetermined amount, said needle positioning attachment comprising, in combination:

• (a) pulley means affixed to the shaft and connected to the motor for rotation thereby;
• (b) a stationary abutment;
• and
• (c) resilient means connected to the pulley means and releasably engageable by the stationary abutment for being restrained against rotation in one direction thereof by the stationary abutment so as to permit the resilient means to accumulate energy by rotation of the pulley means relative to the resilient means, said resilient means including a cup affixed to the pulley means, a stem arranged extending through the cup and disposed substantially coaxial with the main drive shaft of the sewing machine, and a spiral torsion spring disposed within the cup, the spring having an inner end and an outer end, the latter being affixed to the cup and the inner end being connected to the stem for winding tight the spiral torsion spring as the cup, and pulley means to which the cup is affixed, rotate relative to the stem, a nut disposed in the pulley means and provided with internal screw threads, with external screw threads being provided on the stem at a portion thereof disposed adjacent the nut, the threads of the stem being engageable with the threads of the nut for advancing the stem axially relative to the pulley means as the stem is threaded into the nut and connected to the main drive shaft of the sewing machine by means of the pulley means for coupling the stem to the drive shaft.