Automatic needle positioner for sewing machines

Claim 1

A NEEDLE POSITIONER FOR A SEWING MACHINE HAVING A DRIVE SHAFT FOR MOVING THE NEEDLE VERTICALLY THROUGH A STITCHING CYCLE, COMPRISING A ROTATABLE WHEEL HUB, MEANS OPERATIVELY CONNECTING THE WHEEL HUB AND SHAFT SO THAT THE HUB ROTATES IN COORDINATION WITH THE SHAFT AND COMPLETES ONE REVOLUTION WHILE THE NEEDLE MOVES THROUGH ONE STITCHING CYCLE, ANOTHER SHAFT CARRYING SAID WHEEL HUB, A PULLEY ON SAID OTHER SHAFT, A MOTOR, ANOTHER PULLEY DRIVEN BY SAID MOTOR, A BELT LOOSELY ENTRAINED ON THE PULLEYS FOR SLIPPING WITH RESPECT TO THE PULLEYS, A SOLENOID HAVING PLUNGER MEANS FOR ENGAGING SAID TENSIONING SAID BELT WHEN THE SOLENOID IS ENERGIZED SO TAHT THE MOTOR DRIVES THE WHEEL HUB, A NORMALY CLOSED SWITCH IN CIRUCIT WITH SAID MOTOR, A FIRST ARM CARRIED BY THE PLUNGER AND DISPOSED TO CONTACT THE WHEEL HUB WHEN THE SOLENOID IS ENERGIZED, AN OBSTRUTION ON SAID WHEEL HUB FOR ENGAGING SAID ARM AT A CERTAIN POINT ON THE HUB, A SECOND ARM ENGAGED BY THE FIRST SWITCH ARM AND MOVED THEREBY WHEN THE FIRST ARM IS ENGAGED BY SAID OBSTRUCTION, SAID SECOND ARM BEINGDISPOSED ADJACENT TO SAID SWITCH FOR ACTUATING AND OPENING THE SAME WHEN THE SECOND ARM IS MOVED BY THE FIRST ARM, WHEREBY THE MOTOR STOPS WHEN SAID SWITCH OPENS, THE WHEEL HUB STOPS ROTATION WHEN ENGAGED WITH THE FIRST ARM, AND THE NEEDLE IS POSITIONED AT A POINT COORDINATED WITH THE POSITION OF SAID OBSTRUCTION ON THE WHEEL HUB.