Thread pull-off for sewing machines

Claim 1

IN A SEWING MACHINE HAVING A FRAME, A NEEDLE BAR MOUNTED IN SAID FRAME FOR ENDWISE RECIPROCATION AND HAVING A WORK-PENETRATING STROKE AND A RETURN STROKE, A ROTARY SHAFT JOURNALED IN SAID FRAME, A CRANK ON SAID SHAFT. A NEEDLE BAR DRIVING LINK PIVOTALLY CONNECTED AT ONE END TO SAID CRANK AND AT THE OTHER END TO SAID NEEDLE BAR FOR IMPARTING ENDWISE RECIPROCATION TO SAID NEEDLE BAR UPON ROTATION OF SAID SHAFT, A THREAD TAKE-UP MECHANISM MOUNTED IN SAID FRAME, MEANS OPERATIVELY CONNECTING SAID TAKE-UP MECHANISM AND SAID SHAFT FOR ACTUATING SAID TAKE-UP MECHANISM IN SYNCHRONISM WITH SAID NEEDLE BAR TO EFFECT A MAXIMUM TAKE-UP ACTION SUBSTANTIALLY SIMULTANEOUSLY WITH THE END OF THE RETURN STROKE OF SAID NEEDLE BAR, A TENSION DEVICE DISPOSED BETWEEN SAID TAKE-UP MECHANISM AND THE THREAD SUPPLY AND A THREAD PULL-OFF MECHANISM DISPOSED ON THE THREAD SUPPLY SIDE OF SAID TENSION DEVICE AND COMPRISING A PULL-OFF ELEMENT ON SAID NEEDLE BAR DRIVING LINK AND HAVING A THREAD ENGAGING FREE END MOVABLE IN A PLANE PARALLEL TO THE PLANE OF MOVEMENT OF SAID LINK AND HAVING A PATH OF MOVEMENT DEFINED BY THE MOVEMENT OF SAID LINK, SAID FRAME HAVING AN OPENING IN THE PLANE OF MOVEMENT OF THE THREAD ENGAGING END OF SAID PULL-OFF ELEMENT, SAID PULL-OFF ELEMENT BEING EXTENDED TO PROJECT SAID THREAD ENGAGING END THROUGH SAID OPENING DURING THE WORK-PENETRATING STROKE OF SAID NEEDLE AND TO RETRACT THE SAME DURING THE RETURN STROKE THEREOF, AND THREAD GUIDES DEFINING A THREAD LEAD TRANSVERSELY OF THE PATH OF MOVEMENT OF SAID THREAD ENGAGING END OF SAID PULL-OFF ELEMENT WHEREBY SAID THREAD ENGAGING END OF SAID PULL-OFF ELEMENT ENGAGES AND EXPANDS SAID THREAD LEAD DURING THE WORK-PENETRATING STROKE OF SAID NEEDLE AND RELEASES SAID THREAD LEAD DURING THE RETURN STROKE OF SAID NEEDLE.