Thread-cutting mechanism for sewing machines

Claim 1

A THREAD CUTTING AND STOPPING MECHANISM IN COMBINATION WITH A SEWING MACHINE HAVING A STITCH FORMING MECHANISM, COMPRISING A CUTTER, MEANS MOUNTING THE CUTTER IN AN INITIAL POSITION ADJACENT THE STITCH FORMING MECHANISM, MEANS FOR MOVING THE CUTTER FROM SAID INITIAL POSITION TOWARD SAID STITCH FORMING MECHANISM AT A PREDETERMINED SPEED AND IN TIMED RELATION WITH THE STITCH FORMING MECHANISM TO A SECOND POSITION WHERE SAID CUTTER IS ADAPTED TO ENGAGE THE SEWING THREADS, MEANS FOR MOVING THE CUTTER AFTER SAID ENGAGEMENT AT A SPEED GREATER THAN SAID PREDETERMINED SPEED TO SEVER THE THREADS, AND MEANS FOR RETURNING THE CUTTER TO SAID INITIAL POSITION AND STOPPING THE NEEDLE IN A PRESELECTED RAISED POSITION CLEAR OF THE WORK, WHEREIN THE MEANS FOR MOVING THE CUTTER COMPRISES A PINION, A RACK IN ENGAGEMENT WITH THE PINION, AND MEANS FOR TRANSLATING THE RACK, THE MEANS FOR TRANSLATING THE RACK COMPRISING A CAM, ABUTMENT MEANS INTEGRAL WITH THE CAM, AND A LEVER SYSTEM CONNECTING THE CAM AND RACK, WHEREIN SAID LEVER SYSTEM COMPRISES A MOVABLE SUPPORT AND A FIRST BELL CRANK LEVER PIVOTALLY MOUNTED ON SAID MOVABLE SUPPORT FOR PIVOTAL MOVEMENT ABOUT A SELECTED AXIS, A SECOND BELL CRANK LEVEL PIVOTAL MOUNTED ON ONE ARM OF SAID FIRST LEVEL FOR PIVOTAL MOVEMENT ABOUT AN AXIS NORMAL TO SAID SELECTED AXIS, AND MEANS PIVOTALLY CONNECTING THE OTHER ARM OF SAID FIRST LEVER TO THE RACK.