Stitch control mechanism for sewing machines with combined lower and upper feed

Claim 1

IN A SEWING MACHINE OF THE TYPE HAVING A BASE PLATE, A HOUSING INCLUDING AN UPRIGHT AND AN OVERHANGING ARM EXTENDING THEREFROM IN A DIRECTION PARALLEL TO SAID PLATE AND TERMINATING IN A SEWING HEAD, A RECIPROCATORY NEEDLE MOUNTED WITHIN SAID HEAD, TO PRODUCE STITCHES IN A WORKPIECE FED ALONG SAID PLATE, A NEEDLE DRIVE SHAFT WITHIN SAID ARM OPERABLY CONNECTED TO SAID NEEDLE, TO RECIPROCATE SAID NEEDLE IN THE VERTICAL DIRECTION, AND A LOOP TAKER DRIVE SHAFT IN DRIVING CONNECTION WITH SAID FIRST DRIVE SHAFT AND MOUNTED BELOW SAID PLATE; WORK FEEDING MEANS COMPRISING IN COMBINATION: (1) A FIRST ROCKSHAFT MOUNTED WITHIN SAID ARM AND OPERABLY CONNECTED WITH SAID NEEDLE, TO OSCILLATE THE SAME IN THE WORK FEEDING DIRECTION, TO PROVIDE FIRST WORK FEEDING MEANS OF SAID MACHINE, (2) A WORK FEEDING DOG, (3) A SECOND ROCKSHAFT MOUNTED BELOW SAID PLATE AND OPERABLY CONNECTED TO SAID DOG, TO PROVIDE SECOND WORK FEEDING MEANS OF SAID MACHINE, AND (4) DRIVE AND UNITARY STITCH CONTROL MEANS TO OPERATE SAID FIRST AND SECOND ROCKSHAFT AND TO ADJUST THE FEED ADVANCE STROKES OF BOTH SAID WORK FEEDING MEANS, COMPRISING: (A) FIRST MOTION-TRANSMITTING MECHANISM OPERABLY CONNECTING SAID NEEDLE DRIVE SHAFT WITH SAID FIRST ROCKSHAFT, TO CONVERT ROTARY MOTION OF THE NEEDLE DRIVE SHAFT INTO OSCILLATING MOTION OF SAID FIRST ROCKSHAFT, (B) SECOND MOTION-TRANSMITTING MECHANISM OPERABLY CONNECTING SAID LOOP TAKER DRIVER SHAFT WITH SAID SECOND ROCKSHAFT, TO CONVERT ROTARY MOTION OF SAID LOOP TAKER SHAFT INTO OSCILLATING MOTION OF SAID SECOND ROCKSHAFT, (C) A FIRST ROTARY CONTROL SHAFT OF SAID FIRST MECHANISM OPERATIVE TO CONTROL THE FEED STROKE OF SAID NEEDLE IN ACCORDANCE WITH THE ANGULAR ADJUSTING POSITION OF SAID FIRST CONTROL SHAFT, (D) A SECOND ROTARY CONTROL SHAFT OF SAID SECOND MECHANISM OPERATIVE TO CONTROL THE FEED STROKE OF SAID DOG IN ACCORDANCE WITH THE ANGULAR ADJUSTING POSITION OF SAID SECOND CONTROL SHAFT, AND (E) UNI-CONTROL MEANS TO ADJUST BOTH SAID CONTROL SHAFTS, TO SIMULTANEOUSLY VARY THE FEED STROKES OF SAID NEEDLE AND FEED DOG IN SYNCHRONISM.