Control system for zig-zag sewing machines

Claim 1

IN A ZIG-ZAG SEWING MACHINE OF THE TYPE INCLUDING A NEEDLE BAR SUPPORTING A RECIPROCATORY NEEDLE AND MOUNTED FOR OSCILLATION TRANSVERSELY TO THE FEED DIRECTION, DRIVE MEANS FOR SAID MACHINE, AND MEANS OPERATED BY SAID DRIVE MEANS AND INCLUDING MOTION-TRANSMITTING MEANS BETWEEN SAID DRIVE MEANS AND SAID NEEDLE BAR, TO OSCILLATE SAID NEEDLE WITHIN A PREDETERMINED ZIG-ZAG OVERSTITCH WIDTH; FIRST MECHANISM FOR STITCHING BUTTON HOLES COMPOSED OF A PAIR OF ADJOINING ROWS OF ZIG-ZAG BORDERING STITCHES AND ZIG-ZAG BARRING STITCHES AT THE OPPOSITE ENDS OF SAID BORDERING STITCHES HAVING A WIDTH SUBSTANTIALLY TWICE THE WIDTH OF SAID BORDERING STITCHES, SAID MECHANISM COMPRISING FIRST CONTROL MEANS TO REDUCE THE FEEDING SPEED TO ZERO AND TO CHANGE FROM FORWARD TO REVERSE STITCHING, AND VICE VERSA, SECOND CONTROL MEANS OPERATIVE UPON A FIRST INTERMEDIATE POINT OF SAID MOTION-TRANSMITTING MEANS, TO LIMIT THE AMPLITUDE OF THE NEEDLE OSCILLATIONS SUCH AS TO CHANGE FROM BARRING TO BORDERING STITCHES, AND VICE VERSA, THIRD CONTROL MEANS OPERATIVE UPON A SECOND INTERMEDIATE POINT OF SAID MOTION-TRANSMITTING MEANS, TO VARY THE AMPLITUDE OF THE NEEDLE OSCILLATIONS, A COMMON CONTROL SHAFT, A PLURALITY OF CONTROL CAMS CARRIED BY SAID SHAFT, SAID CAMS BEING EQUAL IN NUMBER TO THE NUMBER OF SAID CONTROL MEANS AND HAVING FRACTIONAL PERIPHERAL CAM SURFACES, A CAM FOLLOWER FOR COOPERATION WITH EACH SAID CAM SURFACES AND MEANS OPERABLY CONNECTING THE SAME WITH ONE OF SAID CONTROL MEANS, OPERATING MEANS INCLUDING A UNITARY CONTROL MEMBER FOR STEP-BY-STEP ROTATING SAID SHAFT, TO EFFECT THE SEQUENTIAL PARTIAL BUTTONHOLE SEWING OPERATIONS OF PRODUCING, THROUGH A FIRST FRACTIONAL ANGULAR ADJUSTING RANGE OF SAID SHAFT, BORDERING STITCHES IN A FIRST DIRECTION BY A FIRST ACTUATION OF SAID MEMBER, OF ARRESTING THE FEED MOVEMENT AND SEWING FIRST BARRING STITCHES BY A SECOND ACTUATION OF SAID MEMBER, OF REVERSING THE FEED DIRECTION AND PRODUCING SECOND BORDERING STITCHES BY A THIRD ACTUATION OF SAID MEMBER, AND OF AGAING ARRESTING THE FEED MOVEMENT AND SEWING SECOND BARRING STITCHES BY A FINAL ACTUATION OF SAID MEMBER, AND FURTHER MECHANISM INDEPENDENT OF SAID FIRST MECHANISM AND OPERATIVE WITHIN A SECOND ANGULAR ADJUSTING RANGE OF SAID SHAFT, TO GRADUALLY VARY THE AMPLITUDE OF THE NEEDLE OSCILLATIONS.