Sewing machine

Claim 1

A BUTTONHOLE STITCHING MECHANISM FOR ZIGZAG SEWING MACHINES OF THE TYPE PROVIDED WITH AN AMPLITUDE ADJUSTING DEVICE FOR CONTROLLING LATERAL MOTION OF A NEEDLE BAR, A NEEDLE BASE POSITION ADJUSTING DEVICE FOR CHANGING THE RANGE OF MOTION OF SAID NEEDLE BAR AND A FEED ADJUSTING DEVICE FOR REVERSING FEED DIRECTION AND FOR ADJUSTING FEED AMOUNT, COMPRISING IN COMBINATION A CAM SHAFT ROTATABLY SUPPORTED IN THE MACHINE FRAME, A DRIVE CAM FOR DRIVING SAID CAM SHAFT OPERATIVELY CONNECTED WITH THE MAIN SHAFT OF THE MACHINE, A FIRST LEVER OSCILLATABLY SUPPORTED ON SAID CAM SHAFT, A FIRST SPRING BIASING ONE END OF SAID FIRST LEVER AGAINST SAID DRIVE CAM, MEANS FOR CONVERTING THE MOTION IMPARTED TO SAID FIRST LEVER BY ROTATION OF SAID DRIVE CAM INTO INTERMITTENT ROTARY MOTION OF SAID CAM SHAFT, A FEED REVERSING CAM FOR SAID MACHINE, A NEEDLE BASED POSITION CHANGING CAM FOR SAID MACHINE, SAID FEED REVERSING AND NEEDLE BASE POSITION CAMS BEING SECURED TO SAID CAM SHAFT, A SECOND LEVER PIVOTALLY SUPPORTED ON SAID FRAME, A SECOND SPRING BIASING ONE END OF SAID SECOND LEVER AGAINST SAID NEEDLE BASE POSITION CHANGING CAM, MEANS FOR CONNECTING THE REMAINING END OF SAID SECOND LEVER TO SAID NEEDLE BASE POSITION ADJUSTING DEVICE, WHEREBY SAID ADJUSTING DEVICE IS ACTUATED ACCORDING TO THE OUTLINE OF SAID NEEDLE BASE POSITION CHANGING CAM AND THE RANGE OF MOTION OF NEEDLE BAR IS AUTOMATICALLY CHANGED, A THIRD LEVER PIVOTALLY SUPPORTED ON SAID FRAME, A THIRD SPRING BIASING ONE END OF SAID THIRD LEVER AGAINST SAID FEED REVERSING CAM, MEANS CONNECTING THE OTHER END OF SAID THIRD LEVER TO SAID FEED ADJUSTING DEVICE, WHEREBY SAID FEED ADJUSTING DEVICE IS ACTUATED ACCORDING TO THE OUTLINE OF SAID FEED REVERSING CAM AND FEED DIRECTION IS AUTOMATICALLY REVERSED, ONE OF SAID FEED REVERSING AND NEEDLE BASE POSITION CAMS HAVING A RECESSED PORTION, FOR RECEIVING THE CONTACT PORTION OF ONE OF SAID SECOND OR THIRD LEVERS ASSOCIATED THEREWITH MEANS FOR DISENGAGING SAID FIRST LEVER FROM SAID DRIVE CAM, A MANUAL OPERATING DEVICE AND MEANS FOR WITHDRAWING THE CONTACT PORTION OF THE ONE OF SAID SECOND OR THIRD LEVERS FROM THE RECESS SO AS TO ENGAGE SAID FIRST LEVER WITH SAID DRIVE CAM BY THE OPERATION OF SAID MANUAL OPERATING DEVICE IN ORDER TO OPERATIVELY CONNECT SAID CAM SHAFT WITH SAID MAIN SHAFT.