Zigzag sewing machine

Claim 1

A ZIGZAG SEWING MACHINE COMPRISING, IN COMBINATION, A FRAME; A HORIZONTAL MAIN DRIVE SHAFT ROTATABLY MOUNTED IN SAID FRAME; A NEEDLE BAR GUIDE MOUNTED IN SAID FRAME FOR OSCILLATION TRANSVERSELY OF THE STITCHING PATH; A NEEDLE BAR RECIPROCABLE SUBSTANTIALLY VERTICALLY IN SAID NEEDLE BAR GUIDE; A UNIVERSAL PIVOT CONNECTION ON THE UPPER END OF SAID NEEDLE BAR; A BALANCE WEIGHT FIXED TO AN END OF SAID MAIN DRIVE SHAFT; A CRANK MOUNTED ON SAID BALANCE WEIGHT, FOR ADJUSTMENT TO A SELECTED FIXED POSITION THEREON, ABOUT AN AXIS IN PARALLEL ECCENTRIC RELATION TO THAT OF SAID MAIN DRIVE SHAFT; SAID CRANK HAVING A RADIAL ARM EXTENDING THEREFROM; A VERTIVAL GUIDE RAIL MOUNTED IN SAID FRAME IN DISPLACED PERPENDICULAR RELATION TO THAT OF SAID MAIN DRIVE SHAFT; A CRANK ROD EXTENDING UPWARDLY OF SAID MACHINE AND HAVING A LOWER END PORTION PIVOTALLY CONNECTED TO THE OUTER END OF SAID RADIAL ARM, AND AN UPPER END PIVOTALLY CONNECTED TO SAID UNIVERSAL PIVOT CONNECTION ON THE UPPER END OF SAID NEEDLE BAR AND SLIDABLY CONNECTED TO SAID GUIDE RAIL; WHEREBY THE UPPER END OF SAID CRANK ROD WILL, DURING EACH REVOLUTION OF SAID MAIN DRIVE SHAFT, PROVIDE A RELATIVELY HIGH SPEED OF UPWARD MOVEMENT OF SAID NEEDLE BAR IN THE UPPER RANGE OF THE RECIPROCATION THEREOF AND A RELATIVELY LOW SPEED IN THE LOWER RANGE OF DOWNWARD MOVEMENT THEREOF; AND OSCILLATING MEANS, CONNECTED TO SAID NEEDLE BAR GUIDE AND SAID MAIN DRIVE SHAFT, TO SIMULTANEOUSLY OSCILLATE SAID NEEDLE BAR GUIDE.