suitable adjustments to the regulated voltage applied to the solid state switch 112 or to the resistance 113 so that the reversible linear motor 92 will effect separation of the needle bar 50 from the driving stud 57 during normal stitch formation the output from the microcomputer 102 along line 108 would be for example 5 volts the level shifter 110 inverts the signal applied to its inverting terminal to provide 7 5 volts at point 111 which would open the switch 112 for basting imposition of a null voltage by the microcomputer 102 along line 108 to the level shifter 110 will allow the u00b1 7 5 volt bias voltage to close the switch 112 and apply a regulated voltage to the summing point 114 which will provide the reversible linear motor 92 with the 1 5 volts required to position the needle bar gate 35 to a position where it will uncouple the needle bar 50 from the driving stud 57 in operation actuation of the linear motor 92 to a position beyond the normal range of zigzag motion will take place at a faster rate than was available with the use of cams in the prior art and will provide approximately three times as much force as was available heretofore further increasing speed.