which provides a frictional drive for the yarn in common with fig1 the yarn y is not fed through the gap between the yarn feed wheel 20 and either of the driver rollers 5 6 in fig3 the yarn feed wheel 20 is in its uppermost position in this position the yarn feed wheel 20 is driven by the first drive roller 5 in the lowermost position the yarn feed wheel 20 is driven by the second drive roller 6 thus this arrangement can be used to generate the same patterning effects as shown in fig2 however as the movement of the arm 9 opens and closes the gap between the yarn feed wheel 20 and the two yarn guide bars 21 22 there is no need to provide a spring loaded arrangement as is required of the yarn feed wheel 14 in fig1 as the yarn y can be fed through the arrangement shown in fig3 simply by moving the arm 9 0035 fig4 shows the presently preferred mechanism for the activator used to switch the yarn y between the first 5 and second 6 drive roller the arm 9 is moved by electric or servo motors 30 about the pivot or fulcrum 10 the servo motors 30 drive pistons 32 connected to the arm to move the arm 9 about the fulcrum 10 to move the intermediate wheel 15 to contact one of the first 5 or second 6 drive rollers the yarn feed roll 14 is illustrated as spring loaded by spring 34 in this embodiment numerous alternations of the structure herein disclosed will suggest themselves to those skilled in the art however it is to be understood that the present disclosure relates to the preferred embodiment of the invention which is.