The program carrier can be coupled selectively with one of the two drive rings by {HEAD ~ means} of a coupling member adjustable to radii of different size on {TAIL ~ the same radius vector} 
The program carrier can be coupled selectively with one of the two drive rings by { HEAD ~ means } of a coupling member adjustable to radii of different size on { TAIL ~ the same radius vector }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL