{HEAD ~ a motion device} for effecting relative movement between {TAIL ~ said carriage} and a friction surface in a first direction 
{ HEAD ~ a motion device } for effecting relative movement between { TAIL ~ said carriage } and a friction surface in a first direction
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH