{HEAD ~ Means} are provided for mounting the slotted member upon the substrate and permitting {TAIL ~ the rectilinear movement} thereof in a plurality of parallel spaced steps 
are provided for permitting
{ HEAD ~ Means } are provided for mounting the slotted member upon the substrate and permitting { TAIL ~ the rectilinear movement } thereof in a plurality of parallel spaced steps
HEAD HEAD HEAD HEAD HEAD REL REL REL OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH