a sample holder guided by {HEAD ~ said carriage} for {TAIL ~ movement} relative to said carriage in a direction perpendicular to the friction surface and said first direction, said sample holder being configured to hold a sample in frictional engagement with the friction surface during relative movement between said carriage and friction surface in said first direction 
for
a sample holder guided by { HEAD ~ said carriage } for { TAIL ~ movement } relative to said carriage in a direction perpendicular to the friction surface and said first direction , said sample holder being configured to hold a sample in frictional engagement with the friction surface during relative movement between said carriage and friction surface in said first direction
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH