In {TAIL ~ this instance}, {HEAD ~ the movement} of the slider 20 is smoothly carried out irrespective of the holding means 34, because of the relief 30 
In
In { TAIL ~ this instance } , { HEAD ~ the movement } of the slider 20 is smoothly carried out irrespective of the holding means 34 , because of the relief 30
REL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH