Then, the flat jack 44 is inflated which compresses the elastic block 47 and raises the rod 45 so that {HEAD ~ the rib} 49 of the rod passes through {TAIL ~ the aperture} 53a 
passes through
Then , the flat jack 44 is inflated which compresses the elastic block 47 and raises the rod 45 so that { HEAD ~ the rib } 49 of the rod passes through { TAIL ~ the aperture } 53a
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH