A ram descends due to {HEAD ~ its own weight} and pressure of {TAIL ~ a rod side cylinder chamber} of a hydraulic cylinder which vertically moves the ram is detected by an oil pressure detector 
A ram descends due to { HEAD ~ its own weight } and pressure of { TAIL ~ a rod side cylinder chamber } of a hydraulic cylinder which vertically moves the ram is detected by an oil pressure detector
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH