In the exemplary embodiment shown in FIG 1, the relief opening is connected with {HEAD ~ a return line} 41 that leads to pressure medium reservoir 39, and {TAIL ~ a 2/2 way magnetic valve} 42 having a spring return mechanism is used as shutoff valve 40 
In the exemplary embodiment shown in FIG 1 , the relief opening is connected with { HEAD ~ a return line } 41 that leads to pressure medium reservoir 39 , and { TAIL ~ a 2/2 way magnetic valve } 42 having a spring return mechanism is used as shutoff valve 40
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH